The effect of nighttime dosing versus daytime dosing of mirabegron is undetermined. Thus, this study aimed to clarify the effect of nighttime versus daytime mirabegron dosing. Between August 2017 and August 2023, all women with overactive bladder syndrome were randomly assigned to receive mirabegron 25 mg once with nighttime or daytime dosing for 12 weeks. A total of 109 women were enrolled. Fifty-two patients were in the daytime dosing group, and 57 patients were in the nighttime dosing group. Nocturia episodes improved in the nighttime group (5.65 ± 3.71 at baseline versus 4.26 ± 2.60 at 4 weeks, p = 0.019), but not the daytime group. In addition, after 4 weeks of treatment, the nighttime dosing group had a greater benefit in the decrease in urgency episodes at 06:00–12:00 (change: − 2.1 ± 3.7 versus 0.1 ± 2.4, p = 0.003), 18:00–24:00 (change: − 1.4 ± 3.0 versus 0.4 ± 2.7, p = 0.01) and all day (change: − 6.4 ± 10.8 versus 0.1 ± 8.5, p = 0.005), compared to daytime dosing. However, the daytime dosing group had a significant improvement in emotions (change: − 17 ± 25 versus − 6 ± 19, p = 0.006), compared to nighttime dosing. After 12 weeks of treatment, despite the significant improvement in overactive bladder symptoms in both groups, there were no differences between groups. In addition, young age (coefficient = 0.065, p = 0.039) and high baseline Overactive Bladder Symptom Score (OABSS) total score (coefficient = − 0.389, p = 0.002) were independent predictors of the improvement of OABSS total score. In conclusion, mirabegron nighttime dosing appears to benefit women more suffering from nocturia and urgency (especially urgency in the morning), and daytime dosing appears to benefit women with coexistent emotion dysfunction. Trial registration NCT03251300, registered on 16/08/2017. Available at ClinicalTrials.gov, www.clinicaltrials.gov .
Sheng‐Mou Hsiao (Thu,) studied this question.