Dealing with drug-induced thrombocytopenia.

Unpredictable and potentially life-threatening, immune thrombocytopenia can occur with any drug, at times even after long, uneventful use. Heparin is the most common cause; although the fall in platelet count tends to be modest, these cases are particularly dangerous because of associated thrombosis. Much has been learned about heparin-induced disease, but complex issues remain.