Proportion of drug-related serious rare blood dyscrasias: estimates from the Berlin Case-Control Surveillance Study.

Drugs are an important cause of serious rare blood dyscrasias. To estimate the proportion of drug-related cases, we used data from the ongoing Berlin Case-Control Surveillance Study. The analysis included a total of 171 cases. The number of cases in which a drug etiology was assessed as at least "possible" was n = 29 (97%) for acute agranulocytosis, n = 4 (0.21%) for aplastic anemia, n = 8 (26%) for immune hemolytic anemia, n = 20 (25%) for immune thrombocytopenia, and n = 2 (20%) for thrombotic thrombocytopenic purpura/hemolytic uremic syndrome. Our analysis suggests that a substantial fraction of blood dyscrasias may be attributable to drug therapy.