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Lapatinib is a targeted therapy drug. These drugs work by �targeting� specific proteins (receptors) that make cancer cells grow. Lapatinib works by blocking the action of two proteins:

  • epidermal growth factor receptor (EGFR)
  • human epidermal growth factor receptor 2 (HER2).


This can cause the cells to die or to grow more slowly. You may have tests to measure levels of EGFR or HER2 in the cancer cells. This is to find out if lapatinib is a helpful treatment for you.


Lapatinib is used to treat women with HER2 positive breast cancer that has spread to other parts of the body (secondary or metastatic breast cancer).

It is given with a chemotherapy tablet called capecitabine, or in combination with hormonal therapy. It can also be given with another targeted therapy drug called trastuzumab(Herceptin �). 


The National Institute for Health and Care Excellence (NICE) currently gives advice on which new drugs or treatments should be available on the NHS in England and Wales. The Scottish Medicines Consortium (SMC) makes recommendations on the use of new drugs in the NHS in Scotland. Neither NICE nor the SMC recommend the use of lapatinib. This means that lapatinib may not be available on the NHS, but it may be given as part of a clinical trial.


Lapatinib is given as tablets, which you take once a day. Take the tablets with a glass of water, either an hour before or after food, and at the same time each day. For example, you could always take your tablets one hour before breakfast. Don�t take lapatinib with food or with grapefruit juice.

Always take your tablets exactly as your nurse or pharmacist explained. This is important to make sure they work as well as possible for you.


There are some important things to remember when taking your tablets:

  • If you forget to take your tablets, take them as soon as you remember. This is unless it�s nearly time for your next dose - don�t take a double dose.
  • Keep tablets in the original package and at room temperature, away from heat and direct sunlight.
  • Keep them safe and out of the reach of children.
  • Get a new prescription before you run out of tablets and make sure you have plenty for holidays.
  • Return any unused tablets to the pharmacist if your treatment is stopped.


If you're sick just after taking the tablets, let your doctor know. You may need to take another dose. Don't take another dose without telling your doctor, nurse or pharmacist first.


Each person�s reaction to cancer treatment is different. Some people have very few side effects while others may experience more. The side effects described here won't affect everyone being treated with lapatinib.

We have outlined the most common side effects but haven't included those that are rare and therefore unlikely to affect you. If you notice any side effects that aren't listed here, discuss them with your doctor or specialist nurse.


Because lapatinib is given with other cancer treatments, some side effects may be linked with, or increased because of other treatments.


Common side effects may include:


  • Diarrhoea

This is the most common side effect of lapatinib. It usually develops within the first week after treatment. Tell your cancer doctor or nurse straight away if you have diarrhoea. It�s important to get it treated quickly.

Your doctor can prescribe anti-diarrhoea drugs to control it. It�s important to take them exactly as your nurse or pharmacist explains. Make sure you drink at least two litres (three and a half pints) of fluids every day if you have diarrhoea. If the anti-diarrhoea drugs don�t work quickly, or you still have diarrhoea after 24 hours, contact the hospital straight away on the numbers your nurse gave you.


  • Skin changes

You may develop an acne-like rash and your skin may also become dry and itchy, or feel tender and peel.

The palms of your hands and the soles of your feet may become red and sore, especially if you are having lapatinib with capecitabine. Always tell your doctor or nurse about any skin changes. 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.

It may help to do the following:

  • Wash with tepid water using mild, unperfumed, soap-free cleansers.
  • Moisturise your skin regularly with unperfumed moisturisers � ask your doctor or nurse what�s best.
  • Do not use anti-acne products or any products containing alcohol on your skin.
  • Wear sunscreen with a sun protection factor (SPF) of at least 30 when you�re in the sun.


  • Tiredness (fatigue)

Feeling very tired is a common side effect. Try to pace yourself and get as much rest as you need. It helps to balance this with some gentle exercise, such as short walks. If you feel sleepy, don�t drive or operate machinery.


  • Feeling sick

Your doctor can prescribe very effective anti-sickness (anti-emetic) drugs to help prevent, or control sickness. If it isn't controlled, or if it continues, tell your doctor. They can prescribe other anti-sickness drugs that may be more effective.

Indigestion and heartburn

This is a common side effect, which can usually be relieved by taking an antacid. You should take the antacid at least an hour before or after taking lapatinib. Let your doctor or nurse know if you have any indigestion that isn�t relieved.


  • Stomach cramps and bloating. Let your doctor know if you get any stomach cramps or bloating. They can prescribe medicines that will help relieve this.


  • Some people lose their appetite. This can be mild and may only last a few days. If your appetite 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 keeping to a healthy weight.


  • Your mouth may become sore or dry, or you may get small mouth ulcers. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help to reduce the risk of this happening. Tell your nurse or doctor if you have any mouth problems. They can prescribe mouthwashes and medicine to prevent or clear mouth infections.


  • You may get constipated. This can usually be helped by drinking plenty of fluids, eating more fibre in your diet and doing some gentle exercise. You may need to take medicine (laxatives) to help. Your doctor can prescribe these or you can buy them at a pharmacy.
  • You may have joint or muscle pains, especially in your back. Let your doctor know if you develop these as they can prescribe painkillers.
  • Some people find that lapatinib causes headaches. Let your doctor or nurse know if you get headaches. They can give you painkillers to relieve this.
  • Some people find they have trouble sleeping while taking lapatinib. Using relaxation techniques or CDs may help. If you experience this, talk to your doctor.
  • Contents

    Contains 70 Tablets.

  • Active Ingredient

    Lapatinib Ditosylate Monohydrate

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