Drug Interactions between avacopan and fedratinib

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.

To ensure adequate absorption of the medication, avacopan should be taken with food. You should avoid or limit consumption of grapefruit, grapefruit juice, or any supplements that contain grapefruit extract during treatment with avacopan unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of avacopan. This may increase the risk and/or severity of side effects such as nausea, vomiting, diarrhea, infections, and liver problems. You should seek immediate medical attention if you develop signs and symptoms of liver damage such as fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, dark colored urine, light colored stools, and yellowing of the skin or eyes. Talk to your doctor if you have any questions or concerns. 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.