Chloramphenicol binds to the 50S subunit of ribosomes and inhibits protein synthesis. While active against S pneumoniae, H influenzae, and Neisseria meningitidis, it is used minimally because of its toxicity and the availability of alternative agents. Chloramphenicol is active against certain rickettsiae.
Pharmacokinetics & Administration
Chloramphenicol is widely distributed in tissues, including the
eye and cerebrospinal fluid. Chloramphenicol is metabolized in the
liver, and < 10% is excreted unchanged in the urine.
Thus, no dosage adjustment is needed in kidney disease. Patients
with liver disease may accumulate the drug, and levels should be
Chloramphenicol is an occasional alternative to more standard
therapy for (1) meningococcal, H influenzae, or
pneumococcal infections of the central nervous system; (2) anaerobic
or mixed infections in the central nervous system, eg, brain abscess;
(3) as an alternative to tetracyclines in rickettsial infections,
especially in pregnant women, in whom tetracycline is contraindicated.
Chloramphenicol in excess of 50 mg/kg/d regularly
causes reversible disturbances in red cell maturation within 12
weeks. In contrast, it is also associated with an irreversible aplastic
anemia in 1:40,0001:25,000 courses of chloramphenicol