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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, by doing so, the cat’s gastrointestinal tract has time to heal from ulcers or inflammation.
Pepcid 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, it is never safe to administer medication without consultation with a veterinarian who is familiar with the cat’s medical history. Therefore, only administer if your cat’s veterinarian has recommended you do so.
Pepcid is used in veterinary medicine to treat or prevent the following:
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.
Mast cell tumours: These tumours which originate from mast cells produce large amounts of histamine.
Dosage varies from cat to cat; underlying health problems must be taken into consideration when deciding the safe dose. A typical dose regime is 0.25 to 0.5 mg per pound or 0.5 to 1.0 mg/kg every 12 to 24 hours.
Pepcid is available via injection, suspension or tablet.
Administer on an empty stomach as feeding the cat 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 can 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.
Separate doses by two hours between Pepcid and the following medications:
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.
There is not much data on side effects of Pepcid in cats, side effects reported in people are rare, but can include:
- Dry mouth
- Increased thirst
- Bone marrow suppression
- Loss of appetite
- Jaundice (yellow mucous membranes)
- Hypersensitivity (swelling, itching, rash, anaphylaxis)
Contact your veterinarian if your cat develops side effects.
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.
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.