II. Background
- Semisynthetic derivative of rifamycin
- Rifamycin produced by Streptomyces mediterranei
- Drug resistance emerges rapidly
- Must be used with other antituberculous drugs
III. Indications
IV. Contraindications
- Multiple Drug Interactions (especially lowering the serum levels of HIV Medications)
- Use only with caution with HIV Medications
V. Dosing
- Adult: 600 mg/day PO or IV
- Pediatric: 10-20 mg/kg/day (Max 600/day)
- No Renal Dosing adjustment needed
VI. Adverse Effects
- Drug-Induced Hepatitis (see hepatotoxicity risks below)
- Hyperbilirubinemia (transient)
- Nephritis or Acute Renal Failure
- Pruritus with or without Rash
- Thrombocytopenia
- Hemolytic Anemia
-
Influenza-like Syndrome
- Associated with infrequent dosing
- Immune Reconstitution Inflammatory Syndrome (HIV patients)
- False Positive on drug screening for Opiates
- Body fluids become orange tinged
- Urine
- Sweat
- Tears (may discolor Contact Lenses)
VII. Adverse Effects: Hepatotoxicity - Risk Factors
- Slow acetylators
- Hepatitis C
- Hepatitis B
- Concurrent Hepatotoxin exposure
- Age over 50 years
- Pregnancy and postpartum (within 3 months)
- Malnutrition
VIII. Drug Interactions
- Background
- Strong CYP450 enzyme inducer
- Increases other drug elimination, decreased levels and decreased efficacy
-
Warfarin (Coumadin)
- Obtain INR weekly until stable and then for at least one month after stopping Rifampin
- Warfarin dose may need to increase up to 5x while on Rifampin
- (2014) Presc lett 21(8): 47
- Phenytoin (Dilantin)
-
Oral Contraceptives (as well as Contraceptive Patch, Estrogen Ring)
- Consider alternative contraceptives (e.g. Depo Provera, IUD)
- Ketoconazole
- Chloramphenicol
- Methadone
-
Antiretroviral therapy (HIV)
- Protease Inhibitors (reduced drug level and efficacy)
- Nonnucleoside reverse transcriptase inhibitors (reduced drug level and efficacy)
IX. Monitoring
- Complete Blood Count
- Baseline Liver Function Tests
- Follow labs if abnormal or Active Tuberculosis develops
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Related Studies
rifampin (on 12/21/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
RIFAMPIN 150 MG CAPSULE | Generic | $0.83 each |
RIFAMPIN 300 MG CAPSULE | Generic | $0.73 each |