This study aimed to evaluate the effectiveness of solifenacin succinate in reducing the symptoms of mixed urinary incontinence (MUI) in women, hypothesizing that oral administration of solifenacin would lead to a greater reduction in severity of symptoms compared to placebo.

This double-blind randomized controlled trial was conducted at Taleghani Hospital in Tehran from 2022 to 2024. A total of 200 women diagnosed with mixed urinary incontinence, based on predefined inclusion criteria, were randomly assigned using block randomization into two groups. The intervention group (n = 100) received 5 mg of oral solifenacin succinate once daily for three months, while the control group (n = 100) received placebo. The severity of urinary incontinence was assessed using the validated QUID (Questionnaire for Urinary Incontinence Diagnosis) at baseline, 1.5 months, and 3 months post-treatment. Data analysis was performed using repeated-measures ANOVA, t-tests, and chi-square tests via SPSS v23.

Participants in the solifenacin group demonstrated a statistically significant reduction in QUID scores at both follow-up points compared to placebo. At 1.5 months, the mean QUID score was 6.65 ± 1.08 in the intervention group versus 14.80 ± 2.52 in the control group (p < 0.001). At 3 months, scores were 3.25 ± 1.11 vs. 9.98 ± 4.34 (p < 0.001). The magnitude of reduction from baseline was significantly greater in the solifenacin group (−8.47 and −11.87 at 1.5 and 3 months, respectively) than in the control group (−0.88 and −5.70, respectively) with p < 0.001 for all comparisons.

Solifenacin succinate significantly improved clinical symptoms in women with MUI. The drug was well tolerated, with minimal side effects, and demonstrated superior efficacy over placebo in reducing the severity of both stress and urge components of urinary incontinence.

Solifenacin succinate represents a promising pharmacologic option for treating mixed urinary incontinence in women. Its efficacy and tolerability suggest it could be an effective first-line or adjunctive treatment, particularly in cases where behavioral therapies alone are insufficient.