Famotidine is an acid-reducing medication used in cats to treat stomach ulcers, acid reflux, and inflammation of the stomach lining. Sold under the brand name Pepcid, it’s one of the most commonly prescribed over-the-counter human drugs repurposed for feline use. Veterinarians reach for it whenever a cat’s stomach is producing too much acid, whether from stress, kidney disease, or an irritated esophagus.
How Famotidine Works in Cats
Your cat’s stomach lining contains cells that produce hydrochloric acid to break down food. These cells have specific receptors that respond to histamine, a chemical signal that tells them to ramp up acid production. Famotidine works by blocking those receptors, called H2 receptors, on the acid-producing cells. With the receptors blocked, the cells get fewer signals to make acid, and overall stomach acid levels drop.
This is different from antihistamines used for allergies, which block a separate type of histamine receptor. Famotidine targets only the receptors involved in digestion, so it won’t help with itching or sneezing.
Conditions Vets Prescribe It For
The most common reasons a vet will prescribe famotidine for your cat include:
- Gastrointestinal ulcers: Open sores in the stomach or upper intestine that are worsened by acid exposure.
- Gastritis: General inflammation of the stomach lining, often triggered by stress, medication side effects, or toxin ingestion.
- Acid reflux: Stomach acid flowing backward into the esophagus, causing irritation and discomfort.
- Esophagitis: Inflammation of the esophagus, sometimes seen after anesthesia when stomach contents reflux upward while a cat is unconscious.
You might also see famotidine prescribed as a short-term supportive treatment when your cat is nauseous, vomiting frequently, or refusing food. Reducing stomach acid can ease the discomfort that makes a sick cat reluctant to eat.
Famotidine and Kidney Disease
One of the most important uses of famotidine in cats involves chronic kidney disease, a condition that becomes increasingly common as cats age. When the kidneys lose function, waste products like urea build up in the bloodstream. These toxins irritate the stomach lining and stimulate excess acid production, a condition called uremic gastritis. Cats with uremic gastritis often vomit, lose their appetite, and develop ulcers along the digestive tract.
Famotidine helps by blocking the excess acid that gastrin (a hormone elevated in kidney disease) triggers. For cats in a uremic crisis, where toxin levels spike and symptoms become severe, famotidine is a standard part of the treatment plan alongside fluid therapy and other supportive care. Many cats with chronic kidney disease take it on an ongoing basis to keep nausea and stomach irritation under control, which helps them maintain their appetite and body weight.
How It’s Given
Famotidine comes in tablet form and is typically given once or twice daily, depending on the severity of your cat’s condition. Most cats receive it by mouth, though injectable forms exist for hospitalized patients. It can be given with or without food.
If your vet prescribes famotidine, they’ll determine the appropriate dose based on your cat’s weight and specific condition. Don’t use human Pepcid from your medicine cabinet without veterinary guidance, because the tablet strengths made for people are often far larger than what a cat needs, and some formulations contain additional ingredients (like calcium carbonate in Pepcid Complete) that change how the drug works.
Side Effects and Safety
Famotidine is considered one of the safer medications used in veterinary medicine. Most cats tolerate it well, and serious side effects are uncommon at prescribed doses. When side effects do occur, they tend to be mild: decreased appetite, drowsiness, or occasional digestive upset like vomiting or diarrhea. These usually resolve once the medication is stopped or the dose is adjusted.
One thing worth knowing is that famotidine can affect how well your cat absorbs certain other medications. Because it reduces stomach acid, drugs that need an acidic environment to dissolve properly may not be absorbed as effectively. If your cat takes multiple medications, your vet will account for this and may stagger the timing of different drugs.
What Famotidine Won’t Do
Famotidine addresses acid production, but it doesn’t treat the underlying cause of your cat’s symptoms. A cat vomiting because of a foreign body, inflammatory bowel disease, or a tumor won’t improve with famotidine alone. It’s a supportive medication, meaning it manages one piece of the problem while other treatments or diagnostics address the root cause. If your cat has been vomiting or refusing food for more than a day or two, the priority is figuring out why, not simply suppressing acid.
It’s also worth noting that veterinary specialists have raised questions in recent years about whether acid-reducing drugs are overprescribed in cats, particularly for conditions where excess acid isn’t actually the main issue. For straightforward acid-related problems like ulcers, reflux, and uremic gastritis, the evidence supporting famotidine is solid. But it isn’t a cure-all for every stomach complaint a cat might have.