Cimetadine (Tagamet)


  • Gastrointestinal


  • Antiulcer agent (H-2 receptor antagonist)


  • Short term treatment of duodenal and benign gastric ulcers

  • Erosive gastroesophageal reflux disease (GERD)

  • Pathological hypersecretory conditions (Zollinger-Ellison syndrome, systemic mastocytosis, endocrine adenomas)

  • As part of multiple drug regiment to eradicate Helicobacter pylori in peptic ulcers

Drug Interactions:

  • Increased concentrations of interacting drugs with potential for toxicity: 

    • benzodiazepines

    • calcium channel blockers

    • carbamazepine

    • clozapine

    • cyclic antidepressants

    • glyburide

    • lomustine

    • melphalan

    • narcotic analgesics

    • nicotine

    • phenytoin

    • quinidine

    • tacrine

    • theophylline

    • tolbutamide

    • warfarin

  • Reduced concentrations of interacting drugs:

    • ketoconazole

    • cefuroxime

    • cefpodoxime


  • Pregnancy category B; excreted in breast milk

  • Smoking decreases effectiveness of cimetadine

  • Organic brain syndrome, hepatic disease, renal disease, elderly

Adverse Reactions (Side Effects):

  • Central Nervous System: anxiety, confusion, depression, dizziness, headache, psychosis, seizures, tremors, weakness

  • Cardiovascular: bradycardia, tachycardia

  • Gastrointestinal: abdominal cramps, diarrhea, jaundice, paralytic ileus

  • Genitourinary: Galactorrhea, gynecomastia, impotence

  • Hematological: Agranulocytosis, aplastic anemia, neutropenia, thrombocytopenia

  • Skin: Alopecia, exfoliative dermatitis, flushing rash, sweating, urticaria



Administered orally, intravenously, or intramuscularly

  • Treatment

    • PO 300mg four times daily with meals for 8 weeks or 400mg twice daily or 800mg at bedtime. After 8 weeks, give 300-400mg at bedtime only

    • IV bolus 300mg/20ml 0.9% NaCl over 1-2 minutes every 6 hours

    • IV INF 300mg/50ml D5W over 15-20 minutes every 6 hours

    • Continuous IV INF 37.5mg/hr (900mg/day)

    • IM 300mg every 6 hours not to exceed 2400mg daily.

  • Prophylaxis of duodenal ulcer: 

    • 400mg at bedtime

  • GERD: 

    • PO 800mg twice daily or 400mg four times daily for 12 weeks


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