Cimetidine

General

• Type: H2 blocker
• Dosage Forms: 200, 300, 400, 800 mg
• Common Trade Names: Tagamet HB 200

Adult Dosing

Duodenal Ulcer, Active: 800 mg PO QHS x 4-8 weeks

Duodenal Ulcer, Maintenance: 400 mg PO QHS

Gastric Ulcer, active benign: 800 mg PO QHS x 6 weeks

H. Pylori Infection: 400 mg PO BID x 10-28 days

Pediatric Dosing

GERD/PUD:

   * Neonates: 5- 10 mg/kg/day PO divided q8-12h
   * Infants: 10-20 mg/kg/day PO divided q8-12h
   * Children: 20-40 mg/kg/day PO divided q6H

Special Populations

• Pregnancy Rating: B (animal studies show no risk for adverse fetal effects, human fetal harm possible but unlikely)
• Lactation: Probably Safe
• Renal Dosing
  • Adult: CrCL 10-50: decrease dose 50%, CrCl <10, decrease dose 75%
  • Pediatric: CrCl 20-40, decrease dose 25% or give q8h, CrCL <20: decrease dose 50%
• Hepatic Dosing
  • Adult: Not Defined
  • Pediatric not defined

Contraindications

• Allergy to class/drug

- caution if renal impairment - caution if hepatic impairment - caution in elderly patients - caution if chronic pulmonary disease - caution if DM - caution if immunocompromised

Adverse Reactions

Serious

- neutropenia - thrombocytopenia - agranulocytosis - aplastic anemia - pneumonia -depression -psychosis -hallucinations -pancreatitis -interstital nephritis -bradycardia -tachycardia -AV block - skin reaction

Common

-headche -diarrhea -dizziness -gynecomastia -nausea -vomiting -confusion -agitation -drowsiness -rash -ALT,AST elevation

Pharmacology

• Half-life: 2H
• Metabolism: Liver; CYP450, 1A2, 2C19, 2D6 Inhibitor
• Excretion: urine
• Mechanism of Action: Histamine H2 Receptor blocker