The right dose of famotidine depends on the condition being treated, age, and whether it’s prescription or over‑the‑counter (OTC). Never exceed the recommended dose without a doctor’s advice, as too much can cause side effects.
Common adult doses (by condition)
- Heartburn / occasional acid reflux (OTC):
- 10–20 mg once or twice per day, as needed.
- Do not take more than 40 mg in 24 hours unless directed by a doctor.
- GERD (gastroesophageal reflux disease):
- 20 mg twice daily for up to 6 weeks (for non‑erosive GERD).
- For erosive esophagitis, 20–40 mg twice daily for up to 12 weeks.
- Duodenal or gastric ulcer:
- 40 mg once daily at bedtime for up to 8 weeks, or
- 20 mg twice daily.
- Conditions with very high stomach acid (e.g., Zollinger‑Ellison):
- Starting dose: 20 mg every 6 hours.
- Maximum: up to 160 mg every 6 hours (640 mg/day) in severe cases, under medical supervision.
Maximum daily dose
- For most conditions, the usual maximum is 160 mg every 6 hours (640 mg per day) , but this is only for severe, hospital‑managed conditions like pathological hypersecretion.
- For OTC use (heartburn), the safe limit is generally no more than 40 mg in 24 hours unless a doctor says otherwise.
Important safety notes
- Do not take famotidine for more than 2 weeks in a row for heartburn without talking to a doctor, especially if symptoms don’t improve.
- People with kidney problems may need a lower dose, since famotidine is cleared by the kidneys.
- Avoid alcohol and other stomach irritants while taking famotidine, and tell your doctor about all other medicines you take (some can interact).
For children
- Dosing is based on weight (usually around 0.5 mg/kg per day, up to a max of 40 mg/day), and must be guided by a pediatrician.
- OTC famotidine is not recommended for young children without medical advice.
When to see a doctor
It’s safest to use famotidine only as directed on the label or by a healthcare provider. If you’re unsure which dose is right for your situation (for example, if you have kidney disease, are pregnant, or are taking other medicines), talk to a doctor or pharmacist before taking it.
