Clinical efficacy and safety of mirabegron and imidafenacin in women with overactive bladder: A randomized crossover study (the MICRO study)

We aimed to compare the efficacy and safety of mirabegron, a β3-adrenoceptor agonist, and imidafenacin, an anticholinergic agent, in overactive bladder patients.

We conducted a multicenter, prospective randomized cross-over study at 5 hospitals in Japan from December 2012 to June 2015. We enrolled female patients with overactive bladder aged ≥50 years, who had never received treatment for the condition. The patients were assigned to Group A or B. Group A patients were administered mirabegron (50 mg per day) for 8 weeks, followed by a 2-week washout period, and then imidafenacin (0.2 mg per day) for 8 weeks. This order of drug administration was reversed in Group B.

A total of 33 and 18 patients in Group A and 37 and 26 patients in Group B continued to receive treatment at weeks 8 and 18, respectively. Mirabegron administration significantly improved overactive bladder symptom score (OABSS), the urinary frequency per 24 hr, voided volume per micturition, and number of nocturia episodes per night at week 8. Moreover, imidafenacin administration improved all these variables, except for the number of nocturia episodes per night at week 8. No significant difference was observed in the drug effects between mirabegron and imidafenacin. Although imidafenacin administration significantly increased the scores for dry mouth, blurred vision, and constipation, mirabegron administration did not.

Mirabegron and imidafenacin have the same efficacy. Imidafenacin administration is associated with a higher rate of dry mouth, blurred vision, and constipation as compared to mirabegron administration. Neurourol. Urodynam. © 2016 Wiley Periodicals, Inc.

Neurourology and urodynamics. 2016 Jun 06 [Epub ahead of print]

Kazumasa Torimoto, Chie Matsushita, Atsushi Yamada, Daisuke Goto, Yoshihiro Matsumoto, Yukinari Hosokawa, Makito Miyake, Katsuya Aoki, Akihide Hirayama, Nobumichi Tanaka, Kiyohide Fujimoto

Nara Medical University, Nara, Japan., Saiseikai-Chuwa Hospital, Nara, Japan., Hirao Hospital, Nara, Japan., Hirao Hospital, Nara, Japan., Nara Prefecture General Medical Center, Nara, Japan., Tane General Hospital, Osaka, Japan., Nara Medical University, Nara, Japan., Nara Medical University, Nara, Japan., Nara Hospital Kinki University Faculty of Medicine, Nara, Japan., Nara Medical University, Nara, Japan., Nara Medical University, Nara, Japan.

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