Efficacy and safety of mirabegron, a β3-adrenoceptor agonist, for treating neurogenic bladder in pediatric patients with spina bifida: a retrospective pilot study

Purpose: Antimuscarinics are the first pharmacological treatment option for neurogenic bladder in children with spina bifida but side effects limit their use. Mirabegron, a new β-3 adrenoceptor agonist with a distinct mechanism of action, is a potential agent for the treatment of neurogenic bladder; however, it has yet to be studied in the pediatric population. This study evaluated the efficacy and safety of mirabegron for treating neurogenic bladder in children with spina bifida. Materials and methods: Clinical and urodynamic parameters were retrospectively studied in 66 children (under 18 years of age) with spina bifida who were treated for neurogenic bladder with mirabegron at Severance Children’s Hospital between July 2015 and December 2017. Pediatric patients received 50 mg mirabegron daily for at least 6 weeks either in addition to or instead of antimuscarinic therapy. Urodynamic parameters, including compliance, involuntary detrusor contraction, and maximum cystometric capacity, as well as patient-reported efficacy and adverse events, were measured. Results: In both groups post-treatment, incontinence significantly improved. In addition, maximum cystometric capacity and compliance significantly increased post-treatment. Six patients reported side effects (constipation, 4.5%; headache, 3.0%; and hypertension, 1.5%) and three patients discontinued treatment. Conclusion: We evaluated the efficacy and safety of mirabegron for treating neurogenic bladder in pediatric patients with spina bifida. All clinical and urodynamic parameters improved with treatment. Prospective, placebo-controlled studies are necessary to confirm these findings.