Dapsone in treatment of chronic idiopathic thrombocytopenic purpura in adults.

ABSTRACT

BACKGROUND: When a patient is steroid-dependant, a currently available strategy in chronic idiopathic thrombocytopenic purpura (ITP) is to follow a trial and error approach with any of the known drugs which has been found effective in the condition. OBJECTIVE: To evaluate the response of chronic ITP to dapsone, an inexpensive drug now reported to be effective in the disease. DESIGN: A controlled trial of abstinence and rechallenge type. SUBJECTS: Eight subjects with chronic ITP. INTERVENTIONS: Phase I - Intake of 100 mg of dapsone daily until response (in form of rise of platelet count in blood), Phase II - Above followed by drug abstinence, minimum for four weeks, and then rechallenge with the drug. MAIN OUTCOME MEASURES: Platelet counts during various phases viz during drug intake, withdrawal and rechallenge. RESULTS: Four (50%) patients responded to treatment. The mean pre-dapsone and post-dapsone platelet counts of blood were 29.6 x 10(9)/l and 142.5 x 10(9)/l respectively during the first phase of trial. The rechallenge was done in five patients following withdrawal of drug and the mean values of platelet count before and after rechallenge were 32.2 x 10(9)/l and 83 x 10(9)/l respectively. There was a remarkable response in two patients; one is now off the drug and the other on a maintenance dose of 50 mg of dapsone daily. CONCLUSION: Dapsone caused significant rise of platelet count in some patients of chronic ITP. It can be tried as an alternative to other second-line drugs in chronic ITP.