Mirabegron may improve sexual function in adults with OAB

Mirabegron, a ß3 adrenoceptor agonist, delivers benefit for both men and women with overactive bladder (OAB) who are experiencing sexual dysfunction, a systematic review and meta-analysis reports.

“In women, our data [shows] a beneficial effect of mirabegron in those suffering from sexual dysfunction and OAB,” said Dr Vasileios Sakalis from the Agios Pavlos General Hospital of Thessaloniki, Greece, at EAU 2023. “[There was a] smaller effect on erectile function of men with OAB.”

Sakalis and colleagues reviewed observational and comparative studies evaluating changes in the sexual function of men and women with OAB following treatment with mirabegron 50 mg. Of the six trials that met the inclusion criteria, data were available for 259 adults (n=187 women and 72 men). [EAU 2023, abstract A0698]

After 12 weeks of mirabegron use in females, there was a large-scale, statistically significant improvement in Female Sexual Function Index score from baseline (standard mean difference, -0.99; 95 percent confidence interval [CI], -1.43 to -0.54; p<0.0001).

In males, there was a marginally significant change in the International Index of Erectile Function-5 at 12 weeks (standard mean difference, 0.33, 95 percent CI, -0.69 to 0.03; p=0.07). In one trial, despite significant improvements in Sexual Health Inventory for Men scores at weeks 4 and 8 (p=0.0003), this effect was not sustained by week 12.

“[The positive effect in men could have been due to the] activation of the ß3-adrenergic receptors in the corpus cavernosum tissue, causing vasodilatation independently of the nitric oxide-cyclic GMP pathway,” said Sakalis.

“[Mirabegron may also have] a protective effect on endothelial dysfunction and induces vasorelaxation in both sexes’ genitalia,” he continued.

Taken together, the results suggest that the efficacy of mirabegron may not be confined to the management of OAB symptoms alone, but to other conditions accompanying OAB as well.

Conflicting evidence

The current findings align with studies reflecting the benefit of mirabegron in both men and women with OAB and sexual dysfunction. [Int J Impot Res 2022;34:588-592; BMC Urol 2019;19:7] The are also specific evidence in women, showing that sexual function may improve once OAB symptoms respond favourably to pharmacologic therapy. [World J Urol 2015;33:2095; Int Urogynecol J Pelvic Floor Dysfunct 2008;19:1551; J Surg Med 2023;7:205-208]

For men however, despite some evidence showing benefit, others appear to suggest otherwise, with mirabegron apparently reducing erectile function. [J Chin Med Assoc 2020;83:55-59] “[Moreover, in our study] the positive effect of mirabegron on erectile function is not robustly supported by the available evidence,” noted Sakalis.

“[Hence, our results] should be addressed with caution given the poor quality of the included studies and the absence of randomized trials,” said Sakalis.

Further investigations are thus warranted to ascertain how mirabegron can benefit OAB patients who have concomitant sexual dysfunction.