Drug Interaction Report

ADJUST DOSE: Coadministration with moderate inhibitors of CYP450 3A4 and P-glycoprotein may significantly increase the plasma concentrations of everolimus following oral administration. Everolimus is a substrate of both the CYP450 3A4 isoenzyme and P-glycoprotein drug efflux transporter, thus their inhibition in the intestine can enhance the absorption of everolimus. The risk of side effects such as pneumonitis, stomatitis, infection, dyspnea, diarrhea, anemia, leucopenia, thrombocytopenia, hyperglycemia, and hyperlipidemia may be increased.

MANAGEMENT: Blood trough levels should be closely monitored, and the dosage adjusted accordingly during concomitant administration and after discontinuation of moderate CYP450 3A4 and P-glycoprotein inhibitors. The manufacturer's drug product labeling should be consulted for specific recommendations.

GENERALLY AVOID: Grapefruit juice may significantly increase the plasma concentrations of orally administered everolimus. The mechanism is inhibition of CYP450 3A4 and P-glycoprotein activity in the gut wall by certain compounds present in grapefruit.

MANAGEMENT: Patients treated with everolimus should avoid consumption of grapefruit and grapefruit juice.

ADJUST DOSING INTERVAL: Food enhances the absorption and oral bioavailability of darunavir administered in combination with low-dose ritonavir. The mechanism is unknown. When administered with food, the peak plasma concentration (Cmax) and area under the plasma concentration-time curve (AUC) of darunavir were approximately 30% higher than when administered in the fasting state. Darunavir exposure was similar for the range of meals studied. The total caloric content of the various meals evaluated ranged from 240 Kcal (12 grams fat) to 928 Kcal (56 grams fat).

MANAGEMENT: To ensure maximal oral absorption, darunavir coadministered with ritonavir should be taken with food. The type of food is not important.