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Apo-Cimetidine (CA), Dyspamet (UK), Galenmet (UK), Novo-Cimetine (CA), Nu-Cimet (CA), Tagamet HB

Pharmacologic class: Histamine2-receptor antagonist

Therapeutic class: Antiulcer drug

Pregnancy risk category B


Competitively inhibits histamine action at histamine2-receptor sites of gastric parietal cells, thereby inhibiting gastric acid secretion


Oral liquid: 200 mg/5 ml, 300 mg/5 ml

Tablets: 200 mg, 300 mg, 400 mg, 600 mg, 800 mg

Indications and dosages

Active duodenal ulcer (short-term therapy)

Adults and children older than age 16: 800 mg P.O. at bedtime, or 300 mg P.O. q.i.d. with meals and at bedtime, or 400 mg P.O. b.i.d. Maintenance dosage is 400 mg P.O. at bedtime.

Active benign gastric ulcer (short-term therapy)

Adults and children older than age 16: 800 mg P.O. at bedtime or 300 mg P.O. q.i.d. with meals and at bedtime

Gastric hypersecretory conditions (such as Zollinger-Ellison syndrome); intractable ulcers

Adults and children older than age 16: 300 mg P.O. q.i.d. with meals and at bedtime

Erosive gastroesophageal reflux disease

Adults and children older than age 16: 1,600 mg P.O. daily in divided doses (800 mg b.i.d. or 400 mg q.i.d.) for 12 weeks

Heartburn; acid indigestion

Adults and children older than age 16: 200 mg (two tablets of over-the-counter product only) P.O. up to b.i.d. Give maximum dosage no longer than 2 weeks continuously, unless directed by prescriber.

Dosage adjustment

• Renal impairment

Off-label uses

• Acetaminophen overdose

• Adjunctive therapy in burns

• Barrett's esophagus

• Renal cancer

• Anaphylaxis


• Hypersensitivity to drug

• Alcohol intolerance


Use cautiously in:

• renal impairment

• elderly patients

• pregnant or breastfeeding patients.


• Give with meals.

Adverse reactions

CNS: confusion, dizziness, drowsiness, hallucinations, agitation, psychosis, depression, anxiety, headache

GI: diarrhea

GU: reversible erectile dysfunction, gynecomastia


Drug-drug. Calcium channel blockers, carbamazepine, chloroquine, lidocaine, metformin, metronidazole, moricizine, pentoxifylline, phenytoin, propafenone, quinidine, quinine, some benzodiazepines, some beta-adrenergic blockers (chlordiazepoxide, diazepam, midazolam), sulfonylureas, tacrine, theophylline, triamterene, tricyclic antidepressants, valproic acid, warfarin: decreased metabolism of these drugs, possible toxicity

Drug-diagnostic tests. Creatinine, transaminases: increased levels

Parathyroid hormone: decreased level Skin tests using allergenic extracts: false-negative results (drug should be discontinued 24 hours before testing)

Drug-food. Caffeine-containing foods and beverages (such as coffee, chocolate): increased cimetidine blood level, increased risk of toxicity

Drug-herbs. Pennyroyal: change in formation rate of herb's toxic metabolite

Yerba maté: decreased yerba maté clearance, possible toxicity

Drug-behaviors. Alcohol use: increased blood alcohol level

Smoking: reversed cimetidine effects

Patient monitoring

• Monitor creatinine levels in patients with renal insufficiency or failure.

• Assess elderly or chronically ill patients for confusion (which usually resolves once drug therapy ends).

Patient teaching

• Inform patient with gastric ulcer that ulcer may take up to 2 months to heal. Advise him not to discontinue therapy, even if he feels better, without first consulting prescriber. Ulcer may recur if therapy ends too soon.

• Advise patient not to take over-the-counter cimetidine for more than 2 weeks continuously, except with prescriber's advice and supervision.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, foods, herbs, and behaviors mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


A brand name for CIMETIDINE.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
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