Buserelin (Suprefact)

Buserelin is a hormone therapy drug. It is also known as Suprefact or Suprecur. 

It is a treatment for prostate cancer. 

You pronounce buserelin as bue-se-rel-in.

How does buserelin work?

Buserelin is a type of hormone therapy known as a LH (luteinising hormone) blocker. It stops the pituitary gland releasing luteinising hormone. This stops the testicles producing testosterone.

Most prostate cancers need testosterone to grow. By reducing testosterone levels, the prostate cancer may shrink and stop growing. 

How do you have buserelin?

You have buserelin as an injection under the skin. After several injections you have it as a nasal spray. 

You usually have injections under the skin (subcutaneous injection) into the stomach, thigh or top of your arm.

You might have stinging or a dull ache for a short time after this type of injection, but they don't usually hurt much. The skin in the area may go red and itchy for a while.

The video below shows you how to inject just under your skin (subcutaneously). 

How often do you have buserelin?

You have buserelin as an injection 3 times a day for 7 days. On the 8th day you start using 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 buserelin for as long as it is working. 


You have blood tests before starting treatment and during your treatment. They 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.

At the start of treatment

When you start treatment with buserelin, testosterone can temporarily rise, before it drops to low levels. This is called tumour flare. 

This might cause temporary worsening of side effects such as bone pain or weakness.

What are the side effects of buserelin?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely 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.

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.

You might have one or more of these side effects. They include:

Tummy (abdominal) pain

Tell your treatment team if you have this. They can check the cause and give you medicine to

Muscle or bone pain 

You might feel some pain from your muscles and bones, including pain in your jaw or back. Speak to your doctor or nurse about what painkillers you can take to help with this.


Constipation Open a glossary item is easier to sort out if you treat it early. Drink plenty and eat as much fresh fruit and vegetables as you can. Try to take gentle exercise, such as walking. Tell your healthcare team if you think you are constipated. They can give you a laxative if needed.


Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a stoma, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.

Swollen hands and feet

You may have swelling of your hands, feet, legs and face due to a build up of fluid (oedema). 

Hot flushes

We have some tips for coping with hot flushes and the possible treatments for men. Talk to your doctor if your hot flushes are hard to cope with. They might be able to prescribe you some medicines.

Fast heart beat

Your heart might feel like it is beating faster than usual (palpitations).

Skin rash 

A rash can also be itchy. Tell your doctor or nurse if you have a skin rash. They can prescribe medicine to stop the itching and soothe your skin.

Less interest in sex (low libido)

Talk to your doctor if you have this. You might be able to have some treatments to help with low libido. 

Increased breast size

You might experience swollen or tender breasts (gynaecomastia). 

Loss of appetite and weight changes 

You might lose your appetite for various reasons when you are having cancer treatment. Sickness, taste changes or tiredness can put you off food and drinks.

You might also lose or gain weight. Tell your healthcare team if you are finding it difficult to control your weight. 

Changes in blood pressure 

During treatment, your blood pressure may be lower or higher than normal. Tell your nurse if you feel dizzy, faint, or if you have headaches, nosebleeds, blurred or double vision, or shortness of breath. Your blood pressure usually goes back to normal while you are on treatment or when treatment ends.

Tiredness and weakness (fatigue) 

You might feel very tired and as though you lack energy.

Various things can help you to reduce tiredness and cope with it, for example exercise. Some research has shown that taking gentle exercise can give you more energy. It is important to balance exercise with resting.

Smaller testicles

Your testicles may become smaller (atrophy). 

Mood changes 

You might feel depressed or anxious. Speak to your doctor if your mood is low.

Inflammation around the injection site

Tell your nurse if you notice any signs of redness or irritation around the injection site.

Headaches or dizziness 

Let your doctor or nurse know if you have headaches. They can give you painkillers. Don’t drive or operate machinery if you feel dizzy.

Weak bones

Your bones may become thinner. This can increase your risk of bone fractures.

Hair changes 

You may find that your hair becomes thinner or thicker. 

Numbness or tingling in fingers or toes 

Numbness or tingling in fingers or toes is often temporary and can improve after you finish treatment. Tell your healthcare team if you're finding it difficult to walk or complete fiddly tasks such as doing up buttons. 

Difficulty sleeping

If you have difficulty sleeping, it can help to change a few things about how you try to sleep. Try to go to bed and get up at the same time each day and spend some time relaxing before you go to bed. Some light exercise each day may also help. 

Liver changes 

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.

Nail problems

Your nails may become dry, brittle or split. 

Eye problems 

You might have eye problems including blurred vision, sore, red, itchy, dry eyes (conjunctivitis) or an infection. Tell your healthcare team if you have this. They can give you eye drops or other medication to help. 

Feeling thirsty 

You might feel more thirsty than usual 

Memory problems 

You may have trouble concentrating or have problems with your memory.

Hearing changes

You might have ringing in your ears (tinnitus) or problems with your hearing.

Second cancers

There is a small risk that you may get a second cancer some years after this treatment. Your doctor will discuss this with you.

Allergic reaction

A small number of people have an allergic reaction while having this treatment. Symptoms can include a rash, shortness of breath, redness or swelling of the face, feeling hot, dizziness, and a sudden need to pass urine.

Tell your doctor or nurse immediately if you have any of these symptoms or feel unwell at all while you are having the treatment or shortly afterwards.

Changes in blood sugar levels 

You might have regular blood and urine tests to check this. Some people develop diabetes Open a glossary item . You might need to have blood sugar lowering treatment. 

If you have diabetes already, you might need to check your blood sugar levels more often than usual.

Increased risk of getting an infection 

This side effect is very rare. 

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.

Bruising, bleeding gums or nose bleeds

This side effect is very rare. 

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. 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).

Coping with side effects

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

What else do you need to know?

Other medicines, foods and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.


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

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. 

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

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

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