Osteoporosis associated with megestrol acetate.

Megestrol acetate is a progestational agent for treatment of metastatic breast cancer and endometrial cancer. Megestrol has also been used as an appetite stimulant for patients with human immunodeficiency virus and malignancy who experience cachexia and wasting; also, megestrol can be beneficial in relieving hot flashes in women and men. Megestrol has been shown to have a glucocorticoidlike effect and has been associated with substantial suppression of plasma estradiol levels. We describe 2 patients who recently presented to our Metabolic Bone Disease Clinic with severe osteoporosis complicated by multiple vertebral fractures experienced while the patients were receiving high-dose megestrol therapy. The patients had evidence of adrenal axis suppression but recovered fully after megestrol was discontinued. We speculate that megestrol was an important factor in the development of osteoporosis and subsequent fractures. Further study is warranted to clarify the relationship between megestrol and its potential for adversely affecting the skeleton.