Imatinib

Imatinib is a targeted therapy drug used to treat some types of leukaemia, blood disorders and cancers. It is best to read this information with our general information about the type of cancer you have.

Imatinib is given as tablets and you usually have it as an outpatient. Your cancer doctor or nurse will tell you how often you will have it.

Like all targeted therapy drugs, imatinib can cause side effects. Some of the side effects can be serious, so it’s important to read the detailed information below. How targeted therapy affects people varies from person to person. Your healthcare team can talk to you more about this and give you advice on how to manage any side effects.

Tell your doctor or nurse straight away if you:

  • have a temperature
  • feel unwell
  • have severe side effects, including any we do not mention here.

Rarely, side effects may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

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 imatinib works

Imatinib is a targeted therapy. It is used to treat some types of leukaemia, blood disorders and cancers. It is best to read this with our information about the type of cancer you have.

Imatinib is a tyrosine kinase inhibitor (TKI). Tyrosine kinases are proteins in the body that control how cells grow and divide. Imatinib blocks (inhibits) signals in the cancer cells that make them grow and divide. Blocking the signals causes the cells to die.

How targeted therapies work

This animation shows how targeted therapies work and what effect they have on the body.

About our cancer information videos

How targeted therapies work

This animation shows how targeted therapies work and what effect they have on the body.

About our cancer information videos


When imatinib is used

Imatinib may be used to treat:

It may also be used to treat:

  • gastro-intestinal stromal tumours (GISTs), a rare type of cancer that affects the supporting tissue of the bowel or stomach
  • dermatofibrosarcoma protuberans (DFSP), a rare type of cancer that affects the tissue under the skin
  • other types of cancers as part of a clinical trial.

Imatinib is usually available for CML and GIST. For other conditions and cancers, it may only be available in some situations. Your cancer doctor can tell you if it is suitable for you. Some people may be given it as part of a clinical trial. If a drug is not available on the NHS, there may be different ways you are still able to have it. Your cancer doctor can give you advice.


Taking imatinib

You normally take imatinib once a day. People taking a higher dose (800mg a day) usually take this in two doses of 400mg. You should take the tablets with a meal and a large glass of water.

If you find it hard to swallow the tablets, tell your doctor. They may suggest that you dissolve them in still water or apple juice. The liquid should be about 50ml for a 100mg tablet and 200ml for a 400mg tablet. Stir the liquid with a spoon until the tablets are completely dissolved and drink it immediately. Wash the glass and spoon straight away.

If you are sick just after taking the tablets, contact the hospital. You may need to take another dose.

If you forget to take a tablet, take it as soon as you remember, unless it is nearly time for your next dose. It is important that you do not take a double dose. Keep to your regular schedule and tell your doctor or nurse .

Here are some other things to remember about your tablets:

  • Keep them in the original package and at room temperature, away from heat and direct sunlight.
  • Keep them safe and out of the reach of children.
  • If your treatment is stopped, return any remaining tablets to the pharmacist.


Possible side effects of imatinib

We explain the most common side effects of imatinib here. We have also included some less common and rarer side effects. You may get some of the side effects we mention, but you will not get them all.

If you are also taking other anti-cancer drugs, some side effects may be worse. You may also have side effects not listed here.

Your doctor can prescribe drugs to help control some side effects. It is very important to take them exactly as your nurse or pharmacist has explained.

Your nurse will give you advice about managing side effects. Always tell your doctor or nurse about the side effects you have. After your treatment is over, side effects will slowly 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

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.

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 shaky
  • a sore throat
  • a cough
  • diarrhoea
  • needing to pass urine a lot.

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.

Bruising and bleeding

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot. Tell your doctor or nurse if you have any bruising or bleeding that you can’t explain. This includes:

  • nosebleeds
  • bleeding gums
  • tiny red or purple spots on the skin that may look like a rash.

Anaemia (low number of red blood cells)

This treatment can reduce the number of red blood cells in your blood. These cells carry oxygen around the body. If the number of red blood cells is low, you may be tired and breathless. Tell your doctor or nurse if you feel like this.

If you are very anaemic, you may need a drip to give you extra blood cells. This is called a blood transfusion.

Feeling sick

This is usually mild. Your doctor can prescribe anti-sickness (anti-emetic) drugs to prevent or reduce sickness and vomiting. Taking imatinib with food also helps. Tell your doctor if the sickness isn't controlled or if it continues. They can give you other anti-sickness drugs that may work better for you.

Diarrhoea

If you have diarrhoea, contact the hospital for advice. Try to drink at least 2 litres (3½ pints) of fluids every day. It can help to avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods.

Headaches

This treatment may cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers.

Leg aches or cramps

If you are worried about these, tell your doctor. They can give you drugs to make you more comfortable.

Build-up of fluid

This is fairly common. It is not usually harmful, but can be upsetting. Many people gain weight or develop swelling around the eyes and ankles because of fluid build-up. Drugs that make you pass more urine (diuretics) can help get rid of some fluid, but it often settles down by itself. If you put on a lot of weight quickly, let your doctor know.

Effects on the eyes

Imatinib can cause eye pain, dry or watery eyes, or changes in vision. If your eyes are affected, tell your doctor. You should be careful when driving or operating machinery if your vision has changed.

Skin changes

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

Always tell your doctor or nurse about any skin changes or if they get worse. They can give you advice and may prescribe creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.

Changes to your taste or loss of appetite

You may notice changes to your taste or lose your appetite while you are having imatinib. This can be mild and may only last a few days. If it doesn’t improve, you can ask to see a dietitian or specialist nurse at your hospital. They can give you advice on improving your appetite and coping with taste changes.

Indigestion

Some people have indigestion when taking imatinib. They may also have acid reflux, which is when acid comes up from the stomach and into the gullet. If this happens, tell your doctor.e at your hospital. They can give you advice on improving your appetite and coping with taste changes.

Difficulty sleeping

If you are finding it difficult to sleep, tell your doctor.

Feeling tired

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.

Cough or breathlessness

You may feel breathless or develop a cough. Contact your doctor for advice if you develop these symptoms.

Effects on the liver

Imatinib may cause changes in the way that your liver works. Your doctor will take blood samples to check your liver is working properly.

Hepatitis B

If you have had Hepatitis B (a liver infection) in the past, imatinib can make it active again. Your doctor or nurse will talk to you about this and test you for Hepatitis B. It is important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they are not mentioned above.


Other information about imatinib

Other medicines

Some medicines can be harmful when you are taking imatinib. This includes medicines you can buy in a shop or chemist. They may make imatinib less effective or increase the side effects it can cause. Tell your doctor and check with your pharmacist about any medicines you are taking, including over-the-counter drugs such as paracetamol, complementary therapies and herbal drugs.

People taking thyroid treatment

If you have had your thyroid removed and are taking levothyroxine, talk to your doctor. Imatinib can affect how levothyroxine works.

Effects on the heart

If you have heart problems, these may be made worse by imatinib. Your doctor will monitor you during your treatment to check for any problems. If you have chest pains or any worsening symptoms, speak to your doctor immediately.

Fertility

Imatinib may affect whether you can get pregnant or father a child. If you are worried about this, talk to your doctor before treatment starts.

Contraception

Women are advised not to become pregnant during their treatment. This is because imatinib may harm a developing baby. It is important to use contraception during treatment and for several months afterwards. You can talk to your doctor or nurse about this.

Breastfeeding

Women are advised not to breastfeed during treatment and for a few months afterwards. This is in case there is any imatinib in their breast milk.

Lactose intolerance

Some brands of imatinib contain a small amount of lactose. If you have a lactose intolerance, talk to your doctor before you start taking this.

Medical treatment

If you need to go into hospital for any reason, always tell the doctors and nurses that you are having treatment with imatinib. You shouldn’t stop or restart imatinib without advice from your cancer doctor. Tell the doctors and nurses the name of your cancer doctor so they can ask them for advice.