Drug Interaction Report

Idelalisib may cause serious and life-threatening liver problems, and using it with other medications that can also affect the liver such as zafirlukast may increase that risk. You should avoid or limit the use of alcohol while being treated with these medications. Talk to your doctor if you have any questions or concerns. Your doctor may already be aware of the risks, but has determined that this is the best course of treatment for you and has taken appropriate precautions and is monitoring you closely for any potential complications. 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. You may need a dose adjustment or an interruption in idelalisib therapy if you develop severe liver problems. 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.

Zafirlukast should be taken on an empty stomach 1 hour before or 2 hours after a meal unless otherwise directed by your doctor. You may experience reduced absorption of zafirlukast in the presence of food. This will make it easier for your body to absorb the medication.