Major Uses

Ranitidine is an anti-ulcer drug that belongs to the histamine receptor-2 blocker class of medications. It works by blocking the receptor that stimulates secretion of stomach acid, thereby creating a more favorable stomach pH. The drug is primarily used to prevent and treat intestinal and stomach ulcers, but it may also be used to treat gastritis associated with kidney failure. Ranitidine is also helpful when managing acid reflux disease and may help animals diagnosed with mast cell tumors.

Ranitidine is not approved by the Food and Drug Administration for use in animals, but it is prescribed legally as an extra-label drug by veterinarians. The drug is mainly used in cats and dogs.

Common Precautions

Side effects associated with proper use of ranitidine are rare. Some animals may experience a worsening of existing heart rhythm problems, and mental confusion and headaches have been reported in human patients.

Ranitidine is not for use in animals with kidney or liver disease. Although ranitidine appears safe for use during pregnancy, it should be avoided in lactating animals. The drug may cause urine dipstick tests to show falsely positive for protein.

Ranitidine may interact with certain other supplements and medications, including propranolol, theophylline, ketoconazole, itraconazole, and some antacids.

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


Ranitidine should be stored in its original packaging, in a tightly closed container, and out of the reach of children and animals. It should be kept at room temperature.


Ranitidine is available in tablet form in strengths of 75 mg, 150 mg, and 300 mg. It is also available as granules, an oral syrup, an injectable, and as an effervescent tablet.

The typical dose of ranitidine in dogs and cats is 0.25 to 1 mg/lb (0.5 to 2 mg/kg), every 8 to 12 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 ranitidine is missed, it should be taken as soon as possible. If it is almost time for the next dose, the missed dose should be skipped and the normal schedule resumed. Two doses of this medication should not be taken 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.