Drug Interactions between cetirizine and Zykadia

Do not consume grapefruit or grapefruit juice during treatment with ceritinib unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of ceritinib to dangerous levels, increasing the risk of an irregular heart rhythm that may be serious. Other, more common side effects such as diarrhea, nausea, vomiting, abdominal pain, and hyperglycemia (high blood sugar) may also increase. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with ceritinib. Food may also increase the blood levels of ceritinib. Therefore, you should take ceritinib on an empty stomach, meaning no food should be eaten for at least two hours before or after taking ceritinib. 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.

Alcohol can increase the nervous system side effects of cetirizine 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 cetirizine. Do not use more than the recommended dose of cetirizine, 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.