Drug-Induced Thrombocytopenia

Drug-induced thrombocytopenia (DIT) is a common clinical problem, and numerous drugs have been implicated in the development of thrombocytopenia. The risk of thrombocytopenia for any drug is low, and only a small number of patients taking a suspected medication will develop the problem. However, many patients who develop DIT are taking multiple medications and are critically ill. Rapid recognition of thrombocytopenia in affected patients and identification and removal of the offending agent before clinically significant bleeding occurs is imperative. The thrombocytopenia is usually due to increased platelet destruction, but some cases are secondary to decreased platelet production. Available laboratory tests have limited specificity and sensitivity and lack a rapid turn around time. Thus, DIT is most often a clinical diagnosis supported by resolution of thrombocytopenia after cessation of the drug. Certain drugs have a well-documented association with thrombocytopenia, such as quinine, vancomycin, cimetidine, and valproic acid.