USMLE

Dapsone

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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

Dapsone is an antibiotic that works by inhibiting bacterial folate synthesis. It is clinically used to treat leprosy and pneumocystis pneumonia. Side effects include hemolysis in patients with G6PD deficiency, rare bone marrow failure or agranulocytosis, as well as induction of methemoglobinemia by way of oxidizing the iron in heme to its Fe3+ form.

Key Points

  • Dapsone
    • Mechanism
      • Inhibits bacterial folate synthesis
        • Via competitive antagonism of para-aminobenzoic acid (PABA)
        • Similar to sulfonamides, but structurally distinct agent
    • Clinical Use
      • M. leprae (leprosy)
      • Pneumocystis jiroveci prophylaxis and treatment
    • Adverse Effects
      • Hemolysis in G6PD
        • Dapsone is an oxidizing agent and can increase oxidative stress on RBCs
      • Methemoglobinemia
        • Dapsone is an oxidizing agent
        • Oxidizes Fe2+ (ferrous iron) in heme to Fe3+ (ferric iron)
      • Agranulocytosis