Famotidine is a medication available both over-the-counter and by prescription, used to manage conditions resulting from excess stomach acid production, such as heartburn, acid indigestion, and gastroesophageal reflux disease (GERD). This drug belongs to a class of compounds known as histamine-2 (H2) receptor antagonists, or H2 blockers. Its primary function is to decrease the volume and concentration of stomach acid, providing relief from the uncomfortable symptoms associated with acid reflux.
Timing of Acid Relief
Famotidine typically begins to block the production of stomach acid within 15 to 60 minutes after an adult takes an oral dose. For maximal acid suppression, the medication usually reaches its peak effectiveness within one to three hours following ingestion of the tablet or capsule. If taken to prevent heartburn, the drug is most effective when administered 10 to 60 minutes before consuming food or beverages known to trigger symptoms. Treatment for chronic conditions like a peptic ulcer or GERD requires consistent dosing over several weeks to achieve full therapeutic benefit and healing.
How Famotidine Works
Famotidine functions as a competitive antagonist, meaning it directly interferes with a natural process in the stomach lining. The drug targets the histamine H2 receptors located on the surface of the parietal cells in the stomach, which are responsible for secreting gastric acid. Normally, the binding of histamine to the H2 receptor stimulates a signaling cascade that activates the proton pumps, the final mechanism for acid secretion. Famotidine effectively blocks histamine from binding to these receptors, thereby preventing the full activation of the acid-producing pathway and reducing gastric secretions.
Dosage and Administration Guidelines
The duration of effect for a single dose of famotidine in adults is substantial, with acid secretion remaining suppressed for approximately 10 to 12 hours. Over-the-counter (OTC) famotidine is commonly available in 10 mg or 20 mg strengths for self-treatment of heartburn. Adults should typically take one 10 mg or 20 mg tablet for relief or prevention, but should not exceed a maximum of two tablets (40 mg) within a 24-hour period when using the OTC formulation. If using a chewable tablet, it must be thoroughly chewed before swallowing to ensure proper absorption. Prescription-strength doses are higher and are used to treat more severe conditions, such as active ulcers or erosive esophagitis, often requiring twice-daily dosing.
It is important to note that continuous use of OTC famotidine should not exceed 14 days. If symptoms of heartburn or acid indigestion persist or worsen after two weeks of self-treatment, adults should stop taking the medication and consult a healthcare professional.