The pharmacokinetic evaluation of mirabegron as an overactive bladder therapy option

INTRODUCTION: Mirabegron is a new once-daily, oral treatment for management of overactive bladder (OAB) that is approved in USA, EU and Japan. It activates β3 adrenoceptor to facilitate bladder filling and reduce mean micturition frequency with better safety profile than current treatment of antimuscarinic drugs. AREAS COVERED: The following article reviews the information available from published randomized trials on the metabolism and pharmacokinetics mirabegron. The reader will gain better insight into the variability in plasma exposure of mirabegron due to various causes. Propensity for drug interactions with mirabegron is low as its clearance involves multiple metabolic and excretory pathways. Mirabegron is generally well tolerated, but its pharmacokinetics is altered by dose and gender with implications for cardiovascular toxicity. EXPERT OPINION: Mirabegron is a first-in-class of β3 adrenoceptor agonists that could offer an alternative to antimuscarinics for OAB patients. The marketed dose of 50 mg achieves primary efficacy endpoints but causes only modest improvement over placebo in terms of daily incontinence and voiding episodes. Involvement of saturable efflux transporters is indicated in oral bioavailability of mirabegron. It is well tolerated with hypertension, nasopharyngitis, urinary tract infection and headache being the most common side effects.