Medicine & USMLE


Anti-Infective Drugs
  1. Vancomycin
  2. Metronidazole
  3. Penicillins
  4. Cephalosporins
  5. Macrolides
  6. Fluoroquinolones
  7. Aminoglycosides
  8. Tetracyclines
  9. Sulfonamides
  10. Rifampin
  11. Isoniazid
  12. Ethambutol
  13. Chloroquine
  14. Acyclovir
  15. Oseltamivir
  16. Azoles
  17. Nystatin
  18. Amphotericin B


Rifampin is an antitubercular medication, meaning it is used to treat tuberculosis. It may cause bodily fluids to turn a reddish-orange color, but this is a normal and harmless side effect. It can also cause liver damage, so monitor for signs of hepatotoxicity like jaundice and elevated liver enzymes. Rifampin can decrease the effectiveness of oral contraceptives, so women should be taught to use additional contraception while taking rifampin.

Key Points

  • Rifampin (Rifadin)
    • Mechanism
      • Antitubercular
        • Antimycobacterial 
          • Interference with cellular metabolism - inhibits bacterial RNA synthesis
          • Binds to DNA-dependent RNA polymerase and blocks RNA transcription
        • Used with at least 1 other antitubercular medication
    • Clinical Use
      • Tuberculosis
        • Effectiveness of treatment is determined by 3 negative sputum cultures and a chest X-ray
    • Side Effects and Adverse Reactions
      • Red/Orange body fluids
        • May cause harmless discoloration of urine, saliva, sweat, and tears.
        • This side effect is expected, no need to report to the provider.
        • Soft contact lens can become permanently discolored → wear glasses instead of contacts
      • Hepatotoxicity
        • Watch for signs of hepatitis - jaundice, weakness/fatigue, nausea/vomiting, sore throat, fever, unusual bleeding
        • Do not take with other hepatotoxic drugs (acetaminophen, alcohol, etc.)
        • Monitor liver function enzymes (AST, ALT)
        • Contraindicated in patients with hepatic dysfunction and alcoholism
      • Can decrease effectiveness of oral contraceptives
        • Women taking rifampin for anti-tubercular therapy should switch to non-hormonal methods of birth control
      • GI distress - heartburn, nausea/vomiting, diarrhea, colitis
      • Vision changes
      • Increased uric acid levels
      • Blood dyscrasias