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Macmillan and Cancerbackup merged in 2008. Together we provide free, high quality information for people affected by cancer through our publications, website and phone service. Find out more|.
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This information is about lapatinib, which is also known as Tyverb®. It is mainly being used to treat women with advanced breast cancer|, but it's also being tested as a treatment for people with other cancers|.
Lapatinib belongs to a group of cancer drugs known as tyrosine kinase inhibitors|.
Some cancer cells have proteins called growth factor receptors on their surface. Stimulation of these receptors activates a protein inside the cell called tyrosine kinase. This can prompt the cancer cell to grow.
Specific drugs have been developed to stop (inhibit) tyrosine kinase, and so stop the growth factor receptor from activating the cancer cell. These drugs are known as tyrosine kinase inhibitors (TKIs).
A group of growth factor receptors known as the erbB or HER receptors are found on some types of cancer cells. Lapatinib targets two of these receptors:
Lapatinib stops the action of EGFR and HER2. It targets the inside part of the receptors, and so prevents tyrosine kinase from being activated, which may stop the cell dividing. Lapatinib may therefore stop the cancer cells from growing.
Lapatinib works in a different way from chemotherapy| and hormonal therapy|. It also works differently to trastuzumab (Herceptin®)|, which is another treatment for HER2 that targets and blocks the outside part of the growth factor receptor.
Tests may be done to check the level of EGFR or HER2. These will tell if you are likely to benefit from lapatinib. Testing can be done at the same time as diagnosis, or samples of cancer cells from previous biopsies or surgery may be used.
Lapatinib is available as 250mg oval, yellow tablets.
Lapatinib should be taken at the same time every morning, an hour before or after food. It should not be taken with grapefruit juice.
Lapatinib is mainly used to treat people with HER2 positive breast cancer| that has spread to other parts of the body (advanced or metastatic breast cancer).
When used to treat advanced breast cancer, lapatinib is either given with a chemotherapy tablet called capecitabine (Xeloda®)| or in combination with a type of hormonal therapy.
Lapatinib is also being researched as a treatment for other types of cancer. Your doctor or specialist nurse may invite you to take part in a lapatinib research trial|. It's being studied for use in earlier stages of breast cancer and in other types of cancer, such as stomach cancer| and head and neck cancer|.
Although lapatinib is licensed and can be prescribed in the UK, it may not be widely available on the NHS. We have more information on what to do if a treatment isn't available|.
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 that can occur with lapatinib. Any side effects are generally mild, but as it's a new treatment, not all the possible side effects are known. Because lapatinib is given with other cancer treatments, you may also get side effects associated with these other treatments. If you notice any effects that aren't listed here, discuss them with your doctor or nurse.
This is the most common side effect of lapatinib and develops about one week after treatment. Tell your doctor if you have diarrhoea|, as they can recommend medicines that can help. It is important to drink plenty of fluids if you develop this problem.
You may develop an acne-like rash that affects the head, chest and back. This usually begins during the first 2–3 weeks of treatment and may gradually fade over the following weeks, even if you continue to have treatment.
Your skin may also become dry and itchy or feel tender and peel. Let your doctor know if you develop these side effects as they can prescribe medicines to help.
Taking the following steps while having treatment with lapatinib may help reduce the severity of skin changes, although it may not prevent them completely:
You may feel very tired| during treatment. It may help to balance periods of rest with some gentle exercise such as walking.
Your doctor can prescribe anti-sickness (anti-emetic)| drugs to prevent, or greatly reduce, nausea. If the sickness isn't controlled, or if it continues, tell your doctor; they can prescribe other anti-sickness drugs that may be more effective.
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 your lapatinib. Let your doctor or nurse know if you have any indigestion that isn’t relieved.
Let your doctor know if you get any stomach cramps or bloating as they can prescribe medicines.
A dietitian or specialist nurse at your hospital can give advice about how to boost your appetite|.
Your mouth may become sore| and you may notice small ulcers during your treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush can help reduce the risk of this happening. Tell your nurse or doctor if you have any of these problems, as they can prescribe mouthwashes and medicines to prevent or clear mouth infections.
Constipation| can usually be relieved by drinking plenty of fluids, eating a high-fibre diet and taking gentle exercise. Sometimes you may need to take medicines (laxatives) to stimulate your bowel. These can be prescribed by your doctor.
You may have muscle or joint pains, especially in your back. Let your doctor know if you develop these as they can prescribe painkillers|.
These can usually be controlled with painkillers. Let your doctor know if the headaches are severe or are not relieved by painkillers.
Some people find that they have trouble sleeping while taking lapatinib. Using relaxation techniques or CDs may also help. If you still have trouble sleeping, talk with your doctor about night sedation.
Rarely lapatinib may cause temporary changes in the way your liver| works. The changes are unlikely to cause you any harm, but your doctor will monitor this carefully.
Lapatinib may cause changes in the muscle of the heart. This can affect how the heart works. Tests to montior how well your heart is working may be carried out before and during treatment.
It's important to let your doctors know straight away if you feel unwell or have any severe side effects, even if they're not mentioned above.
Taking some types of medicines can be harmful when you're being treated with lapatinib. Some drugs can interfere with how well lapatinib works. Tell your doctor about any medicines you're taking, including over-the-counter drugs and non-prescribed drugs such as complementary therapies| and herbal drugs|.
Your ability to become pregnant or father a child may be affected by taking this drug. It's important to discuss fertility| with your doctor before starting treatment.
It's not advisable to become pregnant or father a child while having lapatinib, as it may harm the developing baby. It’s important to use effective contraception while having this drug, and for at least a few months afterwards. You can discuss this with your doctor.
It’s not known whether biological therapies can be present in semen or vaginal fluids. To protect your partner it’s safest to either avoid sex or use a barrier form of contraception for about 48 hours after treatment.
This section has been compiled using information from a number of reliable sources including:
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.