Famotidine, sold under the brand name Pepcid among others, is a histamine H2 receptor antagonist medication that decreases stomach acid production. It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and Zollinger-Ellison syndrome. It is taken by mouth or by injection into a vein. famotidine suppliers. It begins working within an hour. Famotidine was patented in 1979 and came into medical use in 1985. It is available as a generic medication. In 2019, it was the 104th most commonly prescribed medication in the United States, with more than 6 million prescriptions.