Video-urodynamic effects of mirabegron, a β3 -adrenoceptor agonist, in patients with low-compliance bladder

To investigate video-urodynamic effects of mirabegron, a β3 -adrenoceptor agonist, on low-compliance bladder.

We retrospectively reviewed nine patients (three men, six women, age 17-68 years) who had been diagnosed with lower urinary tract dysfunction with low-compliance bladder, and who underwent video-urodynamic study before and during administration of mirabegron 50 mg once daily. Urodynamic parameters were compared before and after treatment.

Mirabegron treatment significantly increased first desire to void and cystometric capacity with an average increment of 80 mL (P = 0.027) and 123 mL (P = 0.005), respectively. Bladder compliance also significantly increased (mean value 8.1 mL/cmH2 O before, 18.2 mL/cmH2 O after, P = 0.024). In the six patients who had been taking anticholinergic agents at baseline video-urodynamic study and then switched to mirabegron, mean cystometric capacity and bladder compliance were also increased significantly from 208.3 to 346.8 mL (P = 0.015) and from 7.2 to 17.5 mL/cmH2 O (P = 0.047), respectively. Vesicoureteral reflux grade was improved in three of the four patients who had shown vesicoureteral reflux on cystography before treatment.

Mirabegron improves cystometric capacity and bladder compliance, and it lowers vesicoureteral reflux grade in patients with low-compliance bladder. Thus, mirabegron might represent a good alternative drug for low-compliance bladder refractory to anticholinergic treatment.