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Bicalutamide (Casodex)

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This page is about the hormone therapy bicalutamide that is used to treat advanced prostate cancer. There are sections about


What bicalutamide is

Prostate cancer depends on the male sex hormone, testosterone, to grow. Testosterone is a type of hormone called an androgen. Bicalutamide is a an anti androgen. It stops testosterone reaching the cancer cells. This can shrink the cancer or slow its growth.

You may take bicalutamide either on its own, or with another type of drug for prostate cancer called a luteinising hormone (LH) blocker. LH blockers include buserelin (Suprefact), goserelin (Zoladex), leuprorelin (Prostap) and triptorelin. If you are having bicalutamide with one of these drugs, the aim is to stop what is called a flare reaction. When you first start treatment with LH blockers you actually make more testosterone for the first few days or weeks. This soon settles down, and after a few weeks you stop making testosterone. Bicalutamide helps to reduce any cancer symptoms caused by the temporary increase in testosterone levels.


How you have bicalutamide

You take bicalutamide as a tablet, once a day. You swallow the tablet whole with a drink of water. If you are having bicalutamide to stop a flare reaction, you take it for a few days before starting the LH blocker, and stay on it for about 4 to 6 weeks.

It is very important that you take tablets according to the instructions your doctor or pharmacist gives you. For example, whether you have a full or empty stomach can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

If you accidentally take more bicalutamide than you should, talk to your doctor or go to a hospital straight away. 

If you forget to take a dose, skip the missed dose and take the next dose at the usual time. Don't take a double dose. 

There is general information about hormone therapies in the cancer treatment section.

We've listed the side effects associated with bicalutamide below. You can use the links to find out more about each side effect. Where there is no link, you can go to the cancer drug side effects section or use the search box at the top of the page.


Common side effects

More than 10 in every 100 people have one or more of these.

  • Hot flushes and sweats affect about half the men treated (50%). Unfortunately some men have them for as long as they stay on treatment. Tell your doctor or nurse if your hot flushes are difficult to cope with
  • Breast tenderness and swelling – this can affect about 2 out of 5 men (40%) and can be distressing. If it is a problem for you, speak to your doctor and they can prescribe treatment to help it
  • Feeling sick or being sick affects about 1 in 10 men (10%) – this is usually mild and can be controlled by anti sickness tablets
  • Pain – about 3 out of 10 men (30%) will have general body pain, 3 out of 20 men (15%) will have some back pain, and 1 out of 10 men (10%) will have some pain in their lower abdomen (pelvic pain)
  • Dizziness
  • A low sex drive (low libido) affects most men
  • A skin rash or dry skin and itching
  • Constipation – drink plenty of fluids. Your doctor or nurse can prescribe laxatives if you are constipated for more than 3 days
  • Low levels of red blood cells (anaemia) that may cause tiredness and breathlessness
  • Blood in your urine – tell your doctor or nurse straight away if you have this

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these.

  • Loss of appetite
  • Feeling sleepy – this usually improves within a few weeks of starting treatment
  • Indigestion
  • Problems getting an erection (impotence) – this usually improves after you finish treatment
  • Changes in the way your liver works – you will have blood tests to check for this. Some men need to stop taking the drug. The liver nearly always goes back to normal after treatment ends 
  • A cough and breathlessness this affects about 1 in 20 men (5%)
  • Heart changes – bicalutamide can affect the way the heart works in about 1 in 20 men (5%). This can cause an increase in blood pressure and swelling of the legs (oedema). Let you doctor or nurse know straight away if you have any chest pain
  • You may not be able to father a child immediately after treatment with bicalutamide but this is usually temporary. It is important to talk to your doctor about the possible effect on your fertility before starting treatment
  • Wind (flatulence) – peppermint may help
  • Sadness or depression – this usually improves within a few weeks of treatment. If it goes on for longer, talk to your doctor or nurse about getting some help
  • Hair thinning or extra hair growth
  • Dry skin or a skin rash and itching
  • Weight gain

Rare side effects

Fewer than 1 in 100 people have these.

  • An allergic reaction – let your nurse or doctor know straight away if you have a sudden skin rash, itching, breathlessness or swelling of the lips, face or throat
  • Difficulty in sleeping at night
  • Lung changes causing severe breathlessness or breathlessness that suddenly gets worse – tell your doctor or nurse straight away if you have this

Important points to remember

The side effects above may be mild or more severe. A side effect may get better or worse through your course of treatment. Or you may develop more side effects as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)
  • Other drugs you are having

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together. Drugs that may react with bicalutamide include

  • Cisapride (an indigestion medicine)
  • Some anti histamine medicines
  • The blood thinning drug called warfarin
  • Some heart medicines
  • Some blood pressure drugs
  • A drug called ciclosporin that lowers immunity


Bicalutamide may have a harmful effect on a developing baby. You are advised not to father a child while you are having treatment. If you are sexually active, discuss contraception with your doctor or nurse before you start your treatment.

Lactose and bicalutamide

Bicalutamide contains a type of sugar called lactose. If you have an intolerance to some sugars, contact your doctor before taking this medicine.


More information about bicalutamide

This page does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at

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Updated: 4 October 2013