To evaluate the efficacy of imidafenacin for nocturia and nocturnal polyuria in patients with overactive bladder.

A stratified analysis was conducted on data from a phase III randomized, double-blind, controlled trial of imidafenacin performed at 158 centers in Japan. The subjects received imidafenacin (0.1 mg) twice daily (group I) or placebo twice daily (group P). The 24-hour urine volume, daytime and nighttime voiding frequency, and volume voided/micturition were evaluated from 3-day voiding diaries recorded every 4 weeks during the 12-week study period. Longitudinal data analysis was performed, with all values expressed as the least squares mean ± standard error.

A total of 46 patients (mean age 66.54 ± 9.38 years, 9 men and 37 women) with nocturia and nocturnal polyuria (>33% of urine production at night) were enrolled. Group I (n = 35) and group P (n = 11) showed no baseline differences in the daily voided volume, concomitant diseases, age, or body weight. However, the average daily number of micturitions differed (11.22 ± 2.17 vs 14.45 ± 2.85). Therefore, longitudinal data analysis was performed for each micturition pattern. After 12 weeks of treatment, nighttime micturition was significantly less frequent in group I than in group P (P = .0292), and the nocturnal percentage of 24-hour production was significantly smaller (P = .0053). The interval to the first nighttime void was significantly longer in group I than in group P, but no difference was found in the first nighttime voided volume.

The novel antimuscarinic agent, imidafenacin, decreases the number of urinations and reduces nocturnal urine production, thereby improving both nocturia and nocturnal polyuria.