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Rifampin

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Rifampin, Rifadin, Rifamycin

  • See Also
  1. Active Tuberculosis
  2. Rifapentine
  3. Rifabutin
  • Indications
  1. FDA approved Conditions
    1. Active Tuberculosis
      1. As part of multi-drug regimen
    2. Neisseria Meningitidis Carrier
  2. Off-Label Conditions
    1. Leprosy
    2. Latent Tuberculosis
  • Contraindications
  1. Multiple Drug Interactions (especially lowering the serum levels of HIV Medications)
    1. Use only with caution with HIV Medications
  • Mechanism
  1. Semisynthetic Rifamycin derivative active against Mycobacteria
    1. Rifamycin is produced by Streptomyces mediterranei
  2. Rifamycins inhibit Bacterial DNA-dependent RNA Polymerase, blocking Bacterial RNA formation and transcription
  3. Drug resistance emerges rapidly
    1. Must be used with other antituberculous drugs
  • Dosing
  1. General
    1. No Renal Dosing adjustment needed
    2. Take oral doses on an empty Stomach
  2. Active Tuberculosis (as part of multi-drug regimen)
    1. Adult: 10 mg/kg/day (up to 600 mg) oral or IV daily
    2. Child: 10 to 20 mg/kg/day (up to 600 mg) oral or IV daily
  3. Neisseria Meningitidis Carrier
    1. Adult: 600 mg orally twice daily for 2 days
    2. Child: 10 mg/kg/day (up to 600 mg) orally twice daily for 2 days
      1. Use 5 mg/kg orally twice daily for 2 days IF age <1 month
  • Adverse Effects
  • General
  1. Drug-Induced Hepatitis (see hepatotoxicity risks below)
  2. Hyperbilirubinemia (transient)
  3. Nephritis or Acute Renal Failure
  4. Pruritus with or without Rash
  5. Thrombocytopenia
  6. Hemolytic Anemia
  7. Influenza-like Syndrome
    1. Associated with infrequent dosing
  8. Immune Reconstitution Inflammatory Syndrome (HIV patients)
  9. False Positive on drug screening for Opiates
  10. Body fluids become orange-brown tinged
    1. Urine
    2. Sweat
    3. Dentures
    4. 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
  8. HIV Infection
  9. Alcoholism
  • Safety
  1. Considered safe in Lactation
  2. Pregnancy
    1. Benefit typically outweighs risk
    2. Risk of Hemorrhagic Diathesis of the Newborn (Neonatal Vitamin K Deficiency)
    3. Give Vitamin K 10 mg IM to newborns
  • Drug Interactions
  1. Background
    1. Strong CYP450 enzyme inducer
    2. Increases other drug elimination, decreased levels and decreased efficacy
  2. 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
  3. Phenytoin (Dilantin)
  4. Oral Contraceptives (as well as Contraceptive Patch, Estrogen Ring)
    1. Consider alternative contraceptives (e.g. Depo Provera, IUD)
    2. Use barrier Contraception with Oral Contraceptives
  5. Ketoconazole
  6. Chloramphenicol
  7. Methadone
  8. Antiretroviral therapy (HIV)
    1. Protease Inhibitors (reduced drug level and efficacy)
    2. Nonnucleoside reverse transcriptase inhibitors (reduced drug level and efficacy)
  • Monitoring
  1. Complete Blood Count with Platelets
  2. Baseline Liver Function Tests
  3. Periodic LFT testing
    1. Liver Function Tests repeated 1-2 times monthly if risks for hepatotoxicity
    2. Stop if LFTs >3x baseline if sympomatic (>5x baseline if asymptomatic)
    3. Indications for Liver Function Test monitoring as above (see hepatotoxicity risks)
  4. Follow labs if abnormal or Active Tuberculosis develops
  • Resources
  1. Rifampin Capsule (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=26a2dbca-5090-4f6c-99ed-e11a70bb5af0
  • References
  1. (2019) Presc Lett, Resource #350309, Tuberculosis Treatment in Adults: FAQ
  2. (2012) Med Lett Drugs Ther 10(116): 29-36
  3. (2000) MMWR Recomm Rep 49(RR-6): 1-51 [PubMed]
  4. Hartman-Adams (2014) Am Fam Physician 89(11): 889-96 [PubMed]