Leuprorelin acetate (Prostap® SR, Prostap® 3)

Leuprorelin acetate is a hormonal therapy drug used to treat prostate cancer. It’s best to read this with our general information about prostate cancer.

Leuprorelin is given as an injection, either under the skin (subcutaneously) or into the muscle (intramuscularly). You usually have it as an outpatient. Your cancer doctor or nurse will tell you how often you will have it.

Like all hormonal therapy drugs, leuprorelin can cause side effects. Some of these can be serious so it’s important that you read the detailed information below. How hormonal therapy affects people varies from person to person. It’s important to read about the side effects so that you know what to expect. Your healthcare team 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 seek medical attention for any reason other than cancer, always tell the healthcare staff that you are having this treatment.

How leuprorelin 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 in order 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.

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

When leuprorelin is given

Leuprorelin can be used on its own or with other types of treatment. It may be used before or after surgery or radiotherapy. It may also be used to control prostate cancer that has spread to other parts of the body (advanced or metastatic prostate cancer).

Leuprorelin can be given for months or years, depending on your situation. Some men with advanced prostate cancer may have intermittent therapy with leuprorelin. This involves having leuprorelin treatment 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 leuprorelin when it’s needed.

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

How leuprorelin is given

Leuprorelin is given as an injection. There are two types of leuprorelin:

  • Prostap SR is given once a month.
  • Prostap 3 is given every three months.

Both types can be given under the skin (subcutaneously) of the tummy or arm. Prostap SR can also be given into a muscle (intramuscularly) in the buttocks or thigh.

Tell your doctor or nurse if you are taking any medicines to thin your blood as this may increase bruising.

The injections will usually be given by your practice nurse at your doctor’s surgery. If you are not able to visit the surgery, a district nurse can give you the injection at home. If an injection is delayed by 2 to 3 days, this should not make a big difference. But you should try to have your injections on time as far as possible.

Some people may find the injection slightly uncomfortable and notice redness or a darker colour around the area afterwards. You may have a local anaesthetic cream applied before the injection to reduce any discomfort.

Possible side effects of leuprorelin

We explain the most common side effects of leuprorelin 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 doctor or nurse regularly while you have this treatment. Always tell them about the side effects you have. They can prescribe drugs to help control some side effects and give you advice about managing side effects.

Allergic reaction

Rarely, leuprorelin may cause an allergic reaction within a few hours of being given. Signs of a reaction can include a rash; feeling itchy; flu-like symptoms (headaches, high temperature or chills); feeling flushed, dizzy or short of breath; or feeling generally unwell. If you develop any of these symptoms, contact your doctor straight away for advice.

More information about this drug

We are 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.

Tumour flare

There may be a temporary increase in testosterone levels in the first few days or weeks after starting leuprorelin. 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 leuprorelin and continue taking them for a few weeks after.

Let your doctor know if you notice any increase in symptoms in the first month after starting leuprorelin. If you have back pain, difficulty in passing urine, or numbness or tingling in your legs, tell your doctor straight away.

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 flushes, such as 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 during hormonal therapy. This often returns to normal after you stop taking the drug. But some men continue to have difficulties after treatment has finished. 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.


Tiredness is a common side effect. There is evidence that doing exercise and resistance training (such as lifting weights) at least twice weekly 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.

If tiredness makes you feel sleepy, don’t drive or use machinery.


Some men find that leuprorelin causes headaches. These are usually mild and easily controlled with medicines.

Dizziness, blurred vision, drowsiness

Occasionally leuprorelin can cause dizziness, blurred vision or drowsiness. Don’t drive or operate machinery if you have these side effects. Talk to your doctor if you notice any of these effects.

Feeling sick

Leuprorelin can make you feel sick (nausea) but this is usually mild. If it doesn’t improve, your doctor can prescribe anti-sickness drugs.

Possible side effects of long-term leuprorelin treatment

Men taking leuprorelin 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 you may 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.

Mood changes

You may experience mood swings. Some men feel low or depressed after taking leuprorelin 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. Talk to your doctor if you are having problems.

Breast swelling or tenderness

You may notice breast swelling and tenderness. This is called gynaecomastia. Your doctor can advise you on how this can be prevented or treated.

Bone thinning (osteoporosis)

Taking leuprorelin for a few years increases your risk of bone thinning (osteoporosis), which can increase your risk of a broken bone (fracture). Your doctor can give you advice on how bone thinning can be monitored and treated.

Regular walking and resistance exercises, such as lifting weights, can help to keep your bones strong. Not smoking, eating a healthy diet 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. We have more information about bone health.

Effects on the liver

Your doctor will take blood samples to test how well your liver is working. Leuprorelin can change the amount of certain chemicals produced by the liver. This is usually mild and you can continue to take leuprorelin. Very occasionally you may need to stop taking the drug.

Risk of heart changes and diabetes

There may be an increased risk of developing heart disease, changes in heart rhythm or diabetes when taking leuprorelin. 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 is important to tell your doctors if you have ever had heart rhythm problems or if you are taking any medicines for this.

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

Less common side effects of leuprorelin

Blood clot (thrombosis)

Leuprorelin 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 leuprorelin

Other medicines

Leuprorelin may interact with other drugs. This includes medicine you can buy in a shop or chemist. 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 leuprorelin. 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.