Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of idelalisib, which is a substrate of the isoenzyme. In healthy volunteers, administration of a single 150 mg dose of idelalisib with the potent CYP450 3A4 inducer rifampin (600 mg daily for 8 days) decreased mean idelalisib peak plasma concentration (Cmax) by 58% and systemic exposure (AUC) by 75%. Data are not available for idelalisib in combination with other, less potent CYP450 3A4 inducers.

MANAGEMENT: Patients receiving idelalisib with CYP450 3A4 inducers should be monitored for potentially diminished pharmacologic response to idelalisib. Concomitant use should be avoided if an interaction is suspected.

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

MANAGEMENT: Patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.