USMLE

Metronidazole

1,252 views
Antibiotics / Antiparasitics
  1. Penicillin Overview
  2. Penicillinase-Sensitive vs. Penicillinase-Resistant Penicillins
  3. Anti-Pseudomonal Penicillins
  4. Cephalosporins Overview
  5. 1st Generation Cephalosporins
  6. 2nd Generation Cephalosporins
  7. 3rd Generation Cephalosporins
  8. 4th Generation Cephalosporins
  9. 5th Generation Cephalosporins
  10. Carbapenems
  11. Monobactams (Aztreonam)
  12. Vancomycin
  13. Aminoglycosides
  14. Tetracyclines
  15. Tigecycline
  16. Chloramphenicol
  17. Clindamycin
  18. Linezolid
  19. Macrolides
  20. Polymyxins
  21. Sulfonamides
  22. Dapsone
  23. Trimethoprim
  24. Fluoroquinolones
  25. Daptomycin
  26. Metronidazole
  27. Rifamycins (Rifampin, Rifabutin)
  28. Isoniazid
  29. Pyrazinamide
  30. Ethambutol
  31. Chloroquine

Summary

Metronidazole is an antibiotic medication used to treat a wide variety of parasitic and bacterial infections. It works by creating free radicals, which bind to and damage DNA in pathogens.  Adverse effects of metronidazole include a disulfiram-like reaction to alcohol, as well as a metallic taste in the mouth.

Key Points

  • Metronidazole
    • Mechanism
      • Forms toxic free radicals in the bacterial cell wall that damage DNA
      • Bactericidal, antiprotozoal
    • Clinical Use
      • Giardia
      • Entamoeba histolytica
      • Trichomonas vaginalis
      • Gardnerella vaginalis
      • Anaerobes (Bacteroides, C. difficile)
        • Used to treat anaerobic infections below the diaphragm (clindamycin used above)
      • H. pylori (in patients with penicillin allergies)
    • Adverse Effects
      • Disulfiram-like reaction with alcohol
        • Due to inhibition of acetaldehyde dehydrogenase, a toxic buildup of acetaldehyde occurs
        • Presents with severe flushing, tachycardia, hypotension
      • Metallic taste in mouth
      • GI upset (nausea, vomiting, abdominal pain)
      • Neuropathy (paresthesias, dizziness)
      • Headache