Drug Interaction Report

Coadministration with inducers of CYP450 3A4 and/or P-glycoprotein may decrease the plasma concentrations of mirabegron, which has been shown in vitro to be a substrate of the isoenzyme and efflux transporter. However, in vivo results indicate that these pathways may play a limited role in the overall elimination. In healthy study subjects, mirabegron peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by less than 50% when a single 100 mg dose of mirabegron was administered following multiple dosing of rifampin 600 mg once daily. No dosage adjustment is recommended when mirabegron is administered in combination with rifampin and probably other CYP450 3A4/P-gp inducers.

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.

Food reduces the oral absorption and bioavailability of mirabegron. According to the product labeling, administration of a 50 mg tablet with a high-fat meal decreased mirabegron peak plasma concentration (Cmax) and systemic exposure (AUC) by 45% and 17%, respectively, whereas administration with a low-fat meal decreased mirabegron Cmax and AUC by 75% and 51%, respectively. In phase 3 clinical studies demonstrating both safety and efficacy, mirabegron was administered without regards to food content and intake. Therefore, mirabegron can be taken with or without food at the recommended dosage.