Safety and efficacy of mirabegron in daily clinical practice: a prospective observational study

To determine risks associated with prescribing mirabegron, the first-in-class β3-adrenoreceptor agonist, to non-selected female patients with overactive bladder.

Routine female patients seeking treatment for overactive bladder (n=221) in a urology/gynecology outpatient clinic. Data on adverse events, cardiovascular outcomes, condition specific symptoms and drug discontinuation was collected at two months follow-up (FU). Non-parametric statistics was used as appropriate. Odds ratios (ORs) with 95% confidence intervals (CIs) for outcome association analyses using logistic regression.

16 patients (7.2%) discontinued treatment because of side effects. There were no significant associations between cardiovascular adverse events and pre-existing cardiovascular disease (OR 0.3, 95% CI 0.3-2.6), or pre-existing ECG abnormalities (OR 2.3, 95% CI 0.3-16.3). At FU ECGs there were no de novo cases of tachyarrhythmias and no significant difference in mean QTc between baseline (403ms, SD 21.7) and the 2 months follow-up ECG (403ms, SD 20.3) (p=0.75). There was a significant decrease in the mean systolic blood pressure (p=0.03) but no significant change in mean diastolic pressure (p=0.8) or heart rates (p=0.2) from baseline to FU. Overactive bladder specific symptoms and quality of life improved significantly (p<0.001 respectively).

Mirabegron treatment is associated with a satisfactory cardiovascular safety profile, as well as, significant symptomatic improvement also in a heterogeneous population of non-selected women with overactive bladder presenting in everyday clinical practice.