Aminoglutethimide is an anti-steroid drug marketed under the tradename Cytadren by Novartis around the world. It blocks the production of steroids derived from cholesterol and is clinically used in the treatment of Cushing’s syndrome[1]and metastatic breast cancer. It is also used by body builders.

Mechanism

Aminoglutethimide has two mechanisms of action:

  1. It blocks aromatase in the generation of estrogens from androstenedione and testosterone.
  2. It blocks the conversion of cholesterol to pregnenolone by inhibiting the enzyme P450scc and consequently decreases synthesis of all hormonally active steroids.

At low doses, aminogluthethimide is only an effective inhibitor of aromatase, but at higher doses, it effectively blocks P450scc as well.

Side effects

Its side effects are skin rash, hepatotoxicity, inhibition of cortisol in the human body, and it may also cause hypothyroidism.Since cortisol helps break down muscle, aminoglutethimide is used by bodybuilders in a steroid cycle.

Clinical uses

Aminoglutethimide is indicated in conjunction with other drugs for the suppression of adrenal function in patients with Cushing’s syndrome.

It is also a 2nd or 3rd line choice for the treatment of hormone sensitive (estrogen and progesterone) metastatic breast cancer.

Abuse

Aminoglutethimide is abused by body builders and other steroid users to lower circulating levels of cortisol in the body and prevent muscle loss. Cortisol is catabolic to protein in muscle and effective blockade of P450scc by aminogluthethimide at high doses prevents muscle loss.