Solifenacin is a bladder-selective, muscarinic (M-1 and M-3) receptor antagonist. In animal studies, the selectivity of solifenacin for the bladder over the salivary glands was greater than that of tolterodine, oxybutynin, darifenacin or atropine. In large, 12-week, randomised, double-blind, multi-centre clinical trials, solifenacin 5 and 10mg once daily improved symptoms of overactive bladder syndrome (OAB) [urinary urgency, frequency, incontinence and nocturial and increased functional bladder capacity to a significantly greater extent than placebo. Solifenacin 5 or 10mg once daily was noninferior to tolterodine extended release (ER) 4mg daily for improving urinary frequency and had significantly greater efficacy than tolterodine ER for improving other symptoms of OAB (episodes of urgency, incontinence and urge incontinence) and increasing functional bladder capacity. At least half of all patients receiving solifenacin who were incontinent at baseline were continent by study end in the three comparative studies reporting this parameter. Health-related quality of life was significantly improved with once-daily solifenacin 5 or 10mg versus placebo, as assessed in two 12-week double-blind studies; the improvement was maintained during a 40-week extension study. Solifenacin was generally well tolerated; the most frequently reported adverse events were dry mouth, constipation and blurred vision.