Drug Interaction Report

Fedratinib may increase the blood levels and effects of methadone. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if you experience increased side effects such as excessive drowsiness, tiredness, confusion, disorientation, nausea, vomiting, and shallow or difficult breathing. High blood levels of methadone can also occasionally cause an irregular heart rhythm that may be serious. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or fast or pounding heartbeats. 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.

Do not use alcohol or medications that contain alcohol while you are receiving treatment with methadone. This may increase nervous system side effects such as drowsiness, dizziness, lightheadedness, difficulty concentrating, and impairment in thinking and judgment. In severe cases, low blood pressure, respiratory distress, fainting, coma, or even death may occur. You should also avoid consuming grapefruit and grapefruit juice, as this may increase the blood levels and effects of oral methadone. High blood levels of methadone can also occasionally cause an irregular heart rhythm that may be serious. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or fast or pounding heartbeats. Do not exceed the dose of methadone prescribed for you or use the medication more frequently or for a longer duration than prescribed by your doctor. Also 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 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 medication without first talking to your doctor.

Grapefruit juice can increase the blood levels of fedratinib. This may increase the risk of serious side effects such as Wernicke's encephalopathy, a potentially fatal condition of the brain associated with thiamine (vitamin B1) deficiency; low blood cell counts, which can lead to anemia, bleeding, and infections; severe diarrhea, nausea, and vomiting; problems in the liver or pancreas; and development of other cancers. You should avoid the consumption of grapefruit and grapefruit juice during treatment with fedratinib. You may take the medication with or without food, but taking it with a high-fat meal may help reduce nausea and vomiting. 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.