What is famotidine used for?

Famotidine is an H2 receptor blocker that lowers stomach acid. It’s used for a few different purposes, depending on whether you’re using it OTC or by prescription.

Common uses
- Over-the-counter (OTC): relief of heartburn, acid indigestion, and sour stomach; can be taken as needed for symptoms.
- Prescription uses (for conditions involving excess acid):
- Gastroesophageal reflux disease (GERD) and acid reflux, with or without esophagitis
- Erosive esophagitis
- Duodenal ulcers and gastric ulcers (ulcer treatment and/or prevention)
- Zollinger-Ellison syndrome (acid overproduction, under specialist care)
- Prevention of stress-related (hospital) ulcers in some patients

Forms and dosing
- Available as oral tablets or liquid; IV form is used in hospitals.
- OTC dosing (adult): typically 10–20 mg every 12 hours as needed, not to exceed 40 mg in one day (check the label). Use usually limited to up to 14 days for heartburn/indigestion unless directed by a clinician.
- Prescription dosing varies by condition and response; your doctor will tailor it.

Safety notes
- Tell your clinician if you have kidney disease, are pregnant or breastfeeding, or are taking other medicines.
- Common side effects are usually mild (headache, dizziness, constipation, or diarrhea). Rarely, confusion or other symptoms in older adults.
- It can affect the absorption of medicines that require an acidic stomach (and may interact with certain antifungals or other drugs). If you take other prescription medicines, check with a pharmacist or doctor about possible interactions.

If you have a specific condition or symptom you’re hoping to treat with famotidine, tell me a bit more and I can tailor the information (including typical dosing ranges and duration) to that scenario.