Drug Interactions between lapatinib and Valproate Sodium

Alcohol can increase the nervous system side effects of valproic acid such as dizziness, drowsiness, and difficulty concentrating. Some people may also experience impairment in thinking and judgment. You should avoid or limit the use of alcohol while being treated with valproic acid. Do not use more than the recommended dose of valproic acid, and avoid activities requiring mental alertness such as driving or operating hazardous machinery until you know how the medication affects you. Talk to your doctor or pharmacist if you have any questions or concerns.

Take lapatinib on an empty stomach 1 hour before or 1 hour after a meal unless otherwise directed by your doctor. This will make it easier for your body to absorb the medication. The lapatinib dose is administered once daily and should not be divided. The usual dose of lapatinib is equal to 5 tablets. You may swallow each tablet one at a time, but take the entire lapatinib dose at the same time each day. If you are receiving therapy with lapatinib you should be advised to avoid grapefruits and grapefruit juice. Grapefruit can raise the levels of lapatinib in your body and lead to dangerous side effects.