cyproterone acetate at a glance
Medicine class
Anti-androgen with progestogenic activity
Licensed roles
Specialist management of prostate cancer and restricted control of libido in adult men
Important long-term risk
Meningioma risk rises with increasing cumulative exposure.
Driving
Do not drive or operate machinery if fatigue or weakness affects you.
What is cyproterone acetate used for?
Selected UK products have distinct specialist indications.
Prostate cancer: preventing initial tumour flare when an LHRH analogue is started; palliative treatment when an LHRH analogue or surgery is unsuitable, not tolerated or oral treatment is preferred; and treating hot flushes associated with LHRH analogues or orchidectomy.
Severe hypersexuality or sexual deviation in adult men: controlling libido only when other interventions are considered inappropriate.
High-strength cyproterone acetate has also been used outside its licence in gender-affirming hormone treatment and androgen-sensitive conditions in women, under specialist oversight.
How does cyproterone acetate work?
It blocks androgen receptors, reducing the effects of hormones such as testosterone. Its progestogenic action also reduces pituitary gonadotrophin release, lowering testicular androgen production.
cyproterone acetate preparations and strengths
Tablet
Route: Oral
Strengths: 50 mg
How to take cyproterone acetate
Take only as prescribed. Treatment changes should be planned by the prescriber.
Swallow the tablets with liquid after meals.
Do not reduce or stop treatment without speaking to the prescriber.
The tablets contain lactose; discuss known sugar intolerance with a clinician or pharmacist.
cyproterone acetate side effects
Common or expected effects
- Reduced libido, erectile dysfunction and reduced sperm production
- Weight change, sometimes with fluid retention
- Low mood or restlessness
- Breast swelling or tenderness
- Hot flushes and sweating
- Fatigue or weakness
- Shortness of breath
- Liver problems
Get urgent medical advice
- Allergic reaction causing difficulty breathing or swallowing
- Liver injury or a liver tumour, including persistent upper-abdominal pain or signs of internal bleeding
- Possible blood clot or embolism
- Meningioma symptoms, including worsening headache, seizures, memory loss, limb weakness or changes in vision, hearing or smell
- Suppression of adrenal function, which may cause marked weakness, low blood pressure, vomiting or dehydration
cyproterone acetate in pregnancy
Selected products are licensed for adult men, so their pregnancy information is stated as not applicable. Pregnancy exposure during non-licensed use requires prompt specialist or prescriber review; do not stop prescribed treatment without clinical advice.
cyproterone acetate while breastfeeding
The selected licensed uses do not cover people who are breastfeeding. Any use while breastfeeding requires individual specialist review before treatment is started, changed or stopped.
cyproterone acetate interactions
Tell the prescriber or pharmacist about all prescribed, non-prescribed and herbal products.
Rifampicin, phenytoin and St John's wort
These can increase cyproterone metabolism and reduce its concentration and effect.
Strong CYP3A4 inhibitors, including azole antifungals and ritonavir
These may slow cyproterone metabolism and increase exposure.
Common questions about cyproterone acetate
Answers are fully visible for fast scanning and source review.
Can cyproterone acetate cause a meningioma?
A rare, cumulative-exposure-dependent association is recognised. It must not be used with a current or previous meningioma and must be stopped permanently if one is diagnosed.
Does cyproterone acetate affect fertility?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.