【藥品性質提示】 根據 2019 AGS Beers Criteria，本藥品為【潛在不適當用藥 (PIM)】，不建議用於有瞻妄風險之老年人，腎功能不佳 (CrCl<50mL/min) 須降低劑量。

Gastroesophageal reflux disease (GERD); Esophagitis

Histamine H2 Antagonist
Competitive inhibition of histamine at H2 receptors of the gastric parietal cells, which inhibits gastric acid secretion.

Time to peak concentration: 1-3 h
Bioavailability: 40% to 45%
Vd: (adult) 1.3 L/kg +/- 0.2 L/kg; Protein binding: 15% to 20%
Metabolism: Minimal first-pass metabolism
Excretion: (Renal) 25% to 30% unchanged
Elimination Half Life: 2.5 h to 3.5 h; renal insufficiency may exceed 20 h

History of hypersensitivity to other H2-receptor antagonists and hypersensitivity to famotidine or any component of product.

B [FDA.AUS]

Infant risk cannot be ruled out.

Headache, dizziness, diarrhea, constipation, arthralgia, somnolence, rash.

Duodenal or benign gastric ulcer: 20 mg BID or 40 mg HS
GERD: 20-40mg PO BID
Prophylaxis of recurrent ulcer: 20 mg PO HS

0.5-1 mg/kg/day orally in two divided doses; up to 40 mg BID

1. ClCr >60 ml/min: 20-40 mg BID
2. ClCr 30-60 ml/min: 20 mg QD
3. ClCr <30 ml/min: 20 mg QOD