Drug Interaction Report

GENERALLY AVOID: Coadministration with inhibitors of P-glycoprotein (P-gp) and/or breast cancer resistance protein (BCRP) may increase the plasma concentrations of bictegravir. According to the product labeling, bictegravir is a substrate of both P-gp and BCRP; however, the extent to which each enzymatic pathway contributes to the metabolic clearance of bictegravir has not been reported.

MANAGEMENT: The use of bictegravir with P-gp and/or BCRP inhibitors should generally be avoided. If concomitant use is required, caution and close clinical and laboratory monitoring, including renal function, are recommended. Dosage adjustments may be required whenever a P-gp and/or BCRP inhibitor is added to or withdrawn from therapy.

GENERALLY AVOID: Alcohol may increase the plasma concentrations of ezogabine. In a study of healthy volunteers, the administration of ezogabine 200 mg in combination with ethanol 1g/kg (5 standard alcohol drinks) over 20 minutes resulted in an increase in the ezogabine peak plasma concentration (Cmax) and systemic exposure (AUC) by 23% and 37%, respectively.

Food does not significantly affect the bioavailability of ezogabine. According to the product labeling, high-fat food does not affect the extent to which ezogabine is absorbed, but increases peak plasma concentration (Cmax) by approximately 38% and delays the time to reach peak concentration (Tmax) by 0.75 hour.

MANAGEMENT: In general, alcohol consumption should be avoided or limited during treatment with CNS-depressant agents. Patients should be advised of the potential for increased dose-related adverse reactions of ezogabine (e.g., dizziness, somnolence, nausea, constipation, urinary retention, blurred vision, memory impairment, tremor) when taken with alcohol, and to avoid hazardous activities that require mental alertness and motor coordination until they know how the medication affects them. Ezogabine can be taken with or without food.

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.