Cimetadine (Tagamet)

Category:

• Gastrointestinal

Description:

• Antiulcer agent (H-2 receptor antagonist)

Indications:

• 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

Precautions:

• 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

Dosage:

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