Chloramphenicol: new perspectives on an old drug

Chloramphenicol is an old antibiotic being used with increasing frequency in serious childhood infections largely due to the emergence of ampicillin-resistant Hemophilus influenzae type b. Because of this renewed popularity and the recent availability of accurate analytical techniques for measurement of chloramphenicol, there have been many recent articles examining the pharmacokinetics of chloramphenicol and its two major prodrug esters, chloramphenicol succinate and chloramphenicol palmitate. New data from these studies include the incomplete bioavailability of chloramphenicol succinate, the possible superior bioavailability of chloramphenicol palmitate vs. chloramphenicol succinate, and the wide interpatient variability in chloramphenicol clearance. These observations, coupled with the known serious hematologic toxicity (reversible bone marrow suppression or irreversible aplastic anemia) and metabolic toxicity (gray baby syndrome) associated with chloramphenicol use, require that initial antibiotic doses be selected by age and be carefully individualized by measurement of peak serum chloramphenicol concentrations.