Drug Interaction Report

MONITOR: Coadministration with viloxazine may increase the plasma concentrations of drugs that are substrates of CYP450 3A4 and/or CYP450 2D6 leading to increased toxicity. The proposed mechanism is decreased clearance due to viloxazine-mediated inhibition of CYP450 3A4 and/or CYP450 2D6. The product labeling describes viloxazine as a weak inhibitor of CYP450 3A4 and CYP450 2D6.

MANAGEMENT: Caution is advised if viloxazine is used concomitantly with drugs that are substrates of CYP450 3A4 and/or CYP450 2D6, particularly those with a narrow therapeutic range. Monitor for adverse reactions of the CYP450 3A4 or CYP450 2D6 substrate and adjust dosages as needed.

GENERALLY AVOID: Alcohol may potentiate some of the pharmacologic effects of vilazodone. 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 bioavailability of vilazodone. According to the product labeling, vilazodone blood concentrations in the fasted state can be decreased by approximately 50% compared to the fed state, which may result in diminished effectiveness in some patients. The absolute bioavailability of vilazodone is 72% with food. In study subjects, administration with food (high-fat or light meal) increased vilazodone peak plasma concentration (Cmax) by approximately 147% to 160% and systemic exposure (AUC) by approximately 64% to 85%.

MANAGEMENT: Patients receiving vilazodone 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 vilazodone affects them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities. Vilazodone should be taken with food. Administration without food may result in inadequate drug concentrations and diminished effectiveness.