Objectives: To investigate whether adding an anticholinergic or beta-3 agonist can improve the therapeutic effect of intravesical onabotuliumtoxinA injection in patients with refractory overactive bladder (OAB).
Methods: Ninety OAB patients who received an intravesical 100-U onabotulinumtoxinA injection 1 month previously were consecutively invited into a prospective, randomized, open-label study. They were randomly adding on solifenacin 5 mg daily (QD) (30 patients), mirabegron 50 mg QD (31 patients), or no medication (29 patients, control). All enrolled patients completed a 3-day voiding diary, Overactive Bladder Symptom Score (OABSS) and Urgency Severity Scale (USS) questionnaires, Global Response Assessment (GRA) scale, and uroflowmetry at baseline (1 month after intravesical onabotulinumtoxinA injection) and 3-, 6-, 9-, and 12-month follow-up. The primary end point was the effective therapeutic outcome defined as no OAB wet during the 12-month period. The secondary end point included changes of GRA, OABSS, and the parameters of the voiding diary at 3 months.
Results: The baseline data were comparable among the three groups. The percentage of OAB wet in the mirabegron-added-on group was significantly less than that in the solifenacin-added-on and onabotulinumtoxinA-only groups at four different time points (P = .02). At 3 months, the changes of GRA, OABSS, USS, urge urinary incontinence, frequency, nocturia episodes, and functional bladder capacity in the mirabegron-added-on group were significantly greater than those in the other groups. No serious adverse events were reported.
Conclusions: Adding mirabegron could increase the therapeutic effects, mainly on OAB symptoms and GRA scale, after intravesical onabotulinumtoxinA injection in refractory OAB patients.
Keywords: mirabegron; onabotulinumtoxinA; overactive bladder; solifenacin.
© 2021 John Wiley & Sons Australia, Ltd.