Buserelin (Suprefact) | Cancer Research UK
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What buserelin is

Buserelin is pronounced byoo-serr-uh-lin. It is also called Suprefact. It is a type of hormone therapy drug called a luteinising hormone (LH) blocker and is a treatment for advanced prostate cancer.


How buserelin works

Prostate cancer depends on the hormone testosterone to grow. Buserelin works by stopping the production of testosterone in the body. Lowering the level of testosterone in the body can shrink a prostate cancer or stop it growing.


How you have buserelin

You have buserelin as an injection just under the skin into fatty tissue in your abdomen (tummy), arm, or leg (subcutaneously). You have this 3 times a day for 7 days.

Watch our video about injections under the skin.

On the 8th day of treatment you start taking buserelin as a nasal spray. You spray the drug into each nostril 6 times a day. One way of remembering to do this is to use the spray before and after each meal. So you can have the treatment before and after breakfast, lunch, and your evening meal. 

You continue taking the buserelin for as long as it is working. 


Tests during treatment

You have blood tests before starting treatment and regularly during your treatment. The tests check your levels of testosterone every 3 months. They also check the levels of blood cells and other substances in the blood. Other tests see how well your liver and kidneys are working.


About side effects

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

You may have a few side effects. They may be mild or more severe. A side effect may get better or worse through your course of treatment. Or more side effects may develop 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)

The side effects may be different if you are having buserelin with other medicines.

Tell your doctor or nurse straight away if any of the side effects get severe.


Temporary side effects when treatment starts

You may have an increase in symptoms called tumour flare for the first few weeks of the treatment. To try to prevent this, your doctor may give you another type of hormone drug called cyproterone (Cyprostat). You start the cyproterone about 5 days before the buserelin treatment and continue for 3 to 4 weeks. 

The symptoms of tumour flare include

  • Increased pain or difficulty passing urine
  • Bone pain
  • Back pain  
  • Blood in the urine  
  • A pins and needles feeling in the legs

Tell your doctor or nurse if you have any of these effects.


Common side effects

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

  • Problems getting an erection (impotence) due to low testosterone levels. This may sometimes get better within 3 or 12 months of finishing treatment
  • Lower interest in having sex (low libido)
  • Hot flushes and sweats happens in 1 out of 2 men (50%). For some men this lasts as long as treatment continues. Tell your doctor or nurse if this effect is difficult for you to cope with
  • Tiredness and weakness (fatigue) while having the treatment, which may be due to low red blood cell levels (anaemia)
  • Nose bleeds – the nasal spray can irritate the lining of your nose
  • The spray may change your sense of smell and taste
  • Skin rashes – these are usually mild but let your doctor or nurse know if you have them
  • Breast tenderness and swelling – this can be distressing. Your doctor may suggest medicines to try and prevent it
  • Swelling (puffiness) of the face, arms or legs due to a build up of fluid (oedema) – this is usually mild
  • Changes in your blood pressure – your nurse or doctor will check your blood pressure. Most men can continue taking buserelin and the blood pressure usually goes back to normal either during treatment or when it ends
  • Weight gain can occur – you may be able to control this with diet and exercise. But it is sometimes a struggle to keep your weight down when you are having hormone treatment
  • A feeling that your heart is racing (palpitations)
  • Abdominal (tummy) pain
  • Feeling or being sick is usually mild – let your nurse know as you can have medicines to help
  • Diarrhoea or constipation
  • Muscle or bone pain – mild painkillers can  help

Occasional side effects

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

  • Anxiety and mood changes
  • Worsening of depression – tell your doctor if you suffer from depression
  • Memory problems and difficulty concentrating
  • Bruising of the skin where you have the injection
  • Headaches and dizziness
  • Difficulty sleeping
  • Appetite changes – you may have a poor appetite or a bigger appetite than usual
  • Feeling thirsty – drink more fluids if you have this
  • Bone thinning (osteoporosis) can happen with long term treatment. The bones become weaker and more likely to break. You will have a DEXA scan to check your bone density before you start treatment
  • Splitting nails
  • Hair thinning or thickening – you may also have more body hair growth than usual
  • Unusual skin sensations such as numbness, tingling, prickling, burning or tingling – it can feel like pins and needles. Let your doctor or nurse know if you have this
  • Dry eyes – your nurse can give you eye drops to help
  • Eyesight changes such as blurred vision or a feeling of pressure behind the eyes
  • Liver changes that are very mild and unlikely to cause symptoms – they will almost certainly go back to normal when treatment ends

Rare side effects

Fewer than 1 in 100 people have these.

  • You may find that the levels of sugar in your blood can change. You will have regular blood tests. If you are diabetic, you need to take extra care in checking your blood sugar
  • Bruising more easily due to a drop in platelets – you may have nosebleeds, or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae)
  • An increase in the number of infections you get – due to a drop in the number of white blood cells
  • Some people have an allergic reaction while having the first treatment – let your nurse know if you feel hot or have any skin rashes, itching, dizziness, headaches, or shivering. Also let them know if you have breathlessness, anxiety, flushing of the face, or a sudden need to pass urine
  • There is a small risk of developing a second cancer some years after buserelin treatment
  • Loss of hearing
  • Ringing in the ears (tinnitus)

Important points to remember

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.

If you have a cold and need to use a decongestant nasal spray, don’t use the buserelin spray for 30 minutes before or after you use the decongestant.

Other medical conditions

If you have diabetes, high blood pressure or depression, tell your doctor. All of these conditions can be affected by buserelin treatment.


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


Related information


More information about buserelin

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 www.medicines.org.uk.

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 yellowcard.mhra.gov.uk.

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Updated: 16 September 2015