A randomized, double-blind, parallel-group comparison of controlled- and immediate-release oxybutynin chloride in urge urinary incontinence.
Author(s): Barkin J, Corcos J, Radomski S, Jammal MP, Miceli PC, Reiz JL, Harsanyi Z, Darke AC, UROMAX Study Group
Affiliation(s): University of Toronto, Toronto, Ontario, Canada.
Publication date & source: 2004-07, Clin Ther., 26(7):1026-36.
Publication type: Clinical Trial; Multicenter Study; Randomized Controlled Trial
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 (> or = 7 episode/wk) and frequency (> or = 8 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 > or = 15 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.