What do we know and not know about mirabegron, a novel β3 agonist, in the treatment of overactive bladder?
OBJECTIVE
Mirabegron is a novel β3-adrenoceptor agonist recently approved by Japanese, American, and European authorities for overactive bladder (OAB) therapy. Here we review existing knowledge on this new class of medication, analyze existing literature on the topic, and make recommendations regarding its administration and necessary future studies.


METHODS
We reviewed the current literature and analyzed mirabegron efficacy, safety, and suitability for treating OAB symptoms. We performed a systematic search of Medline/PubMed, and Embase. Studies exploring mechanisms involved in the effects of mirabegron were included. Searches were limited to the English language.


RESULTS
Two phase II and two large-scale phase III multinational randomized controlled trials have supported mirabegron efficacy and tolerability with up to 12 weeks of therapy in OAB patients. The reported frequency and severity of treatment-emergent and serious adverse events were similar to antimuscarinics but with more than threefold lower incidence of dry mouth than with tolterodine. However, effects on the cardiovascular system, cognitive functions, pharmacokinetic interactions with other drugs, and long-term adverse events have not yet been fully investigated.


CONCLUSIONS
Anticholinergic drugs should remain the first-line pharmacologic treatment for OAB until head-to-head comparative study eventually shows that mirabegron has equivalent or superior efficacy. However, it seems logical to use mirabegron as second-line treatment of OAB in patients who are poor responders or intolerant to anticholinergics.
Department of Urology, Jewish General Hospital, McGill University, 3755 cote sainte catherine E-936, Montreal, QC, H3T 1E2, Canada.
Romain
R
Caremel
Oleg
O
Loutochin
Jacques
J
Corcos
D000083:Acetanilides / Q000493:pharmacokinetics / Q000627:therapeutic use*; D058667:Adrenergic beta-3 Receptor Agonists / Q000493:pharmacokinetics / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D018727:Muscarinic Antagonists / Q000627:therapeutic use; D013844:Thiazoles / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016896:Treatment Outcome; D053201:Urinary Bladder, Overactive / Q000188:drug therapy*
D000083:Acetanilides; D058667:Adrenergic beta-3 Receptor Agonists; D018727:Muscarinic Antagonists; D013844:Thiazoles; C520025:mirabegron