LAUSR

AIMS Mirabegron has promising results for OAB symptoms in adults, although the potential for cardiovascular side effects has caused concern. Efficacy and tolerability in children have not been extensively studied. Effectiveness, tolerability, and side effects of Mirabegron are reported in children with refractory OAB. METHODS A retrospective review of children receiving Mirabegron between February 2014 and November 2018 was completed. Frequency, urgency, nocturnal (NE), and daytime incontinence (DI) were analyzed at baseline and 6 months. RESULTS 70 children (50 females), median age 15 [range 8-16] years, commenced Mirabegron 25 mg (n = 29) or 50 mg (n = 41). 37 (53%) were still receiving treatment at 6 months: monotherapy n = 30, and combination therapy n = 7 (Solifenacin n = 4, Desmopressin n = 2, both n = 1). Where undertaken, blood pressure monitoring and ECGs were normal. For patients on monotherapy, 6 of 17 (35%) had improvement in NE, 11 of 19 (58%) in DI, 12 of 20 (60%) in frequency, and 8 of 21 (38%) in urgency symptoms. For patients receiving combination therapy, 2 of 6 (33%) had improvement in NE, 2 of 4 in DI (50%), 2 of 4 (50%) in frequency, and 4 of 6 (67%) had improvement in urgency. Reasons for treatment discontinuation (entire cohort) were: ineffectiveness (n = 28), worse symptoms (n = 4) and/or adverse reactions (n = 7), including dry mouth (n = 2), headaches (n = 4), dizziness (n = 1), nausea/vomiting (n = 3), increased seizures (n = 1), and rash (n = 1). CONCLUSION Mirabegron improved symptoms in 70% of patients with refractory OAB. A prospective RCT should be the next step to establish the role of Mirabegron for the treatment of OAB in children. LEVEL OF EVIDENCE Level II.