791 THE INCIDENCE OF CHLORAMPHENICOL-INDUCED NEUTROPENIA John P. Blank

Abstract

The emergence of resistant organisms has increased the use of chloramphenicol. The hematologic toxicity of chloramphenicol is of two types: idiopathic and dose-related. In the dose-related toxicity, recent reviews emphasized the red cell changes and commented that neutropenia is rare. In order to assess clinically significant marrow toxicity, we reviewed charts of 56 patients treated with chloramphenicol between August 1975 and August 1980. These patients were treated for life-threatening infections, either meningitis or epiglotitis, believed to be caused by Hemophilus influenzae. All patients were treated with chloramphenicol at a dose of 100 mg/kg/d. There were 17 patients with epiglotitis, the mean age being 45 months (range 12-96 mos.). One patient in this group developed neutropenia (ANC<1500/mm3). Thirty-nine patients had meningitis, the mean age being 18.9 months (range 4-84 mos.). Of the 39, eight developed neutropenia. Of patients treated with chloramphenicol, 14 were less than 12 months of age and 42 were older than 12 months of age. The mean onset of neutropenia was 9 days into therapy. The incidence of neutropenia was 2/42 for those patients greater than one year old and 7/14 for those less than one year of age. We believe our data indicates that neutropenia is a clinically significant side effect, particularly in patients less than 12 months of age. Such findings emphasize the need to measure chloramphenicol levels in the child less than one year old.