Cyproterone acetate (Cyprostat®)

Cyproterone acetate (usually called cyproterone) is also called Cyprostat®. It is used to treat prostate cancer.

What is cyproterone acetate (Cyprostat®)?

Cyproterone acetate (also called cyproterone or Cyprostat®) is a hormonal therapy drug used to treat prostate cancer. It can be given alone or with other types of treatment. It is best to read this information with our general information about prostate cancer

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

How cyproterone works

Hormones are chemicals that our bodies make. Hormones act as messengers and help control how cells and organs work. Hormonal therapies are drugs that change the way hormones are made or how they work in the body.

Hormonal therapy for prostate cancer is a treatment to lower the levels of the hormone testosterone in the body. Prostate cancer needs testosterone to grow. Testosterone is mainly made by the testicles. Hormonal therapies reduce the amount of testosterone in the body, or stop it reaching the prostate cancer cells.

Cyproterone may be given for a few weeks when you start taking hormonal drugs called LHRH agonists. This is to prevent a temporary rise in testosterone making symptoms worse (called tumour flare).

It may also be given:

  • on its own to help control prostate cancer
  • to reduce hot flushes caused by other hormonal treatments for prostate cancer.

Your doctor or nurse will explain how long you should take it for.

Taking cyproterone tablets

Cyproterone comes as tablets you can take at home. You may have cyproterone on its own, or with other drugs. Your nurse or doctor will talk to you about your treatment plan. 

Always take the tablets exactly as explained. This is important to make sure they work as well as possible for you. Make sure you:

  • take the tablets after a meal 
  • swallow them whole, with a glass of water 
  • take them at the same time every day.   

If you forget to take the tablets, you should take the missed dose as soon as possible the same day. Take the next dose at the normal time. Do not take a double dose unless your doctor tells you to.

Here are a few other things to remember about your tablets:

  • Keep them in the original package and at room temperature, away from heat and direct sunlight.
  • Keep them safe and out of sight and reach of children.
  • If you are sick just after taking the tablets, contact your healthcare team. Do not take another dose.
  • Get a new prescription before you run out of tablets, and make sure you have plenty for holidays.
  • If your treatment is stopped, return any unused tablets to the pharmacist. 

Your nurse or pharmacist may also give you other medicines to take home. Take all your medicines exactly as they have been explained to you. Do not stop taking any of your medicines unless your doctor tells you to. 

About side effects

About side effects

We explain the most common side effects of this treatment here. We also include some that are less common. 

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you: 

  • drugs to help control some side effects 
  • advice about managing side effects. 

It is important to take any drugs exactly as explained. This means they will be more likely to work for you.

Serious and life-threatening side effects

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Contact the hospital

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Common side effects

Hot flushes and sweats

Hot flushes are a common side effect of this treatment. During a flush, your neck and face may feel warm. If you have white skin, your skin may look red. If you have black or brown skin, your skin colour may deepen. Flushes can last up to 5 minutes. You might also have sweats or feel anxious or irritable during a flush. 

Here are some things you can do to reduce the effects of hot flushes:

  • Wear natural fabrics, such as cotton.
  • Wear layers so you can remove clothes as needed. 
  • Use cotton sheets and layers of bedding you can remove. 
  • Try cooling pads or pillows to keep you cool.
  • Keep rooms cool or use a fan.
  • Have cold drinks and avoid caffeine and alcohol. 

You might have fewer hot flushes as your body adjusts to this treatment. You could try therapies to help you cope with hot flushes, such as:

  • talking therapies like cognitive behaviour therapy (CBT)
  • controlled breathing exercises
  • yoga
  • acupuncture. 

If they do not improve, talk to your doctor. Certain drugs can help to improve hot flushes. 

Flushes usually stop a few months after treatment ends. But some people continue to have them.

Sexual effects

It is common to lose your sex drive and have erection problems during hormonal therapy. Things often return to normal after you stop taking the drug. But some people continue to have problems after treatment is over. Your doctor can prescribe treatments to help with erection problems. But these treatments will not increase your sex drive.

Cyprostat also reduces the number of sperm and the amount of ejaculate you produce.

Weight gain

You may put on weight, or your ankles and legs may become swollen. This is due to fluid building up. Tell your doctor or nurse if this happens. The swelling will get better after your treatment ends.

Mood changes

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

Breast swelling or tenderness

This treatment may cause swelling and tenderness of your breast tissue. This is called gynaecomastia. To prevent this, some people have 1 or more low-dose radiotherapy treatments to the chest before treatment starts. Another type of hormonal drug might be used to treat the breast swelling. Your doctor can give you more advice.

Feeling tired (fatigue)

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

  • helps you sleep better
  • reduces stress
  • improves your bone health.

If you feel sleepy, do not drive or operate machinery.

Breathlessness

You may feel slightly short of breath while you are taking cyproterone. If this happens, tell your doctor or nurse. This should stop when the treatment finishes.

Effects on the liver

This treatment may affect how your liver works. You will have blood tests to check how well your liver is working. Tell your doctor if you notice any yellowing of your skin or eyes.

Very rarely, this treatment may increase the risk of developing a new cancer in the liver.

Raised blood sugar levels

This treatment can raise your blood sugar levels and increase the risk of diabetes. 

Signs of raised blood sugar include:

  • feeling thirsty
  • needing to pass urine (pee) more often than usual
  • feeling more tired than usual. 

Tell your doctor or nurse if you have these symptoms. They can do tests to check your blood sugar level and give you advice.

If you already have diabetes, your blood sugars may be higher than usual. You may need to check them more often, or make changes to your diabetic treatment. Your diabetic doctor or nurse will talk to you about how to manage this.

Less common side effects of cyproterone

Skin changes

This treatment can affect your skin. It may cause a rash, which may be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using soap-free cleansers and unperfumed moisturising cream every day. 

Always tell your doctor or nurse about any skin changes. They can give you advice and may prescribe creams or medicines to help. Changes to your skin usually improve when treatment ends.

Hair changes

There may be changes to how your hair grows. For example, the hair on your head may thicken, or you may lose some body hair. Your hair may also be drier than usual.

Allergic reaction

Rarely, some people have an allergic reaction while having this treatment. Signs of a reaction can include: 

  • feeling hot or flushed 
  • a skin rash
  • itching
  • feeling breathless
  • shivering
  • feeling dizzy.

If you feel unwell or have any of these signs, tell a doctor or nurse straight away. Do not take any more of this treatment until you have spoken to them.

Anaemia (low number of red blood cells)

If you take cyproterone for a long time, it might reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:

  • pale skin 
  • lack of energy
  • feeling breathless 
  • feeling dizzy and light-headed. 

Tell your doctor or nurse if you have these symptoms.

Bone thinning (osteoporosis)

If you take cyproterone for a long time, it might increase the risk of your bones becoming thinner or weaker. There are things you can do to help look after your bones.

Blood clot risk

Cyproterone might increase the risk of a blood clot in people who have had a previous blood clot or other circulation problems. 

Symptoms of a blood clot include:

  • throbbing pain, redness or swelling in a leg or arm
  • suddenly feeling breathless or coughing
  • sharp chest pain, which may be worse when you cough or take a deep breath. 

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

A blood clot is serious, but it can be treated with drugs that thin the blood (anticoagulants). Your doctor or nurse can give you more information. 

You can help reduce the risk of developing a blood clot by:

  • staying active during treatment 
  • drinking plenty of fluids, especially water. 

You may be given anticoagulants to help prevent a clot.

Meningioma risk

When this treatment is taken for a long time, there is a very rare risk of developing a type of brain tumour called a meningioma. Your cancer doctor or nurse can give you more information.

Other information

Other medicines

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

Lactose

These tablets contain a type of sugar called lactose. If you have been told by a doctor that you cannot digest some sugars or are lactose intolerant, talk to your doctor before taking this drug.

Alcohol

Your doctor may advise you to avoid drinking alcohol while you are taking this treatment. This is because drinking alcohol might make cyproterone less effective.

Fertility

Some drugs can affect whether you can make someone pregnant.

There may be ways to preserve your fertility. If you are worried about this, it is important to talk with your doctor before you start treatment.

Contraception

Your doctor, nurse or pharmacist will advise you not to make someone pregnant while having this treatment. The drug may harm the developing baby. It is important to use effective contraception during treatment and for a while after it finishes.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
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  • use illustrations to explain text
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We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

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Date reviewed

Reviewed: 01 September 2022
|
Next review: 01 March 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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