Leuprorelin (Prostap®) for breast cancer

Hormones are chemicals that our bodies make. They act as messengers and help control how cells and organs work. Hormonal therapy drugs change how hormones are made or work in the body.

Oestrogen can encourage breast cancer to grow. Leuprorelin stops the ovaries making oestrogen and lowers the level of oestrogen in the body. You can only have leuprorelin if you have not been through menopause. You may have it with other hormonal therapy drugs or on its own.

We explain the most common side effects of this treatment here. We also include some that are less common.

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

When you have this treatment, you will have regular appointments with a doctor, nurse or pharmacist. Always tell them about any side effects you have. They can give you: 

• drugs to help control most side effects 
• advice about managing side effects. 

Most side effects can be managed. But sometimes side effects are harder to control. It is important not to stop taking hormonal therapy without telling your doctor. If side effects cannot be managed, your doctor may suggest a different type of hormonal therapy.

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

• helps you sleep better
• reduces stress
• improves your bone health.

If you feel sleepy, do not drive or operate machinery.

Leuprorelin can make you feel sick (nausea) but this is usually mild. If it does not improve, your doctor can give you anti-sickness drugs to help.

Leuprorelin may cause some bowel changes, but this is not usually severe. If this is a problem tell your doctor or nurse.

Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. If you have a stoma, it may be more active than usual. Drink enough fluids to keep you hydrated. Your doctor may advise you to take anti-diarrhoea medicines.

Constipation means that you are not able to pass stools as often as you normally do. Drinking plenty of fluids and eating high-fibre foods, such as fruit, vegetables and wholemeal bread, can help. Your doctor may advise you to take drugs called laxatives if needed.

You may gain weight when you are having this treatment. Eating healthily and being active can help you keep to a healthy weight. Your doctor, nurse or dietitian can give you more advice.

This treatment can affect your skin. It may cause a rash, which may be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using soap-free cleansers and unperfumed moisturising cream every day. 

Always tell your doctor or nurse about any skin changes. They can give you advice and may prescribe creams or medicines to help. Changes to your skin usually improve when treatment ends.

Rarely, this treatment can cause a serious skin reaction that needs to be treated immediately in hospital. Contact the hospital straight away on the 24-hour number if you have any of these symptoms:

• a skin rash that is spreading 
• blistering or peeling skin
• flu-like symptoms, such as a high temperature and joint pain
• sores on your lips or in your mouth.

While you are having this treatment, your hair may become thinner, drier and more brittle. This is usually mild. If you are worried about this, ask your nurse for advice on hair care.

Your eyes may become watery and feel sore. Your doctor, nurse or pharmacist can give you advice and eye drops to help with this.

Contact the hospital on the 24-hour number if:

• your eyes get red and inflamed (conjunctivitis)
• you have pain in your eyes
• you notice any change in your vision. 

Leuprorelin may make you feel dizzy. Tell your doctor or nurse if this happens. If you feel dizzy do not drive or operate machinery.

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

You may notice changes in your memory. You may also find it harder to concentrate. 

To help you remember things, try using: 

• reminder alarms or notes on your phone 
• a diary, calendar or phone app 
• a notebook you carry with you.

This treatment may cause swelling and tenderness of your breast tissue. This is called gynaecomastia. To prevent this, some people have 1 or more low-dose radiotherapy treatments to the chest before treatment starts. Another type of hormonal drug might be used to treat the breast swelling. Your doctor can give you more advice.

This treatment can cause vaginal dryness. Non-hormonal creams, gels or lubricants can help with vaginal dryness and any discomfort during sex. You can buy these from a chemist, or your doctor can prescribe them.

You might have slight vaginal bleeding for a short while:

• when you start treatment
• if you change from 1 hormonal treatment to another.

Vaginal dryness can also cause bleeding. Tell your doctor or nurse if you have any vaginal bleeding, especially if it lasts for more than a few days.

Taking this treatment for several months or more can increase the risk of bone thinning. This is called osteoporosis. It can make you more likely to get a broken bone (fracture). 

You may have bone density scans to check your bone health before and during treatment. These scans can diagnose osteoporosis or osteopenia (low bone density) so that it can be monitored. If your scan shows osteoporosis, your doctor usually prescribes:

• drugs to protect your bones called bisphosphonates
• calcium and vitamin D supplements. 

Regular exercise where you support your body weight, like walking, running and dancing, can help look after your bones. This is called weight-bearing exercise. Other types of strength exercises are also helpful. If you have any bone thinning or the cancer is affecting your bones, get advice from your cancer team first. 

Eating a healthy diet and not smoking also helps take care of your bones.

This treatment can affect your appetite. Don’t worry if you do not eat much for 1 or 2 days. But if your appetite does not come back after a few days, or if you are losing weight, tell your doctor, nurse or pharmacist. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.

Leuprorelin may cause tingling in your hands or feet but this is not common. If this happens tell your doctor or nurse.  

This treatment may affect how your liver works. This is usually mild. You will have blood tests to check how well your liver is working.

This treatment might increase certain risk factors for heart problems or cause:

• fast heartbeat (palpitations)
• high blood pressure
• high levels of cholesterol – a fatty substance in your blood.

Talk to your doctor if you are worried about these. They can monitor you or treat you if needed.

Things you can do to take care of your heart include:

• not smoking
• maintaining a healthy weight
• being physically active.

This treatment can raise your blood sugar levels and increase the risk of diabetes. 

Signs of raised blood sugar include:

• feeling thirsty
• needing to pass urine (pee) more often than usual
• feeling more tired than usual. 

Tell your doctor or nurse if you have these symptoms. They can do tests to check your blood sugar level and give you advice.

If you already have diabetes, your blood sugars may be higher than usual. You may need to check them more often, or make changes to your diabetic treatment. Your diabetic doctor or nurse will talk to you about how to manage this.