The Efficacy and Safety Between Intradetrusor OnabotulinumtoxinA Injection and Combined Pharmacotherapy in Patients With Refractory Overactive Bladder: A Randomized Controlled Trial

Abstract

Purpose: We investigated whether intradetrusor onabotulinumtoxinA injection demonstrates superior efficacy and fewer side effects compared with combined pharmacotherapy in patients with refractory overactive bladder.

Materials and methods: In this single-center, open-label, randomized trial, patients with urodynamically confirmed detrusor overactivity and persistent symptoms despite at least 2 months of single pharmacotherapy were randomized to receive onabotulinumtoxinA injection (100 U) or combined pharmacotherapy with solifenacin 5 mg and mirabegron 25 mg. Assessments at baseline and 12 weeks included voiding parameters, adverse events, and patient-reported outcomes using the Urogenital Distress Inventory, Incontinence Impact Questionnaire, and the Overactive Bladder Symptom Score.

Results: Of 74 patients enrolled, 66 completed the study (33 per group). Both treatments reduced urgency episodes to a median of 2.0 per 24 hours at 12 weeks. The mean difference between groups was -0.1 (95% CI: -1.5 to 1.4; P = .925), indicating no significant difference. Improvements in urinary frequency, nocturia, urge incontinence, and quality-of-life measures were observed in both groups, without significant differences. However, adverse effects such as dry mouth, constipation, and blurred vision were significantly more common with pharmacotherapy (all P < .05).

Conclusions: Both intradetrusor onabotulinumtoxinA and combined pharmacotherapy improved symptoms in women with refractory overactive bladder. OnabotulinumtoxinA demonstrated a more favorable safety profile and represents an appropriate option for patients sensitive to systemic anticholinergic effects or preferring nondaily interventions.

Trial registration: ClinicalTrials.gov Identifier: NCT05968885.

Keywords: onabotulinumtoxinA; overactive bladder; urgency; urinary incontinence.