haloperidol (Rx)

Brand and Other Names:Haldol, Haldol Decanoate, more...Haloperidol LA, Peridol
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

tablet

  • 0.5mg
  • 1mg
  • 2mg
  • 5mg
  • 10mg
  • 20mg

oral concentrate

  • 2mg/mL

injectable solution, lactate

  • 5mg/mL

injectable solution, decanoate

  • 50mg/mL
  • 100mg/mL

Schizophrenia, Psychosis

PO

  • Moderate disease, 0.5-2 mg q8-12hr initially
  • Severe disease, 3-5 mg q8-12hr initially; not to exceed 30 mg/day

IM lactate (prompt-acting)

  • 2-5 mg q4-8hr PRN; may require q1hr in acute agitation; not to exceed 20 mg/day

IM decanoate (depot)

  • Initial: IM dose 10-20 times daily PO dose administered monthly; not to exceed 100 mg; if conversion requires initial dose >100 mg, administer in 2 injections (eg, 100 mg initially, then remainder in 3-7 days)
  • Maintenance: Monthly dose 10-15 times daily PO dose

IV (Off-label)

  • May be needed for ICU delirium; use only haloperidol lactate for IV administration; do not use haloperidol decanoate
  • 2-10 mg initially, depending on degree of agitation; if response inadequate, may repeat bolus q15-30min, sequentially doubling initial bolus dose; when calm achieved, administer 25% of last bolus dose q6hr; taper dose after patient is controlled
  • Monitor ECG and QT interval (QT prolongation may occur with cumulative doses ≥35 mg; torsades de pointes reported with single doses ≥20 mg)

Tourette Disorder

0.5-2 mg PO q8-12hr initially; if severe symptoms necessitate increased dosage, titrate upward to 3-5 mg PO q8-12hr; if patient remains inadequately controlled, daily doses up to 100 mg have been used (safety not determined)

Dosage Forms & Strengths

tablet

  • 0.5mg
  • 1mg
  • 2mg
  • 5mg
  • 10mg
  • 20mg

oral concentrate

  • 2mg/mL

injectable solution, lactate

  • 5mg/mL

injectable solution, decanoate

  • 50mg/mL
  • 100mg/mL

Schizophrenia, Psychosis/Sedation

<3 years: Safety and efficacy not established

3-12 years (15-40 kg): 0.25-0.5 mg/day PO divided q8-12hr initially; may be increased by 0.5 mg/day every 5-7 days PRN; maintenance: 0.05-0.15 mg/kg/day PO divided q8-12hr  

6-12 years: Lactate (prompt-acting): 1-3 mg IM q4-8hr PRN; not to exceed 0.15 mg/kg/day

>12 years: Moderate disease, 0.5-2 mg PO q8-12hr initially; severe disease, 3-5 mg PO q8-12hr; not to exceed 30 mg/day

Tourette Disorder

<3 years: Safety and efficacy not established

3-12 years: 0.5 mg/day PO initially; dose increased by 0.5 mg every 5-7 days until therapeutic effect achieved, then reduced to lowest effective maintenance level of 0.05-0.075 mg/kg/day PO divided q8-12hr  

>12 years: 0.5-2 mg PO q8-12hr initially; if severe symptoms necessitate increased dosage, titrate upward to 3-5 mg PO q8-12hr; if patient remains inadequately controlled, daily doses up to 100 mg have been used (safety not determined)

Behavioral Disorders

<3 years: Safety and efficacy not established

3-12 years: 0.5 mg/day PO initially; dose increased PRN by 0.5 mg every 5-7 days until therapeutic effect achieved, then reduced to lowest effective maintenance level of 0.05-0.075 mg/kg/day PO divided q8-12hr  

Acute Agitation

<12 years: Safety and efficacy not established

>12 years: 0.5-3 mg PO, repeated in 1 hour PRN; alternatively, 2-5 mg IM, repeated in 1 hr PRN

Schizophrenia, Psychosis

PO: Lower initial doses and more gradual adjustments recommended; 0.25-0.5 mg PO q8-12hr initially

IM lactate (prompt-acting): Lower adult doses and longer dosing intervals recommended compared with typical adult doses

IM decanoate (depot): Lower initial doses and more gradual adjustments recommended; monthly dose 10-15 times daily PO dose

IV (off-label): 0.25-0.5 mg IV q4hr; use only lactate (not decanoate) for IV administration; monitor with ECG for prolonged QT interval

Not approved for dementia-related psychosis, because of increased risk of cardiovascular or infectious related deaths (see Black Box Warnings)

Tourette Disorder

Lower initial doses and more gradual adjustments recommended; 0.25-0.5 mg PO q8-12hr initially

Dosing Considerations

Elderly at higher risk for tardive dyskinesia associated with higher-potency antipsychotic agents such as haloperidol because of higher ratios of dopaminergic blockage to adrenergic/anticholinergic blockade

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Interactions

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and haloperidol

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            Contraindicated (13)

            • disopyramide

              disopyramide and haloperidol both increase QTc interval. Contraindicated.

            • eliglustat

              haloperidol increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.

            • flibanserin

              haloperidol will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.

            • ibutilide

              haloperidol and ibutilide both increase QTc interval. Contraindicated.

            • indapamide

              haloperidol and indapamide both increase QTc interval. Contraindicated.

            • lefamulin

              lefamulin will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.

            • lomitapide

              haloperidol increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.

            • lonafarnib

              haloperidol will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

            • pentamidine

              haloperidol and pentamidine both increase QTc interval. Contraindicated.

            • pimozide

              haloperidol and pimozide both increase QTc interval. Contraindicated.

            • procainamide

              haloperidol and procainamide both increase QTc interval. Contraindicated.

            • quinidine

              quinidine and haloperidol both increase QTc interval. Contraindicated.

            • sotalol

              haloperidol and sotalol both increase QTc interval. Contraindicated.

            Serious - Use Alternative (124)

            • abametapir

              abametapir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

            • amiodarone

              amiodarone and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • amitriptyline

              amitriptyline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • amoxapine

              amoxapine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • apalutamide

              apalutamide will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

            • apomorphine

              haloperidol decreases effects of apomorphine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • arsenic trioxide

              arsenic trioxide and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • artemether/lumefantrine

              artemether/lumefantrine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              haloperidol and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

            • avapritinib

              haloperidol will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

            • axitinib

              haloperidol increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with moderate CYP3A4 inhibitors, monitor closely and reduce dose if necessary .

            • benzhydrocodone/acetaminophen

              benzhydrocodone/acetaminophen, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • bosutinib

              haloperidol increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • bromocriptine

              haloperidol decreases effects of bromocriptine by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • cabergoline

              haloperidol decreases effects of cabergoline by pharmacodynamic antagonism. Contraindicated.

            • calcium/magnesium/potassium/sodium oxybates

              haloperidol, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • carbamazepine

              carbamazepine will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • ceritinib

              ceritinib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • chloramphenicol

              chloramphenicol will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • chlorpromazine

              chlorpromazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • citalopram

              citalopram will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Increased risk of serotonin syndrome or neuroleptic malignant syndrome. Potential risk for QT prolongation. ECG monitoring is recommended.

              citalopram and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • clarithromycin

              clarithromycin and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

              clarithromycin will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • clomipramine

              haloperidol will increase the level or effect of clomipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              clomipramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • cobimetinib

              haloperidol will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concurrent short term (14 days or less) use of moderate CYP3A inhibitors is unavoidable for patients who are taking cobimetinib 60 mg, reduce the cobimetinib dose to 20 mg. After discontinuation of a moderate CYP3A inhibitor, resume cobimetinib 60 mg. Use an alternative to a moderate CYP3A inhibitor in patients who are taking a reduced dose of cobimetinib (40 or 20 mg daily).

            • crizotinib

              crizotinib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • dacomitinib

              dacomitinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid use with CYP2D6 substrates where minimal increases in concentration of the CYP2D6 substrate may lead to serious or life-threatening toxicities.

            • desipramine

              haloperidol will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              desipramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • dofetilide

              dofetilide and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • dopamine

              haloperidol decreases effects of dopamine by pharmacodynamic antagonism. Contraindicated.

            • doxepin

              haloperidol will increase the level or effect of doxepin by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              doxepin and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • dronedarone

              dronedarone and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • droperidol

              droperidol and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • eliglustat

              haloperidol increases levels of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Moderate CYP3A4 inhibitors are not recommended with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers .

            • entrectinib

              haloperidol and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.

              haloperidol will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.

            • epinephrine

              epinephrine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • epinephrine racemic

              epinephrine racemic and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • eribulin

              eribulin and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Potential for enhanced QTc-prolonging effects; if concurrent use is necessary then ECG monitoring is recommended.

            • erythromycin base

              erythromycin base and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin ethylsuccinate

              erythromycin ethylsuccinate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin lactobionate

              erythromycin lactobionate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • erythromycin stearate

              erythromycin stearate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • fentanyl

              fentanyl, haloperidol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

              haloperidol will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl intranasal

              fentanyl intranasal, haloperidol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

              haloperidol will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl transdermal

              fentanyl transdermal, haloperidol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

              haloperidol will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fentanyl transmucosal

              fentanyl transmucosal, haloperidol. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.

              haloperidol will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

            • fexinidazole

              fexinidazole and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.

              fexinidazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

            • fluconazole

              fluconazole and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • fluoxetine

              fluoxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              haloperidol will increase the level or effect of fluoxetine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • fluphenazine

              fluphenazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • formoterol

              formoterol and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • fosphenytoin

              fosphenytoin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • givosiran

              givosiran will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP2D6 substrates with givosiran. If unavoidable, decrease the CYP2D6 substrate dosage in accordance with approved product labeling.

            • glasdegib

              haloperidol and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.

            • hydrocodone

              hydrocodone, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • hydroxychloroquine sulfate

              hydroxychloroquine sulfate and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • idelalisib

              idelalisib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

            • imipramine

              haloperidol will increase the level or effect of imipramine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              imipramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • indinavir

              indinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • infigratinib

              haloperidol will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • inotuzumab

              inotuzumab and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. If unable to avoid concomitant use, obtain ECGs and electrolytes before and after initiation of any drug known to prolong QTc, and periodically monitor as clinically indicated during treatment.

            • ivabradine

              haloperidol will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inhibitors.

            • ivosidenib

              ivosidenib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of QTc prolonging drugs with ivosidenib or replace with alternate therapies. If coadministration of a QTc prolonging drug is unavoidable, monitor for increased risk of QTc interval prolongation.

              ivosidenib will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternate therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

            • ketoconazole

              haloperidol and ketoconazole both increase QTc interval. Avoid or Use Alternate Drug.

            • lemborexant

              haloperidol will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

            • levodopa

              haloperidol decreases effects of levodopa by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

            • lisuride

              haloperidol decreases effects of lisuride by pharmacodynamic antagonism. Contraindicated.

            • lofepramine

              lofepramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • lopinavir

              lopinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • lumefantrine

              lumefantrine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              haloperidol and lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

            • lurbinectedin

              haloperidol will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • macimorelin

              macimorelin and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Macimorelin causes an increase of ~11 msec in the corrected QT interval. Avoid coadministration with drugs that prolong QT interval, which could increase risk for developing torsade de pointes-type ventricular tachycardia. Allow sufficient washout time of drugs that are known to prolong the QT interval before administering macimorelin.

            • maprotiline

              maprotiline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • methyldopa

              haloperidol decreases effects of methyldopa by pharmacodynamic antagonism. Contraindicated.

            • metoclopramide intranasal

              haloperidol, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

              haloperidol increases toxicity of metoclopramide intranasal by pharmacodynamic synergism. Avoid or Use Alternate Drug. Potential for additive effects, including increased frequency and severity of tardive dyskinesia, other extrapyramidal symptoms, and neuroleptic malignant syndrome.

            • midazolam intranasal

              haloperidol will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

            • mifepristone

              mifepristone will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • mobocertinib

              haloperidol will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

              mobocertinib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, reduce mobocertinib dose and monitor QTc interval more frequently.

            • moxifloxacin

              haloperidol and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

            • naloxegol

              haloperidol will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministation of naloxegol with moderate CYP3A4 inhibitors is unavoidable, reduce naloxegol dose to 12.5 mg qDay

            • neratinib

              haloperidol will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

            • nilotinib

              haloperidol and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.

            • nortriptyline

              haloperidol will increase the level or effect of nortriptyline by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              nortriptyline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • octreotide

              haloperidol and octreotide both increase QTc interval. Avoid or Use Alternate Drug.

            • octreotide (Antidote)

              haloperidol and octreotide (Antidote) both increase QTc interval. Avoid or Use Alternate Drug.

            • olaparib

              haloperidol will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inhibitors cannot be avoided, reduce olaparib dose to 200 mg (capsule) or 150 mg (tablet) PO BID. Do not substitute tablets with capsules.

            • ondansetron

              haloperidol and ondansetron both increase QTc interval. Avoid or Use Alternate Drug. Avoid with congenital long QT syndrome; ECG monitoring recommended with concomitant medications that prolong QT interval, electrolyte abnormalities, CHF, or bradyarrhythmias.

            • panobinostat

              haloperidol and panobinostat both increase QTc interval. Avoid or Use Alternate Drug. Panobinostat is known to significantly prolong QT interval. Panobinostat prescribing information states use with drugs known to prolong QTc is not recommended.

            • paroxetine

              paroxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • pemigatinib

              haloperidol will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

            • perphenazine

              perphenazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • pexidartinib

              haloperidol will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

            • phenytoin

              phenytoin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • pitolisant

              haloperidol and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

            • posaconazole

              posaconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

            • pramipexole

              haloperidol decreases effects of pramipexole by pharmacodynamic antagonism. Contraindicated.

            • prochlorperazine

              prochlorperazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • promazine

              promazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • promethazine

              promethazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • protriptyline

              protriptyline and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • quinidine

              quinidine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

            • quinupristin/dalfopristin

              quinupristin/dalfopristin increases levels of haloperidol by decreasing metabolism. Contraindicated. Risk of prolonged QTc interval.

            • ribociclib

              ribociclib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • romidepsin

              haloperidol and romidepsin both increase QTc interval. Avoid or Use Alternate Drug.

            • ropinirole

              haloperidol decreases effects of ropinirole by pharmacodynamic antagonism. Contraindicated.

            • safinamide

              haloperidol decreases effects of safinamide by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Dopamine antagonists may decrease safinamide effects and exacerbate Parkinson disease symptoms.

            • saquinavir

              saquinavir increases levels of haloperidol by QTc interval. Avoid or Use Alternate Drug. Potential for increased toxicity. Increased risk of QT prolongation and cardiac arrhythmias.

              saquinavir increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity. Increased risk of QT prolongation and cardiac arrhythmias.

            • selinexor

              selinexor, haloperidol. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.

            • selumetinib

              haloperidol will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.

            • siponimod

              haloperidol will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

            • sodium oxybate

              haloperidol, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • sufentanil SL

              sufentanil SL, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • tazemetostat

              haloperidol will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

            • thioridazine

              haloperidol will increase the level or effect of thioridazine by affecting hepatic enzyme CYP2D6 metabolism. Avoid or Use Alternate Drug.

              thioridazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • toremifene

              haloperidol and toremifene both increase QTc interval. Avoid or Use Alternate Drug. Concurrent use of toremifene with agents causing QT prolongation should be avoided. If concomitant use is required it's recommended that toremifene be interrupted. If interruption not possible, patients requiring therapy with a drug that prolongs QT should be closely monitored. ECGs should be obtained for high risk patients.

            • trazodone

              trazodone and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • trifluoperazine

              trifluoperazine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • trimipramine

              trimipramine and haloperidol both increase QTc interval. Avoid or Use Alternate Drug.

            • tucatinib

              tucatinib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

            • umeclidinium bromide/vilanterol inhaled

              haloperidol increases toxicity of umeclidinium bromide/vilanterol inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

            • vandetanib

              haloperidol, vandetanib. Either increases toxicity of the other by QTc interval. Avoid or Use Alternate Drug. Avoid coadministration with drugs known to prolong QT interval; if a drug known to prolong QT interval must be used, more frequent ECG monitoring is recommended.

            • vemurafenib

              vemurafenib and haloperidol both increase QTc interval. Avoid or Use Alternate Drug. Concomitant use of vemurafenib with drugs that prolong QT interval is not recommended.

            • venetoclax

              haloperidol will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a moderate CYP3A inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

            • vilanterol/fluticasone furoate inhaled

              haloperidol increases toxicity of vilanterol/fluticasone furoate inhaled by QTc interval. Avoid or Use Alternate Drug. Exercise extreme caution when vilanterol coadministered with drugs that prolong QTc interval; adrenergic agonist effects on the cardiovascular system may be potentiated.

            • voxelotor

              voxelotor will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

            • ziprasidone

              haloperidol and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.

            Monitor Closely (409)

            • abiraterone

              abiraterone increases levels of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Avoid coadministration of abiraterone with substrates of CYP2D6. If alternative therapy cannot be used, exercise caution and consider a dose reduction of the CYP2D6 substrate.

            • abobotulinumtoxinA

              abobotulinumtoxinA increases effects of haloperidol by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

            • acalabrutinib

              haloperidol will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease acalabrutinib dose to 100 mg once daily if coadministered with a moderate CYP3A inhibitor.

              acalabrutinib, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

            • aclidinium

              aclidinium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of aclidinium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • albuterol

              haloperidol increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              albuterol and haloperidol both increase QTc interval. Use Caution/Monitor.

            • alfentanil

              alfentanil and haloperidol both increase sedation. Use Caution/Monitor.

            • alfuzosin

              haloperidol and alfuzosin both increase QTc interval. Use Caution/Monitor.

              alfuzosin and haloperidol both increase QTc interval. Use Caution/Monitor.

            • almotriptan

              almotriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • alprazolam

              alprazolam and haloperidol both increase sedation. Use Caution/Monitor.

            • amifampridine

              haloperidol increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

            • amitriptyline

              haloperidol and amitriptyline both increase sedation. Use Caution/Monitor.

            • amobarbital

              amobarbital and haloperidol both increase sedation. Use Caution/Monitor.

              amobarbital will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • amoxapine

              haloperidol and amoxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.

              haloperidol and amoxapine both increase sedation. Use Caution/Monitor.

            • anticholinergic/sedative combos

              anticholinergic/sedative combos decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              anticholinergic/sedative combos decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of anticholinergic/sedative combos by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • apomorphine

              haloperidol and apomorphine both increase sedation. Use Caution/Monitor.

              haloperidol and apomorphine both increase QTc interval. Use Caution/Monitor.

            • arformoterol

              haloperidol increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              haloperidol and arformoterol both increase QTc interval. Use Caution/Monitor.

            • aripiprazole

              aripiprazole and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              aripiprazole and haloperidol both increase sedation. Use Caution/Monitor.

              aripiprazole and haloperidol both increase QTc interval. Use Caution/Monitor.

            • armodafinil

              haloperidol increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • artemether

              haloperidol and artemether both increase QTc interval. Use Caution/Monitor.

            • asenapine

              asenapine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and asenapine both increase QTc interval. Use Caution/Monitor.

            • atazanavir

              atazanavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • atomoxetine

              haloperidol will increase the level or effect of atomoxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              atomoxetine and haloperidol both increase QTc interval. Use Caution/Monitor.

            • atracurium

              atracurium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              atracurium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of atracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • atropine

              atropine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              atropine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of atropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • atropine IV/IM

              haloperidol increases effects of atropine IV/IM by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

              atropine IV/IM decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              atropine IV/IM decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

            • avanafil

              haloperidol will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

            • azelastine

              azelastine and haloperidol both increase sedation. Use Caution/Monitor.

            • azithromycin

              azithromycin and haloperidol both increase QTc interval. Use Caution/Monitor.

            • baclofen

              baclofen and haloperidol both increase sedation. Use Caution/Monitor.

            • bedaquiline

              haloperidol and bedaquiline both increase QTc interval. Modify Therapy/Monitor Closely. ECG should be monitored closely

            • belladonna alkaloids

              belladonna alkaloids decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              belladonna alkaloids decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of belladonna alkaloids by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • belladonna and opium

              belladonna and opium and haloperidol both increase sedation. Use Caution/Monitor.

              belladonna and opium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              belladonna and opium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of belladonna and opium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • belzutifan

              belzutifan will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.

            • benperidol

              benperidol and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              benperidol and haloperidol both increase sedation. Use Caution/Monitor.

            • benzhydrocodone/acetaminophen

              haloperidol will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone [benzhydrocodone is prodrug of hydrocodone]) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.

            • benzphetamine

              haloperidol increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • benztropine

              haloperidol increases effects of benztropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic adverse effects may be seen with concurrent use. .

            • bosentan

              bosentan will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • bosutinib

              bosutinib and haloperidol both increase QTc interval. Use Caution/Monitor.

            • brexanolone

              brexanolone, haloperidol. Either increases toxicity of the other by sedation. Use Caution/Monitor.

            • brexpiprazole

              haloperidol will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor.

              haloperidol will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP3A4 inhibitor PLUS a strong/moderate CYP2D6 inhibitor.

            • brompheniramine

              brompheniramine and haloperidol both increase sedation. Use Caution/Monitor.

            • buprenorphine

              buprenorphine and haloperidol both increase sedation. Use Caution/Monitor.

            • buprenorphine buccal

              buprenorphine buccal and haloperidol both increase sedation. Use Caution/Monitor.

            • buprenorphine subdermal implant

              haloperidol will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

            • buprenorphine, long-acting injection

              haloperidol will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

              haloperidol increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.

            • bupropion

              bupropion will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • butabarbital

              butabarbital and haloperidol both increase sedation. Use Caution/Monitor.

            • butalbital

              butalbital and haloperidol both increase sedation. Use Caution/Monitor.

            • butorphanol

              butorphanol and haloperidol both increase sedation. Use Caution/Monitor.

            • cabozantinib

              haloperidol will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • caffeine

              haloperidol increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cannabidiol

              haloperidol will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP3A4 inhibitor.

            • capecitabine

              capecitabine and haloperidol both increase QTc interval. Use Caution/Monitor.

            • carbamazepine

              carbamazepine decreases levels of haloperidol by increasing metabolism. Use Caution/Monitor.

            • carbinoxamine

              carbinoxamine and haloperidol both increase sedation. Use Caution/Monitor.

            • carisoprodol

              carisoprodol and haloperidol both increase sedation. Use Caution/Monitor.

            • carvedilol

              haloperidol will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • celecoxib

              celecoxib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • cenobamate

              cenobamate will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

            • chloral hydrate

              chloral hydrate and haloperidol both increase sedation. Use Caution/Monitor.

            • chlordiazepoxide

              chlordiazepoxide and haloperidol both increase sedation. Use Caution/Monitor.

            • chloroquine

              chloroquine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              chloroquine increases toxicity of haloperidol by QTc interval. Use Caution/Monitor.

            • chlorpheniramine

              chlorpheniramine and haloperidol both increase sedation. Use Caution/Monitor.

            • chlorpromazine

              chlorpromazine and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              chlorpromazine and haloperidol both increase sedation. Use Caution/Monitor.

            • chlorzoxazone

              chlorzoxazone and haloperidol both increase sedation. Use Caution/Monitor.

            • cimetidine

              cimetidine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • cinnarizine

              cinnarizine and haloperidol both increase sedation. Use Caution/Monitor.

            • ciprofloxacin

              ciprofloxacin and haloperidol both increase QTc interval. Use Caution/Monitor. Ciprofloxacin elicits minimal effects on QT interval. Caution if used in combination with other drugs known to affect QT interval or in patients with other risk factors.

            • cisatracurium

              cisatracurium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cisatracurium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of cisatracurium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • clemastine

              clemastine and haloperidol both increase sedation. Use Caution/Monitor.

            • clobazam

              clobazam will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Lower doses of drugs metabolized by CYP2D6 may be required when used concomitantly.

            • clomipramine

              haloperidol and clomipramine both increase sedation. Use Caution/Monitor.

            • clonazepam

              clonazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • clonidine

              clonidine, haloperidol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

              clonidine increases toxicity of haloperidol by Other (see comment). Use Caution/Monitor. Comment: High doses of clonidine IV may increase arrhythmogenic potential (QT-prolongation, ventricular fibrillation) of high dose haloperidol IV in patients experiencing alcoholic delirium.

            • clorazepate

              clorazepate and haloperidol both increase sedation. Use Caution/Monitor.

            • clozapine

              clozapine and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              clozapine and haloperidol both increase sedation. Use Caution/Monitor.

              haloperidol and clozapine both increase QTc interval. Use Caution/Monitor.

            • cobicistat

              cobicistat will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • codeine

              haloperidol decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

              codeine and haloperidol both increase sedation. Use Caution/Monitor.

            • conivaptan

              conivaptan will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • crizotinib

              crizotinib increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A. ECG monitoring is recommended, along with drugs that may prolong the QT interval.

            • crofelemer

              crofelemer increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

            • cyclizine

              cyclizine and haloperidol both increase sedation. Use Caution/Monitor.

              cyclizine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cyclizine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of cyclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • cyclobenzaprine

              cyclobenzaprine and haloperidol both increase sedation. Use Caution/Monitor.

              cyclobenzaprine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              cyclobenzaprine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of cyclobenzaprine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • cyproheptadine

              cyproheptadine and haloperidol both increase sedation. Use Caution/Monitor.

            • dabrafenib

              dabrafenib will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

              dabrafenib and haloperidol both increase QTc interval. Use Caution/Monitor.

            • dantrolene

              dantrolene and haloperidol both increase sedation. Use Caution/Monitor.

            • darifenacin

              darifenacin will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              darifenacin decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              darifenacin decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of darifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • darunavir

              darunavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • dasatinib

              dasatinib and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • deferasirox

              deferasirox will increase the level or effect of haloperidol by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

            • deflazacort

              haloperidol will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

            • degarelix

              haloperidol and degarelix both increase QTc interval. Use Caution/Monitor.

            • desflurane

              desflurane and haloperidol both increase sedation. Use Caution/Monitor.

            • desipramine

              haloperidol and desipramine both increase sedation. Use Caution/Monitor.

            • desvenlafaxine

              desvenlafaxine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Desvenlafaxine inhibits CYP2D6; with higher desvenlafaxine doses (ie, 400 mg) decrease the CYP2D6 substrate dose by up to 50%; no dosage adjustment needed with desvenlafaxine doses <100 mg

            • deutetrabenazine

              haloperidol and deutetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely. The risk for parkinsonism, neuroleptic malignant syndrome, and akathisia may be increased by concomitant use of deutetrabenazine and dopamine antagonists or antipsychotics.

              haloperidol and deutetrabenazine both increase sedation. Use Caution/Monitor.

              haloperidol and deutetrabenazine both increase QTc interval. Modify Therapy/Monitor Closely. For patients requiring deutetrabenazine doses >24 mg/day and are taking other drugs known to prolong QTc, assess the QTc interval before and after increasing the dose of deutetrabenazine or other medications known to prolong QTc.

            • dexchlorpheniramine

              dexchlorpheniramine and haloperidol both increase sedation. Use Caution/Monitor.

            • dexfenfluramine

              haloperidol increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dexmedetomidine

              dexmedetomidine and haloperidol both increase sedation. Use Caution/Monitor.

            • dexmethylphenidate

              haloperidol increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dextroamphetamine

              haloperidol increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dextromethorphan

              dextromethorphan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • dextromoramide

              dextromoramide and haloperidol both increase sedation. Use Caution/Monitor.

            • diamorphine

              diamorphine and haloperidol both increase sedation. Use Caution/Monitor.

            • diazepam

              diazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • diazepam intranasal

              haloperidol will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

            • dicyclomine

              dicyclomine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              dicyclomine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of dicyclomine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • diethylpropion

              haloperidol increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • difenoxin hcl

              difenoxin hcl and haloperidol both increase sedation. Use Caution/Monitor.

            • dihydroergotamine

              dihydroergotamine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • dimenhydrinate

              dimenhydrinate and haloperidol both increase sedation. Use Caution/Monitor.

            • diphenhydramine

              diphenhydramine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              diphenhydramine and haloperidol both increase sedation. Use Caution/Monitor.

              diphenhydramine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              diphenhydramine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of diphenhydramine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • diphenoxylate hcl

              diphenoxylate hcl and haloperidol both increase sedation. Use Caution/Monitor.

            • dipipanone

              dipipanone and haloperidol both increase sedation. Use Caution/Monitor.

            • dobutamine

              haloperidol increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dolasetron

              dolasetron and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • dopamine

              haloperidol increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dopexamine

              haloperidol increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dosulepin

              haloperidol and dosulepin both increase sedation. Use Caution/Monitor.

            • doxepin

              haloperidol and doxepin both increase sedation. Use Caution/Monitor.

            • doxylamine

              doxylamine and haloperidol both increase sedation. Use Caution/Monitor.

            • dronedarone

              dronedarone will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • droperidol

              droperidol and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              droperidol and haloperidol both increase sedation. Use Caution/Monitor.

            • duvelisib

              duvelisib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with duvelisib increases AUC of a sensitive CYP3A4 substrate which may increase the risk of toxicities of these drugs. Consider reducing the dose of the sensitive CYP3A4 substrate and monitor for signs of toxicities of the coadministered sensitive CYP3A substrate.

            • efavirenz

              efavirenz will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • elagolix

              elagolix decreases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

            • eletriptan

              eletriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • eliglustat

              eliglustat increases levels of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the concomitant drug and titrate to clinical effect.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP3A4 inhibitor; contraindicated with CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Cobicistat is a CYP2D6 inhibitor; caution with CYP2D6 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • encorafenib

              encorafenib, haloperidol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

            • enzalutamide

              enzalutamide will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ephedrine

              haloperidol increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • epinephrine

              haloperidol increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • epinephrine racemic

              haloperidol increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • ergoloid mesylates

              ergoloid mesylates, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • ergotamine

              ergotamine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • escitalopram

              haloperidol and escitalopram both increase QTc interval. Use Caution/Monitor.

              escitalopram increases toxicity of haloperidol by QTc interval. Use Caution/Monitor.

            • esketamine intranasal

              esketamine intranasal, haloperidol. Either increases toxicity of the other by sedation. Use Caution/Monitor.

            • estazolam

              estazolam and haloperidol both increase sedation. Use Caution/Monitor.

            • ethanol

              haloperidol and ethanol both increase sedation. Use Caution/Monitor.

            • etomidate

              etomidate and haloperidol both increase sedation. Use Caution/Monitor.

            • etravirine

              etravirine will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ezogabine

              ezogabine, haloperidol. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Slight and transient QT-prolongation observed with ezogabine, particularly when dose titrated to 1200 mg/day. QT interval should be monitored when ezogabine is prescribed with agents known to increase QT interval.

            • fedratinib

              fedratinib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

              fedratinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2D6 substrates as necessary.

            • fenfluramine

              haloperidol increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • fentanyl

              fentanyl, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • fesoterodine

              fesoterodine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              fesoterodine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of fesoterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • finerenone

              haloperidol will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

            • flavoxate

              flavoxate decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              flavoxate decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of flavoxate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • flecainide

              haloperidol will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised.

              flecainide and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • flibanserin

              flibanserin, haloperidol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • fluoxetine

              fluoxetine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • fluphenazine

              fluphenazine and haloperidol both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              fluphenazine and haloperidol both increase sedation. Use Caution/Monitor.

            • flurazepam

              flurazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • fluvoxamine

              fluvoxamine and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • formoterol

              haloperidol increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • foscarnet

              foscarnet and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • fostemsavir

              haloperidol and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

            • frovatriptan

              frovatriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • gemifloxacin

              haloperidol and gemifloxacin both increase QTc interval. Use Caution/Monitor.

            • gemtuzumab

              haloperidol and gemtuzumab both increase QTc interval. Use Caution/Monitor.

            • glycerol phenylbutyrate

              haloperidol decreases effects of glycerol phenylbutyrate by Other (see comment). Use Caution/Monitor. Comment: Haloperidol may induce hyperammonemia; monitor ammonia levels closely when coadministered with glycerol phenylbutyrate.

            • glycopyrrolate

              haloperidol increases effects of glycopyrrolate by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • glycopyrrolate inhaled

              glycopyrrolate inhaled decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              glycopyrrolate inhaled decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of glycopyrrolate inhaled by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • glycopyrronium tosylate topical

              glycopyrronium tosylate topical, haloperidol. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

            • goserelin

              goserelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.

            • guanfacine

              guanfacine, haloperidol. Mechanism: pharmacodynamic synergism. Use Caution/Monitor. Additive hypotensive effects; potential delirium.

              haloperidol will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

            • henbane

              henbane decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              henbane decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of henbane by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • histrelin

              histrelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.

            • homatropine

              homatropine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              homatropine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of homatropine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • hydrocodone

              haloperidol will increase the level or effect of hydrocodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Hydromorphone (<3% of the circulating parent hydrocodone) is mainly formed by CYP2D6 mediated O-demethylation of hydrocodone. Hydromorphone may contribute to the total analgesic effect of hydrocodone.

            • hydromorphone

              haloperidol will increase the level or effect of hydromorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              hydromorphone and haloperidol both increase sedation. Use Caution/Monitor.

            • hydroxyzine

              hydroxyzine and haloperidol both increase sedation. Use Caution/Monitor.

            • hyoscyamine

              hyoscyamine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              hyoscyamine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of hyoscyamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • hyoscyamine spray

              haloperidol increases effects of hyoscyamine spray by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

              hyoscyamine spray decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              hyoscyamine spray decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

            • ibrutinib

              haloperidol increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate CYP3A4 inhibitors, reduce ibrutinib dose to 280 mg qDay (B-cell malignancies) or 420 mg qDay (graft versus host disease). After CYP3A inhibitor discontinuation, resume previous dose of ibrutinib.

            • ifosfamide

              haloperidol decreases effects of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of a CYP3A4 inhibitor may decrease metabolism of ifosfamide, potentially reducing ifosfamide therapeutic effects.

            • iloperidone

              haloperidol will increase the level or effect of iloperidone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and iloperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and iloperidone both increase QTc interval. Modify Therapy/Monitor Closely.

              haloperidol and iloperidone both increase sedation. Use Caution/Monitor.

              iloperidone increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

            • imatinib

              imatinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • imipramine

              haloperidol and imipramine both increase sedation. Use Caution/Monitor.

            • incobotulinumtoxinA

              haloperidol, incobotulinumtoxinA. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Use of anticholinergic drugs after administration of botulinum toxin-containing products may potentiate systemic anticholinergic effects.

            • indacaterol, inhaled

              indacaterol, inhaled, haloperidol. QTc interval. Use Caution/Monitor. Drugs that are known to prolong the QTc interval may have an increased the risk of ventricular arrhythmias.

            • ipratropium

              ipratropium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              ipratropium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of ipratropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • isavuconazonium sulfate

              haloperidol will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • isoniazid

              isoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • isoproterenol

              haloperidol increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • isradipine

              haloperidol and isradipine both increase QTc interval. Use Caution/Monitor.

            • istradefylline

              istradefylline will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

            • itraconazole

              haloperidol and itraconazole both increase QTc interval. Modify Therapy/Monitor Closely.

              itraconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ivacaftor

              haloperidol will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with moderate CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.

            • ivosidenib

              haloperidol will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with moderate CYP3A4 inhibitors may increase ivosidenib plasma concentrations, thus increasing the risk of QTc prolongation. Monitor for increased risk of QTc interval prolongation.

            • ketamine

              ketamine and haloperidol both increase sedation. Use Caution/Monitor.

            • ketoconazole

              ketoconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ketotifen, ophthalmic

              haloperidol and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.

            • lapatinib

              haloperidol and lapatinib both increase QTc interval. Modify Therapy/Monitor Closely.

            • lasmiditan

              lasmiditan, haloperidol. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

            • lemborexant

              lemborexant, haloperidol. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

            • lenvatinib

              haloperidol and lenvatinib both increase QTc interval. Use Caution/Monitor. Lenvatinib prescribing information recommends monitoring ECG closely when coadministered with QT prolonging drugs.

            • letermovir

              letermovir increases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • leuprolide

              leuprolide increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.

            • levalbuterol

              haloperidol increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • levamlodipine

              haloperidol will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

            • levofloxacin

              haloperidol and levofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

            • levomilnacipran

              levomilnacipran, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • levorphanol

              levorphanol and haloperidol both increase sedation. Use Caution/Monitor.

            • linezolid

              linezolid, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • lisdexamfetamine

              haloperidol increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lithium

              lithium, haloperidol. Other (see comment). Use Caution/Monitor. Comment: Risk of neurotoxicity. Multiple mechanisms involved.

              lithium, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • lofepramine

              haloperidol will increase the level or effect of lofepramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and lofepramine both increase sedation. Use Caution/Monitor.

            • lofexidine

              haloperidol and lofexidine both increase sedation. Use Caution/Monitor.

            • loprazolam

              loprazolam and haloperidol both increase sedation. Use Caution/Monitor.

            • lorazepam

              lorazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • lorcaserin

              lorcaserin will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              lorcaserin, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • lorlatinib

              lorlatinib will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • lormetazepam

              lormetazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • loxapine

              haloperidol and loxapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and loxapine both increase sedation. Use Caution/Monitor.

            • loxapine inhaled

              haloperidol and loxapine inhaled both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and loxapine inhaled both increase sedation. Use Caution/Monitor.

            • lurasidone

              lurasidone, haloperidol. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

            • maprotiline

              haloperidol and maprotiline both increase sedation. Use Caution/Monitor.

            • maraviroc

              maraviroc will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • marijuana

              marijuana will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and marijuana both increase sedation. Use Caution/Monitor.

            • meclizine

              meclizine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              meclizine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of meclizine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • mefloquine

              haloperidol and mefloquine both increase QTc interval. Use Caution/Monitor.

              haloperidol will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • melatonin

              haloperidol and melatonin both increase sedation. Use Caution/Monitor.

            • meperidine

              meperidine and haloperidol both increase sedation. Use Caution/Monitor.

              meperidine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • meprobamate

              haloperidol and meprobamate both increase sedation. Use Caution/Monitor.

            • metaproterenol

              haloperidol increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • metaxalone

              metaxalone and haloperidol both increase sedation. Use Caution/Monitor.

            • methadone

              haloperidol and methadone both increase QTc interval. Modify Therapy/Monitor Closely.

              methadone and haloperidol both increase sedation. Use Caution/Monitor.

              methadone, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • methamphetamine

              haloperidol will increase the level or effect of methamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • methocarbamol

              methocarbamol and haloperidol both increase sedation. Use Caution/Monitor.

            • methscopolamine

              methscopolamine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              methscopolamine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of methscopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • methylenedioxymethamphetamine

              haloperidol increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • methylergonovine

              methylergonovine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • methylphenidate

              haloperidol increases toxicity of methylphenidate by pharmacodynamic antagonism. Use Caution/Monitor. Closely monitor for signs of altered clinical response to either methylphenidate or an antipsychotic when using these drugs in combination.

            • metoclopramide

              haloperidol and metoclopramide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

            • metoprolol

              haloperidol will increase the level or effect of metoprolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • mexiletine

              haloperidol will increase the level or effect of mexiletine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised

              haloperidol and mexiletine both increase QTc interval. Use Caution/Monitor.

            • midazolam

              midazolam and haloperidol both increase sedation. Use Caution/Monitor.

            • midazolam intranasal

              midazolam intranasal, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

            • midodrine

              haloperidol increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • mifepristone

              mifepristone, haloperidol. QTc interval. Modify Therapy/Monitor Closely. Use alternatives if available.

            • milnacipran

              milnacipran, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • mirabegron

              mirabegron will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • mirtazapine

              haloperidol and mirtazapine both increase sedation. Use Caution/Monitor.

            • mitotane

              mitotane decreases levels of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

            • modafinil

              haloperidol increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • morphine

              haloperidol will increase the level or effect of morphine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              morphine and haloperidol both increase sedation. Use Caution/Monitor.

            • motherwort

              haloperidol and motherwort both increase sedation. Use Caution/Monitor.

            • moxonidine

              haloperidol and moxonidine both increase sedation. Use Caution/Monitor.

            • nabilone

              haloperidol and nabilone both increase sedation. Use Caution/Monitor.

            • nafcillin

              nafcillin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nalbuphine

              nalbuphine and haloperidol both increase sedation. Use Caution/Monitor.

            • naldemedine

              haloperidol increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.

            • naratriptan

              naratriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • nebivolol

              haloperidol will increase the level or effect of nebivolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • nefazodone

              nefazodone will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nelfinavir

              nelfinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • nilotinib

              nilotinib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • norepinephrine

              haloperidol increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nortriptyline

              haloperidol and nortriptyline both increase sedation. Use Caution/Monitor.

            • ofloxacin

              haloperidol and ofloxacin both increase QTc interval. Modify Therapy/Monitor Closely.

            • olanzapine

              haloperidol and olanzapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and olanzapine both increase sedation. Use Caution/Monitor.

              haloperidol and olanzapine both increase QTc interval. Use Caution/Monitor.

            • oliceridine

              haloperidol will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

              oliceridine, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

            • olodaterol inhaled

              haloperidol and olodaterol inhaled both increase QTc interval. Use Caution/Monitor. Drugs that prolong the QTc interval and may potentiate the effects of beta2 agonists on the cardiovascular system; increased risk of ventricular arrhythmias

            • onabotulinumtoxinA

              onabotulinumtoxinA decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              onabotulinumtoxinA decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • opium tincture

              opium tincture and haloperidol both increase sedation. Use Caution/Monitor.

            • orphenadrine

              orphenadrine and haloperidol both increase sedation. Use Caution/Monitor.

            • osilodrostat

              osilodrostat and haloperidol both increase QTc interval. Use Caution/Monitor.

            • osimertinib

              osimertinib and haloperidol both increase QTc interval. Use Caution/Monitor. Conduct periodic monitoring with ECGs and electrolytes in patients taking drugs known to prolong the QTc interval.

            • oxaliplatin

              oxaliplatin will increase the level or effect of haloperidol by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.

            • oxazepam

              oxazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • oxybutynin

              oxybutynin decreases effects of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              oxybutynin decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              haloperidol increases effects of oxybutynin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxybutynin topical

              oxybutynin topical decreases effects of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              oxybutynin topical decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              haloperidol increases effects of oxybutynin topical by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxybutynin transdermal

              oxybutynin transdermal decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              oxybutynin transdermal decreases effects of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of oxybutynin transdermal by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • oxycodone

              haloperidol will increase the level or effect of oxycodone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              oxycodone and haloperidol both increase sedation. Use Caution/Monitor.

            • oxymorphone

              haloperidol will increase the level or effect of oxymorphone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              oxymorphone and haloperidol both increase sedation. Use Caution/Monitor.

            • ozanimod

              ozanimod and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely. The potential additive effects on heart rate, treatment with ozanimod should generally not be initiated in patients who are concurrently treated with QT prolonging drugs with known arrhythmogenic properties.

            • palbociclib

              haloperidol will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • paliperidone

              haloperidol and paliperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and paliperidone both increase QTc interval. Modify Therapy/Monitor Closely.

              haloperidol and paliperidone both increase sedation. Use Caution/Monitor.

            • pancuronium

              pancuronium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              pancuronium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of pancuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • papaveretum

              papaveretum and haloperidol both increase sedation. Use Caution/Monitor.

            • papaverine

              haloperidol and papaverine both increase sedation. Use Caution/Monitor.

            • parecoxib

              parecoxib will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • paroxetine

              haloperidol will increase the level or effect of paroxetine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and paroxetine both increase QTc interval. Modify Therapy/Monitor Closely.

              paroxetine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • pasireotide

              haloperidol and pasireotide both increase QTc interval. Modify Therapy/Monitor Closely.

            • pazopanib

              haloperidol and pazopanib both increase QTc interval. Use Caution/Monitor.

            • peginterferon alfa 2b

              peginterferon alfa 2b, haloperidol. Other (see comment). Use Caution/Monitor. Comment: When patients are administered peginterferon alpha-2b with CYP2D6 substrates, the therapeutic effect of these drugs may be altered. Peginterferon alpha-2b may increase or decrease levels of CYP2D6 substrate.

            • pentazocine

              pentazocine and haloperidol both increase sedation. Use Caution/Monitor.

            • pentobarbital

              pentobarbital and haloperidol both increase sedation. Use Caution/Monitor.

            • perphenazine

              perphenazine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and perphenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and perphenazine both increase sedation. Use Caution/Monitor.

            • phendimetrazine

              haloperidol increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phenelzine

              phenelzine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • phenobarbital

              phenobarbital and haloperidol both increase sedation. Use Caution/Monitor.

              phenobarbital will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • phentermine

              haloperidol increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phenylephrine

              haloperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phenylephrine PO

              haloperidol increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

            • pholcodine

              haloperidol and pholcodine both increase sedation. Use Caution/Monitor.

            • pimozide

              haloperidol and pimozide both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and pimozide both increase sedation. Use Caution/Monitor.

            • pirbuterol

              haloperidol increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • posaconazole

              haloperidol and posaconazole both increase QTc interval. Modify Therapy/Monitor Closely.

            • pralidoxime

              pralidoxime decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              pralidoxime decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of pralidoxime by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • primidone

              primidone and haloperidol both increase sedation. Use Caution/Monitor.

              primidone will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • procarbazine

              procarbazine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • prochlorperazine

              haloperidol and prochlorperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and prochlorperazine both increase sedation. Use Caution/Monitor.

            • promethazine

              haloperidol and promethazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              promethazine and haloperidol both increase sedation. Use Caution/Monitor.

              promethazine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • propafenone

              haloperidol will increase the level or effect of propafenone by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised.

              haloperidol and propafenone both increase QTc interval. Use Caution/Monitor.

            • propantheline

              propantheline decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              propantheline decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of propantheline by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • propofol

              propofol and haloperidol both increase sedation. Use Caution/Monitor.

            • propranolol

              haloperidol will increase the level or effect of propranolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. If concurrent use cannot be avoided, cautious dosing and telemetric monitoring is advised. Coadministration of beta-blockers and haloperidol may cause an unexpected severe hypotensive reaction.

            • propylhexedrine

              haloperidol increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • protriptyline

              haloperidol and protriptyline both increase sedation. Use Caution/Monitor.

            • quazepam

              quazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • quetiapine

              haloperidol and quetiapine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and quetiapine both increase sedation. Use Caution/Monitor.

              quetiapine, haloperidol. Either increases toxicity of the other by QTc interval. Use Caution/Monitor. Avoid use with drugs that prolong QT and in patients with risk factors for prolonged QT interval. Postmarketing cases show QT prolongation with overdose in patients with concomitant illness or with drugs known to cause electrolyte imbalance or prolong QT.

            • quinacrine

              quinacrine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • quinine

              haloperidol and quinine both increase QTc interval. Use Caution/Monitor.

            • ramelteon

              haloperidol and ramelteon both increase sedation. Use Caution/Monitor.

            • ranolazine

              ranolazine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and ranolazine both increase QTc interval. Modify Therapy/Monitor Closely.

            • rapacuronium

              rapacuronium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              rapacuronium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of rapacuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • remimazolam

              remimazolam, haloperidol. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.

            • ribociclib

              ribociclib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rifabutin

              rifabutin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • rifampin

              rifampin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • rifapentine

              rifapentine will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rilpivirine

              rilpivirine increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Rilpivirine should be used with caution when co-administered with a drug with a known risk of Torsades de Pointes.

            • rimabotulinumtoxinB

              haloperidol, rimabotulinumtoxinB. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Anticholinergics may enhance botulinum toxin effects. Closely monitor for increased neuromuscular blockade.

            • rimegepant

              haloperidol will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid repeating rimegepant dose within 48 hr if coadministered with a moderate CYP3A4 inhibitor.

            • risperidone

              haloperidol and risperidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and risperidone both increase QTc interval. Modify Therapy/Monitor Closely.

              haloperidol and risperidone both increase sedation. Use Caution/Monitor.

            • ritonavir

              ritonavir will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and ritonavir both increase QTc interval. Use Caution/Monitor.

              ritonavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • rizatriptan

              rizatriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • rocuronium

              rocuronium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              rocuronium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of rocuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • rolapitant

              rolapitant will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Rolapitant may increase plasma concentrations of CYP2D6 substrates for at least 28 days following rolapitant administration.

            • rucaparib

              rucaparib will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

            • ruxolitinib

              haloperidol will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • salmeterol

              haloperidol increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • scopolamine

              scopolamine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              scopolamine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of scopolamine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • scullcap

              haloperidol and scullcap both increase sedation. Use Caution/Monitor.

            • secobarbital

              secobarbital and haloperidol both increase sedation. Use Caution/Monitor.

            • selegiline

              selegiline, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • selpercatinib

              selpercatinib increases toxicity of haloperidol by QTc interval. Use Caution/Monitor.

            • sertraline

              sertraline will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and sertraline both increase QTc interval. Use Caution/Monitor.

            • sevoflurane

              sevoflurane and haloperidol both increase sedation. Use Caution/Monitor.

            • shepherd's purse

              haloperidol and shepherd's purse both increase sedation. Use Caution/Monitor.

            • sodium sulfate/?magnesium sulfate/potassium chloride

              sodium sulfate/?magnesium sulfate/potassium chloride increases effects of haloperidol by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.

            • sodium sulfate/potassium sulfate/magnesium sulfate

              sodium sulfate/potassium sulfate/magnesium sulfate increases effects of haloperidol by unknown mechanism. Use Caution/Monitor. Closely monitor for evidence of enhanced CNS depression when using higher dose of magnesium sulfate together with a CNS depressant.

            • solifenacin

              solifenacin decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              solifenacin decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of solifenacin by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

              haloperidol and solifenacin both increase QTc interval. Use Caution/Monitor.

            • sonidegib

              haloperidol will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of sonidegib with moderate CYP3A4 inhibitors. If a moderate CYP3A inhibitor must be used, administer the moderate CYP3A inhibitor for <14 days and monitor closely for adverse reactions, particularly musculoskeletal adverse reactions.

            • sorafenib

              sorafenib and haloperidol both increase QTc interval. Use Caution/Monitor.

            • stiripentol

              stiripentol, haloperidol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

              stiripentol, haloperidol. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

            • sufentanil

              sufentanil and haloperidol both increase sedation. Use Caution/Monitor.

            • sufentanil SL

              haloperidol will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

            • sulfamethoxazole

              sulfamethoxazole and haloperidol both increase QTc interval. Modify Therapy/Monitor Closely.

            • sumatriptan

              sumatriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • sumatriptan intranasal

              sumatriptan intranasal, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • sunitinib

              haloperidol and sunitinib both increase QTc interval. Use Caution/Monitor.

            • suvorexant

              haloperidol will increase the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease suvorexant starting dose to 5 mg HS if coadministered with moderate CYP3A4 inhibitors

            • tacrolimus

              haloperidol and tacrolimus both increase QTc interval. Use Caution/Monitor.

            • tadalafil

              haloperidol will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce tadalafil clearance increasing systemic exposure to tadalafil; increased levels may result in increased associated adverse events.

            • tamoxifen

              haloperidol decreases effects of tamoxifen by decreasing metabolism. Use Caution/Monitor. Inhibition of CYP2D6 metabolism to tamoxifen's active metabolite, endoxifen.

            • tamsulosin

              haloperidol increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

              haloperidol increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • tapentadol

              tapentadol and haloperidol both increase sedation. Use Caution/Monitor.

            • tazemetostat

              tazemetostat will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tecovirimat

              tecovirimat will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

            • teduglutide

              teduglutide increases levels of haloperidol by Other (see comment). Use Caution/Monitor. Comment: Teduglutide may increase absorption of concomitant PO medications; caution with with drugs requiring titration or those with a narrow therapeutic index; dose adjustment may be necessary.

            • telavancin

              haloperidol and telavancin both increase QTc interval. Modify Therapy/Monitor Closely.

            • temazepam

              temazepam and haloperidol both increase sedation. Use Caution/Monitor.

            • terbinafine

              terbinafine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Assess need to reduce dose of CYP2D6-metabolized drug.

            • terbutaline

              haloperidol increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • tetrabenazine

              haloperidol and tetrabenazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Modify Therapy/Monitor Closely.

            • tezacaftor

              haloperidol will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a moderate CYP3A inhibitor.

            • thioridazine

              thioridazine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and thioridazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and thioridazine both increase sedation. Use Caution/Monitor.

            • thiothixene

              haloperidol and thiothixene both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and thiothixene both increase sedation. Use Caution/Monitor.

              haloperidol and thiothixene both increase QTc interval. Use Caution/Monitor.

            • timolol

              haloperidol will increase the level or effect of timolol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • tinidazole

              haloperidol will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tiotropium

              tiotropium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              tiotropium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of tiotropium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • tipranavir

              tipranavir will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              tipranavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tofacitinib

              haloperidol increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with moderate CYP3A4 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors.

            • tolterodine

              tolterodine decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              tolterodine decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of tolterodine by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • topiramate

              haloperidol and topiramate both increase sedation. Modify Therapy/Monitor Closely.

            • trabectedin

              haloperidol will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • tramadol

              tramadol and haloperidol both increase sedation. Use Caution/Monitor.

            • tranylcypromine

              tranylcypromine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • trazodone

              haloperidol and trazodone both increase sedation. Use Caution/Monitor.

            • triazolam

              triazolam and haloperidol both increase sedation. Use Caution/Monitor.

            • triclabendazole

              triclabendazole and haloperidol both increase QTc interval. Use Caution/Monitor.

            • triclofos

              triclofos and haloperidol both increase sedation. Use Caution/Monitor.

            • trifluoperazine

              haloperidol and trifluoperazine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and trifluoperazine both increase sedation. Use Caution/Monitor.

            • trihexyphenidyl

              haloperidol increases effects of trihexyphenidyl by pharmacodynamic synergism. Use Caution/Monitor. Potential for additive anticholinergic effects.

            • trimethoprim

              haloperidol and trimethoprim both increase QTc interval. Modify Therapy/Monitor Closely.

            • trimipramine

              haloperidol and trimipramine both increase sedation. Use Caution/Monitor.

            • triprolidine

              triprolidine and haloperidol both increase sedation. Use Caution/Monitor.

            • triptorelin

              triptorelin increases toxicity of haloperidol by QTc interval. Use Caution/Monitor. Increases risk of torsades de pointes.

            • tropisetron

              haloperidol and tropisetron both increase QTc interval. Modify Therapy/Monitor Closely.

            • trospium chloride

              trospium chloride decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              trospium chloride decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of trospium chloride by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • vardenafil

              haloperidol and vardenafil both increase QTc interval. Use Caution/Monitor.

            • vecuronium

              vecuronium decreases levels of haloperidol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

              vecuronium decreases levels of haloperidol by pharmacodynamic antagonism. Use Caution/Monitor.

              haloperidol increases effects of vecuronium by pharmacodynamic synergism. Use Caution/Monitor. Additive anticholinergic effects, possible hypoglycemia.

            • venlafaxine

              venlafaxine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

              haloperidol and venlafaxine both increase QTc interval. Modify Therapy/Monitor Closely.

              venlafaxine, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • vilazodone

              vilazodone, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • voclosporin

              haloperidol will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce voclosporin daily dosage to 15.8 mg PO in AM and 7.9 mg PO in PM.

              voclosporin, haloperidol. Either increases effects of the other by QTc interval. Use Caution/Monitor.

            • voriconazole

              haloperidol and voriconazole both increase QTc interval. Modify Therapy/Monitor Closely.

              voriconazole will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • vorinostat

              haloperidol and vorinostat both increase QTc interval. Use Caution/Monitor.

            • xylometazoline

              haloperidol increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • yohimbine

              haloperidol increases and yohimbine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • zanubrutinib

              haloperidol will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib dose when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib. See zanubrutinib Dosage Modifications for precise recommendation.

            • ziconotide

              haloperidol and ziconotide both increase sedation. Use Caution/Monitor.

            • ziprasidone

              haloperidol and ziprasidone both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and ziprasidone both increase sedation. Use Caution/Monitor.

            • zolmitriptan

              zolmitriptan, haloperidol. unspecified interaction mechanism. Use Caution/Monitor. Serotonin modulators may enhance dopamine blockade, possibly increasing the risk for neuroleptic malignant syndrome. Antipsychotics may enhance serotonergic effect of serotonin modulators, which may result in serotonin syndrome. Monitor for evidence of serotonin toxicity (eg, mental status changes, autonomic instability, and neuromuscular hyperactivity) or neuroleptic malignant syndrome (eg, hyperthermia, muscle rigidity, autonomic dysfunction).

            • zotepine

              haloperidol and zotepine both increase antidopaminergic effects, including extrapyramidal symptoms and neuroleptic malignant syndrome. Use Caution/Monitor.

              haloperidol and zotepine both increase sedation. Use Caution/Monitor.

            Minor (40)

            • amobarbital

              haloperidol, amobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • aripiprazole

              haloperidol will increase the level or effect of aripiprazole by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • brimonidine

              brimonidine increases effects of haloperidol by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

            • butabarbital

              haloperidol, butabarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • butalbital

              haloperidol, butalbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • chasteberry

              chasteberry decreases effects of haloperidol by pharmacodynamic antagonism. Minor/Significance Unknown. (Theoretical interaction).

            • chlorpromazine

              haloperidol will increase the level or effect of chlorpromazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • dexfenfluramine

              haloperidol will increase the level or effect of dexfenfluramine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • dextroamphetamine

              haloperidol will increase the level or effect of dextroamphetamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • dextromethorphan

              haloperidol will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • donepezil

              haloperidol will increase the level or effect of donepezil by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • duloxetine

              duloxetine will increase the level or effect of haloperidol by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

              haloperidol will increase the level or effect of duloxetine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • encainide

              haloperidol will increase the level or effect of encainide by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • estradiol vaginal

              haloperidol will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • ethanol

              ethanol, haloperidol. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive CNS depression.

            • eucalyptus

              haloperidol and eucalyptus both increase sedation. Minor/Significance Unknown.

            • fesoterodine

              haloperidol will increase the level or effect of fesoterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • fluphenazine

              haloperidol will increase the level or effect of fluphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • galantamine

              haloperidol will increase the level or effect of galantamine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • indomethacin

              indomethacin increases toxicity of haloperidol by unknown mechanism. Minor/Significance Unknown.

            • irinotecan

              haloperidol will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • irinotecan liposomal

              haloperidol will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • loratadine

              haloperidol will increase the level or effect of loratadine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • metyrosine

              metyrosine increases effects of haloperidol by pharmacodynamic synergism. Minor/Significance Unknown.

            • oliceridine

              haloperidol will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

            • oxycodone

              haloperidol decreases effects of oxycodone by decreasing metabolism. Minor/Significance Unknown. Decreased conversion of oxycodone to active metabolite morphine.

            • pentobarbital

              haloperidol, pentobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • perhexiline

              haloperidol will increase the level or effect of perhexiline by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • perphenazine

              haloperidol will increase the level or effect of perphenazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • phenobarbital

              haloperidol, phenobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • primidone

              haloperidol, primidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • prochlorperazine

              haloperidol will increase the level or effect of prochlorperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • promazine

              haloperidol will increase the level or effect of promazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • promethazine

              haloperidol will increase the level or effect of promethazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • risperidone

              haloperidol will increase the level or effect of risperidone by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • sage

              haloperidol and sage both increase sedation. Minor/Significance Unknown.

            • secobarbital

              haloperidol, secobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hyperthermia if haloperidol admin. during barbiturate withdrawal.

            • tolterodine

              haloperidol will increase the level or effect of tolterodine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • trifluoperazine

              haloperidol will increase the level or effect of trifluoperazine by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

            • tropisetron

              haloperidol will increase the level or effect of tropisetron by affecting hepatic enzyme CYP2D6 metabolism. Minor/Significance Unknown.

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            Adverse Effects

            Frequency Not Defined

            Extrapyramidal symptoms

            • Akathisia
            • Dystonia
            • Muscle stiffness
            • Neuroleptic malignant syndrome (NMS; infrequent but serious)
            • Parkinsonism
            • Tardive dyskinesia

            Common

            • Anticholinergic effects
            • Sedation
            • Weight gain
            • Erectile dysfunction
            • Oligomenorrhea or amenorrhea

            Less common

            • Orthostatic hypotension (after IM injection), tachycardia
            • Agitation, anxiety, cerebral edema, depression, dizziness, euphoria, headache, insomnia, poikilothermia, restlessness, weakness, confusion
            • Anorexia, constipation, dyspepsia, ileus, decreased gag reflex
            • Lens opacities (prolonged use)

            Uncommon

            • ECG changes
            • Photosensitivity
            • Pruritus
            • Diarrhea
            • Blood dyscrasia
            • Ejaculatory disorder
            • Galactorrhea

            Rare

            • Seizure
            • Cholestatic jaundice
            • Priapism

            Postmarketing Reports

            Rhabdomyolysis

            Falls

            Hypersensitivity

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            Warnings

            Black Box Warnings

            Patients with dementia-related psychosis who are treated with antipsychotic drugs are at an increased risk for death, as shown in short-term controlled trials; deaths in trials appeared to be either cardiovascular (eg, heart failure, sudden death) or infectious (eg, pneumonia) in nature

            Not approved for treatment of patients with dementia-related psychosis

            Contraindications

            Documented hypersensitivity

            Severe toxic central nervous system depression or comatose states from any cause

            Parkinson disease

            Dementia with Lewy bodies

            Cautions

            Risk of sudden death, torsades de pointes, and prolonged QT interval from off-label IV administration of higher than recommended dose: monitor ECG if administering IV

            Conditions or drugs that prolong QT interval, congenital long QT syndrome

            Safety of prolonged administration of 100 mg/day PO not established

            Avoid use in narrow-angle glaucoma, bone marrow suppression, and severe hypotension

            FDA warning regarding off-label use for dementia in elderly

            Cerebrovascular adverse reactions (eg, stroke, transient ischemic attack), including fatalities reported in elderly patients with dementia-related psychosis; mechanism for increased risk is not known; an increased risk cannot be excluded for antipsychotics; use with caution in patients with risk factors for cerebrovascular adverse reactions

            Leukopenia/neutropenia and agranulocytosis reported; possible risk factors include preexisting low white blood cell (WBC) count and history of drug-induced leukopenia/neutropenia

            If patient has history of clinically significant presence of either risk factor, monitor complete blood count (CBC) frequently during first few months of therapy; discontinue drug at first sign of clinically significant WBC decline <1000/μL in absence of other causative factors, and continue monitoring WBC count until recovery

            Severe neurotoxicity manifesting as rigidity or inability to walk or talk may occur in patients with thyrotoxicosis also receiving antipsychotics

            If administering IV or IM, watch for hypotension; use with caution in diagnosed CNS depression, subcortical brain damage, or cardiac disease; if history of seizures, benefits must outweigh risks; significant increase in body temperature may indicate intolerance to antipsychotics (discontinue if this occurs)

            Use caution in patients at risk of pneumonia (eg, Alzheimer's patients); antipsychotic use reported to be associated with esophageal dysmotility and aspiration

            Extrapyramidal symptoms may occur including acute dystonic reactions, akathisia, tardive dyskinesia, and pseudoparkinsonism; some patients on maintenance treatment experience transient dyskinetic signs after abrupt withdrawal; in certain cases dyskinetic movements are indistinguishable from tardive dyskinesia except for duration; not known whether gradual withdrawal will reduce rate of occurrence of withdrawal emergent neurological signs but until further evidence becomes available, gradually withdraw therapy

            Hyperprolactinemia may occur

            Monitor for mental status changes, muscle rigidity, fever, and/or autonomic instability; neuroleptic malignant syndrome may occur

            Motor instability, somnolence, and orthostatic hypotension reported, which may lead to falls and, consequently, fractures or other fall-related injuries; assess risk of falls when initiating treatment and recurrently for patients receiving repeated doses, particularly the elderly, with diseases, conditions, or medications that could exacerbate these effects

            Association with increased risk of pigmentary retinopathy reported

            Impairment of core body temperature regulation reported; use caution with activities that may increase body temperature including strenuous exercise, heat exposure, dehydration, and concomitant medications with anticholinergic effects

            Caution in patients receiving anticoagulants; isolated instance of interference occurred with effects of one anticoagulant (phenindione)

            When used to control mania in cyclic disorders, there may be rapid mood swing to depression

            May cause anticholinergic effects; use caution in patients with xerostomia, urinary retention, BPH, decreased gastrointestinal motility, paralytic ileus, or visual problems

            May cause CNS depression; may impair ability to operate heavy machinery or driving

            Decreased sensation of thirst due to central inhibition may lead to dehydration, hemoconcentration and reduced pulmonary ventilation; a number of cases of bronchopneumonia, some fatal, reported; if signs and symptoms appear, especially in the elderly, institute remedial therapy promptly

            Use caution in patients with severe cardiovascular disorders, because of possibility of transient hypotension and/or precipitation of anginal pain; should hypotension occur and a vasopressor be required, epinephrine should not be used since haloperidol may block its vasopressor activity and paradoxical further lowering of the blood pressure may occur; use metaraminol, phenylephrine or norepinephrine instead

            Use caution in patients receiving anticonvulsant medications, with a history of seizures, or with EEG abnormalities; haloperidol may lower convulsive threshold; if indicated, adequate anticonvulsant therapy should be concomitantly maintained

            Patients with Parkinson’s disease or dementia with Lewy Bodies are reported to have increased sensitivity to antipsychotic medication; manifestations include severe extrapyramidal symptoms, confusion, sedation, and falls; therapy may impair antiparkinson effects of levodopa and other dopamine agonists

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            Pregnancy & Lactation

            Pregnancy

            There are no well controlled studies in pregnant women; there are reports of cases of limb malformations observed following maternal use with drug along with other drugs which have suspected teratogenic potential during first trimester of pregnancy; causal relationships were not established in these cases; however, such experience does not exclude possibility of fetal damage due to therapy; drug should be used during pregnancy or in women likely to become pregnant only if benefit clearly justifies a potential risk to fetus; infants should not be nursed during drug treatment

            Neonates exposed to antipsychotic drugs during third trimester of pregnancy are at risk for extrapyramidal and/or withdrawal symptoms following delivery; there have been reports of agitation, hypertonia, hypotonia, tremor, somnolence, respiratory distress, and feeding disorder in these neonates; these complications have varied in severity; while in some cases symptoms have been self-limited, in other cases neonates have required intensive care unit support and prolonged hospitalization

            Animal data

            • Rodents given 2- 20 times usual maximum human dose by oral or parenteral routes showed increase in incidence of resorption, reduced fertility, delayed delivery and pup mortality; no teratogenic effect reported in rats, rabbits or dogs at dosages within this range, but cleft palate has been observed in mice given 15 times usual maximum human dose
            • Rats or rabbits administered oral haloperidol at doses of 0.5 to 7.5 mg/kg, which are approximately 0.2 to 7 times maximum recommended human dose (MRHD) of 20 mg/day based on mg/m2 body surface area, showed increase in incidence of resorption, reduced fertility, delayed delivery and pup mortality; no fetal abnormalities were observed at these doses in rats or rabbits
            • Cleft palate observed in mice administered oral haloperidol at dose of 0.5 mg/kg, which is approximately 0.1 times MRHD based on mg/m2 body surface area

            Lactation

            Drug is excreted in human breast milk; infants should not be nursed during drug treatment

            Pregnancy Categories

            A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

            B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

            C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

            D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

            X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

            NA: Information not available.

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            Pharmacology

            Mechanism of Action

            Phenylbutylpiperadine; antagonizes dopamine D1 and D2 receptors in brain; depresses reticular activating system and inhibits release of hypothalamic and hypophyseal hormones

            Absorption

            Bioavailability: 60-70%

            Onset: 30-60 min (IM/IV)

            Duration: 2-4 weeks (decanoate)

            Peak plasma time: 2-6 hr (PO); 10-20 minutes(IM); 6-7 days (decanoate)

            Distribution

            Protein bound: 90%

            Vd: 8-18 L/kg

            Metabolism

            Metabolized by hepatic P450 enzyme CYP3A4

            Metabolites: Hydroxyhaloperidol

            Enzymes inhibited: CYP2D6

            Elimination

            Half-life: 18 hr; 3 weeks (decanoate)

            Excretion: Urine (30%), feces (15%)

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            Administration

            IV/IM Administration

            Haloperidol lactate and haloperidol decanoate are both administered IM; haloperidol lactate has also been administered IV (off-label); haloperidol decanoate should not be administered IV

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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            haloperidol oral
            -
            2 mg tablet
            haloperidol oral
            -
            1 mg tablet
            haloperidol oral
            -
            5 mg tablet
            haloperidol oral
            -
            0.5 mg tablet
            haloperidol oral
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            Patient Handout

            Patient Education
            haloperidol oral

            HALOPERIDOL - ORAL

            (HAL-oh-PER-i-dol)

            COMMON BRAND NAME(S): Haldol

            WARNING: There may be a slightly increased risk of serious, possibly fatal side effects (such as heart failure, fast/irregular heartbeat, pneumonia) when this medication is used by older adults with dementia. This medication is not approved for the treatment of dementia-related behavior problems. Discuss the risks and benefits of this medication, as well as other effective and possibly safer treatments for dementia-related behavior problems, with the doctor.

            USES: Haloperidol is used to treat certain mental/mood disorders (e.g., schizophrenia, schizoaffective disorders). This medicine helps you to think more clearly, feel less nervous, and take part in everyday life. It can also help prevent suicide in people who are likely to harm themselves. It also reduces aggression and the desire to hurt others. It can decrease negative thoughts and hallucinations.Haloperidol can also be used to treat uncontrolled movements and outbursts of words/sounds related to Tourette's syndrome. Haloperidol is also used for severe behavior problems in hyperactive children when other treatments or medications have not worked.Haloperidol is a psychiatric medication (antipsychotic-type) that works by helping to restore the balance of certain natural substances in the brain (neurotransmitters).

            HOW TO USE: Take this medication by mouth with or without food, or as directed by your doctor. If you are using the liquid form of the medication, use the measuring dropper provided in the package to measure your dose. If you do not have the dropper, ask your pharmacist for a measured oral syringe so that your dose will be correct.Dosage is based on your medical condition and response to therapy. Use this medication regularly in order to get the most benefit from it. To help you remember, use it at the same time(s) each day.Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually reduced.Inform your doctor if your symptoms do not improve or if they worsen.

            SIDE EFFECTS: Dizziness, lightheadedness, drowsiness, difficulty urinating, sleep disturbances, headache, and anxiety may occur. If these effects persist or worsen, notify your doctor or pharmacist promptly.Dizziness and lightheadedness can increase the risk of falling. Get up slowly when rising from a sitting or lying position.Tell your doctor promptly if any of these side effects occur: muscle spasm/stiffness, shaking (tremor), restlessness, mask-like facial expression, drooling. Your doctor may prescribe another medication for you to take with haloperidol to decrease these side effects.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.In rare cases, haloperidol may increase your level of a certain chemical made by the body (prolactin). For females, this increase in prolactin may result in unwanted breast milk, missed/stopped periods, or difficulty becoming pregnant. For males, it may result in decreased sexual ability, inability to produce sperm, or enlarged breasts. If you develop any of these symptoms, tell your doctor right away.For males, in the unlikely event you have a painful or prolonged erection (lasting more than 4 hours), stop using this drug and get medical help right away, or permanent problems may occur.This medication may rarely cause a condition known as tardive dyskinesia. In some cases, this condition may be permanent. Tell your doctor right away if you develop any facial/muscle twitching such as tongue thrusting, chewing movements, puffing or puckering of your mouth, or uncontrollable shaking.This medication may rarely cause a very serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, muscle stiffness/pain/tenderness/weakness, severe tiredness, severe confusion, sweating, fast/irregular heartbeat, dark urine, signs of kidney problems (such as change in the amount of urine).Tell your doctor right away if you have any serious side effects, including: persistent nausea/vomiting, stomach/abdominal pain, yellowing of eyes/skin, seizures, signs of infection (such as fever, persistent sore throat).Get medical help right away if you have any very serious side effects, including: slow heartbeat, severe dizziness, chest pain, fainting.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

            PRECAUTIONS: Before taking haloperidol, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: a certain severe nervous system problem (severe CNS depression), Parkinson's disease, bipolar disorder, difficulty urinating (for example, due to prostate problems), glaucoma, heart problems (e.g., angina), overactive thyroid (hyperthyroidism), seizures, low white blood cell count.Haloperidol may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away.The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using haloperidol, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death).Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using haloperidol safely.This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).This medication can reduce sweating, making you more likely to get heatstroke. Avoid hard work and exercise in hot weather.Children may be more sensitive to the side effects of this drug, especially uncontrolled movements.Older adults may be more sensitive to the side effects of this drug, especially drowsiness, dizziness, lightheadedness, difficulty urinating, and heart effects such as QT prolongation (see above). Drowsiness, dizziness, and lightheadedness can increase the risk of falling.During pregnancy, this medication should be used only when clearly needed. Babies born to mothers who have used this drug during the last 3 months of pregnancy may rarely develop symptoms including muscle stiffness or shakiness, drowsiness, feeding/breathing difficulties, or constant crying. If you notice any of these symptoms in your newborn especially during their first month, tell the doctor right away.Since untreated mental/mood problems (such as schizophrenia, schizoaffective disorders) can be a serious condition, do not stop taking this medication unless directed by your doctor. If you are planning pregnancy, become pregnant, or think you may be pregnant, immediately discuss with your doctor the benefits and risks of using this medication during pregnancy.This drug passes into breast milk and could have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: anticholinergic medications (for example, antispasmodics such as belladonna alkaloids, scopolamine), cabergoline, ketoconazole, lithium, methyldopa, drugs for Parkinson's disease (such as levodopa and carbidopa, selegiline), paroxetine, pergolide, quinupristin/dalfopristin, rifampin, saquinavir.Many drugs besides haloperidol may affect the heart rhythm (QT prolongation), including amiodarone, dofetilide, pimozide, quinidine, sotalol, procainamide, macrolide antibiotics (such as erythromycin), among others. Before using haloperidol, report all medications you are currently using to your doctor or pharmacist.Tell your doctor or pharmacist if you are taking other products that cause drowsiness such as opioid pain or cough relievers (such as codeine, hydrocodone), alcohol, marijuana (cannabis), drugs for sleep or anxiety (such as alprazolam, lorazepam, zolpidem), muscle relaxants (such as carisoprodol, cyclobenzaprine), or antihistamines (such as cetirizine, diphenhydramine).Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely.

            OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

            NOTES: Do not share this medication with others.

            MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

            STORAGE: Store at room temperature between 59-86 degrees F (15-30 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

            Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

            IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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            Formulary

            FormularyPatient Discounts

            Adding plans allows you to compare formulary status to other drugs in the same class.

            To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

            Adding plans allows you to:

            • View the formulary and any restrictions for each plan.
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            • Compare formulary status to other drugs in the same class.
            • Access your plan list on any device – mobile or desktop.

            The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

            Tier Description
            1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
            2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
            3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
            4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
            NC NOT COVERED – Drugs that are not covered by the plan.
            Code Definition
            PA Prior Authorization
            Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
            QL Quantity Limits
            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
            ST Step Therapy
            Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
            OR Other Restrictions
            Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.