A targeted cancer tablet
Imatinib
A targeted cancer tablet for chronic myeloid leukaemia and some other cancers, started and monitored by specialists.
What is Imatinib?
Imatinib is a targeted cancer tablet known as a tyrosine kinase inhibitor. It was a landmark treatment for chronic myeloid leukaemia (CML) and is also used for a type of stomach and bowel tumour called GIST, as well as some other cancers driven by particular gene changes. It is started and closely monitored by a cancer or blood specialist but taken regularly at home, usually with food and a large glass of water. Common effects include fluid retention and puffiness, nausea, muscle cramps and low blood counts. It has many drug interactions, so always check before adding anything, and avoid grapefruit.
Education and reference only. This is a plain-language guide to Imatinib — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Imatinib is a targeted cancer therapy, one of the first of a group called tyrosine kinase inhibitors. Unlike traditional chemotherapy, it is designed to block a specific faulty signal that drives certain cancer cells to grow. It is best known for transforming the outlook in chronic myeloid leukaemia, and is also used in gastrointestinal stromal tumours (GIST) and some other rarer conditions. It is a tablet taken by mouth at home, but treatment is always begun and overseen by an oncology or haematology team.
How it works
Many of the cancers imatinib treats are driven by an overactive enzyme (a tyrosine kinase) that constantly tells the cells to multiply. Imatinib blocks this faulty signal, slowing or stopping the growth of the cancer cells while largely sparing healthy ones. In chronic myeloid leukaemia this can bring the disease under deep, lasting control. Because it works on a precise target, it is taken continuously and its effect is tracked with regular blood and specialist tests.
Company & origin
Originated / developed by: Originally Novartis (now also generic).
A landmark targeted cancer tablet used in the UK for certain leukaemias and other cancers driven by specific gene changes.
Practical use
How to take Imatinib
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- Take it with food and a large glass of water to reduce stomach upset, at around the same time each day.
- Take it exactly as your specialist team prescribes and do not change or stop it on your own, even if you feel well.
- Avoid grapefruit and grapefruit juice, which can raise the level of the medicine in your body.
- Check with your cancer team or pharmacist before starting any new medicine, supplement or herbal remedy, as many interact.
- Report swelling, sudden weight gain, breathlessness, signs of infection or unusual bleeding or bruising promptly.
Weighing it up
Advantages & disadvantages of Imatinib
Advantages
- A landmark targeted tablet that transformed the outlook for chronic myeloid leukaemia.
- Taken at home as a tablet rather than given as an infusion, while overseen by specialists.
- Works on a specific cancer target, so it can spare healthy cells more than traditional chemotherapy.
Disadvantages
- Commonly causes fluid retention and puffiness, nausea, muscle cramps and tiredness.
- Can lower blood counts, raising the risk of infection, bleeding and anaemia.
- Has many drug and grapefruit interactions, so combinations must be checked carefully.
Practical use
Good to know
Imatinib often causes some fluid retention, so you may notice puffiness around the eyes, swollen ankles or sudden weight gain — tell your team if this happens, especially with breathlessness. It is processed by the same liver enzyme as many other medicines, so it has a long list of interactions and grapefruit can raise its levels; always check before starting anything new, including over-the-counter remedies and supplements. Report signs of infection (fever, sore throat), unusual bleeding or bruising, as it can lower your blood counts. Take it with food and a large glass of water to ease stomach upset. Do not stop it on your own, even if you feel well, as the cancer can come back; pregnancy must be avoided while taking it.
Who should not take it / use with caution
- It must not be used in pregnancy, and effective contraception is needed because it can harm an unborn baby.
- It is used with caution, and extra monitoring, in people with liver, kidney or heart problems.
- People taking medicines that strongly interact with it may need those changed or carefully managed by the specialist team.
Monitoring
- Regular blood tests to track the leukaemia response and check blood counts and liver function.
- Watching for fluid retention, weight gain and swelling at each review.
- Specialist tests to measure how well the cancer is responding over time.
Side effects
- Fluid retention with puffiness or swollen ankles, nausea, diarrhoea, muscle cramps and tiredness are common.
- Low blood counts can cause infections, easy bruising or bleeding and anaemia, so are monitored.
- Less commonly, skin rashes, liver changes or more serious fluid build-up that need prompt review.
Key interactions
- Processed by the same liver enzyme as many medicines, so some antibiotics, antifungals, epilepsy and heart drugs can change its level.
- Grapefruit and grapefruit juice can raise the level of imatinib and should be avoided.
- It can affect the level of other medicines, including some blood thinners such as warfarin, so monitoring may be needed.
Available as: Tablets taken by mouth.
Answers
Imatinib: frequently asked questions
Why do I need to take imatinib with food and water?
Taking it with food and a large glass of water helps reduce stomach upset and nausea, which are common when starting treatment.
Can I stop taking it if I feel completely well?
No. Even when the disease is well controlled and you feel fine, stopping on your own can let the cancer return; any change must be decided with your specialist team.
Why must I avoid grapefruit?
Grapefruit affects the liver enzyme that processes imatinib, which can raise its level in your body and increase side effects, so it is best avoided.
What is the swelling and puffiness I have noticed?
Imatinib commonly causes some fluid retention, leading to puffiness around the eyes or swollen ankles; tell your team, especially if it is sudden or comes with breathlessness.
Is it safe to take other medicines alongside it?
Imatinib interacts with many medicines and supplements, so always check with your cancer team or pharmacist before starting anything new, including over-the-counter products.
Authoritative sources
- BNF
- NICE CKS
Building a medicines information resource?
We create evidence-led, dose-free drug and formulary references for teams.