Aminoglutethimide: review of pharmacology and clinical use.

Aminoglutethimide blocks several cytochrome P-450 mediated steroid hydroxylation steps, including those required for conversion of cholesterol to pregnenolone and for the aromatization of androgens to estrogens. Through these actions it blocks adrenal steroidogenesis and the production of estrogens in extraglandular tissues. Aminoglutethimide is indicated for treatment of certain patients with Cushing's syndrome and breast cancer. Other potential uses (prostate carcinoma, low renin hypertension, etc.) remain investigational. For treatment of Cushing's syndrome, aminoglutethimide is usually given alone or in combination with metyrapone. In women with breast carcinoma, replacement hydrocortisone must be administered with aminoglutethimide to prevent reflex ACTH hypersecretion from overcoming adrenal inhibition. Administration of aminoglutethimide to patients with Cushing's syndrome results in improvement in clinical status in 56% of cases. Results are most favorable in patients with adrenal tumors and patients with ectopic ACTH production. Aminoglutethimide and replacement glucocorticoid produce objective disease regression in 32% of unselected postmenopausal patients with metastatic breast carcinoma and in 52% of women whose tumors are estrogen receptor positive. Responses are similar in duration and frequency to those produced by surgical adrenalectomy and hypophysectomy and the antiestrogen, tamoxifen.