Bicalutamide (Casodex®)

Bicalutamide is a hormonal therapy drug used to treat prostate cancer. It’s best to read this with our general information about prostate cancer.

You have bicalutamide as tablets. You usually have it as an outpatient. Your cancer doctor or nurse will tell you how often you will have it.

Like all hormonal therapy drugs, bicalutamide can cause side effects. Some of these can be serious, so it’s important that you read the detailed information below. How hormonal therapy affects people varies from person to person. Your doctor or nurse can talk to you more about this and give you advice on how to manage any side effects.

Tell your doctor or nurse straight away if you feel unwell or have severe side effects, including any we don’t mention here. If you need to see a health professional for any reason other than cancer, always tell them that you are having this treatment.

How bicalutamide works

Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies are drugs that interfere with 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 above the kidneys.

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

When bicalutamide is given

Bicalutamide is used to treat prostate cancer. It can be used alone or with other types of treatment such as surgery, radiotherapy or other hormonal therapies. Your doctor or nurse will explain how long you will have bicalutamide. Treatment may continue for as long as it works to control the cancer.

Sometimes bicalutamide is used for a short time when you start other hormonal therapy drugs such as goserelin, buserelin, triptorelin or leuprorelin. These drugs can increase your testosterone levels for a few weeks before the levels fall to a steady low. This increase can make symptoms caused by the cancer worse for a short time. This is called tumour flare. Your doctor may give you bicalutamide to take before and during the first few weeks of these treatments to prevent tumour flare.

Taking your bicalutamide tablets

Bicalutamide is taken as a tablet once a day. You take it at the same time each day. Swallow the tablet whole with a drink of water. Always take your tablets exactly as your nurse or pharmacist explained. This is important to make sure they work as well as possible for you.

Do not stop taking any of your tablets unless your doctor tells you to. Here are some important things to remember:

  • If you forget to take your tablet, do not take a double dose. Just take your usual dose the next day. The levels of the drug in your blood will not change very much.
  • Keep tablets in the original package, and at room temperature away from heat and direct sunlight.
  • Keep them safe and out of the sight and reach of children.
  • Get a new prescription before you run out of tablets and make sure you have plenty for holidays.
  • Return any remaining tablets to the pharmacist if your treatment is stopped.

Possible side effects of bicalutamide

We explain the most common side effects of bicalutamide here. We also include some of the rarer side effects. You may get some of the side effects we mention, but you are very unlikely to get all of them. If you are taking other drugs as well, you may have some side effects that we don’t list here. You will see a doctor or nurse regularly while you have this treatment. Always tell your cancer doctor or nurse about the side effects you have. They can prescribe drugs to help control them and give you advice about managing them.

More information about this drug

We’re not able to list every side effect for this treatment here, particularly the rarer ones. For more detailed information you can visit the electronic Medicines Compendium (eMC).

Breast swelling or tenderness

This is common if you take bicalutamide for more than six months. Breast swelling is called gynaecomastia. To prevent this some men have low-dose radiotherapy to the breast tissue, or take another hormonal therapy drug called tamoxifen. Your doctor can give you more information about these treatments.

Sexual effects

Bicalutamide may lower your sex drive or you may have difficulty with erections. It can be hard to talk about this but your nurse or doctor can give you information about treatments that might help.

Hot flushes and sweats

These are common and can be mild or more severe. During a hot flush, you feel warmth in your neck and face and your skin may redden. Mild flushes can last a few seconds or minutes. More severe flushes can last for 10 minutes or more. You may have sweats and 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 hot flushes. Cutting down on nicotine, alcohol and hot drinks with caffeine, such as tea and coffee, may help.

Your doctor can prescribe drugs to help reduce hot flushes.

Hot flushes and sweats may reduce as your body adjusts to bicalutamide. They usually stop completely a few months after treatment finishes.

We have more information on our website about prostate cancer and hormonal symptoms.

Skin changes

You may get a mild rash or dry and itchy skin. Tell your doctor or nurse if you have a skin rash. They can give you advice and may prescribe creams or medicines to help.

Some people are more sensitive to the sun during treatment. If this happens your skin may burn more easily than usual. You can still go out in the sun, but use a suncream with a sun protection factor (SPF) of at least 30, and cover up with clothing and a hat.

Weight gain and loss of muscle strength

You may gain weight, particularly around your waist, and you may lose some muscle strength. Eating a healthy diet and keeping physically active can help control your weight. Ask your doctor or nurse for advice.

Anaemia (low number of red blood cells)

Bicalutamide can reduce the number of red blood cells in your blood. These cells carry oxygen around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your doctor or nurse if you feel like this.

Feeling sick

Sickness is usually mild. Your doctor can give you tablets to help if needed. It might also help to take your bicalutamide tablets with food.


Bicalutamide may make you constipated. Drinking at least two litres of fluids (three and a half pints) every day will help. Try to eat more foods that contain fibre (such as fruit, vegetables and wholemeal bread) and take some regular gentle exercise.

Let your doctor or nurse know if you are constipated. They can give you medicine to help your bowels move (laxatives).

Tummy or back pain

You may get pain or discomfort in your tummy area (abdomen) or back, feel bloated or have indigestion or wind. Peppermint capsules, mint tea or charcoal tablets may help with indigestion or wind. Tell your doctor if it doesn’t improve or gets worse. They can prescribe drugs to help.

Hair changes

Some men notice that their hair becomes thinner, but this is usually mild. Others may notice their hair gets thicker during treatment.

Blood in your urine

You may have blood in your urine while taking bicalutamide. This is quite common. Tell your doctor or nurse if you notice this.

Dizziness or drowsiness

Tell your doctor or nurse if you have either of these symptoms. It’s important not to drive or operate machinery if you are affected.

Changes in the way the liver works

Bicalutamide may affect how your liver works. This is usually mild and goes back to normal after treatment. It may also cause the skin and whites of your eyes to become yellow (jaundice). Tell your nurse or doctor if you notice this.

You will have regular blood tests to check how well your liver is working.

Less common side effects of bicalutamide

Allergic reaction

Rarely, bicalutamide may cause an allergic reaction. Signs of a reaction can include: 

  • a rash
  • feeling itchy
  • flushed or short of breath
  • swelling of your face or lips
  • feeling dizzy or unwell. 

Contact your doctor straight away if you have any of these symptoms.


Rarely, bicalutamide can cause breathlessness. If you feel breathless while taking bicalutamide, tell your doctor straight away.

It is important to tell your doctor or nurse straight away if you feel ill or have severe side effects. This includes any we don’t mention here.

Other information about bicalutamide

Other medicines

Some medicines, including ones you can buy in a shop or chemist, can interact with or be harmful when you are having bicalutamide. Tell your doctor about any medicines you are taking, including over-the-counter drugs, complementary therapies and herbal drugs.

Problems with lactose

Bicalutamide 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.

Medical treatment

If you need to go into hospital for any reason other than cancer, always tell the doctors and nurses that you are taking bicalutamide. Explain you are taking hormonal therapy and that no one should stop or restart this without checking with your cancer doctor first. Tell them the name of your cancer doctor so they can ask for advice.


Bicalutamide may affect your fertility (being able to father a child). If you are worried about this, talk to your doctor or nurse before treatment starts.