Drug Interaction Report

Using calcium phosphate, tribasic together with futibatinib may increase the levels of phosphate in the blood, which may increase your risk of high phosphate levels (hyperphosphatemia), and a buildup of minerals such as calcium in different tissues in your body. Your doctor will check your blood phosphate level regularly when your first start treatment with futibatinib and regularly throughout treatment. They may recommend changes in your diet, phosphate-lowering therapy, and/or change your dose of futibatinib 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.

Grapefruit juice can increase the blood levels of futibatinib. This may increase side effects including dry or inflamed eyes, inflamed cornea, increased tears, disorder of the retina, high phosphate levels in your blood, redness, swelling, peeling or tenderness, mainly on the hands or feet, nails separating from the bed or poor formation of the nail, urinary tract infection, constipation, diarrhea, dry mouth, abdominal pain, fatigue, muscle and joint pain, decreased levels of blood cells (white blood cells, red blood cells, and platelets), and changes in liver function blood tests. You should avoid the consumption of grapefruit and grapefruit juice during treatment with futibatinib. Be sure to take the medication at approximately the same time every day to maintain consistent blood levels and effects. 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.

Calcium absorption may be increased by taking it with food. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption. Calcium may be taken with food to increase absorption. Consider spacing calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid. 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.

Both smoking and excessive caffeine consumption can alter the blood levels of melatonin, which may affect the dosing. Tobacco smoking reduces, while caffeine increases melatonin blood levels. If you start smoking or undergo smoking cessation, your doctor may need to adjust the dose of melatonin. In addition, alcohol may reduce the effect of melatonin on sleep. It is best to avoid alcohol consumption during melatonin therapy. Talk to a healthcare professional 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.