Cimetidine
TAGAMET
What it isH2 receptor antagonist suppressing gastric acid; GERD and ulcer disease.
Why this oneIts antiandrogen action can cause gynecomastia, a peculiar liability not shared by famotidine.
What limits itIt inhibits multiple CYP enzymes and tubular creatinine secretion, creating interactions and a false creatinine rise; famotidine has replaced it.
FDA-approved for
- ulcers (1977)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Heartburn relief (OTC) | Adults & children ≥12 yr | 200 mg (1 tablet) with water PRN | 200 mg PRN | 2 tablets/24h |
| Heartburn prevention (OTC) | Adults & children ≥12 yr | 200 mg (1 tablet) up to 30 min before trigger food/drink | 200 mg PRN | 2 tablets/24h |
Renal Undefined
Hepatic Undefined
Instructions
- Swallow 1 tablet with a glass of water
- For prevention, take right before or up to 30 minutes before eating/drinking trigger foods
- Do not take more than 2 tablets in 24 hours
- Children under 12 years: ask a doctor
Pregnancy Undefined
Lactation Undefined
NO BOXED WARNINGS
Principal riskInhibits four CYP enzymes; famotidine has replaced it
Cost, est. cash$20–$1,500/dose or month
Generic entry1994
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityLong-term infection, magnesium/B12 and bone risks; selected agents have clinically important CYP interactions.
Mechanism of action: Cimetidine ballicule
Open Cimetidine in the interactive console ↗
Memory aids: mascots and interaction avatars
Cimetidine (left) increases levels of metformin (Mr Met, right)
