Fesoterodine is a muscarinic receptor antagonist that is rapidly and extensively converted to the active and more potent metabolite 5-hydroxy-methyltolterodine. The drug is approved for once-daily oral administration in patients with overactive bladder syndrome (OAB). In two large, 12-week, randomized, double-blind, multicentre, phase III trials, oral fesoterodine 4 or 8 mg once daily improved the symptoms of OAB (frequency of micturition, urgency and urge incontinence) significantly more than placebo. Furthermore, significantly more patients receiving fesoterodine 4 or 8 mg once daily had a positive response to therapy than those receiving placebo, as determined by a treatment questionnaire. Health-related quality of life was improved to a significantly greater extent in patients with OAB who received fesoterodine 4 or 8 mg once daily than in those who received placebo in a post hoc analysis of pooled data from the phase III trials. Fesoterodine 4 or 8 mg once daily was generally well tolerated in patients with OAB; the most frequent adverse event was dry mouth, which was generally mild to moderate in severity.