Cytadren, aka aminoglutethimide, inhibits several enzymes that are responsible for steroid synthesis including aromatase. It has been used to not only inhibit estrogen production but also to lower cortisol levels. Clinically it has been used to treat breast cancer in doses of 500-1000 mg/day along with hydrocortisone 20 mg twice per day to replace glucocorticoid levels1. This is to prevent cortisol levels from dropping too low (acute adrenal insufficiency), or to prevent a rise in ACTH that might overcome the inhibition. This drug has also been used to treat Cushing’s syndrome which is a state of cortisol excess2. Along with inhibiting cortisol synthesis and aromatase, aminoglutethimide has also been shown to disrupt thyroid function3. Aminoglutethimide is a very potent inhibitor of aromatase, offering up to 90% inhibition. However, it is also very effective at suppressing cortisol levels and therefore its use can be dangerous. Some steroid users will use Cytadren without knowing about its suppressive effects on cortisol. Since some steroids also suppress cortisol production, this effect may go unnoticed but once aminoglutethimide is stopped, the user may experience significant side effects due to acute adrenal insufficiency.
1. Wilson, Jean D., and Foster, Daniel W., eds. Williams Textbook of Endocrinology. 9th ed. Philadelphia: Saunders, 1997.
2. Santen RJ, Misbin RI: Aminoglutethimide: review of pharmacology and clinical use. Pharmacotherapy. Sep-Oct;1(2):95-120, 1981
3. Hughss SW, Burley DM. Aminoglutethimide: a “side-effect” turned to therapeutic advantage. Postgrad Med J. 46(537):409-16, 1970