Cancer drugs A to Z list
Cyproterone acetate is a hormone treatment. You pronounce it as sy-proh-te-rone-a-suh-tayt.
You might have cyproterone acetate as a treatment for prostate cancer:
that has spread to other parts of the body (advanced prostate cancer) and you can’t have surgery or other medicines to treat your cancer
to treat hot flushes after surgery or medicine to stop the testicles producing the male sex hormone testosterone
to stop an increase in testosterone called a tumour flare
Prostate cancer cells depend on the hormone testosterone to grow. Cyproterone acetate lowers levels of testosterone in the body and also blocks testosterone from reaching the cancer cells. This means it can slow or stop the growth of prostate cancer. It’s also known as anti androgen therapy.
You have cyproterone acetate as tablets. You take them either on their own or with another type of drug for prostate cancer called .
You take your tablets with a drink after meals and try to take them at evenly spaced times during the day.
Whether you have a full or an empty stomach can affect how much of a drug gets into your bloodstream.
You should take the right dose, no more or less.
Talk to your healthcare team before you stop taking a cancer drug or if you miss a dose.
You take cyproterone acetate tablets daily. The amount you have and how often you have them during the day depends on why you are taking them.
Your doctor, nurse, or pharmacist will explain how many tablets you need to take and when to take them. Let them know if you have problems swallowing the tablets.
You take cyproterone acetate for as long as it is working, and the side effects aren’t too bad.
You might take cyproterone acetate with a medicine called a luteinising hormone (LH) blocker. LH blockers stop the production of luteinising hormone, so the testicles stop making testosterone.
LH blockers can take a few weeks to lower your testosterone. During this time your symptoms can get worse. This is called tumour flare. Cyproterone acetate helps stop the tumour flare from happening.
In this situation, you usually take cyproterone acetate for a few days before starting the LH blocker and stay on it for about 4 to 6 weeks.
You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.
Side effects can vary from person to person. They also depend on what other treatment you are having.
Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:
you have severe side effects
your side effects aren’t getting any better
your side effects are getting worse
We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.
Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.
These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:
Talk to your doctor if you have this. You might be able to have some treatments to help with low sex drive.
You might have problems getting an erection (impotence). Talk to your doctor or nurse if you have this. There are treatments that can help, such as medicines, vacuum pumps and injections or pellets. Your doctor or nurse can refer you to a specialist in this area.
Your sperm count and the amount you ejaculate reduce over a few months after you start taking cyproterone acetate. This usually goes back to normal after you stop your treatment. But the effects of long term treatment with cyproterone acetate on the sperm count are not yet known.
Ask your healthcare team about this before starting treatment.
These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:
breast swelling-rarely the breast can feel tender, lumpy or ooze white milky fluid
tiredness and weakness (fatigue)
depression
mood changes
hot flushes or sweats
swelling in parts of the body (fluid build up)
weight loss and weight gain. The weight gain can be due to fluid build up
liver changes - symptoms include loss of appetite, feeling or being sick, and itchy skin- your skin may also look yellow. You have regular blood tests to check for this. Very rarely there is a risk of developing cancer of the liver or non cancerous lumps in the liver that may cause bleeding in the tummy (abdomen)
shortness of breath
These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:
skin rash
an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness. This can be life threatening. Call your advice line straight away if you have any of these symptoms
risk of developing a type of brain tumour (meningioma)
There isn't enough information to work out how often these side effects might happen. You might have one or more of them. They include:
blood clots that can be life threatening; signs are pain, redness and swelling where the clot is. Feeling breathless can be a sign of a blood clot in the lung. Contact your advice line or doctor straight away if you have any of these symptoms
weakening and thinning of the bones (osteoporosis)
breathlessness and looking pale due to a low number of red blood cells (anaemia)
dryness of the skin and scalp
changes to how well the hair grows and loss of hair
We have more information about side effects and tips on how to cope with them.
Read more about how to cope with side effects
Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.
Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.
Cyproterone acetate may harm a baby developing in the womb. It is important not to get someone pregnant while you are having treatment and for some time after finishing treatment. This can be up to 20 months but it varies from person to person.
Before you start, talk to your doctor or nurse about effective contraception. They can tell you when to start and how long you should continue to use it. Let them know straight away if your partner falls pregnant while you're having treatment.
This drug can cause infertility, but this is often temporary. Fertility can return in a few months or longer after treatment ends. The time it takes can vary from person to person. The effects of long term treatment on fertility are not known.
Talk to your doctor before starting treatment if you think you may want to have a baby in the future.
If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.
For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.
You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.
Last reviewed: 21 Sept 2023
Next review due: 21 Sept 2026
Prostate cancer is cancer that starts in the prostate gland. The prostate gland is found at the base of the bladder and is about the size of a walnut.
Hormone therapy blocks or lowers the amount of hormones in the body to stop or slow down the growth of cancer.
Coping with cancer can be difficult. There is help and support available. Find out about the emotional, physical and practical effects of cancer and how to manage them.
Cancer drugs have side effects and these can vary from person to person. But there are things that you can do to help you cope.
About Cancer generously supported by Dangoor Education since 2010. Learn more about Dangoor Education
Search our clinical trials database for all cancer trials and studies recruiting in the UK.
Connect with other people affected by cancer and share your experiences.
Questions about cancer? Call freephone 0808 800 40 40 from 9 to 5 - Monday to Friday. Alternatively, you can email us.
