USMLE

Linezolid

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Antibiotics / Antiparasitics
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  2. Penicillinase-Sensitive vs. Penicillinase-Resistant Penicillins
  3. Anti-Pseudomonal Penicillins
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  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
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  27. Rifamycins (Rifampin, Rifabutin)
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  31. Chloroquine

Summary

Linezolid is a last-resort antibiotic used to treat bacterial infections resistant to other antibiotics. Linezolid works by binding to the 50S ribosomal subunit of bacteria to prevent bacterial protein synthesis. Adverse effects include bone marrow suppression, neuropathy, and serotonin syndrome.

Key Points

  • Linezolid
    • Mechanism
      • Binds to 50S subunit of bacterial ribosomes
        • Prevents formation of initiation complex and inhibits bacterial protein synthesis
    • Clinical Use
      • Gram-positive species including MRSA and VRE
      • Usually used as a last-resort for multi-drug resistant infections
    • Adverse Effects
      • Bone marrow suppression
        • Anemia, leukopenia, and thrombocytopenia are common
      • Neuropathy
        • Includes optic neuritis and peripheral neuropathy
      • Serotonin syndrome
        • Due to partial monoamine oxidase (MAO) inhibition
        • Risk is compounded with use of other serotonergic drugs (e.g. MAOIs, SSRIs)
    • Resistance
      • Point mutation of ribosomal RNA changes 50S binding site