An anti-androgen
Cyproterone
A medicine that blocks the effects of male hormones, used in prostate cancer, severe acne and some other conditions.
What is Cyproterone?
Cyproterone is an anti-androgen, a medicine that blocks the action of male hormones (androgens) such as testosterone. It is used in prostate cancer, in severe acne and excess hair growth that have not responded to other treatments, and in some cases of distressing, uncontrolled sexual urges. Because long-term, higher use has been linked to a brain tumour called meningioma, it is used at the lowest effective amount for the shortest time. It can affect the liver, so liver function is monitored.
Education and reference only. This is a plain-language guide to Cyproterone — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Cyproterone is an anti-androgen — a medicine that opposes the effects of male sex hormones (androgens). By blocking androgens, it is used to slow hormone-driven prostate cancer, to treat severe acne and excess hair growth in women when other treatments have failed, and to reduce strong, distressing sexual urges in certain situations. It is taken by mouth as a tablet, sometimes on its own and sometimes combined with other hormone treatment, and is prescribed under specialist guidance.
How it works
Cyproterone works by blocking androgen receptors, so testosterone and related hormones cannot exert their usual effects, and it also reduces the body's overall production of these hormones. In prostate cancer, this deprives the cancer of the hormones that drive its growth. In severe acne and excess hair growth, blocking androgens reduces the oil and hair stimulation they cause. In cases of overpowering sexual urges, lowering androgen activity reduces sex drive. Its effects build up over weeks and reverse after stopping.
Company & origin
Originated / developed by: Several manufacturers.
An anti-androgen medicine used in the UK to block male hormones, for prostate cancer, severe acne and certain other conditions.
Practical use
How to take Cyproterone
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it exactly as prescribed, usually with or after food, and do not change the amount yourself.
- It is used at the lowest effective amount for the shortest necessary time because of the meningioma risk.
- Attend your liver function blood tests, as it can affect the liver.
- Report yellowing of the skin or eyes, dark urine, severe tiredness or persistent headaches promptly.
- Tell your prescriber if you develop new headaches, vision changes or other unusual brain-related symptoms.
- Discuss its effects on sex drive and fertility, and any mood changes, at your reviews.
Weighing it up
Advantages & disadvantages of Cyproterone
Advantages
- Effectively blocks male hormones in prostate cancer and other hormone-driven conditions.
- Can help severe acne and excess hair growth in women when other treatments have not worked.
- Useful in specific situations of distressing, uncontrolled sexual urges under specialist care.
Disadvantages
- Long-term, higher use is linked to meningioma, a brain tumour, so use is limited and monitored.
- It can affect the liver, sometimes seriously, requiring regular blood tests.
- It lowers sex drive and can affect fertility, and may cause breast tenderness or enlargement.
Practical use
Good to know
An important safety point is that long-term use, particularly at higher amounts, has been linked to meningioma, a usually non-cancerous brain tumour, so it is given at the lowest effective amount for the shortest necessary time and stopped if a meningioma is found. It can affect the liver, sometimes seriously, so liver function tests are done and any yellowing of the skin, dark urine or marked tiredness should be reported. In men it lowers sex drive and can affect fertility, and it can cause breast tenderness or enlargement. It is not a casual treatment but a specialist medicine for specific, often difficult, situations, used with careful monitoring and review.
Who should not take it / use with caution
- People with a current or past meningioma must not use it.
- It is avoided in serious liver disease and certain liver conditions.
- It should not be used in those with severe depression or a history of blood clots without specialist advice.
Monitoring
- Regular liver function blood tests before and during treatment.
- Watching for new headaches, vision changes or other symptoms that could suggest meningioma.
- Reviewing mood, sex drive and the ongoing need for treatment at the lowest effective amount.
Side effects
- Reduced sex drive, tiredness and, in men, breast tenderness or enlargement.
- Liver problems, which can be serious, with yellowing of the skin, dark urine or marked tiredness.
- Mood changes including low mood, and rarely meningioma with long-term higher use.
Key interactions
- Alcohol and other medicines that affect the liver can add to the strain on it.
- It can affect blood sugar control, so diabetes treatment may need review.
- Other hormone treatments and certain medicines can interact, so tell your prescriber what you take.
Available as: Tablets taken by mouth.
Answers
Cyproterone: frequently asked questions
What is cyproterone used for?
It is an anti-androgen used in prostate cancer, in severe acne and excess hair growth that have not responded to other treatments, and in certain cases of distressing, uncontrolled sexual urges.
Why is the length of treatment limited?
Long-term use, especially at higher amounts, has been linked to meningioma, a usually non-cancerous brain tumour, so it is given at the lowest effective amount for the shortest necessary time.
Does it affect the liver?
It can affect the liver, sometimes seriously, so liver blood tests are done and you should report yellowing of the skin, dark urine or severe tiredness.
Will it lower my sex drive?
Yes, by blocking male hormones it reduces sex drive — which is the intended effect in some uses — and it can also affect fertility, so discuss this with your prescriber.
What symptoms should I report straight away?
Report new or persistent headaches, vision changes, yellowing of the skin or eyes, dark urine, severe tiredness or marked mood changes promptly.
Authoritative sources
- BNF
- NICE CKS
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