A 28-year-old woman with polycystic ovary syndrome (PCOS) and hirsutism is started on spironolactone. Which pharmacological property of spironolactone is primarily responsible for its anti-androgenic effect in this patient?

• A Inhibition of 5-alpha reductase reducing DHT synthesis
• B Competitive antagonism at androgen receptors and inhibition of ovarian androgen synthesis ✓
• C Suppression of LH secretion via progestogenic feedback on the pituitary
• D Enhanced hepatic clearance of testosterone by inducing CYP450 enzymes

Explanation

Spironolactone has dual anti-androgenic actions: it competitively blocks androgen receptors and inhibits ovarian steroidogenesis (including androgen synthesis). Its efficacy in PCOS hirsutism is well established. It does not primarily inhibit 5-alpha reductase (that is finasteride), suppress LH via progestogenic activity (that is combined OCPs), or induce testosterone clearance. Patients must be counselled about its potassium-sparing diuretic effect and teratogenicity risk in pregnancy.

Reference: Williams Textbook of Endocrinology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.