Do not take this medicine with any of the following:

-cisapride
-dronedarone
-fluconazole
-pimozide
-posaconazole
-saquinavir
-thioridazine
This medicine may also interact with the following medications:

-antiviral medicines for HIV or AIDS
-certain antibiotics like clarithromycin, erythromycin, and telithromycin
-certain antibiotics like rifabutin, rifampin, and rifapentine
-certain medicines for depression, anxiety, or psychotic disturbances
-certain medicines for fungal infections like itraconazole, ketoconazole, or voriconazole
-certain medicines for seizures like carbamazepine, phenobarbital, phenytoin
-dexamethasone
-digoxin
-nefazodone
-other medicines that prolong the QT interval (cause an abnormal heart rhythm) like dofetilide, ziprasidone
-St. John''s Wort

They need to know if you have any of these conditions:

-heart disease
-heart rhythm problems (irregular heartbeat)
-high blood pressure
-history of low levels of potassium or magnesium
-liver disease
-an unusual reaction to lapatinib, other medicines, foods, dyes, or preservatives
-pregnant or trying to get pregnant
-breast-feeding

Visit your doctor for checks on your progress. You will need to have regular blood tests while on this medicine.
Do not become pregnant while taking this medicine or for 1 week after stopping it. Women should inform their doctor if they wish to become pregnant or think they might be pregnant. Men should not father a child while taking this medicine and for 1 week after stopping it. There is a potential for serious side effects to an unborn child. Talk to your health care professional or pharmacist for more information. Do not breast-feed an infant while taking this medicine or for 1 week after stopping it.

Keep out of the reach of children.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from moisture. Keep tightly closed. Throw away any unused medicine after the expiration date.