Imidafenacin, an antimuscarinic agent, improves nocturia and reduces nocturnal urine volume.

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

Materials And Methods: 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.

Results: 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.

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