A comparison of danazol and placebo in the treatment of adult idiopathic gynaecomastia: results of a prospective study in 55 patients.

In an attempt to define the efficacy of danazol in the treatment of idiopathic gynaecomastia, 55 patients were enrolled into a randomised double-blind comparison of danazol 200 mg twice daily for 3 months against placebo. The results of 52 patients were evaluated, three patients being excluded because of protocol violations. Danazol improved breast tenderness to a significantly greater degree than did placebo (P = 0.022, danazol vs placebo) and was associated with statistically significant improvement in the degree of gynaecomastia and in its measured size (P less than 0.05). The intended management of patients who had received danazol was less likely to be surgery compared to the placebo group when assessed at the end of treatment (27% vs 50%). Minor side effects were common in both groups, but significant weight gain was noted in the danazol group alone. If there is no urgent need for rapid resolution of gynaecomastia, danazol 200 mg twice daily can provide effective control of symptoms and may obviate the need for surgery.