Flutamide 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 flutamide works
Hormones are chemicals that our bodies make. Hormones act as messengers and help control how cells and organs work. Hormonal therapies such as flutamide change the way hormones are made or how they work in the body.
Most prostate cancers need the hormone testosterone to grow. Almost all testosterone in men is made by the testicles. A very small amount is made by the adrenal glands, which sit above the kidneys.
Flutamide blocks testosterone from reaching the cancer cells. This may shrink or stop the prostate cancer from growing.
You may have flutamide for a few weeks when you first start other hormonal therapies. These hormonal therapies are called luteinising hormone (LH) blockers, for example, goserelin (Zoladex®) and leuprorelin (Prostap®). They cause a short-term increase in testosterone levels. This makes some symptoms, such as bone pain or problems passing urine, worse before they get better. Doctors call this tumour flare. Flutamide helps prevent this happening.
Flutamide is also used to treat prostate cancer that has spread to other parts of your body (advanced or metastatic prostate cancer).
Your doctor or nurse will explain why you are having flutamide and how long you will have it for.
Taking your flutamide tablets
Flutamide comes as a tablet you can take at home. You take it 3 times a day. 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
- do not chew, or crush the tablets
- take them at the same time every day.
If you forget to take your tablets you should take the missed dose as soon as possible, unless it is almost time for your next tablet. If this happens, skip the missed tablet and take the next tablet on time. If a full day has passed, let your doctor or nurse know. Do not take a double dose unless your doctor tells you to.
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.
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.
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.
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. You may also notice a small amount of liquid leaking from your nipples. Your doctor can talk to you about how this can be prevented or treated, and it is usually reversible when you stop treatment.
This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.
If you have diarrhoea:
- try to drink at least 2 litres (3½ pints) of fluids each day
- avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
- contact the hospital for advice.
Feeling or being sick
Your doctor can give you anti-sickness drugs to prevent or reduce sickness or vomiting. Take the drugs exactly as your nurse or pharmacist tells you. If the sickness continues, tell your doctor. They can prescribe other anti-sickness drugs that may work better for you.
Loss of sex drive
Your sex drive may be lower while taking this treatment. Talk to your doctor or nurse for advice. We have more information about coping with the effects of treatment on your sex life.
Most men lose their sex drive and have erection problems during hormonal therapy. Things often return to normal after you stop taking the drug. But some men 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.
Tiredness and difficulty sleeping
Tiredness is a common side effect. Flutamide may also cause problems with falling or staying asleep. Your doctor or specialist nurse may be able to give you some help and advice with these side effects.
You should not drive or operate machinery if you feel sleepy.
Flutamide can sometimes affect the liver. You will have regular blood tests to check your liver. Tell your doctor straight away if you notice any yellowing of your skin or eyes.
Flutamide may give you a bigger appetite and you might eat more than usual. It is important to try to have a healthy diet, which includes plenty of fruit and vegetables. This is so you do not put on too much weight. Ask your doctor or nurse for advice about healthy eating.
Rarely, this treatment can cause blurred vision. This may develop a few months after treatment has started. Let your doctor know about any changes to your vision.
Some people have an allergic reaction while having this treatment. Signs of a reaction can include:
- feeling hot or flushed
- a skin rash
- feeling dizzy
- a headache
- feeling breathless.
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.
Talk to your doctor or nurse about safe levels of alcohol intake while you are taking flutamide. Let them know if you need help or advice on staying within safe levels.
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.
Blood clot risk
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
- 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.
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.
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.
Problems with 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.
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.