Drug Interaction Report

Zafirlukast may increase the blood levels of infigratinib in some patients. This may increase the frequency and severity of serious side effects such as infections; decreased red blood cell, white blood cell, and platelet counts; fever; abdominal pain; increased blood calcium and phosphate levels above normal; eye and vision problems; mouth sores and inflammation; diarrhea; redness, swelling, peeling or tenderness, mainly on the hands and feet ('hand-foot syndrome'); nails separating from the bed or poor formation of the nail; and changes in kidney function blood tests. Talk to your doctor if you have any questions or concerns. 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 your use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Infigratinib should be taken on an empty stomach, at least 1 hour before or 2 hours after food. Do not consume grapefruit, grapefruit juice, or any supplements that contain grapefruit extract during treatment with infigratinib unless directed otherwise by your doctor. Grapefruit juice can increase the blood levels of infigratinib. This may increase the frequency and severity of serious side effects such as infections; decreased red blood cell, white blood cell, and platelet counts; fever; abdominal pain; increased blood calcium and phosphate levels above normal; eye and vision problems; mouth sores and inflammation; diarrhea; redness, swelling, peeling or tenderness, mainly on the hands and feet ('hand-foot syndrome'); nails separating from the bed or poor formation of the nail; and changes in kidney function blood tests. 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.

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.