Famotidine is an acid-suppressing agent that may be used to treat a wide range of gastric-acid related disorders including gastric ulcers, heartburn, and GERD. A headache is the most common side effect. Drug interactions with famotidine are uncommon. 5. Tips. May be taken with or without food. Take with a glass of water and take the exact dosage as directed on the packet (self-medicating) or. Prilosec and Prilosec OTC contain the same active ingredient, omeprazole, which effectively stops acid production. Used to treat symptoms of gastroesophageal reflux disease (GERD) and other conditions involving excessive stomach acid is used to treat certain conditions where there is too much acid in the stomach Famotidine inhibits both basal and nocturnal gastric acid secretion, as well as acid secretion stimulated by food, caffeine, insulin, and pentagastrin. 5,6. Famotidine has a dose-dependent therapeutic action, with the highest dose having the most extended duration of action and the highest inhibitory effect on gastric acid secretion. Following. Prescription famotidine oral tablet is used to treat symptoms of acid reflux and heartburn. It’s prescribed for conditions such as gastroesophageal reflux disease (GERD). It comes as a generic.