Spironolactone is prescribed to a 24-year-old woman with polycystic ovary syndrome for hirsutism. Which counselling point regarding contraception is essential before starting therapy?

• A It causes virilisation of a female fetus if taken during pregnancy
• B It feminises a male fetus if taken during pregnancy, so reliable contraception is mandatory ✓
• C It reduces efficacy of combined oral contraceptives by enzyme induction
• D It must be stopped three months before attempting conception because it causes ovarian fibrosis

Explanation

Spironolactone acts as an androgen receptor antagonist and also inhibits androgen biosynthesis. If taken during pregnancy it can feminise a male fetus, producing ambiguous genitalia, so effective contraception is required. Conveniently, combined oral contraceptives remain fully effective alongside spironolactone since there is no enzyme induction, and they themselves help the hirsutism. There is no requirement for a prolonged washout period before conception beyond stopping once pregnancy is planned.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.