Drug Interactions between pazopanib and Tembexa

GENERALLY AVOID: Grapefruit juice may increase the plasma concentrations of pazopanib. The proposed mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. Although not studied, the interaction may increase the risk of QT interval prolongation and torsade de pointes arrhythmia as well as severe and fatal hepatotoxicity associated with the use of pazopanib.

ADJUST DOSING INTERVAL: Food increases the oral bioavailability of pazopanib. The mechanism of interaction is unknown. Administration of pazopanib with a high-fat or low-fat meal results in an approximately 2-fold increase in peak plasma concentration (Cmax) and systemic exposure (AUC).

MANAGEMENT: Patients treated with pazopanib should avoid consumption of grapefruit, grapefruit juice, and any supplement containing grapefruit extract. Pazopanib should be administered at least one hour before or two hours after a meal.

ADJUST DOSING INTERVAL: Administration with food decreases the oral bioavailability of brincidofovir. According to the product labeling, administration of brincidofovir tablets with a low-fat meal (approximately 400 calories, 25% of calories from fat) was associated with a reduction in the systemic exposure (AUC) and peak plasma concentration (Cmax) of brincidofovir by 31% and 49%, respectively, compared to administration under fasting. However, no clinically meaningful changes in intracellular concentrations of cidofovir diphosphate were observed. The effect of food on the oral suspension formulation has not been evaluated.

MANAGEMENT: Brincidofovir oral tablets and suspension should be taken on an empty stomach. If necessary, the oral tablets may be taken with a low-fat meal.