Efficacy and Safety of Mirabegron Compared to Solifenacin in Treatment of Non-neurogenic Overactive Bladder in Children: A Randomized Controlled Trial.

Purpose: Non-neurogenic overactive bladder (OAB) is a common problem in children. Antimuscarinics have been widely used as first-line medical treatment. However, their frequent side effects necessitate searching for therapeutic alternatives. We aimed to assess the efficacy and safety of the beta 3 agonist, mirabegron.

Materials and methods: A randomized controlled trial enrolled child with non-neurogenic OAB refractory to behavioral urotherapy. Patients were randomized to receive either Mirabegron 25/50 mg based on a 40-kg body weight cutoff or solifenacin 5 mg for 12 weeks. Patients were assessed using Dysfunctional Voiding Scoring System questionnaire (DVSS), 3-day voiding diary and uroflowmetry. Vital signs and adverse effects were recorded at baseline and follow-up. The study primary endpoint was ≥50% reduction of the baseline DVSS.

Results: Among 128 patients screened, 72 patients (36 in each group) completed the study with a mean age of 9.2±2.3 years. Both groups had significant improvement of DVSS and voiding diary (p<0.001) at 12 weeks. In mirabegron group, 94.4% (34/36) had greater than 50% improvement of DVSS compared to 75% (27/36) of solifenacin group (P=0.02). Complete symptom resolution was observed in 22.2% (8/36) patients on mirabegron versus 8.3% (3/36) on solifenacin (P=0.1). Patients on mirabegron had less adverse effects (19.4% vs 47.2%; p=0.01).

Conclusion: Mirabegron is more effective with fewer adverse effects than solifenacin for treatment of children with OAB. Mirabegron treatment improves daytime symptoms and nocturnal enuresis with less risk of constipation. It may be considered as first-line pharmacotherapy in this patient population.