Drug Interaction Report

ADJUST DOSING INTERVAL: Food delays the oral absorption and reduces the oral bioavailability of entecavir. According to the product labeling, administration of entecavir 0.5 mg with a standard high-fat meal or a light meal resulted in a delay in absorption by 0.25 to 0.75 hours, a decrease in the peak plasma concentration (Cmax) by 44% to 46%, and a decrease in the area under the plasma concentration-time curve (AUC) by 18% to 20% compared to administration in the fasting state.

MANAGEMENT: To ensure maximal oral absorption, entecavir should be administered on an empty stomach at least 2 hours after a meal and 2 hours before the next meal.

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.