Imatinib (Glivec)

How does imatinib work?

Imatinib is a type of cancer growth blocker called a tyrosine kinase inhibitor (TKI). Tyrosine kinases are proteins that cells use to signal to each other to grow. They act as chemical messengers. There are a number of different tyrosine kinases and blocking them stops the cancer cells growing.

Imatinib targets different tyrosine kinases, depending on the type of cancer.

Find out more about TKI's

How do you have imatinib?

You have imatinib as a tablet or capsule that you swallow whole, with food and a glass of water after food. Speak to your pharmacist if you have problems swallowing the tablets or capsules. If you can’t swallow them you might be able to:

• dissolve the tablets in a glass of water

• open the capsule and pour the powder into a glass of water or apple juice

Talk to your pharmacist about the best way to do this.

• Taking your tablets

You have the tablet or capsule with a meal on a full stomach. This helps to reduce the risk of stomach problems.

You should take the right dose, no more or less.

Talk to your healthcare team before you stop taking a cancer drug or if you miss a dose.

How often do you have imatinib?

You have imatinib either once or twice a day, depending on the condition you have. You usually continue taking imatinib for as long as it works, unless the side effects get too bad. For acute lymphoblastic leukaemia that is Philadelphia chromosome positive, you may have imatinib on its own, or with chemotherapy.

Tests

You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working. Before treatment starts, you may have a blood test to check for viruses such as hepatitis B, hepatitis C, and HIV. This is called a viral screen. It’s important for your doctor to know if you have had any of these viruses. This is because this treatment can weaken your immune system and can cause the virus to become active again (reactivation).

What are the side effects of imatinib?

Side effects can vary from person to person. They also depend on what other treatments you're having. 

When to contact your team

Your doctor, nurse or pharmacist will go through the possible side effects. They will monitor you during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

• you have severe side effects 

• your side effects aren’t getting any better

• your side effects are getting worse

Early treatment can help manage side effects better. 

We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.

Remember it is very unlikely that you will have all of these side effects. But you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Increased risk of getting an infection 

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, cough, headaches, feeling cold and shivery, pain or a burning feeling when peeing, or generally feeling unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Breathlessness and looking pale 

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

Bruising, bleeding gums or nosebleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs. This is known as petechiae.

Tiredness and weakness (fatigue) 

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Fluid build-up (oedema)

A build up of fluid may cause swelling in your arms, hands, ankles and legs. You might also have swelling around the eyes, and less commonly the eyelids and your face. Rarely you might have a build up of fluid in other parts of the body, including the tummy and lungs. Contact your healthcare team if you notice any unusual swelling, feel breathless or have a bloated tummy.

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help. Rarely, you might see blood if you are being sick

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.

Diarrhoea

Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a ​stoma​, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.

Headaches

You might have headaches. Rarely, you might get a migraine. This is a severe headache with sickness and your eyes may be sensitive to light. Let your healthcare team know if you keep getting headaches, they can give you painkillers to help.

Indigestion

Contact your doctor or pharmacist if you have indigestion or heartburn. They can prescribe medicines to help.

Skin rash

Skin problems include a skin rash, dry skin and itching. Your skin may become sensitive to light, but this is less common. Rarely, patches of skin may become darker. Other rare changes include flaky skin on the scalp, elbows or lower back, or sore lips with blisters that can become inflamed. Or a rash with blisters on the skin. Other rare problems might include infection in the skin, causing swelling and redness, known as cellulitis. Speak to your healthcare team if you notice any changes in your skin.

Muscle and joint pain

You might feel some pain in your muscles and joints. Less commonly, you might have severe pain, swelling, or redness in your joints. Speak to your doctor or nurse about treatment to help with this.

Weight gain

You might gain weight while having this treatment. Or you might lose weight, but this is less common. You may be able to control it with diet and exercise. Your nurse will check your weight regularly during your treatment. Tell your healthcare team if you are finding it difficult to control your weight.

Tummy (abdominal) pain

You might get pain in your tummy with this treatment. You might also have a distended or bloated tummy, but this is less common. Rarely, you might get an infection, causing sickness, diarrhoea, and tummy pain. If you have these symptoms, your healthcare team will check the cause and give you medicine to help.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

• constipation

• liver changes. Rarely you might have inflammation of the liver, causing a high temperature, tummy pain, feeling sick and yellowing of the skin

• taste changes

• dizziness, rarely you might also feel your head is spinning or you might feel unsteady on your feet (vertigo)

• difficulty sleeping (insomnia)

• problems with your eyes, including dry itchy eyes, blurred vision, watering of your eyes, red patches in the whites of your eyes caused by bleeding and eye infections. Rarely you might have pain and inflammation of the eyelids

• changes in your appetite (anorexia)

• wind (flatulence)

• numbness in your hands or feet or loss of sensation and pain in different parts of the body. Rarely you might have cold or numb fingers and toes, that can sometimes be painful

• high temperature (fever)

• hair thinning or hair loss

• cough

• nosebleeds

• feeling cold, with shivers or shaking

• flushing

• dry mouth. You might also have a sore mouth and mouth ulcers, but this is rare

• inflammation of the lining of the stomach and digestive tract. Symptoms include feeling or being sick, indigestion, and loss of appetite. Rarely, you might have very dark looking poo

• night sweats

• difficulty swallowing

• difficulty breathing

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

• problems with your heart, including palpitations, a fast heartbeat, or difficulty pumping blood around the body

• chest pain and heart attack – if you have this, call 999 straight away

• breast pain and breast feeling bigger or pain in your nipples

• chest infection including pneumonia

• depression

• decreased interest in sex and low sex drive

• memory problems

• hearing problems including ringing in the ears (tinnitus)

• changes to your blood pressure

• irregular periods (menstruation)

• problems getting or maintaining an erection

• swollen scrotum

• sore throat, runny nose and nasal congestion, sneezing, and generally feeling weak

• flu or flu-like symptoms, with a high temperature, aches and pains and feeling very tired

• inflammation of the pancreas, symptoms include feeling and being sick, a high temperature, yellowing of the eyes and skin, and loss of appetite

• urine infection, this can cause burning or pain when you pee, peeing more often, cloudy or dark looking pee and feeling tired

• a serious complication of an infection that can be life threatening (sepsis)

• different types of blood conditions, where the body makes too many platelets, or too many or not enough white blood cells

• swollen lymph nodes around the body, you may notice swollen nodes in your neck, armpit and groin

• dehydration

• high blood sugar

• changes in your electrolytes such as higher levels of salts and minerals in your blood, you have regular blood tests to check this

• feeling very worried (anxiety)

• feeling very sleepy

• fainting or sudden loss of consciousness

• nerve pain in your back and legs

• shaky or trembling movements or feeling that you want to keep moving your legs

• bleed on the brain, symptoms include difficulty speaking, confusion, weakness in your arms and legs, feeling sick and loss of consciousness

• bruising that can also look like a lump

• burping

• kidney problems, including pain, blood in your pee, needing to wee more often, and renal failure

Other side effects

There isn't enough information to work out how often these side effects might happen. You might have one or more of them. They include:

• changes to the levels of chemicals in your blood due to the breakdown of tumour cells (tumour lysis syndrome) - you have regular blood tests to check for this

• a condition where small blood vessels are damaged. The symptoms you have depend on where the damaged blood vessels are. They can include dizziness, shortness of breath, bruising, bleeding, confusion, fits (seizures) and pain

• Stevens Johnson syndrome (SJS) -a severe skin reaction that may start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish, and your eyes may be more sensitive to light. This is serious and could be life threatening

Coping with side effects

We have more information about side effects and tips on how to cope with them.

Read more about how to cope with side effects

What else do you need to know?

Other medicines, food and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you're having treatment and for at least 15 days after stopping treatment.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner becomes pregnant while having treatment.

Fertility

It is not known whether this treatment affects fertility in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.

Men might be able to store sperm before starting treatment. And women might be able to store eggs or ovarian tissue. But these services are not available in every hospital, so you would need to ask your doctor about this.  

Breastfeeding

Don’t breastfeed during this treatment and for at least 15 days after you finish your treatment. This is because the drug may come through into your breast milk.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.

Immunisations

Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having.

Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, and yellow fever.

You can usually have:

• other vaccines, but they might not give you as much protection as usual

• the flu vaccine (as an injection)

• the coronavirus (COVID-19) vaccine

Talk to your doctor or pharmacist about the best time to have a vaccine in relation to your cancer treatment.

Contact with others who have had immunisations 

You can be in contact with other people who have had live vaccines as injections. If someone has had a live vaccine by mouth or nasal spray there may be a small risk the vaccine virus can be passed onto you if your ​immune system​ is weakened.

Your healthcare team will let you know if you need to take any precautions if you are in close contact with someone who has had a live vaccine.

Read more about immunisations and cancer treatment

Children and adolescents

Some children and adolescents taking imatinib may have slower than normal growth. The treatment team will monitor this carefully.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

eMC website

You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.

Report a side effect to the MHRA