Drug Interaction Report

MONITOR: Urinary retention has been reported during postmarketing use of mirabegron in patients receiving antimuscarinic medications for the treatment of overactive bladder.

MANAGEMENT: Caution is advised if mirabegron is prescribed in combination with antimuscarinic medications used for the treatment of overactive bladder.

ADJUST DOSING INTERVAL: Food may reduce the oral absorption and bioavailability of trospium chloride. According to the product labeling, administration of trospium chloride with a high fat meal reduced the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) by 70% to 80% compared to administration while fasting.

MANAGEMENT: To ensure maximal oral absorption, trospium chloride should be administered at least 1 hour before meals or on an empty stomach. If trospium chloride is administered as a combination with xanomeline, the manufacturer recommends administering the capsules at least 1 hour before a meal or at least 2 hours after a meal. Capsules should be taken whole.

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.