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Lapatinib tablets


Lapatinib is given for the treatment of breast cancer. It is taken once a day, either one hour before a meal or one hour afterwards.

You will need to have regular check-ups so it is important that you keep your appointments with your doctor and/or hospital.

Contact your doctor straightaway if you feel short of breath or develop severe diarrhoea.

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About lapatinib

Type of medicine

A tyrosine kinase inhibitor chemotherapy medicine

Used for

Treatment of breast cancer

Also called


Available as


Lapatinib is a medicine which is given for the treatment of breast cancer which has progressed despite other treatment, or which has spread into other areas of your body. It is taken alongside other anti-cancer medicines.

In cancer, certain cells in the body grow and multiply in a way that is 'out of control'. Chemotherapy (anti-cancer) medicines work by inhibiting the way cells grow and increase in number. Lapatinib belongs to a group of anti-cancer medicines known as tyrosine kinase inhibitors. These medicines work by blocking the chemical messengers (called tyrosine kinases) which send signals to cells to grow. This in turn stops cancer cells from growing and spreading.

Before taking lapatinib

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking lapatinib it is important that your doctor knows:

  • If you have an infection or feel particularly unwell.

  • If you have any problems with the way your liver works, or any problems with the way your kidneys work.

  • If you have a heart condition or if you have been told you have an unusual heart rhythm.

  • If you are pregnant or breastfeeding.

  • If you are taking or using any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.

  • If you have ever had an allergic reaction to a medicine.

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How to take lapatinib tablets

  • Before you start the treatment, read any printed information you have been given by your doctor and the printed manufacturer's leaflet from inside the pack of tablets. These will give you more information about lapatinib and will provide a full list of the side-effects which you may experience from taking it.

  • Lapatinib will be prescribed for you by a specialist doctor who is experienced in treating your condition. It is important that you take the tablets exactly as you are told to. You will be asked to take one dose of lapatinib each day. The number of tablets that you will be asked to take for each dose will depend upon what other treatment you are having - it will be in the range of 4-6 tablets per dose. The directions for taking the tablets will be printed on the label of the pack to remind you, but should you have any concerns, contact your doctor or hospital clinic for further advice.

  • Swallow the tablets with a drink of water.

  • Take lapatinib at the same time of day each day, as this will help you to remember to take your doses regularly. You can choose whether to take the tablets before or after meals, but you should continue to take all of your doses in the same way. So, either always take your doses one hour before meals, or always one hour afterwards.

  • If you forget to take a dose, make sure you remember to take your next dose when it is due. Do not take two doses on the same day to make up for a forgotten dose.

  • Do not drink grapefruit juice while you are on lapatinib. This is because a chemical in grapefruit juice can interfere with the amount of lapatinib in your bloodstream.

Getting the most from your treatment

  • You must try to keep your regular appointments with your doctor or hospital. This is so your doctor can check on your progress. You will need to have regular check-ups during treatment. If at any time you feel short of breath or if you develop a high temperature (fever) or a dry cough, you must let your doctor know about it straightaway so that it can be investigated.

  • If you buy or take any other medicines, check with a pharmacist that they are suitable to take alongside lapatinib. You should not take any preparations which contain St John's wort (a herbal remedy used for low moods), as these can reduce the effectiveness of lapatinib.

  • If you are having an operation or dental treatment, always tell the person carrying out the treatment which medicines you are taking.

  • It is important that you do not get pregnant while you are taking lapatinib. If relevant, make sure you discuss with your doctor which types of contraception are suitable for you and your partner.

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Can lapatinib tablets cause problems?

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with lapatinib. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Very common lapatinib side-effects (these affect more than 1 in 10 people)

What can I do if I experience this?


Drink plenty of water. If this continues or becomes severe, you should let your doctor know

as soon as possible

Feeling sick (nausea) or being sick (vomiting), indigestion, abdominal (tummy) discomfort

Stick to simple meals - avoid rich or spicy foods

Cough, feeling short of breath

Speak with your doctor

as soon as possible

Feeling tired

Do not drive and do not use tools or machines unless you feel well enough

Headache, sore mouth, constipation, aches and pains

Ask your doctor or pharmacist to recommend a suitable remedy

Loss of appetite, sleeping problems, hot flushes, nosebleeds, loss or thinning of hair, itchy rash

If any become troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to the tablets, ask your doctor or pharmacist for advice.

How to store lapatinib

  • Keep all medicines out of the reach and sight of children.

  • Store in a cool, dry place, away from direct heat and light.

  • Please return any unused or unwanted tablets to your clinic or pharmacy to destroy.

Important information about all medicines

Important information about all medicines

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Report side effects to a medicine or vaccine

If you experience side effects, you can report them online through the Yellow Card website.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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