Megestrol Acetate (MA) is a progesterone-like hormone that has been utilized as a birth control agent, chemotherapeutic drug, and more recently, to induce appetite and weight gain in patients malnourished as a result of radiation therapy, chemotherapy, cystic fibrosis, AIDS, or dementia. The mechanism of MA-stimulated appetite and weight gain is unknown.

Although only approved to combat weight loss associated with AIDS and cancer, MA is frequently prescribed for long periods of time to prevent or reverse weight loss in nursing home residents and in elderly patients with serious illnesses in the community. Little data is available to support this practice. Among its many properties, MA acts as a partial glucocorticoid agonist, and long term and short term use of MA may results in adrenal suppression. The rapidity of the onset of MA-induced adrenal suppression and the time course of resumption of normal adrenal function after discontinuation of MA is completely unknown. As a consequence, it is unclear whether MA can be given safely for short periods of time or whether glucocorticoid administration is necessary after abruptly stopping MA treatment. The increased use of MA in the frail elderly, where even partial adrenal insufficiency may pose a substantial risk of adrenal crisis after an illness, requires a clear understanding of these issues. To address these concerns, we will evaluate adrenal function before, during, and after MA administration in healthy volunteers between the ages of 60 and 85 years.