Introduction

Overactive bladder (OAB) causes urgency, frequency, and nocturia, impacting women's quality of life. Mirabegron, a beta-3 agonist, offers similar efficacy to antimuscarinics with fewer side effects. Medication timing affects outcomes due to circadian rhythms and drug interactions. Though mirabegron improves nocturia and insomnia, its optimal dosing time remains unclear. There is not much scientific evidence to decide whether nighttime dosing better reduces OAB symptoms like urgency and nocturia.

Aim

To compare the clinical effectiveness of nighttime versus daytime administration of mirabegron in women with overactive bladder.

Method

Study Design

Treatment Strategy

• This study screened women aged >20 years with recent urinary urgency
• After excluding those with conditions contraindicating beta-3 agonists, eligible participants were diagnosed with OAB and randomized to receive mirabegron 25 mg daily either in the morning or at night for 12 weeks
• Assessments included pad tests, bladder diaries, urodynamic studies, and validated questionnaires
• Statistical analysis compared symptom changes between groups, focusing on urgency, nocturia, and quality of life, using paired t-tests and regression models to evaluate dosing time effects

Endpoints

Primary Endpoints

• Number of nocturia episodes
• Number of urgency episodes

Secondary Endpoints

• OAB symptoms
• Health-related quality of life 

Results

• A total of 109 women with OAB were enrolled: 57 in the nighttime group and 52 in the daytime group
• After 12 weeks, 46 nighttime and 40 daytime participants completed treatment
• The nighttime group showed a significant reduction in nocturia episodes at 4 weeks (5.65 ± 3.71 to 4.26 ± 2.60, p = 0.019) and a near-significant reduction at 12 weeks (6.58 ± 3.15 to 4.33 ± 3.84, p = 0.060)
• The daytime group showed no significant changes
• Nighttime dosing significantly reduced urgency episodes at 06:00–12:00 (−2.1 ± 3.7 vs. 0.1 ± 2.4, p = 0.003), 18:00–24:00 (−1.4 ± 3.0 vs. 0.4 ± 2.7, p = 0.01), and all day (−6.4 ± 10.8 vs. 0.1 ± 8.5, p = 0.005)
• Daytime dosing improved emotional scores more at 4 weeks (−17 ± 25 vs. −6 ± 19, p = 0.006)
• However, emotional improvements (depression, anxiety, self-esteem) were not correlated with OABSS changes
• Both groups showed significant improvements in urgency severity scale (USS), overactive bladder symptoms score (OABSS), and King’s health questionnaire (KHQ) scores by week 12
• Regression analysis identified younger age (p = 0.039) and higher baseline OABSS (p = 0.002) as independent predictors of better symptom improvement

Conclusion

• Nighttime dosing of mirabegron significantly reduced nocturia and morning urgency in women with overactive bladder
• Daytime dosing showed greater improvement in emotional well-being, especially after 4 weeks of treatment

 Sci Rep 2025; 15:30687. Doi:10.1038/s41598-025-15780-5.