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Drugs, Supplies and Delivery
Famotidine
Famotidine is a histamine H2 receptor antagonist (H2RA) widely used to reduce gastric acid secretion. It is effective in treating conditions such as peptic ulcers, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome. Famotidine is known for its potency, long duration of action, and favorable safety profile. This article synthesizes information from the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology to provide a detailed overview of famotidine, including its mechanism, uses, dosing, side effects, precautions, and drug interactions.
Famotidine competitively inhibits histamine H2 receptors on parietal cells in the stomach. By blocking these receptors, it reduces:
- Basal and stimulated gastric acid secretion, including acid secretion induced by food, histamine, and gastrin.
- Pepsin secretion, which contributes to its therapeutic effects in ulcer healing (Lippincott, Lange).
Famotidine is more potent and longer-acting than other H2RAs like cimetidine and ranitidine, with fewer drug interactions (BNF).
- Peptic Ulcer Disease:
- Used for the treatment and prevention of gastric and duodenal ulcers (BNF).
- Gastroesophageal Reflux Disease (GERD):
- Provides symptomatic relief and promotes healing of esophagitis (Lippincott).
- Zollinger-Ellison Syndrome:
- Manages excessive gastric acid secretion in this rare condition (Lange).
- Stress Ulcer Prophylaxis:
- Used in critically ill patients to prevent stress-related mucosal damage (BNF).
- Peptic Ulcer Disease:
- Treatment: 20–40 mg once daily at bedtime or 20 mg twice daily for 4–8 weeks.
- Maintenance: 20 mg once daily at bedtime (BNF).
- GERD:
- 20 mg twice daily for 6–12 weeks (Lippincott).
- Zollinger-Ellison Syndrome:
- Initial dose: 20 mg every 6 hours, adjusted based on acid secretion levels (Lange).
- Stress Ulcer Prophylaxis:
- 20 mg twice daily or 40 mg once daily (BNF).
Administration:
- Can be taken with or without food.
- Tablets should be swallowed whole with water (Lippincott).
- Common: Headache, dizziness, constipation, and diarrhea (Lippincott).
- Serious: Rare cases of confusion, arrhythmias, and blood dyscrasias (Lange).
- Renal Impairment: Dose reduction is required in patients with severe renal impairment (eGFR <30 mL/min/1.73 m²) (BNF).
- Pregnancy: Generally considered safe but should be used under medical supervision (Lippincott).
- Elderly Patients: Increased risk of central nervous system (CNS) side effects, such as confusion (Lange).
- Antacids: May reduce famotidine absorption; administer famotidine 1–2 hours before antacids (BNF).
- Ketoconazole/Itraconazole: Reduced absorption of these antifungals due to increased gastric pH (Lippincott).
- Proton Pump Inhibitors (PPIs): Additive acid suppression; monitor for excessive reduction in gastric acidity (Lange).
Famotidine is the generic name for this medication. It is marketed under the brand name Pepcid® in some regions. Generic versions are widely available and cost-effective
