Mirabegron versus Solifenacin after intravesical Onabotulinum toxin-A injection in patients with refractory overactive bladder

Objective: To evaluate if administering an antimuscarinic or Beta-3agonist in addition to intravesical OnabotuliumtoxinA injection can enhance its therapeutic benefit in patients with refractory overactive bladder.Methods: A retrospective randomized clinical trial study involving 93 patients with OAB who had received intravesical 100-U OnabotulinumtoxinA injection one month ago. One group of patients received Solifenacin 5 mg QD (30 patients), another group received Mirabegron 50 mg QD (32 patients), and the control group received no medication (31 patients). A 3-day voiding diary, uro-flowmetry, the Urgency Severity Scale (USS), Overactive Bladder Symptom Score (OABSS) questionnaires, and the Global Response Assessment (GRA) scale were completed by all enrolled patients at baseline (one month following intravesical OnabotulinumtoxinA injection) and at the 3, 6, 9, and 12-month follow-up. Effective treatment success, which was defined as no OAB wet during the course of the 12-month period, was the primary end point and changes in the remaining parameters after 3 months were the secondary end point.Results: All three groups had comparable baseline data. At 4 distinct time intervals, the group that received Mirabegron had a much lower percentage of OAB wet than the groups who received Solifenacin and the OnabotulinumtoxinA-only group (P- value < 0.01). In comparison to the other groups, the Mirabegron group at 3 months showed noticeably greater better changes. There were no documented severe adverse effects.Conclusion: In patients with refractory OAB, adding Mirabegron may enhance the therapeutic effects of intravesical Onabotulinumtoxin A injection, primarily on OAB symptoms and the GRA scale.