Enzalutamide (Xtandi®) is a hormonal therapy drug used to treat prostate cancer that has spread to other parts of the body.
Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.
How enzalutamide works
Hormones are chemicals that our bodies make. Hormones act as messengers and help control how cells and organs work. Hormonal therapies are drugs that change the way hormones are made or how they work in the body.
Prostate cancer needs the hormone testosterone to grow. Almost all testosterone in men is made by the testicles. Enzalutamide blocks testosterone from reaching the prostate cancer cells. This may slow down the growth of the cancer cells and help control advanced prostate cancer.
Enzalutamide is used to treat prostate cancer that has spread to other parts of the body. This is known as advanced (metastatic) prostate cancer.
We explain the most common side effects of this treatment here. We also include some less common side effects. You may get some of the side effects we mention, but you are unlikely to get all of them.
If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.
Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.
Serious and life-threatening side effects
Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.
Contact the hospital
Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.
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 (eMC).
Hot flushes and sweats
These are common. During a flush, your neck and face may feel warm and look red. Flushes can last for a few seconds or for up to 10 minutes. You may have sweats 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:
- Wear clothes made from natural fabrics, such as cotton.
- Dress in layers of clothes that you can remove as needed.
- Use cotton sheets and have layers of bedding.
- Keep the room temperature cool or use a fan.
- Have cold drinks rather than hot ones. Try to avoid drinks with caffeine in them.
You may have fewer hot flushes and sweats as your body adjusts to hormonal treatment. Or your doctor can prescribe drugs to help. Some people continue to have flushes and sweats, but they usually stop a few months after treatment finishes.
You can read more about coping with hot flushes and managing hormonal symptoms in our information on prostate cancer.
Feeling tired is a common side effect. It is often worse towards the end of treatment and for some weeks after it has finished. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.
This treatment may cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers.
High blood pressure (hypertension)
Enzalutamide may cause your blood pressure to increase. Your doctor or nurse may check your blood pressure before you start taking enzalutamide and during your treatment.
Muscle or bone pain
You may get pain in your muscles or bones. If this happens, tell your doctor so they can give you painkillers. Let your doctor or nurse know if it does not get better.
You may find you get restless legs while taking this treatment. This is when you feel you need to move your legs regularly. It is more common at night time. Talk to your doctor or nurse if you get this. They can check that it is caused by the tablets and not any other reasons. They can also give you ways to help manage it.
This treatment may affect your skin. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day. The treatment may cause a rash, which may be itchy.
Always tell your doctor or nurse about any skin changes. They can give you advice and may give you creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.
You may have some mood changes during this treatment. You may feel low or depressed. Let your doctor or nurse know if you notice any changes.
Memory or concentration
You may notice changes in your memory. You may also find it harder to concentrate. To help you remember things, try using:
- a notebook
- notes on your phone
- a calendar.
Dizziness, blurred vision, and drowsiness
Enzalutamide may cause dizziness, blurred vision, and drowsiness. Let your doctor know if you have any of these side effects. Don’t drive or operate machinery if you have them.
These can also increase your risk of falls and broken bones (fractures). If you feel dizzy when walking, you should sit down straight away until it passes. Try to keep areas that you walk through clear to reduce the risk of tripping. Make sure rooms are well lit and always put a light on if you get up during the night.
Some people have indigestion or acid reflux (acid comes up from the stomach into the gullet) when taking this treatment. Tell your doctor if you are affected as they can prescribe treatment to help.
Breast swelling or tenderness
This treatment can cause swelling and tenderness of your breast tissue. This is called gynaecomastia. Your doctor can give you advice on how this can be prevented or treated.
Most men lose their sex drive and have erection difficulties 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 treatments will not increase sex drive.
Bone thinning (osteoporosis)
Taking enzalutamide, over time, increases your risk of bone thinning (osteoporosis). Sometimes this can increase the risk of a broken bone (fracture). Your doctor can give you advice on how your bone health can be monitored. They can also tell you about treatments for bone thinning.
Regular walking and resistance exercises, such as lifting weights, can help to keep your bones strong. Eating a healthy diet, not smoking and not drinking more alcohol than the recommended limit also helps to protect your bones. Let your doctor know if you have any pain in your bones or joints.
Risk of infection
This treatment can reduce the number of white blood cells in your blood. These cells fight infection.
If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is called neutropenia.
If you have an infection, it is important to treat it as soon as possible. Contact the hospital straight away on the 24-hour contact number you have if:
- your temperature goes over 37.5°C (99.5°F)
- you suddenly feel unwell, even with a normal temperature
- you have symptoms of an infection.
Symptoms of an infection include:
- feeling shivery
- a sore throat
- a cough
- needing to pass urine often.
It is important to follow any specific advice your cancer treatment team gives you.
The number of white blood cells will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time.
Very rarely, enzalutamide can cause seizures (fits). If you have a seizure, stop taking enzalutamide and see a doctor straight away. Let your doctor know if you are already taking medication for seizures.
If you suddenly feel unwell, with symptoms such as worsening headache, feeling confused, or problems with your sight, contact the hospital straight away.
Rarely, enzalutamide can cause an allergic reaction. Signs of a reaction include swelling of the lips, tongue, or throat. It can also cause shortness of breath. If you have any of these signs, contact the hospital straight away.
Blood clot risk
Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:
- pain, redness or swelling in a leg or arm
- chest pain.
If you have any of these symptoms, contact a doctor straight away.
A blood clot is serious, but can be treated with drugs that thin the blood. Your doctor or nurse can give you more information.
Some medicines can affect the hormonal treatment or be harmful when you are having it. This includes medicines you can buy in a shop or chemist. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.
Your doctor will advise you not to father a child while having this treatment. The drug may harm the developing baby. It is important to use effective contraception during your treatment.
Some drugs can affect whether you can make someone pregnant.
There may be ways to preserve your fertility. If you are worried about this, it is important to talk with your doctor before you start treatment.
Medical and dental treatment
If you need medical treatment for any reason other than cancer, always tell the doctors and nurses that you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.
If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.