A randomized, double-blind, parallel-group comparison of controlled- and immediate-release oxybutynin chloride in urge urinary incontinence

Objective: The aim of this study was to evaluate the efficacy and safety of a new PO controlled-release (CR) QD oxybutynin tablet relative to PO immediate-release (IR) TID oxybutynin in patients with urge urinary incontinence (UI). Methods: In this multicenter, double-blind trial, patients with UI (greater than or equal to7 episodes/wk) and frequency (greater than or equal to8 micturitions/d) were randomized to CR or IR oxybutynin for 6 weeks. Patients initiated treatment at 15 mg/d and the dose was adjusted (in 5-mg/d increments) over 2 weeks according to tolerability Efficacy (UI episodes, voids, absorbent pads used, urgency, and volume voided per micturition) was assessed during the final 2 weeks of treatment. Tolerability was assessed by evaluating adverse events and treatment withdrawals. Results: Of the 125 patients randomized, 94 (75%) were evaluable for efficacy; tolerability was assessed in all patients. In the CR group, 48 patients (91%) were women and 5 (9%) were men; the mean (SD) age was 58.0 (12.4) years (range, 26-78 years). In the IR group, 37 patients (90%) were women and 4 (10%) were men; the mean (SD) age was 60.6 (14.8) years (range, 26-83 years). Both CR and IR oxybutynin significantly reduced the mean number of total UI episodes per week (both P < 0.001 vs baseline). Both treatments produced equivalent reductions in mean voiding frequency and urinary urgency (all P < 0.001 vs baseline). Significantly more patients rated CR oxybutynin tolerable on the initial dose of 15 mg/d (P = 0.020) and completed the study at a dose of greater than or equal to15 mg/d (P = 0.018). Dry mouth was the most common adverse event, reported by 68% and 72% of patients in the CR and IR oxybutynin groups, respectively Conclusions: Among the patients with urge UI. included in this study, CR oxybutynin was as effective as IR oxybutynin for improving primary symptoms, with the additional benefit of QD administration. Copyright (C) 2004 Excerpta Medica, Inc.