Drug Interactions between eliglustat and lapatinib

Do not consume grapefruit or grapefruit juice during treatment with eliglustat unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of eliglustat to dangerous levels. This may increase the risk of serious and potentially life-threatening cardiac side effects such as irregular heart rhythm, heart block, and cardiac arrest. Talk to your doctor if you have any questions or concerns. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, slow heart rate, weak pulse, or heart palpitations during treatment. 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.