Fifteen patients with refractory chronic idiopathic thrombocytopenic purpura (ITP) were treated with dapsone (100 mg/d) for 1-31 months. The overall response rate to dapsone was 40 percent. Five patients responded in 1 month and one patient in 2 months. No pretreatment characteristics - sex, age, platelet count or duration of ITP - were correlated with response to dapsone.
Treatment was well tolerated.The most frequent adverse effect was dose-related haemolytic anaemia. In our experience, dapsone provides an inexpensive and well-tolerated alternative for patients with ITP who had inadequate responses to conventional therapy.