Rifampin (Rifampicin)

Rifampin (Rifampicin) In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Binds to the beta subunit of RNA polymerase causing abortive initiation of RNA synthesis.

Uses of Rifampin (Rifampicin)

• Antimicrobial Activity: Rifampin exhibits a broad spectrum of antimicrobial activity. It is effective against various microorganisms, including:
  • Bacteria, particularly Gram-positives.
  • Chlamydia and Rickettsia.
  • Some protozoans.
  • Poxviruses.
• Susceptibility: Rifampin is active against bacteria such as Staphylococcus aureus, Staphylococcus pseudintermedius, and Mycobacteria. Gram-negative aerobic bacteria are usually resistant, but obligate anaerobes (both Gram-positive and Gram-negative) are typically susceptible.
• Veterinary Use: The exact indications for rifampin in small animal veterinary practice are not fully established. However, it has been suggested for various conditions, including:
  • Tuberculous and non-tuberculous mycobacterial infections.
  • Lesions in cats associated with Rhodococcus equi.
  • Chlamydiosis, ehrlichiosis, and bartonellosis management.
  • Treatment of staphylococcal pyoderma resistant to first-line treatments.
• Resistance Risk: Chromosomal mutations can readily lead to resistance when rifampin is used alone. Therefore, it is recommended to use rifampin in combination with other antimicrobial drugs to prevent the emergence of resistant organisms. Combinations like clarithromycin, enrofloxacin, clofaxamine, and doxycycline have been used with rifampin in the management of mycobacteriosis.
• Empirical Recommendations: The recommendations for rifampin use in these infections are often empirical, as controlled studies to determine its precise value are lacking. Further research is needed to establish its efficacy and optimal applications.

Dose of Rifampin (Rifampicin) in Dogs and Cats

Dogs, Cats:

• 10–15 mg/kg p.o. q24h.

Side Effects of Rifampin (Rifampicin) in Dogs and Cats

• In dogs, increases in serum levels of hepatic enzymes are commonly seen and this can progress to clinical hepatitis.
• Rifampin metabolites may colour urine, saliva and faeces orange-red.

Contraindications of Rifampin (Rifampicin) in Dogs and Cats

• Rifampin may be teratogenic at high doses and should not be administered to pregnant animals.
• It should not be administered to animals with liver disease.

Some Notes:

• Rifampin is a potent hepatic enzyme inducer and increases the rate of metabolism of other drugs in humans, including barbiturates, theophylline and itraconazole.
• Increased dosages of these drugs may be required if used in combination with
  rifampin.