Stomach cramps and bloating Let your doctor know if you get any stomach cramps or bloating. If necessary they can prescribe medicines to help relieve this.
Loss of appetite A dietitian or specialist nurse at your hospital can give advice about how to boost your appetite, cope with eating difficulties and maintain your weight.
Mouth sores and ulcers Your mouth may become sore and you may notice small ulcers during your treatment. Drink plenty of fluids and clean your teeth regularly and gently with a soft toothbrush, as this can help to reduce the risk mouth problems. Tell your nurse or doctor if you have these problems, as special mouthwashes and medicines to prevent or clear mouth infection, can be prescribed.
Constipation This 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 to stimulate your bowel (laxatives). These can be prescribed by your doctor.
Muscle and joint pains You may notice that you have muscle or joint pains, especially in your back. Let your doctor know if you develop these as they can prescribe painkillers.
Headaches These can usually be controlled with simple painkillers. Let your doctor know if the headaches are severe or are not relieved with painkillers.
Difficulty sleeping Some people find that they have trouble sleeping while taking lapatinib. Having a warm bath or a hot milky drink before bed can be helpful. Using relaxation techniques or CDs may also help. If you still have trouble sleeping, talk with your doctor about night sedation.
Your liver may be temporarily affected Rarely lapatinib may cause changes in the way that your liver works, although it will return to normal when the treatment is finished. The changes are unlikely to cause you any harm, but your doctor will monitor this carefully. Samples of your blood will be taken from time to time to check that your liver is working properly.
Changes in the way your heart works Lapatinib may cause changes in the muscle of the heart. This can affect how the heart works. Tests to see how well your heart is working may sometimes be carried out before the drug is given and during treatment.