Bicalutamide (Casodex)

Bicalutamide is a cancer treatment drug and is also known by its brand name, Casodex.

It is a treatment for prostate cancer.

How it works

Prostate cancer needs the male hormone testosterone to grow. Testosterone is also called an androgen. 

Bicalutamide is a type of hormone drug called an anti androgen. It stops testosterone from reaching the cancer cells. This can slow the growth of your cancer and may shrink it.

When you have bicalutamide

Bicalutamide is a treatment for prostate cancer. You might have bicalutamide:

  • on its own
  • after radiotherapy
  • after an operation to remove your prostate (prostatectomy)
  • before you have other hormone treatments such as goserelin (Zoladex), leuprorelin and triptorelin

Reducing tumour flare

You need to take bicalutamide before you start some other types of hormone treatment because they take a few weeks to lower your testosterone. During this time they can make your symptoms worse. This is called tumour flare. 

If you are having bicalutamide to stop tumour flare, you take it for a few days before starting the luteinising hormone blocker, and stay on it for about 4 to 6 weeks. 

How you have it

Bicalutamide is a tablet you take once a day.

You should swallow the tablet whole with a glass of water. 

Taking tablets

You must take tablets according to the instructions your doctor or pharmacist gives you.

Speak to your pharmacist if you have problems swallowing the tablets.

Whether you have a full or an empty stomach can affect how much of a drug gets into your bloodstream.

You should take the right dose, no more or less.

Talk to your healthcare team before you stop taking or miss a dose of a cancer drug.


You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Side effects

How often and how severe the side effects are can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects 
  • your side effects aren’t getting any better
  • your side effects are getting worse

Early treatment can help manage side effects better. 

Contact your advice line immediately if you have signs of infection, including a temperature above 37.5C or below 36C.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Breast swelling and tenderness (gynaecomastia)

Talk to the team looking after you about this.

Tiredness and weakness (fatigue)

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Skin rash

Skin problems include a skin rash, dry skin and itching. This usually goes back to normal when your treatment finishes. Your nurse will tell you what products you can use on your skin to help.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

  • hot flushes
  • lowered interest in sex
  • erection problems
  • feeling sick
  • constipation
  • being very sleepy or dizzy
  • lowered appetite
  • indigestion
  • liver changes such as yellowing of the skin or whites of the eyes (jaundice)
  • changes to body hair (hair loss on the head but increased hair growth on the body)
  • weight gain
  • blood in urine
  • depression
  • fluid build up (oedema)
  • breathlessness and looking pale (due to lower levels of red blood cells)
  • tummy (abdominal pain)
  • passing wind
  • chest pain

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness - some allergic reactions can be life-threatening alert your nurse or doctor if notice any of these symptoms
  • breathlessness and cough caused by changes to the lung tissue making it less flexible

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do I need to know?

Other medicines, foods or drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.


It is important not to father a child while you are having treatment with this drug and for 4 months afterwards. This drug may harm a baby developing in the womb. Talk to your doctor or nurse about effective contraception before starting treatment.


It is not known whether his treatment might affect your fertility. You may not be able to father a child after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Some men might be able to store sperm before starting treatment.


This drug contains lactose (milk sugar). If you have an intolerance to lactose, contact your doctor before taking this medicine.

Treatment for other conditions

Always tell other doctors, nurses, pharmacists or dentists that you’re having this treatment. For example, if you need treatment for anything else, including teeth problems.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

This page is due for review. We will update this as soon as possible.

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