Drug-induced thrombocytopenia: clinical data on 309 cases and the effect of corticosteroid therapy

To analyse the clinical picture and the course of thrombocytopenia induced by non-cytotoxic drugs, and to evaluate a possible therapeutic effect of corticosteroids.

A retrospective analysis of 309 well-documented cases of drug-induced thrombocytopenia was performed. Data sources were reports from the files of the Danish Committee on Adverse Drug Reactions and discharge summaries.

The median length of exposure to the offending drug, before development of thrombocytopenia, was 21 days. The median nadir platelet count was 11 x 10(9).l-1, and 74% of the patients had clinical haemorrhage. Bone marrow examination generally showed hyperplastic reactive changes and a variable number of megakaryocytes. Slight leucopenia was present in 6% of the patients and 16% were anaemic. Complete recovery was seen in 87% of cases, with a median recovery rate of 8 days. The standard treatment was corticosteroids, which were administered in 53% of the cases. No difference in recovery between corticosteroid-treated and untreated patients was observed. No other clinical parameter affected the recovery rate. The mortality rate due to haemorrhage was 3.6%.

Thrombocytopenia induced by non-cytotoxic drugs is characterised by heterogeneous clinical picture and recovery is generally rapid. Although corticosteroids seem inefficient, we still recommend that severe symptomatic cases of drug-induced thrombocytopenia are treated as idiopathic thrombocytopenic purpura due to the difficult initial differentiation between the two conditions.