Cyproterone acetate (Cyprostat®)

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.

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. 

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.

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.

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.

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.

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 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.

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.

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.

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.

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: 

• medicines you have been prescribed
• medicines you buy in a shop, pharmacy or online
• vitamins or supplements 
• herbal drugs and complementary or homeopathic therapies
• recreational drugs – for example, cannabis.

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.

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.

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.

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.