Abstract
A multicenter co-operative study was performed to assess the efficacy of danazol in chronic refractory idiopathic thrombocytopenic purpura. Seventy-one patients were included in this study. Twenty-four of 57 evaluable patients were benefited from danazol, 10 with excellent response and 14 with good response. The platelet count started to increase within two weeks of the therapy in most of responding patients, but it tended to decrease after discontinuance of administration. Response to the danazol therapy could not be predicted from the result of the previous therapy. Side effects such as liver injury, androgenic effects, hypoestrogenic symptoms and skin rash occurred in as many as 82% of patients, which, however, were generally mild and promptly improved after withdrawal of the drug.
The observation in mice showed that danazol accelerated the platelet production, and that it inhibited the clearance of immune-injured platelets from circulation. Both of these mechanisms may explain the clinical effect of danazol in patients with idiopathic thrombocytopenic purpura.
