Blood Dyscrasias Attributed to Chloramphenicol

Reports of 576 published and unpublished cases of blood dyscrasias attributed to chloramphenicol have been studied. Pancytopenia (aplastic anaemia) was the commonest type of dyscrasia, accounting for about 70% of the cases; hypoplastic anaemia, agranulocytosis, thrombocytopenia and bone marrow inhibition made up the remainder. Among the patients with pancytopenia the outcome was apparently unrelated to the dose of chloramphenicol taken. However, the longer the interval which elapsed between the last dose of chloramphenicol and the appearance of the first sign of the blood dyscrasia, the greater the mortality: nearly all patients in whom this interval was longer than two months died. The two sexes were approximately equally affected, and cases occurred at all ages. In most cases the condition for which chloramphenicol had been prescribed seemed not to justify its use.