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Steroidal Anti-Androgen

Cyproterone Acetate

Brand names: Cyprostat

Cyproterone acetate is a steroidal antiandrogen and progestogen used in prostate cancer, to suppress the testosterone flare at the start of GnRH agonist therapy, and to control severe hypersexuality.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It competitively blocks androgen receptors and exerts a central progestogenic effect that suppresses gonadotrophin and hence testosterone secretion.

Prescribing in practice

  • Dose-dependent hepatotoxicity (including fatal hepatic failure) and a risk of meningioma with cumulative high-dose exposure mean liver function and clinical review are essential and use should be limited to licensed indications.
  • It can cause venous thromboembolism, so assess cardiovascular and thrombotic risk before and during treatment.
  • Gynaecomastia, breast tenderness and reduced fertility are common and should be discussed before starting.

Monitoring

Monitor liver function before and periodically during treatment, with adrenocortical function on long-term high-dose use, and review for symptoms suggestive of meningioma.

Counselling the patient

  • Report any abdominal pain, yellowing of the skin or eyes, or dark urine promptly as these may indicate liver injury.
  • Seek urgent advice for new persistent headaches, visual changes or seizures.
  • Be aware that treatment can reduce fertility and cause breast changes.

Evidence & guidelines

MHRA guidance highlights the cumulative dose-related risk of meningioma with cyproterone acetate, prompting restrictions on long-term high-dose use.

Reference: MHRA Drug Safety Update 2020 (cyproterone and meningioma); NICE NG131; EAU Guidelines 2024; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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