Drug Interaction Report

Using erdafitinib together with magnesium hydroxide may alter the levels of phosphate in the blood, which may affect the dose of erdafitinib. Your doctor will check your blood phosphate level between 14 and 21 days after starting treatment with erdafitinib and then monthly, and may change your dose if necessary. Talk to your doctor if you have any questions or concerns. Contact your doctor as soon as possible if you develop signs and symptoms of high phosphate levels in the blood (hyperphosphatemia) such as muscle cramps, convulsions, tingling or numbness around the mouth, and bone pain. 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.