Danazol in the Treatment of Gynaecomastia

Summary

Gynaecomastia develops in association with a variety of underlying factors. Many cases are mild in degree and of short duration and do not require treatment. However, quite severe and painful gynaecomastia can occur. In such cases treatment with danazol can lead to a marked reduction in size and a lessening of pain and tenderness of the breasts. In 60 % of all patients a marked reduction of gynaecomastia can be expected and in a further 24 % a moderate reduction. Variable degrees of response occur in relation to the underlying aetiological cause. Therapy is associated with a demonstrable fall in the plasma concentrations of follicle stimulating hormone (FSH) and luteinising hormone (LH) with a decreased urinary excretion of FSH and LH in most patients studied. A significant fall in plasma testosterone occurs in the majority of patients. Estimations of thyroidal and adrenal function show no change. Dosage schedules in adults range from 300 to 600mg a day and in adolescents from 200 to 300mg a day. Side effects of therapy relate mostly to the androgenic properties of danazol which may result in weight gain with fluid retention and acne. Muscle weakness and muscle cramps and spasms occur in a small percentage of patients.