Omeprazole and Pepcid (famotidine) are both medications that work to decrease stomach acid, but they do so in different ways. Omeprazole is a proton pump inhibitor (PPI) while famotidine is an H2 blocker. Veterinarians may recommend one product over another, based on what condition your pet is being treated for. No vet writer or qualified reviewer has received any compensation from the manufacturer of the medication as part of creating this article. All content contained in this article is sourced from public sources or the manufacturer.