Cetuximab (Erbitux®)

Cetuximab (Erbitux^®) is used to treat bowel (colon and rectum) cancer, and head and neck cancer. It is best to read this information with our general information about the type of cancer you have.

Cetuximab belongs to a group of targeted therapy drugs known as monoclonal antibodies.

Cetuximab is used to treat advanced bowel cancer when tests show the cancer cells do not have a change (mutation) in a gene called RAS. It is usually given with chemotherapy or sometimes targeted therapies.

Cetuximab is used to treat some head and neck cancers which have spread. It may be given with radiotherapy or chemotherapy.

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

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 chemotherapy or radiotherapy, 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.

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.

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.

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.

Cetuximab often causes an acne-like rash or other skin changes such as dry, itchy or flaky skin. This is most likely to start in the first 3 weeks of treatment.

Always tell your doctor or nurse about any skin changes. They can give you advice and prescribe creams for your skin or medicines to help. If you have severe skin problems, your doctor may need to delay your next treatment or lower the dose.

Skin changes usually improve when treatment finishes. We have information about coping with skin changes during treatment.

Very rarely, cetuximab causes a very severe skin reaction. Contact the hospital straight away if you have:

• a rash that blisters or peels
• sores on your lips or in your mouth
• flu-like symptoms or a fever (high temperature).

Magnesium helps keep nerves and muscles working properly. You will have regular blood tests to check your levels of magnesium. Your doctor may prescribe you magnesium supplements if the levels are too low.

The lining of your mouth and nose may become sore. You may have mouth ulcers or nosebleeds. Tell your nurse or doctor if you have any of these changes. They can give you medicines to help.

Clean your teeth or dentures morning and night and after meals. Use a soft-bristled or children’s toothbrush. Your nurse can give you advice on looking after your mouth.

Feeling tired is a common side effect. 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.

If you have diarrhoea, it can usually be controlled with medicines. Follow any advice you have been given about taking anti-diarrhoea drugs. Tell your doctor if the diarrhoea is severe or if continues after taking the anti-diarrhoea drugs. It is important to drink at least 2 litres (3½ pints) of fluids each day. This stops you getting too dehydrated. It can help to avoid:

• alcohol
• caffeine
• milk products
• high-fat foods
• high-fibre foods.

Your eyelashes may grow longer and more curly than usual. You may notice your head and body hair becomes finer, curlier or more brittle. Some people may lose their hair slowly over several months. These changes are usually temporary and gradually improve after treatment has finished. Your nurse can talk to you about ways to cope with hair loss.

You may notice changes to your nails. They may become brittle and break easily. Wear gloves when washing dishes or using detergents to help protect your hands and nails. If the area around your nails becomes inflamed, tell your doctor straight away.

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

• throbbing pain, redness or swelling in a leg or arm
• suddenly feeling breathless or coughing
• sharp chest pain, which may be worse when you cough or take a deep breath.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

A blood clot is serious, but it can be treated with drugs that thin the blood (anticoagulants). Your doctor or nurse can give you more information.

You can help reduce the risk of developing a blood clot by:

• staying active during treatment
• drinking plenty of fluids, especially water.

You may be given anticoagulants to help prevent a clot.

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

• medicines you have been prescribed
• medicines you buy in a shop or chemist
• vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.

Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.

Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus (covid) vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations. 

If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.

Your doctor or nurse can give you more information.

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses 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.