Drug Interaction Report

Using stiripentol together with lapatinib may alter the blood levels of both medications. Specifically, the blood levels of stiripentol may increase, which may lead to increased side effects such as loss of appetite, nausea, vomiting, weight loss, drowsiness, dizziness, confusion, difficulty concentrating, impaired muscle coordination, muscle weakness, tremor, speech problems, and low white blood cell and platelet counts (which can increase the risk of infection and bleeding). At the same time, stiripentol may have varying effects on other medications, which may result in increased or decreased blood levels. Talk to your doctor if you have any questions or concerns. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Stiripentol should be taken during a meal to help with its absorption; however, it should not be taken with milk, dairy products (e.G., yogurt, soft cream cheese), fruit juice, or carbonated (fizzy) beverages. Also avoid or limit the use of alcohol because it can increase side effects of stiripentol such as dizziness and drowsiness. Patients should not engage in activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them. Food and beverages that may contain caffeine or theophylline such as colas, chocolate, coffee, tea, or energy drinks should also be avoided, since stiripentol may affect the clearance of these substances from the body. Some medications may also contain caffeine, so check product labels to verify the ingredients before taking, or ask a pharmacist or other healthcare provider for assistance. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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.