Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of zaleplon. According to the prescribing information, CYP450 3A4 is a minor metabolizing enzyme of zaleplon. When zaleplon was coadministered with the potent CYP450 3A4 inducer rifampin (600 mg daily for 14 days), zaleplon plasma concentration (Cmax) and systemic exposure (AUC) decreased by approximately 80%. The extent to which other, less potent CYP450 3A4 inducers may interact with zaleplon is unknown.

MANAGEMENT: Caution is advised when zaleplon is coadministered with CYP450 3A4 inducers. Monitoring for diminished therapeutic response to zaleplon is recommended.

MONITOR: Isolated case reports have suggested that the ingestion of alcohol during griseofulvin therapy may rarely cause disulfiram-like reactions, flushing, tachycardia, or increased effects of alcohol. The mechanism is unknown.

MANAGEMENT: Patients should be advised of the possibility of increased adverse effects or a disulfiram-like reaction.

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

ADJUST DOSING INTERVAL: Administration of zaleplon with a high-fat or heavy meal may delay the onset of hypnotic effects. In healthy adult subjects, administration of zaleplon with a high-fat meal resulted in a 2-hour delay in the time to reach peak plasma drug concentration (Tmax) and a 35% reduction in the peak plasma drug concentration (Cmax) compared to fasting. Zaleplon systemic exposure (AUC) and elimination half-life were not significantly affected.

MANAGEMENT: Patients receiving zaleplon should be advised to avoid the consumption of alcohol. For faster sleep onset, zaleplon should not be administered with or immediately after a high-fat or heavy meal.