Drug Interaction Report

GENERALLY AVOID: Coadministration with polyvalent cation-containing products may decrease the plasma concentrations and therapeutic efficacy of baloxavir. The proposed mechanism is chelation of baloxavir by polyvalent cations, forming a complex that is poorly absorbed from the gastrointestinal tract. A significant decrease in baloxavir exposure was observed in monkeys when the prodrug, baloxavir marboxil, was coadministered with calcium, aluminum, magnesium, or iron. However, clinical data in humans are lacking.

MANAGEMENT: Concurrent administration of baloxavir marboxil with polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., aluminum, calcium, iron, magnesium, selenium, zinc) should generally be avoided.

ADJUST DOSING INTERVAL: Administration with food may increase the absorption of calcium. However, foods high in oxalic acid (spinach or rhubarb), or phytic acid (bran and whole grains) may decrease calcium absorption.

MANAGEMENT: Calcium may be administered with food to increase absorption. Consider withholding calcium administration for at least 2 hours before or after consuming foods high in oxalic acid or phytic acid.

GENERALLY AVOID: Coadministration with foods or medications that contain polyvalent cations such as dairy products, calcium-fortified beverages, certain laxatives, antacids, or oral supplements may decrease the plasma concentrations and therapeutic efficacy of baloxavir. The proposed mechanism is chelation of baloxavir by polyvalent cations, forming a complex that is poorly absorbed from the gastrointestinal tract. A significant decrease in baloxavir exposure was observed in monkeys when the prodrug, baloxavir marboxil, was coadministered with calcium, aluminum, magnesium, or iron. However, clinical data in humans are lacking.

When baloxavir marboxil was administered with food, baloxavir peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 48% and 36%, respectively, relative to administration under fasting. These changes are not considered clinically significant.

MANAGEMENT: Baloxavir marboxil may be taken with or without food. However, coadministration with dairy products, calcium-fortified beverages, or polyvalent cation-containing laxatives, antacids, or oral supplements (e.g., calcium, iron, magnesium, selenium, or zinc) should be avoided.