Pepcid (Famotidine) For Cats – Uses, Dosage and Side Effects

Uses    Dosage    Administration    Side effects     Contraindications     Storage


Pepcid (famotidine) for cats

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. The medicine is not labelled for use in cats but is commonly prescribed by veterinarians as an extra-label medication.

As with any drugs, prescription or non-prescription, only administer if your cat’s veterinarian has recommended you do so. It is never safe to administer medication without consultation with a veterinarian who is familiar with the cat’s medical history.


In veterinary medicine, Pepcid is used in the prevention or treatment of the following conditions:

Stomach (gastric) ulcers or intestinal ulcers: Build up of toxins in cats with kidney disease, stressed cats, drug-induced or cats with stomach cancer, Helicobacter infection, ingestion of toxins),

Gastritis (inflammation of the stomach): Dietary indiscretion, ingestion of toxins, foreign bodies, infection.

Esophagitis (inflammation of the esophagus):  Reflux, certain medications, excessive vomiting, thermal injury, hernia), reflux and cancer.

Mast cell tumours: These tumours which originate from mast cells produce large amounts of histamine.

By blocking the secretion of stomach acid, the cat’s gastrointestinal tract has time to heal from ulcers or inflammation.


Dosage varies from cat to cat, underlying health problems must be taken into consideration when deciding the safe dosage for cats. The typical dose of Pepcid is 0.25 to 0.5 mg per pound or 0.5 to 1.0 mg/kg every 12 to 24 hours.


Cats receive Pepcid either via injection, tablet or suspension.

Administer on an empty stomach as giving it with a meal will cause stomach acid secretion before the medication has had time to work.

Always follow your veterinarian’s instructions and avoid the following:

  • Giving a larger dose than prescribed
  • Administering Pepcid more often than prescribed
  • Skipping a dose

If your cat does miss a dose, symptoms may return, so it is important to remember to give the cat the medication, as directed.

What happens if I miss a dose? 

Administer as soon as possible, however, if it is close to the time for your cat’s next dose, do not administer, wait until the scheduled time. Never exceed the total stated dose.

If your cat does accidentally receive a double dose, contact your veterinarian for advice.

Drug interactions:

Separate doses by two hours between Pepcid and the following medications:

  • Antacids
  • Metoclopramide
  • Sucralfate
  • Digoxin
  • Ketoconazole


Do not give to cats with a known hypersensitivity to the drug.

Use with caution in cats with cardiac disease, impaired liver or kidney function and only under the close supervision of a veterinarian.

Side effects: 

There is not much data on side effects of Pepcid in cats, side effects reported in people are rare, but can include:

  • Vomiting
  • Diarrhea
  • Dry mouth
  • Increased thirst
  • Lethargy
  • Bone marrow suppression
  • Loss of appetite
  • Jaundice (yellow mucous membranes)
  • Hypersensitivity (swelling, itching, rash, anaphylaxis)

Contact your veterinarian if your cat develops side effects.

How to store Pepcid:

Store in a cool, dry place, away from children and pets. It is always safest to keep human and pet medication in separate containers to avoid mixing medications.

Similar medications:

One trial in humans found that the duration of action of famotidine was 30 percent longer than that of either cimetidine or ranitidine. Famotidine was nine times more potent than ranitidine and 32 times more potent than cimetidine.