Rifampin
Also known as: Rifadin, Rimactane
- **Harmless Discoloration:** This medication will likely cause your pet's urine, tears, sweat, and saliva to turn a red-orange color. This is completely normal and harmless, but be aware that it can permanently stain fabrics, carpets, or light-colored fur. - **Administration:** For the best absorption, give this medication on an empty stomach. If it causes stomach upset, you may give it with a small treat. - **Combination Therapy:** Rifampin is almost always prescribed alongside another antibiotic. It is critical to give both medications exactly as directed and finish the entire course. Never stop early, as bacteria can quickly become resistant to rifampin. - **What to Watch For:** Contact your veterinarian if you notice severe diarrhea, loss of appetite, extreme lethargy, or yellowing of the eyes/gums (jaundice), as these could be signs of liver stress.
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
What it is used for
- Susceptible infections (e.g., mycobacteriosis, Rhodococcus equi, chlamydiosis, bartonellosis)
- Treatment of Rhodococcus equi (C. equi) infections in foals
- Treatment of Rhodococcus equi (C. equi) infections in foals
- Treatment of proliferative enteropathy caused by Lawsonia intracellularis in foals
- Treatment of mycobacteriosis
- Combination therapy of atypical Mycobacteria infections; treatment of resistant Staph endocarditis
- Alternate treatment for scarred pyogranulomatous pyoderma
- Actinomycosis
- Susceptible infections (e.g., mycobacteriosis, resistant staphylococcal pyoderma, ehrlichiosis)
How it is given
Possible side effects
- Red-orange discoloration of bodily fluids (urine, tears, sweat, saliva)
- Gastrointestinal distress (anorexia, vomiting, diarrhea)
- Elevated liver enzymes and potential hepatotoxicity
- Rashes and erythema (noted in cats and humans)
- In horses (especially with macrolides): mild diarrhea to severe enterocolitis, hyperthermia, and acute respiratory distress
- Intravenous use in horses (rare): CNS depression, sweating, hemolysis, anorexia
- Elevated serum hepatic enzymes
- Clinical hepatitis
- Orange-red discoloration of urine, saliva, tears, and feces
- Gastrointestinal upset (anorexia, vomiting, diarrhea)
Cautions & contraindications
- Hypersensitivity to rifampin or other rifamycins
- Use with extreme caution in patients with preexisting hepatic dysfunction
- Pregnancy (teratogenic at high doses)
- Pre-existing liver disease or hepatic dysfunction
- Use with caution in patients with preexisting hepatic dysfunction; dosage reduction may be necessary. **Never use as a monotherapy** due to the rapid development of bacterial resistance. Rifampin is a potent inducer of hepatic microsomal enzymes, which can significantly alter the metabolism of concurrently administered drugs. It is excreted in maternal milk; use with caution in nursing veterinary patients. May cause false-positive BSP (bromosulfophthalein) test results and interfere with microbiologic assays of serum folate and vitamin B12.
Drug interactions
- Fluoroquinolones: In vitro antagonism has been reported; concurrent use should be avoided.
- Barbiturates: Decreased serum levels and shortened half-life due to hepatic microsomal enzyme induction by rifampin.
- Benzodiazepines (e.g., diazepam): Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Chloramphenicol: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Corticosteroids: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Dapsone: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Ketoconazole: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Propranolol: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Quinidine: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
- Warfarin: Decreased serum levels and shortened half-life due to hepatic enzyme induction.
Frequently asked questions
What is Rifampin used for in pets?
- **Harmless Discoloration:** This medication will likely cause your pet's urine, tears, sweat, and saliva to turn a red-orange color. This is completely normal and harmless, but be aware that it can permanently stain fabrics, carpets, or light-colored fur. - **Administration:** For the best absorption, give this medication on an empty stomach. If it causes stomach upset, you may give it with a small treat. - **Combination Therapy:** Rifampin is almost always prescribed alongside another antibiotic. It is critical to give both medications exactly as directed and finish the entire course. Never stop early, as bacteria can quickly become resistant to rifampin. - **What to Watch For:** Contact your veterinarian if you notice severe diarrhea, loss of appetite, extreme lethargy, or yellowing of the eyes/gums (jaundice), as these could be signs of liver stress.
Is Rifampin safe for my pet?
Dosage must be set by your veterinarian for your specific pet. Never give human medication or another pet’s prescription without veterinary guidance.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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