Thrombocytopenic purpura may follow the administration of a wide variety of drugs (1). With some medications, thrombocytopenia is the result of diminished platelet production secondary to megakaryocytic damage; with others, it is due to massive platelet destruction on an immunologic basis.
Thrombocytopenia due to Sedormid®, quinidine, and quinine is clearly of the immunologic variety. These and certain other drugs act as haptenes, combining loosely with platelets to provide the antigenic stimulus. The resultant antibody destroys platelets only in the presence of the offending drug. Withdrawal of the medication, therefore, provides complete recovery.
Prompt recognition of this syndrome depends on eliciting