PEPCID® is a histamine-2 blocker (H2 blocker) with the active ingredient famotidine that helps relieve heartburn by reducing the amount of acid in the stomach. PEPCID® is the original famotidine brand and, for 35 years, has been effective and safe acid reducer when used as directed. PEPCID® is clinically proven to provide heartburn relief and is backed by 50+ clinical studies. Pepcid (famotidine): H2 blocker for heartburn/GERD and ulcers. OTC/Rx dosing, onset, interactions, side effects, and prices by country. Pepcid is a histamine-2 blocker that works by decreasing the amount of acid the stomach produces. Pepcid is used to treat and prevent ulcers in the stomach and intestines. It also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Famotidine is used to treat stomach ulcers (gastric and duodenal), erosive esophagitis (heartburn or acid indigestion), and gastroesophageal reflux disease (GERD). GERD is a condition where the acid in the stomach washes back up into the esophagus. Famotidine is a histamine-2 blocker that works by decreasing the amount of acid the stomach produces. Famotidine is used to treat and prevent ulcers in the stomach and intestines. It also treats conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome. Pepcid's Famotidine-powered heartburn relief tablets provide protection from acid indigestion and sour stomach for adults and children 12+. Overview: Famotidine is used to treat heartburn, ulcers, and other conditions caused by too much stomach acid. It is available by prescription and over-the-counter (OTC). Famotidine is an H2. Pepcid (Famotidine) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. Famotidine, sold under the brand name Pepcid among others, is a histamine H 2 receptor antagonist medication that decreases stomach acid production. [4] It is used to treat peptic ulcer disease, gastroesophageal reflux disease, and Zollinger–Ellison syndrome. [4].