cimetidine (Rx)

Brand and Other Names:Tagamet HB
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Dosing & Uses

AdultPediatricGeriatric

Dosage Forms & Strengths

injectable solution

  • 150mg/mL

oral solution

  • 300mg/5mL

tablet

  • 200mg
  • 300mg
  • 400mg (Rx)
  • 600mg (Rx)
  • 800mg (Rx)

Benign Gastric Ulcer

800 mg PO qHS OR

400 mg PO q12hr OR

300 mg PO q6hr

Duodenal Ulcer

800 mg PO qHS OR

400 mg PO q12hr OR

300 mg PO q6hr

Erosive Gastroesophageal Reflux Disease

800 mg PO q12hr OR

400 mg PO q6hr

Heartburn

Over the counter only

To relieve symptoms: 200 mg PO up to q12hr

To prevent symptoms: 200 mg PO with glass of water right before or any time up to 30 minutes before eating food or drinking beverages that cause heartburn

Pathological Hypersecretory Conditions

300 mg PO q6hr with meals and HS

Renal Impairment

CrCl<30 mL/min

300 mg IV/IO q12hr

Prevention of upper GI bleeding: 25 mg/hour continuous IV infusion

Other Indications & Uses

PUD (treatment, maintenance), gastric ulcer treatment, GI bleeding prevention in critically ill patients, hypersecretory conditions (e.g., Zollinger-Ellison)

Dosage Forms & Strengths

injectable solution

  • 150mg/mL

oral solution

  • 300mg/5mL

tablet

  • 200mg
  • 300mg
  • 400mg (Rx)
  • 600mg (Rx)
  • 800mg (Rx)

Duodenal Ulcer (Off-label)

<16 years: Use only if benefit outweighs risks

20-40 mg/kg/day IV/PO divided q6hr  

Neonates (<28 days old): 5-20 mg/kg/day IV/PO divided q8-12hr

Infants: 10-20 mg/kg/day IV/PO divided q6-12hr

Not drug of choice in elderly because of increased potential for confusion and drug interactions

Benign Gastric Ulcer

800 mg PO qHS OR

400 mg PO q12hr OR

300 mg PO q6hr

Duodenal Ulcer

800 mg PO qHS OR

400 mg PO q12hr OR

300 mg PO q6hr

Erosive Gastroesophageal Reflux Disease

800 mg PO q12hr OR

400 mg PO q6hr

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Interactions

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            Contraindicated (4)

            • dofetilide

              cimetidine increases levels of dofetilide by decreasing renal clearance. Contraindicated. Risk of prolonged QTc interval.

            • eliglustat

              cimetidine 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.

            • lomitapide

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

            • pimozide

              cimetidine increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.

            Serious - Use Alternative (142)

            • alitretinoin

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

            • alosetron

              cimetidine will increase the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • alprazolam

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

            • amiodarone

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

            • aprepitant

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

            • aripiprazole

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

            • artemether/lumefantrine

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

            • atazanavir

              cimetidine will decrease the level or effect of atazanavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Atazanavir solubility decreases as pH increases. Substantially reduced plasma concentrations of atazanavir are expected if H2-receptor antagonists (H2RA) are coadministered. For treatment-naïve patients, take atazanavir simultaneously with the H2RA or at least 10 h afterwards. See dosage adjustment recommendations if coadministered in treatment-experienced patients.

            • atorvastatin

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

            • axitinib

              cimetidine 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 .

            • bazedoxifene/conjugated estrogens

              cimetidine will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • belladonna and opium

              cimetidine increases effects of belladonna and opium by decreasing metabolism. Avoid or Use Alternate Drug.

            • bosutinib

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

            • budesonide

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

            • buprenorphine

              cimetidine increases effects of buprenorphine by decreasing metabolism. Avoid or Use Alternate Drug.

            • buprenorphine buccal

              cimetidine increases effects of buprenorphine buccal by decreasing metabolism. Avoid or Use Alternate Drug.

            • buspirone

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

            • butorphanol

              cimetidine increases effects of butorphanol by decreasing metabolism. Avoid or Use Alternate Drug.

            • chloroquine

              cimetidine increases levels of chloroquine by decreasing metabolism. Avoid or Use Alternate Drug.

            • cilostazol

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

            • cinacalcet

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

            • clopidogrel

              cimetidine decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .

            • clozapine

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

            • conjugated estrogens

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

            • conjugated estrogens, vaginal

              cimetidine will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • cyclosporine

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

            • darifenacin

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

            • darolutamide

              darolutamide will increase the level or effect of cimetidine by Other (see comment). Avoid or Use Alternate Drug. Darolutamide is a BCRP inhibitor. Avoid coadministration with BCRP inhibitors. If use is unavoidable, closely monitor for adverse reactions and consider dose reduction of BCRP substrate drug (refer BCRP substrate prescribing information).

            • darunavir

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

            • dasatinib

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

              cimetidine will decrease the level or effect of dasatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • dexamethasone

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

            • diazepam

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

            • difenoxin hcl

              cimetidine increases effects of difenoxin hcl by decreasing metabolism. Avoid or Use Alternate Drug.

            • dihydroergotamine

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

            • dihydroergotamine intranasal

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

            • diphenoxylate hcl

              cimetidine increases effects of diphenoxylate hcl by decreasing metabolism. Avoid or Use Alternate Drug.

            • dofetilide

              cimetidine will increase the level or effect of dofetilide by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.

            • dronedarone

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

            • duloxetine

              cimetidine will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • eletriptan

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

            • eliglustat

              cimetidine 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 .

            • erdafitinib

              erdafitinib will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.

            • ergotamine

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

            • erythromycin base

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

            • erythromycin ethylsuccinate

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

            • erythromycin lactobionate

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

            • erythromycin stearate

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

            • estradiol

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

            • estrogens conjugated synthetic

              cimetidine will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • estropipate

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

            • etravirine

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

            • everolimus

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

            • fedratinib

              cimetidine will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

            • felodipine

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

            • fentanyl

              cimetidine 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

              cimetidine 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

              cimetidine 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

              cimetidine 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.

            • fesoterodine

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

            • fludrocortisone

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

            • fluoxetine

              fluoxetine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

            • fluvoxamine

              fluvoxamine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

            • fosamprenavir

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

            • hydrocortisone

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

            • hydromorphone

              cimetidine increases effects of hydromorphone by decreasing metabolism. Avoid or Use Alternate Drug.

            • hydroxyprogesterone caproate

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

            • iloperidone

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

            • indinavir

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

              cimetidine will decrease the level or effect of indinavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • infigratinib

              cimetidine will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before or 10 hr after administration of a H2-antagonist.

            • irinotecan

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

            • irinotecan liposomal

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

            • ivabradine

              cimetidine 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.

            • ivacaftor

              ivacaftor increases levels of cimetidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.

            • ixabepilone

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

            • ketoconazole

              cimetidine will decrease the level or effect of ketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • lasmiditan

              lasmiditan increases levels of cimetidine by Other (see comment). Avoid or Use Alternate Drug. Comment: Lasmiditan inhibits BCRP in vitro. Avoid coadministration of lasmiditan with BCRP substrates.

            • levorphanol

              cimetidine increases effects of levorphanol by decreasing metabolism. Avoid or Use Alternate Drug.

            • lonafarnib

              cimetidine will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

            • lopinavir

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

            • loratadine

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

            • lovastatin

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

            • lumefantrine

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

            • maraviroc

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

            • meperidine

              cimetidine increases effects of meperidine by decreasing metabolism. Avoid or Use Alternate Drug.

            • mestranol

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

            • methadone

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

              cimetidine increases effects of methadone by decreasing metabolism. Avoid or Use Alternate Drug.

            • midazolam

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

            • morphine

              cimetidine increases effects of morphine by decreasing metabolism. Avoid or Use Alternate Drug.

            • nalbuphine

              cimetidine increases effects of nalbuphine by decreasing metabolism. Avoid or Use Alternate Drug.

            • nelfinavir

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

            • neratinib

              cimetidine will decrease the level or effect of neratinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • nicardipine

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

            • nilotinib

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

            • nimodipine

              cimetidine will increase the level or effect of nimodipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • nisoldipine

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

              cimetidine will increase the level or effect of nisoldipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • olaparib

              cimetidine 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.

            • opium tincture

              cimetidine increases effects of opium tincture by decreasing metabolism. Avoid or Use Alternate Drug.

            • oxycodone

              cimetidine increases effects of oxycodone by decreasing metabolism. Avoid or Use Alternate Drug.

            • oxymorphone

              cimetidine increases effects of oxymorphone by decreasing metabolism. Avoid or Use Alternate Drug.

            • papaveretum

              cimetidine increases effects of papaveretum by decreasing metabolism. Avoid or Use Alternate Drug.

            • pazopanib

              cimetidine will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; consider short-acting antacids in place of PPIs and H2 antagonists; separate antacid and pazopanib dosing by several hours

            • pentazocine

              cimetidine increases effects of pentazocine by decreasing metabolism. Avoid or Use Alternate Drug.

            • pexidartinib

              cimetidine will increase the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate pexidartinib by 2 hr before or 10 hr after taking an H2-antagonist.

            • pirfenidone

              cimetidine will increase the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration of pirfenidone and moderate CYP1A2 inhibitors result in moderately increased exposure to pirfenidone; if unable to avoid, decrease dose of moderate CYP1A2 inhibitor

            • ponatinib

              cimetidine decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

            • prednisone

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

            • procainamide

              cimetidine will increase the level or effect of procainamide by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.

            • quetiapine

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

            • quinidine

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

              quinidine will increase the level or effect of cimetidine by basic (cationic) drug competition for renal tubular clearance. Avoid or Use Alternate Drug.

            • ranolazine

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

            • repaglinide

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

            • risedronate

              cimetidine will increase the level or effect of risedronate by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Applies only to delayed release formulation; accelerates pH-sensitive dissolution of delayed release risedronate

            • ritonavir

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

            • romidepsin

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

            • saquinavir

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

            • secretin

              cimetidine, secretin. Other (see comment). Avoid or Use Alternate Drug. Comment: Concomitant use of H2-receptor antagonists may cause a hyperresponse in gastrin secretion in response to stimulation testing with secretin, falsely suggesting gastrinoma. Discontinue H2-receptor antagonists at least 2 days before administering secretin to aid in the diagnosis of gastrinoma.

            • silodosin

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

            • simvastatin

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

            • sirolimus

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

            • solifenacin

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

            • sotorasib

              cimetidine will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid.

              sotorasib will decrease the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

            • sufentanil

              cimetidine increases effects of sufentanil by decreasing metabolism. Avoid or Use Alternate Drug.

            • sunitinib

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

            • tacrolimus

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

            • tafenoquine

              tafenoquine will increase the level or effect of cimetidine by Other (see comment). Avoid or Use Alternate Drug. Tafenoquine inhibits organic cation transporter-2 (OCT2) and multidrug and toxin extrusion (MATE) transporters in vitro. Avoid coadministration with OCT2 or MATE substrates. If coadministration cannot be avoided, monitor for substrate-related toxicities and consider dosage reduction if needed based on product labeling of the coadministered drug.

            • tapentadol

              cimetidine increases effects of tapentadol by decreasing metabolism. Avoid or Use Alternate Drug.

            • temsirolimus

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

            • tepotinib

              tepotinib will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

            • theophylline

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

            • thioridazine

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

            • tipranavir

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

            • tizanidine

              cimetidine will increase the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

            • tofacitinib

              cimetidine increases levels of tofacitinib by decreasing metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with 1 or more concomitant medications that result in both moderate CYP3A4 inhibition and potent CYP2C19 inhibition.

            • tolterodine

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

            • tolvaptan

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

            • triamcinolone acetonide injectable suspension

              cimetidine will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

            • triazolam

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

            • trilaciclib

              trilaciclib will decrease the level or effect of cimetidine by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of trilaciclib (OCT2, MATE1, and MATE-2K inhibitor) with substrates where minimal increased concentration in kidney or blood may lead to serious or life-threatening toxicities.

            • vardenafil

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

            • verapamil

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

            • vilazodone

              cimetidine increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If intolerable adverse effects occur when coadministered with moderate CYP3A4 inhibitors, reduce daily dose to 20 mg.

            • warfarin

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

            Monitor Closely (209)

            • acalabrutinib

              cimetidine decreases levels of acalabrutinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Acalabrutinib solubility decreases with increasing gastric pH. Administer acalabrutinib 2 hr before an H2-receptor antagonist.

              acalabrutinib increases levels of cimetidine by Other (see comment). Use Caution/Monitor. Comment: Acalabrutinib may increase exposure to coadministered BCRP substrates by inhibition of intestinal BCRP.

            • alfentanil

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

            • alfuzosin

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

            • alosetron

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

            • amitriptyline

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

            • apalutamide

              apalutamide will decrease the level or effect of cimetidine by increasing elimination. Use Caution/Monitor. Apalutamide weakly induces BCRP and may decrease systemic exposure of drugs that are BCRP substrates.

            • armodafinil

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

            • atazanavir

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

            • atogepant

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

            • atomoxetine

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

            • avanafil

              cimetidine 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

            • avapritinib

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

            • azelastine

              cimetidine increases effects of azelastine by decreasing metabolism. Use Caution/Monitor.

            • bendamustine

              cimetidine increases levels of bendamustine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Decreased conversion of bendamustine to active metabolites. Concentration of active metabolites of bendamustine may be decreased.

            • benzhydrocodone/acetaminophen

              cimetidine 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.

            • berotralstat

              berotralstat will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.

            • bexarotene

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

            • bortezomib

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

            • bosentan

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

            • bosutinib

              bosutinib increases levels of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

            • brexpiprazole

              cimetidine 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.

              cimetidine 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.

            • budesonide

              cimetidine decreases effects of budesonide by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Enteric-coated budesonide dissolves at pH >5.5. Also, dissolution of extended-release budesonide tablets is pH dependent. Coadministration with drugs that increase gastric pH may cause these budesonide products to prematurely dissolve, and possibly affect release properties and absorption of the drug in the duodenum.

            • cabazitaxel

              cimetidine will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

            • cabozantinib

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

            • carbamazepine

              cimetidine will increase the level or effect of carbamazepine by decreasing metabolism. Modify Therapy/Monitor Closely. Monitor plasma levels when used concomitantly

            • carbonyl iron

              cimetidine will decrease the level or effect of carbonyl iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • carmustine

              cimetidine, carmustine. Mechanism: decreasing metabolism. Use Caution/Monitor. Enhanced myelotoxicity.

            • carvedilol

              cimetidine will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

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

            • cefdinir

              cimetidine will decrease the level or effect of cefdinir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • cefditoren

              cimetidine will decrease the level or effect of cefditoren by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • cefpodoxime

              cimetidine will decrease the level or effect of cefpodoxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • cefuroxime

              cimetidine will decrease the level or effect of cefuroxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • cevimeline

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

            • chlordiazepoxide

              cimetidine increases levels of chlordiazepoxide by decreasing metabolism. Use Caution/Monitor.

            • cilostazol

              cimetidine increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite).

            • citalopram

              cimetidine increases levels of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Citalopram 20 mg/day is the maximum recommended dose for patients taking CYP2C19 inhibitors because of the risk of QT prolongation.

            • clarithromycin

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

              clarithromycin will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

            • clomipramine

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

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

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

            • clonazepam

              cimetidine increases levels of clonazepam by decreasing metabolism. Use Caution/Monitor.

            • clopidogrel

              cimetidine decreases effects of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clopidogrel efficacy may be reduced by drugs that inhibit CYP3A4. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP3A4. .

            • clorazepate

              cimetidine increases levels of clorazepate by decreasing metabolism. Use Caution/Monitor.

            • clozapine

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

            • codeine

              cimetidine will increase the level or effect of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

            • conivaptan

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

            • crizotinib

              cimetidine decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. .

            • dabrafenib

              cimetidine will decrease the level or effect of dabrafenib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that alter upper GI tract pH (eg, PPIs, H2-blockers, antacids) may decrease dabrafenib solubility and reduce its bioavailability

            • desipramine

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

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

            • dexmethylphenidate

              cimetidine will increase the level or effect of dexmethylphenidate by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Applies only to extended release formulation

            • dienogest/estradiol valerate

              cimetidine will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

            • diltiazem

              cimetidine will increase the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider alternatives to cimetidine in patients receiving diltiazem. If no alternative is available, monitor for the effects of diltiazem following cimetidine initiation/discontinuation.

              cimetidine will increase the level or effect of diltiazem by basic (cationic) drug competition for renal tubular clearance. Modify Therapy/Monitor Closely. Exercise caution when concomitantly using diltiazem with atazanavir. Consider reducing the diltiazem dose by 50%. ECG monitoring is recommended.

            • disopyramide

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

            • docetaxel

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

            • donepezil

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

            • doxepin

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

            • doxepin cream

              cimetidine increases levels of doxepin cream by decreasing metabolism. Use Caution/Monitor.

            • doxorubicin

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

            • doxorubicin liposomal

              cimetidine will increase the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • duloxetine

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

            • dutasteride

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

            • elagolix

              elagolix will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

            • eliglustat

              eliglustat increases levels of cimetidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.

            • eluxadoline

              cimetidine increases levels of eluxadoline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2C19 inhibitors.

              eluxadoline increases levels of cimetidine by decreasing metabolism. Use Caution/Monitor. Eluxadoline may increase the systemic exposure of coadministered BCRP substrates.

            • epirubicin

              cimetidine increases levels of epirubicin by decreasing metabolism. Use Caution/Monitor. Cimetidine increased the AUC of epirubicin by 50%. Cimetidine treatment should be stopped during treatment with epirubicin.

            • eplerenone

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

            • erdafitinib

              erdafitinib increases levels of cimetidine by decreasing renal clearance. Modify Therapy/Monitor Closely. Consider alternatives that are not OCT2 substrates or consider reducing the dose of OCT2 substrates based on tolerability.

            • erlotinib

              cimetidine decreases levels of erlotinib by Other (see comment). Use Caution/Monitor. Comment: Avoid combination when possible. If concurrent use is required erlotinib should be taken 10 hours after a H2-antagonist and at least 2 hours before the next dose of H2-antagonist.

            • eslicarbazepine acetate

              eslicarbazepine acetate will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

            • estrogens esterified

              cimetidine will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • ethinylestradiol

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

            • ethotoin

              cimetidine will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • etoposide

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

            • etravirine

              cimetidine will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • eucalyptus

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

            • ferric maltol

              cimetidine will decrease the level or effect of ferric maltol by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ferrous fumarate

              cimetidine will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ferrous gluconate

              cimetidine will decrease the level or effect of ferrous gluconate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ferrous sulfate

              cimetidine will decrease the level or effect of ferrous sulfate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • finerenone

              cimetidine 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 weak CYP3A4 inhibitors. Adjust finererone dosage as needed.

            • flecainide

              cimetidine will increase the level or effect of flecainide by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Flecainide dosage should be carefully titrated on initiation of therapy. Careful monitoring of flecainide plasma concentration should be instituted when cimetidine is coadministered or discontinued.

            • flibanserin

              cimetidine will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

            • fluoxetine

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

            • fluvastatin

              cimetidine increases levels of fluvastatin by decreasing metabolism. Use Caution/Monitor.

            • fluvoxamine

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

            • fosamprenavir

              cimetidine will decrease the level or effect of fosamprenavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • fosphenytoin

              cimetidine will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • fostamatinib

              fostamatinib will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.

            • fostemsavir

              fostemsavir will increase the level or effect of cimetidine by Other (see comment). Modify Therapy/Monitor Closely. Fostemsavir inhibits BCRP transporters. If possible, avoid coadministration or modify dose of BCRP substrate coadministered with fostemsavir.

            • galantamine

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

            • gefitinib

              cimetidine decreases levels of gefitinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Separate gefitinib and H2-antagonist doses by at least 6 hr.

            • glecaprevir/pibrentasvir

              glecaprevir/pibrentasvir will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

            • glipizide

              cimetidine will increase the level or effect of glipizide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • glyburide

              cimetidine will increase the level or effect of glyburide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • haloperidol

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

            • hydrocodone

              cimetidine 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

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

            • iloperidone

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

            • imatinib

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

            • imipramine

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

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

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

            • iron dextran complex

              cimetidine will decrease the level or effect of iron dextran complex by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • iron sucrose

              cimetidine will decrease the level or effect of iron sucrose by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • isavuconazonium sulfate

              cimetidine 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 cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

            • isradipine

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

            • istradefylline

              istradefylline will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.

            • itraconazole

              cimetidine will decrease the level or effect of itraconazole by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Administer acid neutralizing medicines at least 2 hours before or 2 hours after itraconazole. When taking with cimetidine, administer with non-diet cola to increase GI acidity.

            • ivacaftor

              cimetidine increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Reduce ivacaftor dose if coadministered with moderate CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification. .

            • ketoconazole

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

            • lapatinib

              cimetidine will decrease the level or effect of lapatinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ledipasvir/sofosbuvir

              cimetidine decreases levels of ledipasvir/sofosbuvir by Other (see comment). Use Caution/Monitor. Comment: Ledipasvir solubility decreases as pH increases; drugs that increase gastric pH are expected to decrease levels of ledipasvir; H2-receptor antagonists may be administered simultaneously with or 12 hr apart from ledipasvir/sofosbuvir at a dose that does not exceed doses comparable to famotidine 40 mg BID.

            • lemborexant

              cimetidine will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

            • lidocaine

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

            • lomitapide

              lomitapide increases levels of cimetidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.

            • lomustine

              cimetidine, lomustine. Mechanism: decreasing metabolism. Use Caution/Monitor. Enhanced myelotoxicity.

            • lonafarnib

              lonafarnib will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Lonafarnib is a weak P-gp inhibitor. Monitor for adverse reactions if coadministered with P-gp substrates where minimal concentration changes may lead to serious or life-threatening toxicities. Reduce P-gp substrate dose if needed.

            • lurasidone

              cimetidine increases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Manufacturer recommends decreasing starting dose of lurasidone to 20 mg/day and maximum daily dose of lurasidone 80 mg when coadministered with moderate CYP3A4 inhibitors. Concurrent use may increase risk of lurasidone-related adverse reactions.

            • mebendazole

              cimetidine increases levels of mebendazole by decreasing metabolism. Use Caution/Monitor.

            • mefloquine

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

            • memantine

              cimetidine will increase the level or effect of memantine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • metformin

              cimetidine will increase the level or effect of metformin by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • methamphetamine

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

            • methylphenidate

              cimetidine decreases effects of methylphenidate by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Since the characteristics of methylphenidate extended release capsules (Ritalin LA) are pH dependent, coadministration of antacids or acid suppressants could alter the release of methylphenidate. Consider separating the administration of the antacid and the methylphenidate extended-release capsules may be avoided.

            • metoprolol

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

            • mexiletine

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

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

            • midazolam intranasal

              cimetidine will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.

            • midodrine

              cimetidine will increase the level or effect of midodrine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • mizolastine

              cimetidine increases levels of mizolastine by decreasing metabolism. Use Caution/Monitor.

            • morphine

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

            • nateglinide

              cimetidine will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • nebivolol

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

            • nelfinavir

              cimetidine will increase the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • nicotine inhaled

              cimetidine increases levels of nicotine inhaled by decreasing renal clearance. Use Caution/Monitor.

            • nicotine intranasal

              cimetidine increases levels of nicotine intranasal by decreasing metabolism. Use Caution/Monitor.

              cimetidine increases levels of nicotine intranasal by decreasing renal clearance. Use Caution/Monitor.

            • nifedipine

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

            • nilotinib

              cimetidine decreases levels of nilotinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Avoid this interaction by administering H2 antagonists 10 hr after or 2 hr before nilotinib.

            • nimodipine

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

            • nortriptyline

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

            • olanzapine

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

            • oliceridine

              cimetidine 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.

            • oxybutynin

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

            • oxycodone

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

            • oxymorphone

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

            • paclitaxel

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

            • paclitaxel protein bound

              cimetidine will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • palbociclib

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

            • parecoxib

              cimetidine will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

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

            • paroxetine

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

            • pentoxifylline

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

            • phenytoin

              cimetidine will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • pimozide

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

            • pioglitazone

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

            • polysaccharide iron

              cimetidine will decrease the level or effect of polysaccharide iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ponatinib

              ponatinib increases levels of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

              ponatinib increases levels of cimetidine by Other (see comment). Use Caution/Monitor.

            • posaconazole

              cimetidine will decrease the level or effect of posaconazole by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • pramipexole

              cimetidine will increase the level or effect of pramipexole by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • praziquantel

              cimetidine increases levels of praziquantel by decreasing metabolism. Use Caution/Monitor.

            • propafenone

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

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

            • propranolol

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

            • quinine

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

              cimetidine will increase the level or effect of quinine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • rabeprazole

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

            • ramelteon

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

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

            • rasagiline

              cimetidine will increase the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Recommended dose of rasagiline is 0.5mg daily in combination with CYP1A2 inhibitors.

            • regorafenib

              regorafenib will increase the level or effect of cimetidine by Other (see comment). Modify Therapy/Monitor Closely. Regorafenib likely inhibits BCRP (ABCG2) transport. Coadministration with a BCRP substrate may increase systemic exposure to the substrate and related toxicity.

            • rilpivirine

              cimetidine will decrease the level or effect of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Concurrent use, may cause treatment failure and/or the development of rilpivirine or NNRTI resistance owing to decreased levels. Administer H2 antagonists at least 12 hours before or at least 4 hours after rilpivirine.

            • roflumilast

              cimetidine increases levels of roflumilast by Other (see comment). Modify Therapy/Monitor Closely. Comment: Coadministration with dual inhibitors of CYP3A4 and CYP1A2 may increase systemic exposure and result in increased adverse reactions.

            • ropinirole

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

            • rose hips

              cimetidine will decrease the level or effect of rose hips by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • ruxolitinib

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

            • safinamide

              safinamide will increase the level or effect of cimetidine by Other (see comment). Use Caution/Monitor. Safinamide and its major metabolite may inhibit intestinal BCRP. Monitor BCRP substrates for increased pharmacologic or adverse effects.

            • sarecycline

              sarecycline will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

            • saxagliptin

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

            • sildenafil

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

            • sofosbuvir/velpatasvir

              cimetidine will decrease the level or effect of sofosbuvir/velpatasvir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Velpatasvir solubility decreases as gastric pH increases (practically insoluble at pH >5). H2 receptor antagonists may be administered simultaneously with or 12 hr apart from sofosbuvir/velpatasvir at a dose that does not exceed doses comparable to famotidine 40 mg BID.

              sofosbuvir/velpatasvir will increase the level or effect of cimetidine by Other (see comment). Use Caution/Monitor. Velpatasvir is an inhibitor of the drug transporter BCRP. Coadministration may increase systemic exposure of drugs that are BCRP substrates.

            • sonidegib

              cimetidine 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.

            • stiripentol

              stiripentol will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

              stiripentol will increase the level or effect of cimetidine by Other (see comment). Modify Therapy/Monitor Closely. Stiripentol is a BCRP transport inhibitor. Consider dosage reduction for BCRP substrates if adverse effects are experienced when coadministered.

            • sufentanil

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

            • sulfamethoxazole

              cimetidine will increase the level or effect of sulfamethoxazole by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • suvorexant

              cimetidine 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

            • tadalafil

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

            • tafamidis

              tafamidis will increase the level or effect of cimetidine by Other (see comment). Use Caution/Monitor. Tafamidis inhibits breast cancer resistant protein (BCRP) in vitro and may increase exposure of BCRP substrates following tafamidis or tafamidis meglumine administration. Dosage adjustment of these BCRP substrates may be necessary.

            • tafamidis meglumine

              tafamidis meglumine will increase the level or effect of cimetidine by Other (see comment). Use Caution/Monitor. Tafamidis inhibits breast cancer resistant protein (BCRP) in vitro and may increase exposure of BCRP substrates following tafamidis or tafamidis meglumine administration. Dosage adjustment of these BCRP substrates may be necessary.

            • tamoxifen

              cimetidine, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

            • tamsulosin

              cimetidine increases levels of tamsulosin by decreasing renal clearance. Use Caution/Monitor. Decreases tamsulosin clearance by 26% resulting in increased AUC (44%).

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

            • tazemetostat

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

            • tenofovir DF

              cimetidine, tenofovir DF. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

            • tetanus toxoid adsorbed or fluid

              cimetidine increases levels of tetanus toxoid adsorbed or fluid by decreasing metabolism. Use Caution/Monitor.

            • theophylline

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

            • timolol

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

            • tinidazole

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

            • tofacitinib

              cimetidine 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.

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

            • tolbutamide

              cimetidine will increase the level or effect of tolbutamide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

            • tramadol

              cimetidine decreases effects of tramadol by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite.

              cimetidine decreases effects of tramadol by decreasing metabolism. Use Caution/Monitor. Decreased conversion of tramadol to active metabolite.

            • trazodone

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

            • triamterene

              cimetidine will increase the level or effect of triamterene by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • trimethoprim

              cimetidine will increase the level or effect of trimethoprim by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • tucatinib

              tucatinib will increase the level or effect of cimetidine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.

            • valacyclovir

              cimetidine increases levels of valacyclovir by decreasing renal clearance. Use Caution/Monitor.

            • vandetanib

              vandetanib increases levels of cimetidine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Vandetanib inhibits the uptake of substrates of organic cation transporter type 2 (OCT2).

            • verapamil

              cimetidine will increase the level or effect of verapamil by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor.

            • vinblastine

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

            • vincristine

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

            • vincristine liposomal

              cimetidine will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • vinorelbine

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

            • vismodegib

              cimetidine will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown

            • warfarin

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

              cimetidine will increase the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

            • zaleplon

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

            • ziprasidone

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

            • zolmitriptan

              cimetidine increases levels of zolmitriptan by unknown mechanism. Modify Therapy/Monitor Closely. Half-life and blood levels of zolmitriptan and its active N-desmethyl metabolite are approximately doubled when coadministered with cimetidine; limit zolmitriptan to 2.5 mg/dose and 5 mg/day.

            • zolpidem

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

            • zonisamide

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

            Minor (66)

            • alosetron

              cimetidine will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • amobarbital

              amobarbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • antipyrine

              cimetidine will increase the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • aripiprazole

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

            • armodafinil

              armodafinil will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • asenapine

              cimetidine will increase the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • blessed thistle

              blessed thistle decreases effects of cimetidine by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction.

            • bosentan

              cimetidine will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • butabarbital

              butabarbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • butalbital

              butalbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • caffeine

              cimetidine will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • celecoxib

              cimetidine will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • chlorpromazine

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

            • cyanocobalamin

              cimetidine decreases levels of cyanocobalamin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

            • devil's claw

              devil's claw decreases effects of cimetidine by pharmacodynamic antagonism. Minor/Significance Unknown.

            • dextroamphetamine

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

            • dextromethorphan

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

            • diclofenac

              cimetidine will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • digoxin

              cimetidine will increase the level or effect of digoxin by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown.

              cimetidine will increase the level or effect of digoxin by basic (cationic) drug competition for renal tubular clearance. Minor/Significance Unknown.

            • donepezil

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

            • efavirenz

              efavirenz will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • eltrombopag

              cimetidine will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

              cimetidine will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • encainide

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

            • etravirine

              etravirine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • famciclovir

              cimetidine, famciclovir. aldehyde dehydrogenase inhibition. Minor/Significance Unknown. The conversion of 6-deoxy penciclovir to penciclovir is catalyzed by aldehyde oxidase. Interactions with other drugs metabolized by this enzyme and/or inhibiting this enzyme could potentially occur. Clinical interaction studies of famciclovir with cimetidine did not show relevant effects on the formation of penciclovir.

            • felbamate

              felbamate will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • felodipine

              felodipine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • fesoterodine

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

            • fluconazole

              fluconazole will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • fluphenazine

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

            • flurbiprofen

              cimetidine will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • fluvastatin

              cimetidine will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • galantamine

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

            • green tea

              cimetidine will increase the level or effect of green tea by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown. Green tea may contain caffeine. CYP1A2 inhibitors may inhibit the hepatic oxidative metabolism of caffeine.

            • ibuprofen

              cimetidine will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • ibuprofen IV

              cimetidine will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • isavuconazonium sulfate

              isavuconazonium sulfate will increase the level or effect of cimetidine by Other (see comment). Minor/Significance Unknown. Isavuconazonium sulfate, an OCT2 inhibitor, may increase the effects or levels of OCT2 substrates.

            • loratadine

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

            • losartan

              cimetidine will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

            • modafinil

              modafinil will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • ospemifene

              cimetidine increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • oxcarbazepine

              oxcarbazepine will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • parecoxib

              parecoxib will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • pefloxacin

              cimetidine increases levels of pefloxacin by decreasing metabolism. Minor/Significance Unknown.

            • pentobarbital

              pentobarbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • perhexiline

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

            • perphenazine

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

            • phenobarbital

              phenobarbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • phytoestrogens

              cimetidine decreases levels of phytoestrogens by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

            • piroxicam

              cimetidine will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • primidone

              primidone will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • prochlorperazine

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

            • promazine

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

            • promethazine

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

            • ramelteon

              cimetidine will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • rifampin

              rifampin will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • riluzole

              cimetidine will increase the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

            • risperidone

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

            • secobarbital

              secobarbital will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

            • sulfamethoxazole

              cimetidine will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • tolbutamide

              cimetidine will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

            • tolterodine

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

            • trifluoperazine

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

            • tropisetron

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

            • varenicline

              cimetidine increases levels of varenicline by decreasing renal clearance. Minor/Significance Unknown.

            • voriconazole

              voriconazole will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

              cimetidine will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

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            Adverse Effects

            1-10%

            Headache (2.1%)

            Dizziness (1%)

            Somnolence (1%)

            Gynecomastia (0.3-4%)

            Frequency Not Defined

            Confusion (elderly)

            Impotence

            Diarrhea

            Nausea

            Vomiting

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            Warnings

            Contraindications

            Hypersensitivity to cimetidine or other H2 receptor antagonists

            Cautions

            Antiandrogen: may cause feminization & sexual dysfunction in males

            If patient taking a prescription drug, the patient should ask a doctor or a pharmacist whether cimetidine can be taken concomitantly with it

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            Pregnancy & Lactation

            Pregnancy Category: B

            Lactation: enters breast milk/not recommended

            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

            H2-receptor antagonist; blocks H2-receptors of gastric parietal cells, leading to inhibition of gastric secretions

            Pharmacokinetics

            Bioavailability: PO: 60-70% (undergoes minimal 1st pass metabolism)

            Protein Bound: 15-20%

            Metabolism: Liver, inhibit microsomal enzymes

            Metabolites: Cimetidine sulfoxide, 5-hydroxymethyl derivative (inactive met)

            Dialyzable: Yes, removed by HD and PD

            Enzymes inhibited: hepatic CYP1A2, CYP2D6, CYP3A4

            Half-Life

            • Adults: 2 hr; increases to 4-5 hr with renal impairment
            • Infant: 2.1-3.6 hr

            Onset

            • IV: 30 min
            • PO: <1 hr

            Duration

            • IV/IM: 4-5 hr
            • PO: 4-8 hr

            Peak Plasma Time

            • IM: 15 min
            • PO: 45-90 min

            Vd

            • Adults: 1 L/kg
            • Children 1-12 years: 2.13 L/kg

            Clearance

            • Total Body: 30-48 L/hr
            • Renal: 13.8-30 L/hr (removed by HD & PD)

            Excretion

            • Urine: 48-75%
            • Feces: 2-3% (<2% in bile)
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            Administration

            IV/IM Administration

            Administered IM with no dilution, OR

            Slow direct IV injection over 5 min or more after dilution to a total of 20 mL with compatible diluent (NS), OR

            Intermittent IV infusion over 15 to 20 min in at least 50 mL of compatible diluent, OR

            Continuous IV infusion in 100 to 1000 mL of compatible diluent over 24 hr

            IV Compatibilities

            Additive: cefazolin, clindamycin, epinephrine, erythromycin, furosemide, gentamicin, lidocaine, norepinephrine, KCl, vancomycin, verapamil, vitamin B/C

            Syringe: atropine, heparin

            Y-site: esmolol, heparin

            Not spec: carbenicillin, tetracycline

            IV Incompatibilities

            Additive: amphotericin B

            Syringe: cefazolin, pentobarbital, atropine/pentobarbital, chlorpromazine, heparin (?), secobarbital

            Y-site: allopurinol, amphotericin B, amsacrine, cefepime, indomethacin, warfarin

            IV Preparation

            Solution

            • Injections: in 5% sodium bicarbonate injection, NS, D5W, D10W or LR to a volume of 20 mL
            • Infusions: 300 mg in 100 mL D5W
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            Images

            BRAND FORM. UNIT PRICE PILL IMAGE
            cimetidine oral
            -
            400 mg tablet
            cimetidine oral
            -
            300 mg tablet
            cimetidine oral
            -
            200 mg tablet
            cimetidine oral
            -
            800 mg tablet
            cimetidine oral
            -
            800 mg tablet
            cimetidine oral
            -
            400 mg tablet
            cimetidine oral
            -
            300 mg tablet
            cimetidine oral
            -
            200 mg tablet

            Copyright © 2010 First DataBank, Inc.

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            Patient Handout

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            cimetidine oral

            CIMETIDINE - ORAL

            (sye-MET-uh-deen)

            COMMON BRAND NAME(S): Tagamet

            USES: Cimetidine is used to treat ulcers of the stomach and intestines and prevent them from coming back after they have healed. This medication is also used to treat certain stomach and throat (esophagus) problems caused by too much stomach acid (e.g., Zollinger-Ellison syndrome, erosive esophagitis) or a backward flow of stomach acid into the esophagus (acid reflux disease/GERD). Decreasing extra stomach acid can help relieve symptoms such as stomach pain, heartburn, difficulty swallowing, persistent cough, and trouble sleeping. It can also prevent serious acid damage to your digestive system (e.g., ulcers, cancer of the esophagus).Cimetidine belongs to a class of drugs commonly called H2 blockers. It works by reducing the amount of acid in your stomach.This medication is also available without a prescription. It is used to treat occasional heartburn caused by too much acid in the stomach (also called acid indigestion or sour stomach). It is also used to prevent heartburn and acid indigestion caused by certain foods and beverages. If you are taking this medication for self-treatment, it is important to read the manufacturer's package instructions carefully so you know when to consult your doctor or pharmacist. (See also Precautions.)

            HOW TO USE: Take this medication by mouth with or without food as directed by your doctor.The dosage and length of treatment are based on your medical condition and response to therapy. Follow your doctor's instructions carefully. If you are also taking antacids to relieve stomach pain as recommended by your doctor, separate them from this medication by at least 1 hour.Take this medication regularly as prescribed in order to get the most benefit from it. To help you remember, take it at the same time(s) each day. Do not increase your dose or take it more often than directed. Continue to take this medication for the prescribed length of treatment even if you are feeling better. Stopping treatment too early may delay the healing process.If you are using nonprescription cimetidine for self-treatment of acid indigestion or heartburn, take 1 tablet by mouth with a glass of water as needed. To prevent heartburn, take 1 tablet by mouth with a glass of water right before or up to 30 minutes before eating food or drinking beverages that cause heartburn. Do not take more than 2 tablets in 24 hours unless directed by your doctor. Do not take for more than 14 days in a row without talking with your doctor.Inform your doctor if your symptoms do not improve or if they worsen.

            SIDE EFFECTS: Headache, dizziness, drowsiness, or diarrhea may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.If your doctor has directed you to use this medication, remember that 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.Tell your doctor right away if any of these unlikely but serious side effects occur: mental/mood changes (e.g., agitation, confusion, depression, hallucinations), trouble urinating, muscle/joint pain, breast swelling/soreness in males, decreased sexual ability (with very high doses of this medication).Tell your doctor right away if any of these rare but very serious side effects occur: easy bruising/bleeding, signs of infection (e.g., fever, persistent sore throat, cough, trouble breathing), fast/slow/irregular heartbeat, unusual tiredness, persistent nausea/vomiting, severe stomach/abdominal pain, dark urine, yellowing eyes/skin, signs of kidney problems (such as change in the amount of urine).A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: 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 cimetidine, tell your doctor or pharmacist if you are allergic to it; or to other H2 blockers (e.g., famotidine, nizatidine, ranitidine); 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: immune system problems, kidney problems, liver problems, certain lung diseases (chronic obstructive pulmonary disease-COPD), diabetes, other stomach problems (e.g., tumors).Some symptoms may actually be signs of a more serious condition. Get medical help right away if you have: heartburn with lightheadedness/sweating/dizziness, chest/jaw/arm/shoulder pain (especially with shortness of breath, unusual sweating), unexplained weight loss.In addition, before you self-treat with this medication, get medical help right away if you have any of these signs of a serious condition: trouble/pain swallowing food, bloody vomit, vomit that looks like coffee grounds, bloody/black stools, heartburn for over 3 months, frequent chest pain, frequent wheezing (especially with heartburn), nausea/vomiting, stomach pain.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).Do not use this medication to treat children younger than 12 unless directed by the doctor.Older adults may be more sensitive to the side effects of this drug, especially confusion and lung infection (pneumonia). Confusion can increase the risk of falling.During pregnancy, cimetidine should be used only when clearly needed. Discuss the risks and benefits with your doctor.Cimetidine passes into breast milk. Consult your doctor before breast-feeding.

            DRUG INTERACTIONS: See also How to Use section.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: cisapride, dofetilide, epirubicin, ticlopidine, artemether, clopidogrel, lumefantrine, metformin, moclobemide, moricizine, quinidine, silver sulfadiazine.This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include metoprolol, propranolol, tacrine, warfarin, zaleplon, calcium channel blockers (such as diltiazem), tricyclic antidepressants (such as amitriptyline), theophylline, among others.Since cimetidine reduces the amount of acid in your stomach, it may also change the absorption of certain medications and affect how they work. Some examples of affected drugs include atazanavir, dasatinib, delavirdine, certain azole antifungals (such as itraconazole, ketoconazole), pazopanib, among others. Ask your doctor or pharmacist if any of the medications you take are affected by cimetidine and how to manage this interaction.Check the labels on all your medicines because they may contain nonsteroidal anti-inflammatory drugs (NSAIDs such as aspirin, ibuprofen, naproxen) that may cause stomach irritation/ulcers. Ask your pharmacist about the safe use of those products. Low-dose aspirin should be continued if prescribed by your doctor for specific medical reasons such as heart attack or stroke prevention (usually 81-162 milligrams a day). Consult your doctor or pharmacist for more details.Cigarette smoking can affect this medication. Tell your doctor if you smoke and if you stop or start smoking while using this medication.This medication and similar H2 blockers (such as famotidine, nizatidine, ranitidine) are available both with and without a prescription. Do not take them at the same time.

            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. Symptoms of overdose may include mental/mood changes, trouble speaking, difficulty awakening.

            NOTES: Do not share this medication with others.Lifestyle changes such as stress reduction programs, stopping smoking, limiting alcohol, and diet changes (e.g., avoiding caffeine and spicy foods) may increase the effectiveness of this medication. Talk to your doctor or pharmacist about lifestyle changes that might benefit you.Laboratory and/or medical tests may be performed to monitor your progress or check for side effects. Consult your doctor for more details.

            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 in a tightly closed container at room temperature between 59-86 degrees F (15-30 degrees C) away from moisture and light. 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 September 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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            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.
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            Code Definition
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            Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
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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.