Progestogens and Cushing's syndrome.

We report 3 patients where Medroxyprogesterone Acetate (MPA = Provera) and Megestrol Acetate (Megace) in doses used for therapy of breast cancer, caused clinical hypercortisolism and Cushing's syndrome. Studies of the toxicity of Medroxyprogesterone Acetate list the commonest adverse events at 500 mg/day as weight gain, water retention, increased blood pressure, tremor, moon face, sweating, muscle cramps, vaginal bleeding and increased appetite. Glucocorticoid-like effects are seen in up to 30% of patients treated for longer than 6 weeks with mostly large doses of the order of 1500 mg/day but Cushing's syndrome has been reported in patients taking 400 mg/day. Neither the glucocorticoid-like effects or Cushing's syndrome have been previously observed with Megestrol Acetate. In the elderly female population receiving progestogens for neoplastic disease the progestogen itself could be an appreciable cause of morbidity both by causing glucocorticoid-like effects and Cushing's syndrome but also by lack of awareness of the danger of sudden withdrawal of these compounds when the hypothalmic-pituitary-adrenal (HPA) axis is suppressed. The signs and symptoms could be easily overlooked unless appropriate testing for Cushing's syndrome is carried out. While the progestogen may have to be continued indefinitely a dose decrease may be feasible with reduction of morbidity.