Efficacy, tolerability and safety of darifenacin, an M3 selective receptor antagonist: an investigation of warning time in patients with OAB

Summary This double‐blind, randomised placebo‐controlled, multicentre study evaluated the efficacy, tolerability and safety of 12 weeks' treatment with controlled release darifenacin 15 mg once daily (qd), in 445 patients with overactive bladder (OAB). The primary endpoint was warning time (time from first sensation of urgency to voiding), and secondary endpoints included urge incontinence episodes and volume voided. Darifenacin treatment resulted in numerical increases in warning time, but these were not significant compared with placebo – highlighting difficulties in assessing this parameter. Significant improvements were seen with darifenacin vs. placebo in urge incontinence episodes/week, volume voided and quality of life (QoL). Darifenacin was associated with increases in urgency‐free time (UFT; time between any void to the next urgency event) vs. placebo. Treatment was well tolerated; the most commonly reported adverse events were the typical antimuscarinic effects of dry mouth and constipation, both infrequently leading to discontinuation. This study demonstrated the difficulty in measuring warning time, due in part to its subjective nature; the authors believe further investigation is warranted to allow urgency to be better defined. Further investigation of UFT is required to determine its role in evaluating urgency. The study confirmed that darifenacin 15 mg qd is an effective and well‐tolerated treatment for OAB, which improves QoL.