What is cyproterone acetate (Cyprostat®)?

Cyproterone acetate (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 hormonal therapies and the type of cancer you have.

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

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.

Most prostate cancers need the hormone testosterone to grow. Cyproterone reduces the amount of testosterone made by your body. This can:

  • help shrink a prostate cancer or stop it growing.
  • prevent side effects caused by a short-term rise in testosterone when you start taking another type of hormonal therapy drug called an LH blocker, such as goserelin (Zoladex®) or leuprorelin (Prostap®).
  • reduce hot flushes caused by LH blockers or if you have had part of your testicles removed (subcapsular orchidectomy).

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. They may advise you to avoid drinking alcohol while you are taking this treatment. This is because drinking alcohol regularly makes cyproterone less effective.

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 meals.
  • swallow them whole with a glass of water.

If you forget to take the tablets, you should take the next tablet as usual. Do not take a double dose.

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.
  • 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

We explain the most common side effects of this treatment here. We also include some less common side effects. You may get some of the side effects we mention, but you are unlikely to get all of them.

If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

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

Contact the hospital

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

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Common side effects

Sexual effects

Most men lose their sex drive and have erection difficulties during hormonal therapy. Things often return to normal after you stop taking the drug, but some men continue to have difficulties after treatment is over.

Your doctor can prescribe treatments to help with erection difficulties. But these treatments will not increase sex drive.

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 have some mood changes during this treatment. You may feel low or depressed. Let your doctor or nurse know if you notice any changes.

Hot flushes and sweats

These are common. During a flush, your neck and face may feel warm and look red. Flushes can last for a few seconds or for up to 10 minutes. You may have sweats then feel cold and clammy. Some people feel anxious or irritable during a hot flush.

There are things you can do to try to reduce flushes:

  • Wear clothes made from natural fabrics, such as cotton.
  • Dress in layers of clothes that you can remove as needed.
  • Use cotton sheets and have layers of bedding.
  • Keep the room temperature cool or use a fan.
  • Have cold drinks rather than hot ones. Try to avoid drinks with caffeine in them.

You may have fewer hot flushes and sweats as your body adjusts to hormonal treatment. Or your doctor can prescribe drugs to help. Some people continue to have flushes and sweats, but they usually stop a few months after treatment finishes.

You can read more about coping with hot flushes and managing hormonal symptoms in our information on prostate cancer.

Breast swelling or tenderness

This treatment can cause swelling and tenderness of your breast tissue. This is called gynaecomastia. Your doctor can give you advice on how this can be prevented or treated.

Feeling tired

Feeling tired is a common side effect. It is often worse towards the end of treatment and for some weeks after it has finished. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Breathlessness

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

Effects on the liver

Treatment may affect how your liver works. This is usually mild. 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.

Raised blood sugar levels

If you have diabetes, your blood sugar levels may be higher than usual. Your doctor will talk to you about how to manage this. You may need to adjust your insulin or tablet dose.

Less common side effects of cyproterone

Blood clots

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

  • pain, redness or swelling in a leg or arm
  • breathlessness
  • chest pain.

If you have any of these symptoms, contact a doctor straight away.

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

Skin changes

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

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

Other information about cyproterone

Lactose

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

Other medicines

Some medicines can affect the hormonal treatment or be harmful when you are having it. This includes medicines you can buy in a shop or chemist. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.

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 will advise you not to father a child while having this treatment. The drug may harm the developing baby. It is important to use effective contraception during your treatment.

Medical and dental treatment

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

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.

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