Buserelin (Suprefact®)

Buserelin 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 buserelin as an injection for the first week. After that, you have it as a nasal spray. Your cancer doctor or nurse will tell you how long you take it for.

Like all hormonal therapy drugs, buserelin can cause side effects. Some of these can be serious so it’s important to 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 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 profession for any reason other than cancer, always tell them that you are having this treatment.

How buserelin 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 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, which sit above the kidneys.

Buserelin stops the testicles from making testosterone. This reduces testosterone levels, and may shrink the prostate cancer or stop it growing.

When buserelin is given

Buserelin is given to treat prostate cancer that has spread to other parts of the body (advanced or metastatic prostate cancer).

Some men may have intermittent therapy with buserelin. This involves having buserelin for a few months until the cancer is at a very low level. This level is measured by a blood test called a PSA test. You then have a break from treatment and restart it when needed.

Your doctor or nurse will explain how long you have buserelin treatment for.

How buserelin is given

For the first seven days, buserelin is given as an injection under the skin (subcutaneously). You will be given the injection three times a day. The injection can be given by your GP, practice nurse or at your local hospital. Some men, or their partners, are taught how to give it themselves.

Sometimes people find the injection slightly uncomfortable. You may notice an area of redness at the injection site afterwards.

From the eighth day, you take buserelin as a nasal spray six times a day in each nostril. Your doctor or nurse will advise you how to use the spray and at what times of the day. You will be asked to avoid using nasal decongestants for 30 minutes before and after using the nasal spray.

Don’t stop taking buserelin without talking to you doctor first. Here are some important things to remember:

  • If you forget to take the buserelin spray, just take your next dose at the usual time. Don’t take a double dose.
  • Keep buserelin in a safe place and out of the sight and reach of children.
  • Get a new prescription before you run out and make sure you have plenty for holidays.
  • Return any remaining buserelin to the pharmacist if your treatment is stopped.

Possible side effects of buserelin

We explain the most common side effects of buserelin here. We also include some 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 having other drugs as well, you may have some side effects that we don’t list here.

You will see a cancer doctor or nurse regularly while you have this treatment. Always tell your doctor or nurse about the side effects you have. They can prescribe drugs to help control them and give you advice about managing them. Don’t stop taking buserelin without talking to your doctor first.

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).

Allergic reaction

Rarely, buserelin may cause an allergic reaction. Signs may include:

  • a skin rash
  • itching
  • wheezing
  • difficulty breathing
  • breathlessness.

Let your nurse or doctor know straight away if you have any of these symptoms. Don’t take any more buserelin until you have spoken to them.

Tumour flare

There may be a temporary increase in your testosterone levels in the first few days or weeks after starting buserelin. This may make symptoms caused by the cancer worse. Doctors call this tumour flare. Your doctor may prescribe a hormonal therapy for you to take as a tablet to prevent or reduce tumour flare. You usually begin taking the tablets before starting treatment with buserelin, and continue taking them for a few weeks after.

If you notice any more symptoms in the first month after starting buserelin, let your doctor know. Tell your doctor straight away if you have problems passing urine, back pain, or numbness or tingling in your legs.

Nasal problems

The nasal spray may cause temporary irritation to the lining of your nose. Some people may have nose bleeds or notice changes in their sense of smell. Tell your doctor if you notice any of these symptoms.

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 last for a few seconds up to about a couple of 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. Try cutting down on nicotine, alcohol and hot drinks that contain caffeine, such as tea and coffee.

If hot flushes are troublesome, your doctor can prescribe drugs to help reduce them.

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

Sexual effects

Most men lose their sex drive and have erection difficulties (ED) during hormonal therapy. Things often return to normal after you stop taking the drug, but some men continue to have difficulties after treatment is over. Your doctor can prescribe treatments to help with erection difficulties, but these don’t affect sex drive.

If you need support coping with sexual difficulties, your nurse or doctor can give you information and refer you to specialist support services.


These can usually be relieved with painkillers such as paracetamol. Tell your doctor or cancer nurse if headaches are troublesome.


Tiredness is a common side effect. Exercising and resistance training, such as lifting weights, at least twice a week can reduce tiredness in men on hormonal therapy. It’s important to get medical advice before starting exercise. Ask your doctor or nurse what is safe for you to do.

Skin changes

You may find that your skin gets dry. Using an unperfumed moisturising cream every day may help. Some men develop a skin rash, but this is usually mild and often gets better without treatment. Tell your doctor if you notice any skin changes.

Dizziness, blurred vision, drowsiness

Occasionally buserelin can cause these side effects. Don’t drive or operate machinery if you have them.

Possible side effects of long-term buserelin treatment

Men taking buserelin for more than six months may also have some of the following side effects:

Weight gain and loss of muscle strength

You may gain weight, particularly around your waist, and lose some muscle strength. Eating a healthy diet and exercising regularly can help control your weight. Resistance exercises, such as lifting weights, may help you to reduce loss of muscle strength. Ask your doctor or nurse for advice.

Bone thinning (osteoporosis)

Taking buserelin for a few years increases your risk of bone thinning (osteoporosis). In some men, this can increase the risk of a broken bone (fracture). Your doctor can give you advice on how this can be monitored and treated if needed.

Gentle exercises, such as regular walking, and resistance exercises like lifting weights can help to keep your bones strong. Eating a healthy diet, not smoking and staying within the recommended limits for alcohol will also help to protect your bones.

Let your doctor know if you have any discomfort in your bones or joints.

Mood changes

You may experience mood swings. Some men can become low in mood or depressed after taking buserelin for several months or more. Tell your doctor if you notice any mood changes.

Memory and concentration

You may notice changes in your memory or ability to concentrate. Try using a notebook, post it notes and a calendar to help you keep track of things.

Muscle and joint pain

If you have soreness or stiffness in the joints or shoulders, your doctor can prescribe painkillers to ease this.

Breast swelling or tenderness

Occasionally, buserelin may cause breast swelling or tenderness. This is known as gynaecomastia. Your doctor can advise you about how this can be prevented or treated.

Risk of heart disease and diabetes

There may be an increased risk of developing heart disease, changes in heart rhythm or diabetes when taking buserelin. But the benefits of hormonal treatment generally outweigh the possible risks. You can talk to your specialist about the possible risks and benefits in your situation. It’s important to tell your doctors if you have ever had heart rhythm problems or if you’re taking any medicines for this.

You can help reduce your risk of heart disease and diabetes by:

Less common side effects of buserelin

Blood clot (thrombosis)

Buserelin may increase your risk of getting a blood clot. If you have any pain, redness or swelling in an arm or leg, breathlessness or chest pain, let your doctor know immediately.

Always let your doctor or nurse know about any side effects you have. There are usually ways in which they can be controlled or improved.

Other information about buserelin

Other medicines

Some medicines, including ones you can buy in a shop or chemist, can interact with or be harmful when you are having buserelin. Tell your doctor about any medicines you are taking, including ones you can buy for yourself, complementary therapies, vitamins and herbal drugs.

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 buserelin. Explain you are taking hormonal therapy that no one should stop or restart without advice from your cancer doctor. Tell them the name of your cancer doctor so they can ask for advice.