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 (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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