Medicine & USMLE


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


Daptomycin is an antibiotic that kills bacterial cells by disrupting the cell membrane. Daptomycin is primarily active against gram-positive bacteria, and is clinically used to treat complicated infections with drug resistant bacteria, like MRSA or VRE infections. However, it is important to note that daptomycin is not effective in treating pneumonia, as the drug is inactivated by alveolar surfactant. The main adverse effect of daptomycin is myopathy, which can rarely present as rhabdomyolysis.

Key Points

  • Daptomycin
    • Note: This is a distinct drug from dapsone
    • Mechanism
      • Disrupts cell membranes by creating transmembrane channels
        • Causes intracellular leakage and membrane depolarization
        • Ultimately inhibits DNA, RNA, and protein synthesis, leading to bacterial death
    • Clinical Use
      • Gram-positive cocci
        • S. aureus skin infections (esp. MRSA), bacteremia, endocarditis
        • VRE
      • Not used for pneumonia
        • Avidly binds to and is inactivated by alveolar surfactant
    • Adverse Effects
      • Myopathy, Rhabdomyolysis
        • Creatinine kinase (CK) levels may rise due to release from skeletal muscle