Drug Interaction Report

ADJUST DOSING INTERVAL: Food enhances the oral bioavailabilities of both elvitegravir and tenofovir. When a single dose of cobicistat/elvitegravir/emtricitabine/tenofovir (trade name Stribild) was given with a light meal (approximately 373 kcal; 20% fat), mean elvitegravir and tenofovir systemic exposures (AUCs) increased by 34% and 24%, respectively, relative to fasting conditions. When administered with a high-fat meal (approximately 800 kcal; 50% fat), the mean AUC of elvitegravir and tenofovir increased by 87% and 23%, respectively, relative to fasting conditions. The alterations in mean AUCs of cobicistat and emtricitabine were not clinically significant with either the light or high-fat meal.

MANAGEMENT: Cobicistat/elvitegravir/emtricitabine/tenofovir as a fixed-dose preparation should be administered once daily with food. Elvitegravir as a single-ingredient preparation should also be administered once daily with food.

The recommended maximum number of medicines in the 'integrase strand transfer inhibitors' category to be taken concurrently is usually one. Your list includes two medicines belonging to the 'integrase strand transfer inhibitors' category:

• Isentress (raltegravir)
• Vitekta (elvitegravir)

Note: In certain circumstances, the benefits of taking this combination of drugs may outweigh any risks. Always consult your healthcare provider before making changes to your medications or dosage.