Famotidine

H2 receptor antagonist

An H2 receptor antagonist that reduces stomach acid production, used for acid reflux and peptic ulcers.

Uses

Gastric (stomach) ulcer
Duodenal ulcer
Gastro-oesophageal reflux disease (GERD)/acid reflux
Heartburn/indigestion
Erosive oesophagitis

Common brands available in Hong Kong

Pepcid (internationally well-known brand, reportedly sold in HK — exact HK-registered name/packaging not fully independently verified)

Common formulations

20mg (tablet)
40mg (tablet)
Injectable solution (hospital use)

What is Famotidine used for?

Famotidine is a histamine H2-receptor antagonist that blocks the H2 receptor on stomach lining cells to reduce gastric acid secretion, relieving heartburn, indigestion, and reflux symptoms caused by excess stomach acid, and helping gastric and duodenal ulcers to heal.

How to take Famotidine and adjust the dose

Gastric ulcer: typically 40mg once nightly, for up to 8 weeks. Duodenal ulcer: 40mg once nightly, or 20mg twice daily, for up to 8 weeks; after healing, may switch to 20mg nightly for maintenance to prevent recurrence. GERD: typically 20mg twice daily for up to 6 weeks. Can be taken with or without food. This dosing information is compiled from general international drug references, not an official HK product insert — follow your doctor's/pharmacist's actual prescription (moderate confidence).

Famotidine side effects

Common: headache, dizziness, constipation, diarrhoea
Serious (rare, especially in renal impairment): irregular heartbeat, mood or mental status changes (e.g. confusion, depression, more common in elderly/renal-impaired patients), seizures

Who should not take Famotidine?

Contraindicated in hypersensitivity to famotidine or other H2-receptor antagonists
Dose adjustment and caution needed in renal impairment
Long-term use may reduce vitamin B12 and iron absorption — monitor
Consult a doctor during pregnancy and breastfeeding
Concurrent use with drugs requiring stomach acid for absorption (e.g. ketoconazole, itraconazole) may reduce their effectiveness — inform your doctor

Check the Department of Health Drug Office register →

Sources: www.mims.com · www.otandp.com · www.drugs.com

This page is general reference information only, not medical advice. Always confirm dosage, interactions, and whether this medicine is suitable for you with a pharmacist or doctor before use.

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