Cyproterone acetate is a hormone treatment used to treat prostate cancer.


Hormones are substances produced naturally in the body. These act as chemical messengers and help control the activity of cells and organs. Hormone therapies interfere with the way hormones are made or formed in the body.

Most prostate cancers need the hormone testosterone to grow. Almost all of the testosterone in men is made by the testicles. A small amount is made by the adrenal glands, which are located above the kidneys.

Cyproterone acetate lowers the amount of testosterone produced by the body. This lowers testosterone levels and may shrink the prostate cancer or stop its growth.


You may have cyproterone acetate if other treatments such as surgery are not appropriate.

You may also need cyproterone acetate during the first weeks after starting to take other hormone therapies such as goserelin, buserelin, triptorelin, or leuprorelin. These drugs can cause a short-term increase in testosterone. This makes symptoms such as bone pain or problems urinating get worse before they get better. Doctors cause this tumor flare. Cyproterone acetate helps prevent this from happening.

You may have cyproterone acetate over four weeks to reduce hot flushes caused by hormone treatments or if you have had your testicles removed (orchidectomy).

Your doctor or nurse can explain why you are receiving cyproterone acetate and how long you will be taking it.


Cyproterone acetate is taken in pill form from one to three times a day. Take the pills after meals, swallowing them whole with a glass of water. Always take the pills exactly as your nurse or pharmacist has told you. This is important to ensure that it is working as well as possible.

It is important that you not stop taking any of your pills if not told to do so by your doctor. Here are some important things to remember:

  • Do not double the dose if you forget to take one of your pills. Just take the next dose at the normal time.
  • Keep the pills in their original packaging at room temperature. They should be stored away from heat and direct sunlight.
  • Keep them safe and out of the reach of children.
  • Get a new prescription before the one you have runs out, and keep track of holidays, when pharmacies may be closed.
  • Return the remaining pills to the hospital if the treatment is discontinued.


You may experience some of the side effects mentioned here, though it is rare for a patient to have all of them. If you are taking other drugs, you may have certain side effects that are not listed here.

Always inform your doctor or nurse of the side effects you experience. They can prescribe drugs to help control them and can also give you advice on managing side effects.


Most men can lose their sex drive and have erection difficulties during the hormone therapy. Things often return to normal after they stop taking the medication, though some keep having difficulties after the treatment is over. Your doctor can prescribe treatments to help with erection problems, though these do not influence sex drive.

If you need support in coping with sexual difficulties, your nurse or doctor can give you information and refer you to specialized support services.


You may notice weight gain or swollen ankles and legs. This is due to a build-up of fluid. Let your doctor or nurse know if this happens. The swelling will improve after your treatment ends.


You may have mood swings or feel anxious, restless, or depressed. This is more likely if you already have depression or low moods. Your doctor or nurse can give you support or advice on this.


These are common and can be mild or more severe. While having a hot flash, you feel warmth in the neck and face, and your skin may turn red. Mild hot flashes can last from a few seconds to about a couple of minutes. More severe hot flashes can last 10 minutes or more. You may have sweats and then feel chills and clamminess. Some people feel anxious or irritable during a hot flash.

There are things you can do to try to reduce your hot flashes such as giving up nicotine, alcohol, and hot beverages containing caffeine, such as coffee and tea.

If the hot flashes are bothersome, your doctor can prescribe medication to help lessen them.

Hot flashes and sweating get better as your body adapts to the hormone treatment. They usually stop completely a few months after the treatment ends.


You may notice slight swelling and tenderness in the chest area. This is called gynecomastia. Your doctor can give you advice on how to prevent or treat this.


You may feel tired or lacking in energy while taking cyproterone acetate. Try to pace yourself if you feel tired. Try to strike a balance between periods of rest and staying physically active. Evidence indicates that exercise may reduce tiredness in men who are having hormone therapy. If you feel drowsy, don't drive or use heavy machinery.


You may feel slightly short of breath while taking cyproterone acetate. Let your doctor or nurse know if this happens. This should stop once the treatment ends.


Your doctor will take blood samples from you to see how well your liver is working. Cyproterone acetate can sometimes change the way the liver functions. If this happens, you will stop taking the drug, and your liver should return to normal. Tell your doctor if you notice any yellowish coloring on your skin or in your eyes.


Cyproterone acetate can increase the risk of having a blood clot if you have a history of clotting, sickle-cell anemia, or diabetes. If you are taking cyproterone acetate and have pain, reddening, or swelling in one of your legs or difficulty difficulty breathing or chest pain, tell your doctor immediately.



If you have diabetes, your blood sugar may rise more than normal and you may need more frequent monitoring. Your doctor will talk to you about how to manage this. Your blood sugar levels should return to normal after treatment with cyproterone acetate has finished.


Cyproterone acetate can interact with other drugs. This includes medications that can be purchased in a store or pharmacy. Tell your doctor if you are taking any drugs, including complementary therapies, vitamins, and herbal remedies.


Your doctor will advise you not to conceive during the treatment. This is because the drugs can harm developing babies. It is important to use effective methods of contraception during chemotherapy and for a few months after the treatment ends.


If you have to go to the hospital for whatever reason other than cancer, always tell the doctors and nurses that you are taking cyproterone acetate. Explain to them that you are undergoing hormone therapy that no one should stop or restart if it is not done under the advice of a cancer doctor.