Major Uses

Rifampin is a semi-synthetic antibiotic medication primarily used to treat infections caused by certain types of bacteria and fungi. It is a derivative of rifamycin B and eliminates infections by inhibiting protein synthesis in susceptible organisms, resulting in death. The drug is commonly used in the treatment of infections caused by Staphylococcus, Mycobacterium, Rhodococcus, Aspergillus, and Histoplasma. It is not effective against parasites, molds, or viruses.

Rifampin is often used in conjunction with flucytosine and amphotericin B. The drug is not approved by the Food and Drug Administration for use in animals, but it is commonly prescribed as an extra-label drug for this purpose.

Common Precautions

Although side effects associated with proper use of rifampin are rare, some animals may develop loose stools or diarrhea from the drug. Other possible side effects include rash, anemia, loss of appetite, and vomiting. Some animals may develop orange or red-orange urine and other bodily fluids while undergoing treatment with rifampin. This side effect is not harmful and will disappear when treatment is finished.

Rifampin should be used cautiously in animals suffering from liver disease. Because the drug has not been extensively studied in pregnant animals, it should only be used during pregnancy when absolutely necessary.

Rifampin is known to interact with other medications and supplements, including vitamin B12, barbiturates, corticosteroids, anticoagulants, quinidine, benzodiazepines, propranolol, chloramphenicol, ketoconazole, and dapsone.

Rifampin 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.


Rifampin should be stored at room temperature, in a tightly-sealed container, and out of the reach of pets and children. The tablets should be kept away from heat and direct sunlight and should not be stored in the bathroom or above the kitchen sink. Liquid forms of this medication may require refrigeration.


Rifampin is available as tablets in strengths of 150 mg and 300 mg. A powdered form of the medication is also available for the purpose of aqueous reconstitution and injection.

In most cases, the dose of rifampin is 5 to 10 mg/lb (10 to 20 mg/kg) by mouth, three times daily. The drug should be given on an empty stomach.

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 rifampin is missed, it should be administered 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 given 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.