Drug Interaction Report

Safinamide may increase the blood levels and effects of lapatinib. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. 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.

Safinamide may be taken with or without food. While there is no need to strictly avoid most foods and beverages that contain tyramine (usually aged, fermented, cured, smoked, or pickled foods such as air-dried and fermented meats or fish, aged cheeses, most soybean products, yeast extracts, red wine, beer, and sauerkraut) during treatment with safinamide, certain foods such as some of the aged cheeses (for example, Boursault, Liederkrantz, Mycella, and Stilton) and pickled herring may contain very high amounts of tyramine and should generally be avoided if possible. Consumption of very high levels of tyramine (greater than 150 mg) while on safinamide treatment may lead to dangerous increases in your blood pressure, a condition known as hypertensive crisis. Talk to your doctor or pharmacist if you are uncertain about what foods, if any, to avoid. You should seek immediate medical attention if you experience sudden and severe headache, blurred vision, confusion, seizures, chest pain, nausea or vomiting, sudden numbness or weakness (especially on one side of the body), speech difficulties, fever, sweating, lightheadedness, and/or fainting during treatment with safinamide, as these may be signs and symptoms of a hypertensive crisis. Do not take larger doses or use the medication more frequently than prescribed. 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.