Aminoglutethimide interferes with several of the biosynthetic steps involved in steroid biosynthesis, exerting its effects on the C20-, C22-, 11b-, 18-, 19- and 21-hydroxylases, and also on aromatase. Since it inhibits biosynthesis early in the pathway, it is useful as a blocking agent when alleviating the effects of excessive steroid production, as in the treatment of patients with Cushing's syndrome that has resulted from adrenal carcinoma. The action of aminoglutethimide on aromatase is useful in the treatment of breast cancer since it inhibits peripheral formation of oestrogens; however, it has now been superseded for this purpose by more selective aromatase inhibitors such as 4-hydroxyandrostenedione, which do not cause the problem of cortisol deficiency (as seen with aminoglutethimide).
