Effect of mirabegron on erectile function in sexually active men with bothersome overactive bladder symptoms

To evaluate the change of erectile function (EF) in sexually active male overactive bladder (OAB) patients treated with Mirabegron. Mirabegron, a selective β3 adrenoceptor agonist, approved for the treatment of OAB, has been reported to relax human and rat corpus cavernosum and might have beneficial effect on EF.

A total of 128 consecutive men with lower urinary tract symptoms attended urology outpatient clinic were evaluated for OAB and EF. Thirty-four sexually active OAB patients were prospectively enrolled in this study and received mirabegron 50 mg oral once a day. The evaluation of EF and OAB was based on a self-administered questionnaire containing International Index of Erectile Function (IIEF-5) and OAB symptom score (OABSS), respectively. Men with an OABSS urgency score of ≥2 and sum score of ≥3 were considered to have OAB. The therapeutic outcomes were assessed at baseline, 4, and 12 weeks.

Mirabegron usage was associated with a statistically significant improvement of OAB symptoms (OABSS 32.1% decrease) at 4-week follow-up and the therapeutic effects were maintained at 12-week follow-up. Mirabegron usage did not improve EF (IIEF-5 4.9% decrease at 4-week; p = 0.106, and 9.1% decrease at 12-week follow-up; p = 0.077). However, the IIEF-5 was significantly decreased in the higher baseline IIEF-5 (≥17) group (11.7% decrease; p = 0.044), noncoronary artery disease (13.2%; p = 0.007), or non-DM group (13.9% decrease; p = 0.021) at 12-week follow-up.

This preliminary study demonstrates that mirabegron treatment of men with OAB improved OAB symptoms, but has no beneficial effect on EF.