Successful therapy with danazol in refractory autoimmune thrombocytopenia associated with rheumatic diseases

The objective was to assess the efficacy of therapy with danazol in refractory immune thrombocytopenia associated with different rheumatic diseases. Patients with severe immune thrombocytopenia (platelet counts < 40 x 10(9)/l) with a bone marrow biopsy showing megakaryocytes in normal or increased number and normal morphology were included if they fulfilled at least one of the following criteria: (a) thrombocytopenia refractory to prednisone (> or = 1 mg/kg/day during > or = 4 weeks); (b) patients requiring an unacceptably high dose of prednisone for > 2 months (prednisone dose > or = 20 mg/day); (c) no response to at least another drug besides corticosteroids. Other causes of thrombocytopenia were excluded. They were treated with danazol (100-200 mg q.i.d.) and followed for at least 12 months. Four patients diagnosed with systemic lupus erythematosus, two with rheumatoid arthritis and one with primary antiphospholipid syndrome met the inclusion criteria. All of them achieved acceptable platelet counts within the first 4 weeks of danazol therapy that allowed the prednisone dosage to be tapered. No important side-effects related to danazol therapy were observed. Danazol therapy seems to be a useful and well-tolerated treatment for refractory immune thrombocytopenia associated with different rheumatic diseases.