Pharm

Rifampin

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Rifampin

  • Background
  1. Semisynthetic derivative of rifamycin
  2. Rifamycin produced by Streptomyces mediterranei
  3. Drug resistance emerges rapidly
    1. Must be used with other antituberculous drugs
  • Indications
  1. Multi-drug Tuberculosis Treatment regimen
  • Contraindications
  1. Multiple Drug Interactions (especially lowering the serum levels of HIV Medications)
    1. Use only with caution with HIV Medications
  • Dosing
  1. Adult: 600 mg/day PO or IV
  2. Pediatric: 10-20 mg/kg/day (Max 600/day)
  • Adverse Effects
  1. Nephritis or Acute Renal Failure
  2. Pruritus with or without Rash
  3. Thrombocytopenia and Hemolytic Anemia
  4. Influenza-like Syndrome
    1. Associated with infrequent dosing
  5. Body fluids become orange tinged
    1. Urine
    2. Sweat
    3. Tears (may discolor Contact Lenses)
  • Adverse Effects
  • Hepatotoxicity - Risk Factors
  1. Slow acetylators
  2. Hepatitis C
  3. Hepatitis B
  4. Concurrent Hepatotoxin exposure
  5. Age over 50 years
  6. Pregnancy and postpartum (within 3 months)
  7. Malnutrition
  • Drug Interactions
  • Increases other drug elimination, decreased levels and decreased efficacy (Strong CYP450 enzyme inducer)
  1. Warfarin (Coumadin)
    1. Obtain INR weekly until stable and then for at least one month after stopping Rifampin
    2. Warfarin dose may need to increase up to 5x while on Rifampin
    3. (2014) Presc lett 21(8): 47
  2. Phenytoin (Dilantin)
  3. Oral Contraceptives (as well as Contraceptive Patch, Estrogen Ring)
    1. Consider alternative contraceptives (e.g. Depo Provera, IUD)
  4. Antiretrovirals
  5. Ketoconazole
  6. Chloramphenicol
  7. Methadone
  8. Protease Inhibitors (reduced drug level and efficacy)
  9. Nonnucleoside reverse transcriptase inhibitors (reduced drug level and efficacy)
  • Monitoring
  1. Complete Blood Count
  2. Baseline Liver Function Tests
  3. Follow labs if abnormal or Active Tuberculosis develops