dextromethorphan/guaifenesin (OTC)

Brand and Other Names:Mucinex DM, Robitussin Peak Cold Cough+Chest Congestion DM, more...Delsym Cough + Chest Congestion, Children's Delsym Cough + Chest Congestion, Robitussin Peak Cold Maximum Strength Cough+Chest Congestion DM, Vicks 44E, Coricidin HBP Chest Congestion & Cough, Diabetic Tussin DM, Diabetic Tussin DM Maximum Strength, Duratuss DM, Genatuss DM, Guaicon DM, Guaifenex DM, Guiatuss DM, Mucinex Fast-Max DM Max, Phanatuss DM, Q-Tussin DM, Robafen DM, Safetussin DM, Siltussin DM, St. Joseph Chest Congestion & Cough, Touro DM, Vicks Pediatric Formula 44E
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

dextromethorphan/guaifenesin

capsule

  • 10mg/200mg

granules

  • (5mg/100mg)/packet

liquid

  • (5mg/100mg)/5mL
  • (10mg/100mg)/5mL
  • (10mg/150mg)/5mL
  • (10mg/200mg)/5mL
  • (15mg/100mg)/5mL
  • (15mg/200mg)/5mL
  • (20mg/200mg)/5mL
  • (20mg/300mg)/5mL

liquid oral drops

  • (5mg/100mg)/2.5mL

caplet

  • 15mg/400mg
  • 20mg/400mg

tablet

  • 60mg/1000mg
  • 60mg/1200mg

tablet, extended-release

  • 30mg/600mg
  • 60mg/1200mg

tablet, timed release

  • 60mg/1200mg

tablet, sustained-release

  • 60mg/1200mg

Cough

Indicated for temporary control of cough due to minor throat and bronchial irritation

General Guidelines: 200-400 mg guaifenesin and 10-20 mg dextromethorphan q4hr; not to exceed 2400 mg guaifenesin and 120 mg dextromethorphan

Mucinex DM: 1-2 tablets q12hr; not to exceed 4 tablets/24 hours

Robitussin Peak Cold Cough+Chest Congestion DM: 10 mL PO q4hr; not to exceed 6 doses/24 hours

Robitussin Peak Cold Maximum Strength Cough+Chest Congestion DM: 10 mL PO q4hr; not to exceed 6 doses/24 hr

Vicks 44E: 15 mL PO q4hr; not to exceed 6 doses/24 hours

Vicks Pediatric Formula 44E: 30 mL PO q4hr; not to exceed 6 doses/24 hours

Safe Tussin DM: 10 mL PO q4hr prn (10 mg/100 mg per 5 mL)

Dosage Forms & Strengths

dextromethorphan/guaifenesin

capsule

  • 10mg/200mg

granules

  • (5mg/100mg)/packet

liquid

  • (5mg/100mg)/5mL
  • (10mg/100mg)/5mL
  • (10mg/150mg)/5mL
  • (10mg/200mg)/5mL
  • (15mg/100mg)/5mL
  • (15mg/200mg)/5mL
  • (20mg/200mg)/5mL

liquid oral drops

  • (5mg/100mg)/2.5mL

caplet

  • 15mg/400mg20mg/400mg

tablet

  • 20mg/400mg

tablet, extended-release

  • 30mg/500mg
  • 30mg/575mg
  • 30mg/600mg
  • 60mg/1000mg

tablet, long-acting

  • 30mg/500mg
  • 30mg/650mg
  • 50mg/1000mg
  • 60mg/1000mg

tablet, sustained-release

  • 30mg/800mg
  • 55mg/1000mg
  • 60mg/1000mg
  • 60mg/1200mg

Cough

Indicated for temporary control of cough due to minor throat and bronchial irritation

<6 years

  • Ask a pediatrician

6-12 years

  • Guifenex DM, Touro DM: 1 tablet PO q12hr; not to exceed 2 tablets/24 hours
  • Robitussin DM, Robitussin Sugar Free Cough: 5 mL PO q4hr; not to exceed 6 doses/24 hours
  • Vicks 44E 7.5 mL q4hr; maximum 6 doses/24 hours
  • Vicks Pediatric Formula 44E: 15 mL PO q4hr; not to exceed 6 doses/24 hours

>12 years

  • Guaifenex DM, Mucinex DM, Touro DM: 1-2 tablets q12hr; not to exceed 4 tablets/24 hours
  • Robitussin Peak Cold Cough+Chest Congestion DM: 10 mL PO q4hr; not to exceed 6 doses/24 hr
  • Robitussin Peak Cold Maximum Strength Cough+Chest Congestion DM: 10 mL PO q4hr; not to exceed 6 doses/24 hr
  • Vicks 44E: 15 mL PO q4hr; not to exceed 6 doses/24 hours
  • Vicks Pediatric Formula 44E: 30 mL PO q4hr; not to exceed 6 doses/24 hours
  • Safetussin DM: 10 mL PO q4hr prn (10 mg/100 mg per 5 mL)
Next:

Interactions

Interaction Checker

and dextromethorphan/guaifenesin

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      Serious - Use Alternative

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            Contraindicated (7)

            • isocarboxazid

              isocarboxazid and dextromethorphan both increase serotonin levels. Contraindicated.

            • phenelzine

              phenelzine and dextromethorphan both increase serotonin levels. Contraindicated.

            • procarbazine

              procarbazine and dextromethorphan both increase serotonin levels. Contraindicated. Combination is contraindicated within 2 weeks of MAOI use.

            • rasagiline

              rasagiline and dextromethorphan both increase serotonin levels. Contraindicated. Risk of psychosis episodes or bizarre behavior.

            • safinamide

              dextromethorphan, safinamide. Other (see comment). Contraindicated. Comment: Coadministration of MAOIs and dextromethorphan has been reported to cause episodes of psychosis or bizarre behavior.

            • selegiline

              selegiline and dextromethorphan both increase serotonin levels. Contraindicated.

            • tranylcypromine

              tranylcypromine and dextromethorphan both increase serotonin levels. Contraindicated.

            Serious - Use Alternative (34)

            • amitriptyline

              amitriptyline and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • amoxapine

              amoxapine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • buspirone

              buspirone and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • citalopram

              citalopram and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug. Combination may increase risk of serotonin syndrome or neuroleptic malignant syndrome-like reactions.

            • clomipramine

              clomipramine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • desipramine

              desipramine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • desvenlafaxine

              dextromethorphan and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

            • doxepin

              doxepin and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • duloxetine

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

              duloxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • escitalopram

              escitalopram and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • fluoxetine

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

              fluoxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • fluvoxamine

              fluvoxamine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • grapefruit

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

            • imipramine

              imipramine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • levomilnacipran

              levomilnacipran and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • linezolid

              linezolid and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 2 weeks of monitoring, whichever comes first.

            • lofepramine

              lofepramine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • lorcaserin

              dextromethorphan and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.

            • maprotiline

              maprotiline and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • memantine

              memantine, dextromethorphan. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.

            • meperidine

              dextromethorphan and meperidine both increase serotonin levels. Avoid or Use Alternate Drug.

            • methylene blue

              methylene blue and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug. Methylene blue may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last methylene blue dose or after 2 weeks of monitoring, whichever comes first.

            • milnacipran

              milnacipran and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • nefazodone

              nefazodone and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • nortriptyline

              nortriptyline and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • paroxetine

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

              paroxetine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • protriptyline

              protriptyline and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • selegiline transdermal

              selegiline transdermal and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • sertraline

              sertraline and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • St John's Wort

              dextromethorphan and St John's Wort both increase serotonin levels. Avoid or Use Alternate Drug.

            • trazodone

              trazodone and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • trimipramine

              trimipramine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • venlafaxine

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

              venlafaxine and dextromethorphan both increase serotonin levels. Avoid or Use Alternate Drug.

            • vilazodone

              dextromethorphan, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .

            Monitor Closely (58)

            • 5-HTP

              5-HTP and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • abiraterone

              abiraterone increases levels of dextromethorphan 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.

            • almotriptan

              almotriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • aripiprazole

              dextromethorphan, aripiprazole. 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).

            • artemether/lumefantrine

              artemether/lumefantrine will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

            • asenapine

              dextromethorphan, asenapine. 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).

            • bupropion

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

            • cariprazine

              dextromethorphan, cariprazine. 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).

            • clobazam

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

            • clozapine

              dextromethorphan, clozapine. 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).

            • cocaine

              cocaine and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • desvenlafaxine

              desvenlafaxine will increase the level or effect of dextromethorphan 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

            • dexfenfluramine

              dexfenfluramine and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • dextroamphetamine

              dextroamphetamine and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • dihydroergotamine

              dextromethorphan and dihydroergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

            • dihydroergotamine intranasal

              dextromethorphan and dihydroergotamine intranasal both increase serotonin levels. Modify Therapy/Monitor Closely.

            • eletriptan

              eletriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • ergotamine

              dextromethorphan and ergotamine both increase serotonin levels. Modify Therapy/Monitor Closely.

            • fenfluramine

              dextromethorphan and fenfluramine both increase serotonin levels. Modify Therapy/Monitor Closely.

              fenfluramine, dextromethorphan. Either increases effects of the other by serotonin levels. Use Caution/Monitor. Coadministration with drugs that increase serotoninergic effects may increase the risk of serotonin syndrome.

            • fluphenazine

              dextromethorphan, fluphenazine. 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).

            • frovatriptan

              frovatriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • haloperidol

              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).

            • iloperidone

              dextromethorphan, iloperidone. 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).

            • isoniazid

              dextromethorphan and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

            • L-tryptophan

              dextromethorphan and L-tryptophan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • letermovir

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

            • lithium

              dextromethorphan and lithium both increase serotonin levels. Modify Therapy/Monitor Closely.

            • loxapine

              dextromethorphan, loxapine. 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).

            • loxapine inhaled

              dextromethorphan, loxapine inhaled. 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).

            • lsd

              dextromethorphan and lsd both increase serotonin levels. Modify Therapy/Monitor Closely.

            • lumefantrine

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

            • lurasidone

              dextromethorphan, lurasidone. 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).

            • mirtazapine

              dextromethorphan and mirtazapine both increase serotonin levels. Modify Therapy/Monitor Closely.

            • molindone

              dextromethorphan, molindone. 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).

            • morphine

              dextromethorphan and morphine both increase serotonin levels. Modify Therapy/Monitor Closely.

            • naratriptan

              naratriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • olanzapine

              dextromethorphan, olanzapine. 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).

            • paliperidone

              dextromethorphan, paliperidone. 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).

            • panobinostat

              panobinostat will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Panobinostat can increase the levels and effects of sensitive CYP2D6 substrates or those with a narrow therapeutic index CYP2D6.

            • pazopanib

              pazopanib increases levels of dextromethorphan by decreasing metabolism. Use Caution/Monitor.

            • peginterferon alfa 2b

              peginterferon alfa 2b, dextromethorphan. 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

              dextromethorphan and pentazocine both increase serotonin levels. Modify Therapy/Monitor Closely.

            • perphenazine

              dextromethorphan, perphenazine. 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).

            • pimavanserin

              dextromethorphan, pimavanserin. 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).

            • pimozide

              dextromethorphan, pimozide. 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).

            • quetiapine

              dextromethorphan, quetiapine. 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).

            • quinidine

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

            • risperidone

              dextromethorphan, risperidone. 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).

            • rizatriptan

              rizatriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • rolapitant

              rolapitant will increase the level or effect of dextromethorphan by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Monitor for adverse reactions when unable to avoid coadministration with narrow therapeutic index CYP2D6 substrates.

            • SAMe

              dextromethorphan and SAMe both increase serotonin levels. Modify Therapy/Monitor Closely.

            • sumatriptan

              sumatriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • sumatriptan intranasal

              sumatriptan intranasal and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            • thiothixene

              dextromethorphan, thiothixene. 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).

            • tramadol

              dextromethorphan and tramadol both increase serotonin levels. Modify Therapy/Monitor Closely.

            • trifluoperazine

              dextromethorphan, trifluoperazine. 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).

            • ziprasidone

              dextromethorphan, ziprasidone. 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).

            • zolmitriptan

              zolmitriptan and dextromethorphan both increase serotonin levels. Modify Therapy/Monitor Closely.

            Minor (22)

            • amiodarone

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

            • asenapine

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

            • celecoxib

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

            • chloroquine

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

            • cimetidine

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

            • darifenacin

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

            • diphenhydramine

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

            • dronedarone

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

            • haloperidol

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

            • imatinib

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

            • maraviroc

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

            • marijuana

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

            • nilotinib

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

            • parecoxib

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

            • perphenazine

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

            • propafenone

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

            • quinacrine

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

            • ranolazine

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

            • ritonavir

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

            • sertraline

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

            • thioridazine

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

            • tipranavir

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

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            Adverse Effects

            Frequency Not Defined

            Dizziness

            Drowsiness

            Headache

            Nausea

            Vomiting

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            Warnings

            Contraindications

            Documented hypersensitivity to either drug or components

            Within 14 days of taking MAO inhibitor

            Cautions

            Dextromethorphan

            • Do not take for persistent or chronic cough associated with smoking, asthma, or emphysema, or if it is accompanied by excessive phlegm unless directed by a healthcare provider; may slow respiration rate
            • Hallucinations, confusion, agitation, hyper-reflexia, shivering, myoclonus, and tachycardia may occur
            • Caution in children younger than 6 years
            • Not for OTC use in children <4 years
            • Use caution in patients who are sedated, debilitated or confined to supine position

            Guaifenesin

            • Guaifenesin is not for administration in persistent cough associated with chronic bronchitis, smoking, asthma, or accompanied with excessive secretions
            • If cough is accompanied by excessive phlegm, consult healthcare provider prior to use
            • Consult healthcare provider if symptoms are accompanied by fever, rash, or persistent headache
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            Pregnancy & Lactation

            Pregnacy Category: C

            Lactation: excretion in milk unknown; use with caution

            Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs

            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

            Guaifenesin increases respiratory tract fluid secretions and helps to loosen phlegm and bronchial secretions.

            Dextromethorphan is a cough suppressant that acts centrally on the cough center in the medulla.

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            Images

            No images available for this drug.
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            Patient Handout

            A Patient Handout is not currently available for this monograph.
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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.