Efficacy and safety of tamsulosin versus its combination with mirabegron in the management of lower urinary tract non-neurogenic overactive bladder symptoms (OABS) due to Benign Prostatic Enlargement (BPE)-An open label randomised controlled clinical study.

PURPOSE The efficacy and safety of βeta-3 agonists (Mirabegron 50 mg) has been sparingly assessed in the published English literature. We aim to do an efficacy-safety analysis of Mirabegron-Tamsulosin combination therapy versus tamsulosin-placebo monotherapy in a select subset of medication virgin Benign Prostatic Enlargement (BPE) patients with coexisting predominant non-neurogenic overactive bladder symptoms (OABS). METHODS After prior written informed consent and IEC, 80 patients of uncomplicated BPE with coexisting non-neurogenic OABS and IPSS of >7 without contraindications to drug therapy were computer randomized/allocated to receive either[50mg Mirabegron plus Tamsulosin 0.4 mg (Intervention arm-I)]or [Tamsulosin 0.4 mg plus capsule lactobacillus (Comparator arm-II)] once daily for 8 weeks. Efficacy was evaluated using the OABS Score (OABSS), mean change in nocturnal frequency(NF), PVR and IPSS while safety was assessed by recording treatment emergent adverse events (TEAE). Follow up visits were done at 2nd , 4th and 8th week. RESULTS Patient data in both groups was generally comparable with the exception of NF and IPSS storage sub score(IPSS-ss). Significant improvements were visualised in the 8th week primary endpoint total OABS sub score (OABSS-ss) in combination group (p< 0.001).Similar significant improvements were seen with most secondary parameters such as the mean change in NF, IPSS, IPSS-ss, OABS-ss, voided volume, Qmax, and Quality of life index (QOL) (p<0.001). No significant increase in PVR was observed in the Mirabegron arm and no patient developed urinary retention. The TEAE were minor, self-limiting and managed symptomatically without drug discontinuity. CONCLUSION Mirabegron can be significantly efficacious and safe in ameliorating non-neurogenic OABS induced by BPE versus placebo by initiating combination therapy from the start as opposed to the usual 'add on therapy' protocol. This combination appeared to be superior in terms of overall safety, minimal side effects, better compliance and tolerability versus Tamsulosin monotherapy in select BPE patients with predominant non-neurogenic OABS.