Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of rolapitant, which is primarily metabolized by the isoenzyme. When the potent CYP450 3A4 inducer rifampin was administered at 600 mg once daily for 7 days before and 7 days after a single 180 mg dose of rolapitant, mean rolapitant peak plasma concentration (Cmax) and systemic exposure decreased by 30% and 85%, respectively, compared to administration of rolapitant alone. Mean half-life of rolapitant decreased from 176 hours to 41 hours with rifampin. No data are available for other, less potent CYP450 3A4 inducers.

MANAGEMENT: The potential for diminished pharmacologic effects of rolapitant should be considered during coadministration with CYP450 3A4 inducers. Alternative treatments may be required if an interaction is suspected.

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of rufinamide. Use in combination may result in additive central nervous system depression and/or impairment of judgment, thinking, and psychomotor skills.

ADJUST DOSING INTERVAL: Food enhances the oral absorption and bioavailability of rufinamide. In healthy volunteers, administration of a single 400 mg dose of rufinamide with food resulted in an approximately 56% increase in mean peak plasma concentration (Cmax) and a 34% increase in systemic exposure (AUC) compared to administration during a fasting state.

MANAGEMENT: To ensure maximal oral absorption, it is preferable to administer rufinamide with food. Patients receiving rufinamide should be advised to avoid consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how rufinamide affects them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.