Aims:  Efficacy of antimuscarinic therapy for overactive bladder (OAB) has been demonstrated; however, the durability of its effects is unknown. The study was conducted to evaluate symptom change and retreatment rate after discontinuation of antimuscarinic therapy. Also, we tried to find risk factors for retreatment.

Methods:  This was a prospective, randomised, open-label, multicentre trial at four university hospitals. Women who had OAB symptoms for ≥ 6 months and who showed successful response to 1 month of Tolterodine 4 mg medication were randomly assigned to one of three groups: (A) discontinue medication, (B) 2-month additional medication and (C) 5-month additional medication. After completion of the 1-, 3- or 6-month treatment, patients stopped the medication and were followed up for additional 3 months to assess symptom relapse and retreatment rates. Risk factors for retreatment were evaluated.

Results:  Of a total of 558 patients who took the study medication, 173 were randomised and 108 (A: 40, B: 40, C: 28) were included in the analysis. At the end of the treatment, the mean micturition frequency was decreased to 8.3/24 h from 11.7/24 h, and the mean urgency episode was decreased to 2.2/24 h from 8.0/24 h. Three months after discontinuation, the micturition frequency and the urgency episode were increased to 9.1/24 and 4.4/24 h respectively. Sixty five per cent of patients requested retreatment, and 62% experienced symptom relapse. Baseline health-related quality of life was the only independent risk factor for retreatment.

Discussion and conclusion:  Discontinuation of antimuscarinic therapy resulted in high symptom relapse and retreatment rates regardless of treatment duration. The results provide new information on the durability of the efficacy of antimuscarinics, and may improve treatment efficacy by promoting the medication persistence of antimuscarinics in OAB patients.