Flutamide is a hormone therapy drug 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 such as flutamide 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.

Flutamide blocks testosterone from reaching the cancer cells. Without testosterone, the prostate cancer may shrink or stop growing.


Flutamide can be given over the short term (over a number of weeks) with other hormonal treatments. It is used to manage a condition called tumor flare, which can happen to you when starting treatments such as goserelin, buserelin, triptorelin, leuprorelin, or histrelin. Tumor flares are temporary increases in testosterone levels; this can lead to an increase in symptoms, such as problems urinating. Flutamide can be given during the first weeks of these treatments so that this does not happen.

Flutamide is also used to treat prostate cancer that has spread to other parts of the body (advanced cancer). It can be given alone or with other hormonal treatments.

Your doctor or nurse will explain how long you are going to be undergoing treatment with flutamide.


Flutamide is taken three times a day in tablet form. You should spread your doses out evenly throughout the 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 tablets if not told to do so by your doctor. Here are some important things to remember:

  • If you forget to take a pill, do not take a double dose. Take the second dose at the normal time. The levels of the drug in your blood won't change much.
  • 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. Do not stop taking flutamide without talking to your doctor first.


This is a common side effect of long-term treatment with flutamide. It is called gynecomastia. Your doctor can give you advice on how to prevent or treat this. You may have one or two treatments with low-dose radiotherapy to the breast tissue, or weekly treatment with a hormone drug.


Flutamide can cause diarrhea. You may also have stomach pain or discomfort. If you have diarrhea, you should drink lots of fluids (at least 2 liters a day). Tell your doctor if your pain or discomfort doesn't go away or if it worsens. Your doctor can prescribe pills for diarrhea if necessary. Sometimes you may have to reduce or stop treatment with flutamide and consider other types of hormone therapy.


This is a common side effect. Your doctor can prescribe anti-sickness drugs if this is necessary.


Most men can lose their sex drive and have erection difficulties during the hormone therapy. These 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.


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 try to reduce your hot flashes such as cutting down on 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.


Tiredness is a common side effect. Taking flutamide can make it hard to fall asleep and stay asleep. Your doctor or nurse may be able to give you a bit of help and advice on these side effects.

Evidence indicates that exercise may reduce tiredness caused by hormone therapy. It is important to get medical advice before starting to exercise.

If you feel drowsy, don't drive or operate heavy machinery.


Flutamide can sometimes affect the liver. Your doctor will give you periodic blood tests to check on your liver. Tell your doctor if you notice a yellowish coloring on your skin or in your eyes.


Flutamide may increase your appetite, causing you to eat more than usual. It is important to try to eat healthy foods such as fruit and vegetables so you do not put on too much weight. As your doctor or nurse for advice on eating healthy.



On rare occasions, flutamide can cause allergic reactions. The signs of a reaction may include the following: rash, itchiness, flushed or short of breath, swelling in the face or lips, or feeling dizzy or unwell. Get in touch with your doctor immediately if you have any of these symptoms.


Blurred vision is a rare side effect of flutamide. This may develop some months after starting the treatment. Tell your doctor if you notice any changes in your vision.



If you have to go to the hospital for whatever reason other than cancer, always tell the doctors and nurses that you are taking flutamide. 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.


Talk to your doctor or nurse about safe levels of alcohol consumption for people taking flutamide. Let them know if you need any other help or advice on staying within safe levels.


Flutamide can affect how well other drugs work. If you are taking other drugs to thin your blood (such as warfarin) or are taking theophylline to help with breathing, tell your doctor before you start the treatment.

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.