Serum concentrations and adverse effects of chloramphenicol in pediatric patients

Chloramphenicol serum concentration is often monitored to assure efficacy and prevent toxicity. We studied the relationship between steady-state chloramphenicol serum concentration and hematologic adverse effects in 45 pediatric patients. The mean peak serum concentration of chloramphenicol in patients with and without toxicity were not different (p less than 0.01): 22.7 micrograms/ml in neutropenic patients versus 23.1 micrograms/ml in those without neutropenia; 18.2 micrograms/ml in leukopenic patients versus 23.3 micrograms/ml in those without leukopenia; 22.2 micrograms/ml in patients with eosinophilia versus 23.9 micrograms/ml in those without eosinophilia; 23.7 micrograms/ml in patients with anemia versus 22.1 micrograms/ml in those without anemia. None of the patients developed thrombocytopenia. These data clearly demonstrate that chloramphenicol toxicity may not be predictable by serum concentration in pediatric patients receiving therapeutic doses of chloramphenicol succinate. Thus, frequent monitoring of chloramphenicol serum concentration does not appear warranted unless a patient appears unresponsive to a therapeutic dose or has received an excessive dose.