What is Famotidine? Famotidine is a non-prescription medication used in dogs and cats to reduce the amount of stomach acid being produced. Although Famotidine is not FDA-approved for use in veterinary medicine, it is a commonly accepted practice for veterinarians to prescribe this medication for dogs and cats. This why we need to approach Pepcid a/c (famotidine), Zantac (ranitidine) and PPIs like Prilosec (omeprazole) with caution. There is a place for these drugs in the short term care of cats in gastric distress, no doubt. But ultimately the solution is to understand and cure or mitigate the underlying problem, rather than continue to mask it with a remedy that might be making your cat sicker in. Famotidine is a drug intended for humans -- better known as Pepcid -- that can be prescribed by vets. Its purpose is to prevent acid from forming in Socks' stomach. Pepcid or Pepcid AC (famotidine) is a class of medicine known as a histamine 2 blocker or histamine H₂ receptor antagonist. It works by inhibiting the production of stomach acid by blocking histamine receptors in the stomach that are responsible for triggering acid production. Famotidine can be dosed once or twice a day, and it can also be used in cats (although, again, it is not licensed for this species) If your dog is vomiting persistently, seek veterinary attention rather than dosing with famotidine. When using Famotidine, please consult your veterinarian with any other medications you are currently giving your pet, including supplements, as interaction could occur. Antacids, Metoclopramide , Sucralfate , Digoxin , or Ketoconazole may cause interactions with Famotidine. Risks and Side Effects of Famotidine Famotidine is typically considered safe for use in both cats and dogs. However, it nonetheless requires a veterinarian's prescription and guidance because of the potential side effects of the drug. Dosing of Pepcid AC for Cats. Medication must never ever be administered without first consulting your veterinarian. The typical dosage of famotidine administered is 0.25 to 0.5 mg per pound (0.5 to 1.0 mg/kg) every 12 to 24 hours. Overview of Famotidine (Pepcid®) for Canines and Felines. Famotidine, commonly known by the brand name Pepcid or Pepcid AC, is one of the most common over-the-counter medications used in dogs and cats. Pepcid is often referred to as Famotidine, which is its technical name. Famotidine is in the group of drugs known as histamine-2 blockers. It works by reducing the amount of stomach acid the stomach produces. This can prevent cats from vomiting, which is a common complaint of cat owners.