Effectiveness and tolerability of extended-release oxybutynin vs extended-release tolterodine in women with or without prior anticholinergic treatment for overactive bladder

The efficacy and the tolerability of extended-release oxybutynin chloride, 10 mg daily, and extended-release tolterodine tartrate, 4 mg daily, in women with or without prior anticholinergic treatment for overactive bladder (OAB) were compared in a post-hoc analysis of data from the Overactive Bladder: Performance of Extended Release Agents (OPERA) trial. The patient population and study methods have been described previously (Diokno et al., for the OPERA Study Group, Mayo Clin Proc 78:687-695, 2003). Among the group with anticholinergic experience, extended-release oxybutynin was significantly more effective than extended-release tolterodine in reducing micturition frequency at last observation (p=0.052). Complete freedom from urge incontinence was reported by significantly more patients taking oxybutynin than tolterodine at last observation (23.6 vs 15.1%, p=0.038). In addition, among patients completing a full 12 weeks of oxybutynin treatment, significantly greater reductions were observed compared with those taking tolterodine on the primary efficacy variable, number of urge incontinence episodes (p=0.049), and the combined total of urge and non-urge episodes (p=0.012), although the differences between treatment groups were not significant at last observation. In the anticholinergic-naive group, efficacy and tolerability outcomes were similar across treatments, except that oxybutynin was associated with a significantly lower frequency of micturition at last observation (p=0.035). No efficacy differences favoring tolterodine were observed, and tolerability of the treatments was comparable. Dry mouth (mostly mild to moderate in severity) was reported significantly more often among participants taking extended-release oxybutynin than extended-release tolterodine (32.2 vs 19.2%, p=0.004), but only among those with previous anticholinergic experience. Discontinuation rates were comparably low across groups. The results demonstrate the appropriateness of initiating treatment for OAB with extended-release oxybutynin, particularly in women presenting with incontinence.