Major Uses

Famotidine is a type of antihistamine that binds to histamine receptors in the stomach to stop symptoms such as nausea and vomiting. These receptors, called H2 receptors, are involved in gastric acid production and play a role in ulcer formation when overstimulated.

Famotidine is an over-the-counter medication that is not approved for use in pets but is commonly used in animals to treat conditions where stomach irritation and ulceration are concerns. It is very useful in the treatment of Helicobacter infections, canine parvovirus, toxin ingestion, inflammatory bowel disease, and other conditions. It may also be beneficial when treating mast cell tumors, inflammation associated with kidney failure, and acid reflux disease. This drug works for about 24 hours after administration.

Common Precautions

Side effects associated with use of famotidine are minimal. Some heart rhythm problems have been reported in animals with existing heart rhythm issues. In humans, side effects include vomiting, diarrhea, loss of appetite, dry mouth, and headache. There is potential for these side effects to occur in animals.

Famotidine is considered safe for use during pregnancy. However, lactating animals should not take this medication. Animals with liver or kidney disease may need to take a lower dose of famotidine. Additionally, some drugs, such as itraconazole and ketoconazole, are better absorbed when adequate levels of stomach acid are present. The prescribed dose of these medications may require adjusting when taken along with famotidine. Famotidine may also interact with digoxin.

Famotidine should not be used in animals with a known allergy or hypersensitivity to the drug. Any suspected or known overdose should be reported to a veterinarian immediately.


Famotidine should be stored in its original packaging, away from excessive heat, and out of the reach of animals and children.


Famotidine is available as 10 mg, 20 mg, and 40 mg tablets and in injectable form.

A typical dose of famotidine is 0.25 to 0.5 mg per pound (0.5 to 1.0 mg/kg) administered every 12 to 24 hours. Doses may vary in different species, when the drug is given by a different route or concurrently with other medications, and with regards to a patient's age, breed, and health status. A veterinarian's dosing instructions and/or those printed on the medication label should be followed closely.

If a dose of famotidine is skipped, the missed dose should be administered as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the regular dosing schedule should be resumed. It is important not to give pets two doses at once.

This information is for general reference only and should not be used for the diagnosis or treatment of any condition of your pet. It's intended as a general reference, this information may not include all possible uses, precautions, directions, reactions (including allergic), drug interactions, or withdrawal times. Always consult your local veterinarian and have your pet examined for any advice concerning the diagnosis and treatment of your pet, including which products and doses are most appropriate. Any trademarks are the property of their respective owners. VetDepot is not a pharmacy. All prescription products are dispensed by our Pharmacy Partner. Article last updated 2/2014.