Drug Interaction Report

ADJUST DOSING INTERVAL: Coadministration with medications or supplements containing polyvalent cations such as zinc may decrease the plasma concentrations of integrase strand transfer inhibitors (INSTIs). The proposed mechanism involves chelation of the INSTI by polyvalent cations, forming a complex that is poorly absorbed from the gastrointestinal tract.

MANAGEMENT: If concomitant use is required, monitor for virologic efficacy and administer the INSTI at least 2 hours before or 6 hours after products containing polyvalent cations such as zinc.

Food enhances the oral absorption and bioavailability of tenofovir, the active entity of tenofovir disoproxil fumarate. According to the product labeling, administration of the drug following a high-fat meal increased the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of tenofovir by approximately 14% and 40%, respectively, compared to administration in the fasting state. However, administration with a light meal did not significantly affect the pharmacokinetics of tenofovir compared to administration in the fasting state. Food delays the time to reach tenofovir Cmax by approximately 1 hour. Tenofovir disoproxil fumarate may be administered without regard to meals.