Drug Interaction Report

MONITOR: Coadministration with inducers of CYP450 3A4 and/or P-glycoprotein (P-gp) may decrease the plasma concentrations of silodosin, which is a substrate of both the isoenzyme and efflux transporter.

MANAGEMENT: The potential for diminished pharmacologic effects of silodosin should be considered during coadministration with CYP450 3A4 and/or P-gp inducers. Alternative treatments may be required if an interaction is suspected.

ADJUST DOSING INTERVAL: Food may reduce the oral bioavailability of silodosin. The effect of a moderate-fat, moderate-calorie meal on silodosin pharmacokinetics was variable and decreased silodosin maximum plasma concentration (Cmax) by approximately 18% to 43% and systemic exposure (AUC) by 4% to 49% across three different studies. The maximum effect of food (i.e., coadministration with a high-fat, high-calorie meal) on the pharmacokinetics of silodosin was not evaluated. Safety and efficacy clinical trials for silodosin were always conducted in the presence of food intake.

MANAGEMENT: Patients should be instructed to take silodosin with a meal to reduce the risk of adverse events.