Lapatinib is used together with other medicines to treat breast cancer.
Take Lapatinib exactly as directed by your doctor or according to the instructions on the label. Do not take more or less than instructed by your doctor.
This medicine should be taken on an empty stomach, at least 1 hour before or 1 hour after a meal. Try to take it at the same time each day.
Lapatinib must be taken regularly for it to be effective. Continue taking this medicine even when you feel better. Do not stop taking it unless instructed by the doctor.
Take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and return to your normal dosing schedule.
DO NOT double a dose under any circumstances.
If you often forget to take your medicine, let your doctor and pharmacist know.
Inform your doctor if you have liver disease.
It is important that you do not get pregnant while being treated with this medicine. You may wish to discuss birth control methods with your doctor or pharmacist.
Do not breastfeed while you are being treated with this medicine.
Some genetic traits can cause serious side effects from Lapatinib. If you have certain pair of genes called HLA-DRB1*07:01 and HLA-DQA1*02:01, you are more likely to develop liver injury. Your doctor may perform genetic testing before giving you this medicine. If you have or even if you don’t have these gene types, your doctor may need to monitor your liver function while being treated with this medicine.
Lapatinib may cause any of the following side effects: headache, nausea, vomiting, diarrhea, indigestion, stomach pain, difficulty sleeping, loss of appetite, mouth ulcers, tiredness, weakness, limb pain, back pain, nosebleed, rashes, nail disease (e.g. nail fold infection), hair loss, dry skin, and itching.
Some side effects may need immediate medical help. Alert your doctor quickly if you experience any of the following:
- irregular or abnormal heartbeat
- squeezing sensation of the chest
- rashes with skin peeling or blisters/rashes with peeling of the skin or blistering of the lips, mouth or eyes accompanied by fever
- difficulty breathing, dry cough
- severe diarrhea (having more than 10 loose, watery stools in a day)
Inform your doctor if any of these side effects do not go away or are severe, or if you experience other side effects.
Inform your doctor and pharmacist if you are taking any of these medicines:
- other medicines to treat cancer e.g. paclitaxel, docetaxel, irinotecan
- medicines for high blood pressure or heart disease e.g. quinidine, verapamil, digoxin
- medicines to treat fungal infections e.g. ketoconazole, itraconazole, voriconazole
- medicines for stomach problems e.g. esomeprazole, cisapride
- antibiotics e.g. clarithromycin, telithromycin, erythromycin
- medicines for epilepsy (fits or seizures) e.g. carbamazepine, phenytoin
- medicines to treat TB (lung infection known as tuberculosis) e.g. rifampicin
- medicines for HIV infection e.g. such as atazanavir, indinavir, nelfinavir, saquinavir, ritonavir
- St. John's wort (herbal medicine)
- other medicines such as dexamethasone, Phenobarbital
This list does not include all medicines that may interact with Lapatinib.
Always notify your doctor and pharmacist if you are taking any other medicines, including herbal tonics such as traditional Chinese medicines, supplements and medicines that you buy without a prescription.
Avoid alcohol and excessive consumption (more than 1 litre a day) of grapefruit juice.
Store in a cool, dry place away from the reach of children.
As this is a cancer medicine, always return any unused or expired tablets to the clinic, hospital or pharmacy for disposal. Do not throw it away in the household waste.
Medicines must not be used past the expiry date.