rn Please consult your physician before taking any medication. Generic Name: famotidine (fa MAH ti deen) Brand Names: Pepcid, Pepcid AC, Durater What is famotidine? Famotidine is in a class of drugs called histamine receptor antagonists. Famotidine works by decreasing the amount of acid the stomach produ ces. Famotidine is used to treat and prevent ulcers in the stomach and intestines. Famotidine is also used to treat conditions in which the stomach produces too much acid and conditions in which acid comes up into the esophagus and causes heartburn, such as gastroesophageal reflux disease (GERD). Famotidine may also be used for conditions other than those listed in this medication guide.