Clinical efficacy and safety of tolterodine in the treatment of overactive bladder: A pooled analysis

Objectives. To examine the safety, efficacy, and tolerability of tolterodine in four randomized, double-blind, parallel, multicenter, 12-week studies of patients with overactive bladder, Methods. Two of the four studies compared tolterodine (2 mg twice daily) to oxybutynin (5 mg three times daily) and placebo, one study compared tolterodine (2 mg twice daily) to oxybutynin (5 mg three times daily), and one study compared two dosages of tolterodine (1 and 2 mg twice daily) to placebo. Efficacy was determined from micturition diaries and patient perception of their bladder condition. Safety and tolerability were assessed from adverse events and laboratory measures. Results. A total of 1,120 patients were randomized and treated at 134 centers, For the primary efficacy variable, the number of micturitions/24 hours, pooled results showed a significant decrease from baseline for the 1 mg tolterodine (P <0.001), 2 mg tolterodine (P <0.007), and 5 mg oxybutynin (P <0.01) groups, compared to placebo. Both tolterodine doses and oxybutynin significantly decreased incontinence episodes/24 hours and significantly increased volume voided/micturition, compared to placebo, Tolterodine at a dose of 2 mg twice daily and 5 mg oxybutynin twice daily were significantly more effective in improving patient perception of bladder condition than placebo. Tolterodine at a dose of 2 mg and 5 mg oxybutynin were equivalent in their effectiveness. Tolterodine at doses of 1 mg and 2 mg were tolerated significantly better than oxybutynin when adverse events, dry mouth (both frequency and intensity), dose reductions, and patient withdrawals were considered. Conclusions. Although oxybutynin is highly effective, its clinical utility is limited by systemic side effects that lead to frequent discontinuation of treatment or dose reductions. Patients receiving tolterodine should not experience these limitations and instead will get safe and long-term effective treatment for their condition. (C) 1997, Elsevier Science Inc. All rights reserved.