Imatinib (Glivec)

Imatinib is pronounced im-at-tin-ib. It is a type of biological therapy 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.

Imatinib blocks these protein kinases and stops the cancer cells growing. It is also known by its brand name Glivec (pronounced glee-vec).

Imatinib is a treatment for

• Chronic myeloid leukaemia which is Philadelphia chromosome positive
• GIST – a rare type of stomach cancer
• Acute lymphoblastic leukaemia which is Philadelphia chromosome positive
• A rare type of sarcoma called dermatofibrosarcoma protuberans
• Adults with myelodysplastic disorders
• Adults with myeloproliferative disorders
• Adults with advanced HES (hypereosinophilic syndrome) or chronic eosinophilic leukaemia

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

You have imatinib as a tablet that you swallow whole, with a glass of water after food. If you can’t swallow the tablets, you can dissolve them in a glass of mineral water or apple juice. Drop the whole tablets into the fluid, and stir with a spoon until the tablets have broken up completely. Then drink the whole glassful.

It is very important that you take tablets according to the instructions your doctor or pharmacist gave you. Whether you have a full or empty stomach, for example, can affect how much of a drug gets into your bloodstream. You should take the right dose, not more or less. And never stop taking a cancer drug without talking to your specialist first.

You have the imatinib either once or twice a day, depending on the dose you are taking. 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.

The side effects associated with imatinib are listed below. Remember, most people won’t have all of them.

More than 10 in every 100 people have one or more of the side effects listed below.

Temporary drop in the number of blood cells made by the bone marrow, causing

• Increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, sore throat, pain passing urine or feel cold and shivery
• Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
• Bruising easily due to a drop in platelets – you may have nosebleeds, bleeding gums after brushing your teeth, or lots of tiny red spots or bruises on your arms or legs (known as petechia)

Some of these side effects can be life threatening, particularly infections. You should contact your doctor if you have any of these effects. Your doctor will check your blood counts regularly to see how well your bone marrow is working.

Other common side effects include

• Fatigue during and after treatment in about 3 out of 10 people (30%) – most people find that their energy levels are back to normal within 6 months to a year
• Fluid build up in about 6 out of 10 people (60%) – it may cause weight gain, or fluid around the lungs, making you feel breathless. Rarely, you may also get fluid in your abdomen and around your eyes
• Feeling sick in about 3 in 10 people (30%) – this is usually well controlled with anti sickness medicines
• Diarrhoea in about 1 in 3 people (30%) – drink plenty of fluid and tell your doctor if diarrhoea becomes severe, or continues for more than 3 days
• Headaches
• Indigestion
• Loss of appetite
• A skin rash in about 4 out of 10 people (40%) – your skin may be dry and itchy
• Weakness
• A high temperature (fever) and night sweats
• Loss of fertility – we don’t know exactly what effect this drug may have on your fertility, so talk to your doctor before starting treatment if having a baby is important to you
• This drug may have a harmful effect on a developing baby – do talk to your doctor about contraception before having treatment if there is any chance that you or your partner could become pregnant

Between 1 and 10 in every 100 people have one or more of these.

• Constipation – your doctor or nurse may give you laxatives to help prevent this but do tell them if you are constipated for more than 3 days
• A sore mouth
• A mild effect on the liver – you are unlikely to notice any symptoms from this and your liver will almost certainly go back to normal after the treatment finishes. Your doctor will do regular blood tests to check how your liver is working

Fewer than 1 in 100 people have these.

• A build up of fluid around the heart, causing low blood pressure
• Breast tenderness and swelling – doctors think this is because imatinib lowers the amount of the sex hormone (testosterone)

The side effects above may be mild or more severe. A side effect may get worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

• How many times you've had the drug before
• Your general health
• The amount of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so that they can help you manage them. Your specialist, clinic or ward nurse should give you a contact number. You can ring if you have any questions or problems. They can give you advice or reassure you. If in doubt, call them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies – some drugs can react together. Also, if you want to start taking any new medicine or supplement while you are taking imatinib, you should talk to your doctor first. Some drugs can reduce the effectiveness of imatinib.

You should not have immunisations with live vaccines while you are having treatment or for 6 months afterwards if your level of neutrophils (white blood cells) is low. But you can have live vaccines if your level of white blood cells is normal. Your doctor can tell you if it is OK for you to have vaccines. 

In the UK, live vaccines include rubella, mumps, measles (usually given together as MMR), BCG and yellow fever. You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with oral vaccines, but not many people in the UK have oral vaccines now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.