Drug Interaction Report

Talk to your doctor before using istradefylline together with lumacaftor. Combining these medications may reduce the blood levels and effects of istradefylline. Contact your doctor if your symptoms worsen or your condition changes during treatment with these medications. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. 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.

Ivacaftor should be taken with fat-containing foods such as eggs, avocados, nuts, meat, butter, peanut butter, cheese pizza, and whole-milk dairy products to help with its absorption. Do not consume grapefruit juice or any food that contains grapefruit or Seville oranges during treatment with ivacaftor unless directed otherwise by your doctor. Grapefruit juice can significantly increase the blood levels of ivacaftor. This may increase the risk and/or severity of serious side effects such as liver damage. Call your doctor immediately if you have fever, chills, joint pain or swelling, unusual bleeding or bruising, skin rash, itching, loss of appetite, fatigue, nausea, vomiting, abdominal pain, dark urine, pale stools, and/or yellowing of the skin or eyes, as these may be signs and symptoms of liver damage. 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.

Smoking tobacco may reduce the blood levels and effects of istradefylline. Contact your doctor if istradefylline is not adequately controlling your symptoms. It is best to avoid smoking during istradefylline 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 monitor you more closely to determine if you need a dose adjustment of istradefylline. Your doctor may already be aware of the risks and may have taken appropriate precautions including adjusting your dose and monitoring you closely for any potential complications. 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.