Urodynamics and safety of the β₃-adrenoceptor agonist mirabegron in males with lower urinary tract symptoms and bladder outlet obstruction.

PURPOSE: Bladder outlet obstruction often presents as storage and voiding symptoms. We investigated urodynamic parameters in men with lower urinary tract symptoms and bladder outlet obstruction treated with the β₃ agonist mirabegron, a new therapy for overactive bladder symptoms.

MATERIALS AND METHODS: A total of 200 men 45 years old or older with lower urinary tract symptoms and bladder outlet obstruction were randomized to receive once daily mirabegron 50 mg (70) or 100 mg (65), or placebo (65) for 12 weeks. The primary urodynamic parameters assessed were change from baseline to end of treatment in maximum urinary flow and detrusor pressure at maximum urinary flow (noninferiority margins -3 ml per second and 15 cm H2O, respectively). We evaluated adverse events and vital signs.

RESULTS: Treatment with mirabegron 50 and 100 mg was noninferior to placebo based on the lower and upper limits of the 95% CI, respectively, for maximum urinary flow and detrusor pressure at maximum urinary flow. The adjusted mean difference vs placebo was 0.40 (95% CI -0.63, 1.42) and 0.62 ml per second (95% CI -0.43, 1.68) for maximum urinary flow, and -5.94 (95% CI -13.98, 2.09) and -1.39 cm H2O (95% CI -9.73, 6.96), respectively, for detrusor pressure at maximum urinary flow. The incidence of adverse events was similar for mirabegron and placebo.

CONCLUSIONS: Mirabegron did not adversely affect voiding urodynamics (maximum urinary flow and detrusor pressure at maximum urinary flow) compared with placebo after 12 weeks of treatment.