Drug Interactions between ceritinib and doxazosin

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.

Ask your doctor before using doxazosin together with ethanol (alcohol). Using doxazosin with ethanol (alcohol) can lower your blood pressure. This can cause dizziness or feeling like you might pass out, especially when getting up from a sitting or lying position. This may be more likely to occur when you first start taking either of these medications. You may need a dose adjustment or need your blood pressure checked more often if you take both medications. You may develop flushing, warmth or redness under your skin or tingly feeling after alcohol intake (especially in you are of Asian descent) and should be advised to avoid alcohol or limit your intake. 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.