Pepcid

Pepcid is the brand name for famotidine, a histamine‑2 (H2) receptor antagonist used primarily to reduce gastric acid secretion. Famotidine competitively inhibits the action of histamine at H2 receptors on gastric parietal cells, thereby decreasing the stimulus for acid production. This mechanism makes Pepcid effective for the treatment of gastro‑oesophageal reflux disease (GERD), peptic ulcer disease, Zollinger‑Ellison syndrome, and acute ulcer bleeding. It is also employed for prophylaxis of stress‑induced ulcers in critically ill patients.

The drug is administered orally as tablets or in liquid form, and also available as a rapid‑infusion intravenous formulation. A typical maintenance dose for GERD is 20 mg twice daily, while for ulcer prophylaxis it may range from 10 mg to 20 mg once daily. The onset of action is within 30–60 minutes, and peak plasma concentrations are reached in approximately one hour. Famotidine has a relatively short half‑life of 2–3 hours in healthy adults but is prolonged in renal impairment due to its renal excretion.

Common adverse effects include headache, dizziness, constipation, and diarrhea. Rare side effects may involve hypokalemia, metabolic alkalosis, or altered mental status in elderly patients. Allergic reactions are uncommon but can occur; patients with known hypersensitivity to famotidine or other H2 antagonists should avoid it. Famotidine is contraindicated in patients taking monoamine oxidase inhibitors or other medications that may interact with H2 antagonists.

Pepcid was developed by Eli Lilly and Company and approved by the U.S. Food and Drug Administration in 1978. The generic formulation of famotidine has been available since the late 1990s and provides a cost‑effective alternative to the brand name drug. The compound remains one of the most widely prescribed agents for acid‑related disorders worldwide.