Obstetrics & Gynaecology/Anti-androgen

Anti-androgens (hirsutism/PCOS)

also: cyproterone · co-cyprindiol · Dianette · spironolactone · finasteride

Overview

Reduce androgen action for hirsutism and acne in PCOS. All are teratogenic (feminise a male fetus) — reliable contraception is essential.

Mechanism

Cyproterone acetate is an androgen-receptor antagonist with progestogenic activity (combined with ethinylestradiol as co-cyprindiol/Dianette — also contraceptive). Spironolactone antagonises the androgen receptor and reduces androgen synthesis. Finasteride inhibits 5α-reductase → ↓dihydrotestosterone.

Indications

Hirsutism / acne in PCOS
Androgenetic patterns (specialist)

The agents

Co-cyprindiol (cyproterone + EE)AR antagonist + contraceptive

oral

Dianette; VTE risk — stop a few months after acne/hirsutism controlled.

SpironolactoneAR antagonist

oral

Off-label hirsutism; cross-references the cardiovascular MRA card.

Finasteride5α-reductase inhibitor

oral

Off-label; teratogenic.

Adverse effects

Teratogenicity (feminisation of male fetus)serious

Effective contraception mandatory.

VTE (co-cyprindiol)serious

Hepatotoxicity, meningioma (high-dose long-term cyproterone)serious

Spironolactone: hyperkalaemia, menstrual irregularitycommon

Cautions & contraindications

Pregnancypregnancy

Male fetus feminisation.

History of VTE (co-cyprindiol)all

Hepatic diseaseall

Interactions

Spironolactone + ACEi/ARB/K⁺ → hyperkalaemia

Monitoring & kinetics

LFTs (cyproterone); K⁺ (spironolactone); pregnancy avoidance

Oral; effect on hair takes months (hair cycle).

Source: BNF — Anti-androgens · NICE CKS — Hirsutism