Famotidine is an acid-reducing active ingredient available in over-the-counter (OTC) medicines that relieve or prevent heartburn symptoms associated with acid indigestion and sour stomach. Famotidine is part of a group of acid reducers called Histamine-2 antagonists, or H2 blockers. It can be the only active ingredient in heartburn medicines that provide long-lasting relief of symptoms, or it can be found in medicines that provide both short- and longer-term symptom relief.
Famotidine is approved by the U.S. Food and Drug Administration (FDA) and is safe and effective when used according to the Drug Facts label. But if your heartburn symptoms continue or get worse while you are taking an OTC medicine containing famotidine, contact your healthcare provider. Chronic heartburn may be a sign of a more serious condition.