OB-GYN 101
Pharmacy

Category:

• Gastrointestinal

Description:

• Antiulcer agent (H2 antagonist)

Indications:

• Duodenal ulcer; benign gastric ulcer

• Pathological hypersecretory conditions (Zollinger-Ellison syndrome)

• Gastroesophageal reflux disease (GERD)

• Erosive gastritis

• Stress ulcer prophylaxis

Drug Interactions:

• Reduced efficacy: cefuroxine, cefpodoxime

• Enhanced hypoglycemic effect: glipizide

• Increased bioavailability: nifedipine, nitrendipine, nisoldipine

• Decreased plasma concentrations: ketoconazole, enoxacin

Precautions:

• Pregnancy category B; compatible with breast feeding

• Stagger doses of ranitadine and antacids

Adverse Reactions (Side Effects):

• CNS: dizziness, insomnia, malaise, somnolence, vertigo

• CV: atrioventricular block, bradycardia, premature ventricular beats, tachycardia

• GI: Abdominal discomfort or pain, constipation, hepatitis, increased liver function tests, nausea, vomiting, pancreatitis (rare)

• HEME: granulocytopenia, leukopenia, thrombocytopenia

• SKIN: alopecia, erythema multiforme (rare), rash

• MS: arthralgias, myalgias

Administered PO (tablets, gelatin capsules, syrup), IV, and IM

• Adult: 

  • Duodenal and gastric ulcer: PO 150mg twice daily or 300mg at bedtime for 4-8 weeks, maintenance 150mg every night at bedtime

  • GERD: 

    • PO 150mg twice daily

  • Erosive esophagitis: 

    • PO 150mg four times daily, maintenance 150mg twice daily

  • Pathological hypersecretory conditions: 

    • PO 150mg twice daily initially, titrate to desired response up to 6 grams daily

    • IV INF start 1mg/kg/hr, increase by 0.5mg/kg/hr intervals every 4 hours as needed up to 2.5mg/kg/hr

    • IM/IV 50mg every 6 to 8 hours, do not exceed 400mg per day; 

    • IV INF 6.25mg/hr

• Child:

  • PO 1.25mg/kg every 12 hours, max 300mg/kg/day

  • IM/IV 0.75-1.5mg/kg every 6-8 hours, max 6mg/kg/day or 300mg/day

  • IV INF 0.1-0.25mg/kg/hr