Drug Interaction Report

MONITOR: Coadministration with inducers of hepatic CYP450 isoenzymes may decrease the plasma concentrations of montelukast, which is metabolized by CYP450 2C8, 2C9, and 3A4 . When a single 10 mg dose of montelukast was administered in combination with phenobarbital, montelukast systemic exposure (AUC) decreased by approximately 40%.

MANAGEMENT: No dosage adjustment for montelukast is recommended when used concomitantly with CYP450 inducers. However, clinical monitoring for potentially reduced therapeutic effects may be appropriate, especially for potent inducers such as carbamazepine, dexamethasone, enzalutamide, phenobarbital, phenytoin, rifamycins, and St. John's wort.

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.