Medroxyprogesterone induced Cushing's syndrome.

A 74-year old female taking medroxyprogesterone acetate (MPA) presented with Cushing's syndrome together with low serum cortisol and plasma ACTH and an impaired response to synthetic ACTH (Synacthen, CIBA). When the medroxyprogesterone therapy was ceased the cushingoid features resolved and serum cortisol, ACTH and ACTH responsiveness all returned to normal. The MPA was acting as an exogenous glucocorticoid causing Cushing's syndrome.