Pharm 101: Chloramphenicol

Class

Antibiotic

Pharmacodynamics
  • Bacteriostatic
  • Inhibits protein synthesis:
    • Binds reversibly to 50S subunit of the bacterial ribosome
    • Inhibits peptide bone formation
Pharmacokinetics
  • IV administration of prodrug
  • Widely distributed to all tissues
    • CNS/CSF concentrations equal to serum
  • Metabolism to inactive metabolites by:
    • Conjugation with glucuronic acid (hepatic)
    • Reduction to inactive aryl amines
  • Renal excretion of active (10%) and inactive drug
Antimicrobial activity
  • Broad spectrum antibiotic active against both gram-positive and gram-negative organisms
    • H influenza, Neisseria are highly susceptible
  • Also active against rickettsiae
  • Does not treat chlamydiae
  • Clinical uses:
    • Rarely used
    • Rickettsial infections
    • Bacterial meningitis if penicillin allergic
Adverse effects
  • GI upset
  • Bone marrow suppression
    • Dose-related reversible suppression of RBC production
  • Gray baby syndrome (flaccidity and shock) in newborn infants
    • Lack effective glucuronic acid conjugation mechanism
    • Require dose reduction
  • CYP enzyme inhibitor
    • Half-life of phenytoin and warfarin prolonged
Precautions/contraindications
  • Caution in hepatic and renal insufficiency
  • Dose reduction in newborns and premature infants
References
Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

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