Carbamazepine-induced thrombocytopenia defined by a challenge test

Carbamazepine (CBZ), a widely used anticonvulsant, occasionally causes seri ous hematologic disorders. A 12-year-old boy was admitted because of a diff use petechial rash and profound thrombocytopenia (10 x 10(9) platelets/l), after having been treated for epilepsy with CBZ for 12 days. Seven days fol lowing withdrawal of CBZ and initiation of prednisolone therapy, the platel et count recovered. In a subsequent challenge test with CBZ, platelet count s again decreased, and the levels of platelet-associated IgG and serum inte rleukin-6 increased. No antibodies against platelet glycoprotein Ilb/IIIa o r Ib were detected in plasma. We believe that this is the first reported oc casion when CBZ-induced thrombocytopenia has been defined by a rechallenge test. Am. J. Hematol. 84:52-55, 1999. (C) 1999 Wiley-Liss, Inc.