Drug Interactions between erlotinib and zanubrutinib

Grapefruit juice and Seville orange juice can increase the blood levels of zanubrutinib. This may increase side effects such as rash, diarrhea, constipation, cough, hemorrhage, development of other cancers, abnormal heart rhythm, and impaired bone marrow function resulting in low numbers of different types of blood cells. You may also be more likely to develop anemia, bleeding problems, or infections due to low blood cell counts. You should avoid the consumption of Seville oranges, Seville orange juice, grapefruit and grapefruit juice during treatment with zanubrutinib. Be sure to take the medication at approximately the same time(s) everyday to maintain consistent blood levels and effects. Talk to your doctor or pharmacist if you have questions on how to take this or other medications you are 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.

Erlotinib should be taken on an empty stomach at least 1 hour before or 2 hours after a meal and at the same time each day unless otherwise directed by your doctor. You should also avoid grapefruit and grapefruit juice while taking erlotinib. Food and grapefruit juice can increase the absorption of erlotinib from the gastrointestinal tract, which may lead to higher blood levels of the medication and possibly increased side effects. If you are a smoker, you should try to quit as soon as you can. Cigarette smoking can reduce the blood levels of erlotinib, which may make the medication less effective in treating your cancer. It is best to avoid smoking during erlotinib therapy. Talk to a healthcare professional if you have any questions or concerns. If you start smoking or undergo smoking cessation, your doctor may need to adjust your dose of erlotinib. 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.