Which drug is used to inhibit adrenal cortex function in the treatment of Cushing's syndrome?

• A. Fludrocortisone (Florinef)
• B. Dexamethasone (generic)
• C. Aminoglutethimide (Cytadren)
• D. Hydrocortisone (Solu-Cortef)

Answer: (C)

Reducing adrenal cortisol production is the goal when managing Cushing's syndrome with medication. Aminoglutethimide achieves this by blocking the cholesterol side-chain cleavage enzyme in the adrenal cortex, the first step in making steroids. By inhibiting this enzyme, the synthesis of all adrenal steroids—cortisol included—drops, which helps control hypercortisolism. Because this suppression can affect other steroids as well, patients may need temporary glucocorticoid replacement and careful monitoring to prevent adrenal insufficiency. The other options either replace hormones (like a mineralocorticoid or cortisol) or add glucocorticoid activity rather than suppress adrenal steroid production, so they don’t address the mechanism of inhibiting adrenal cortex function in Cushing's.