Central nerve system (CNS) disease, such as cerebrovascular accident (CVA), white matter disease like parkinsonism or Parkinson’s disease (PD) and dementia are common chronic ischemic brain diseases in the elderly, were associated with higher incidence of overactive bladder (OAB). Treatment with antimuscarinics or mirabegron is the mainstay treatment for OAB. However, there has been no consensus which medication is favorable. The objective of this study is to evaluate and compare the therapeutic efficacy and adverse events between mirabegron 50 mg QD, solifenacin 5 mg QD, and combined solifenacin 5 mg and mirabegron 50 mg QD, in patients with OAB due to CNS diseases such as CVA, PD, and early dementia.

Patients aged over 40 years old with OAB symptoms and previous history of CVA, PD or dementia were enrolled. Patients were medicated with tamsulosin 0.4 mg QD for two weeks without adding any OAB medication (wash out period). Then they were randomized to one of the three subgroups and received (A) solifenacin 5 mg QD, (B) mirabegron 50 mg QD, and (C) combined solifenacin 5 mg and mirabegron 50 mg QD. Efficacy and safety parameters such as overactive bladder symptom score (OABSS), urgency severity score (USS), international prostate symptom score (IPSS) and subscore, maximum flow rate (Qmax), voided volume, postvoid residual (PVR) volume, and void efficiency (VE) were compared between baseline and 3 months after treatment.

Of the 67 patients (mean age, 73.0 years) enrolled, 24 received mirabegron monotherapy, 25 received solifenacin monotherapy, and 18 received combination therapy. The baseline characteristics and urodynamic parameters were similar among groups. OAB symptoms improved in both mirabegron and solifenacin treatment. There was no significant difference of symptom score changes among 3 groups. However, there was significant increased of PVR and decreased of VE in combination group. Most adverse events (AEs) were mild. Dry mouth was complained in 6 patients (24%) in the solifenacin group and 5 patients (27.8%) in the combination group. Constipation was noted in 2 patients (8%) in the solifenacin group while dysuria was complained in 5 patients (273.8%) in the combination group.

In previous clinical trial, combined mirabegron and solifenacin was well tolerated. However, combination therapy resulted in increased PVR and higher AEs rate in patients with CNS disease. In addition, the improvement of symptoms was also not superior to monotherapy. It seems mirabegron monotherapy is more preferable as first -line treatment for patients with CNS disease.

Both mirabegron and solifenacin can improve OAB symptoms. Patients receiving mirabegron had less AEs than those receiving solifenacin and combination treatment. Patients receiving combination treatment had higher PVR and lower VE than monotherapy.