Objectives: To evaluate the efficacy and tolerability of a new extended-release (ER), once-daily, capsule formulation of tolterodine, relative to placebo and the existing immediate-release (IR), twice-daily, tablet formulation, for treatment of the overactive bladder.
Methods: This was a double-blind, multicenter, randomized, placebo-controlled trial. One thousand five hundred twenty-nine patients (81% women) with urinary frequency (eight or more micturitions every 24 hours) and urge incontinence (five or more episodes per week) were randomized to oral therapy with tolterodine ER 4 mg once daily (n = 507), tolterodine IR 2 mg twice daily (n = 514), or placebo (n = 508) for 12 weeks. Efficacy was assessed at the end of the treatment period on the basis of the micturition diary variables. Tolerability and safety were assessed by evaluating the adverse events, electrocardiogram parameters, laboratory values, and treatment withdrawals.
Results: Tolterodine ER 4 mg once daily (P = 0.0001) and tolterodine IR 2 mg twice daily (P = 0.0005) both significantly reduced the mean number of urge incontinence episodes per week compared with placebo. The median reduction in these episodes as a percentage of the baseline values was 71% for tolterodine ER, 60% for tolterodine IR, and 33% for placebo. The ER formulation was 18% more effective than the IR formulation (P <0.05). Treatment with both formulations of tolterodine was also associated with statistically significant improvements in all other micturition diary variables compared with placebo. For both formulations, the mean decreases in micturition frequency (P <0.0079) and pad usage (P <0.0145) were significant, and the mean volume voided per micturition increased (P = 0.0001). The rate of dry mouth (of any severity) was 23% for tolterodine ER, 30% for tolterodine IR, and 8% for placebo. The overall dry mouth rate for patients taking tolterodine ER was 23% lower than for tolterodine IR (P <0.02), and the rate of severe dry mouth in the ER group was only 1.8%. The rates of withdrawal were comparable for the two active groups and the placebo group. No safety concerns were noted.
Conclusions: Tolterodine ER 4 mg once daily is effective and well tolerated in the treatment of overactive bladder with no safety concerns. Tolterodine ER demonstrated an improved efficacy for reducing urge incontinence episodes and a lower frequency of dry mouth compared with the existing IR twice-daily formulation.