Efficacy and safety of mirabegron versus solifenacin as additional therapy for persistent OAB symptoms after tamsulosin monotherapy in men with probable BPO

Purpose To investigate the efficacy and safety of mirabegron versus solifenacin as add-on for persistent OAB symptoms after tamsulosin monotherapy in men with probable BPO. Patients and methods This prospective randomized single-blind study was conducted on patients with persistent OAB symptoms after at least 12 weeks of tamsulosin 0.4 mg. The patients were randomized into group A in which mirabegron (50 mg once daily) was added and group B in which solifenacin (5 mg once daily) was added. Before and 12 weeks after addition of either drugs, we assessed the efficacy of the treatment using the OABSS, IPSS, Q max, MVV/mic and PVR. Results Ninety two men were included in this study (46 patients in each group). All the study parameters were significantly improved after the 12-week treatment period in both groups except mean PVR which showed non-significant change in group A and a significant change in group B despite of being clinically irrelevant with only one case of acute urine retention. Overall, no significant difference has been observed between both groups after 12 weeks of treatment regarding all studied parameters except PVR. The incidence of side effects in group A was 10.9% versus 26.1% in group B. Main side effects included dry mouth in 2.2% and 8.7% and constipation in 2.2% and 6.5% in group A and B, respectively. Conclusion Our results indicate that the addition of either mirabegron or solifenacin to patients with persistent OAB symptoms after tamsulosin monotherapy has significant efficacy in controlling these symptoms. The adequate balance between efficacy and tolerability reported in this study with mirabegron may result in better QOL and overall patient satisfaction if compared with antimuscarinics.