A Clinical Study in Patients With Overactive Bladder With Leakage of Urine, to Find Out if the Medicine, Fesoterodine, Works in Those Patients Who Did Not Have Enough Response to the Medicine, Tolterodine.

Patients with overactive bladder are often treated with tolterodine, a medication that helps relax the bladder, helping symptoms of urinary incontinence and urinary frequency. Sometimes patients do not have a satisfactory response, and may benefit from trying an alternative oral medicine. Fesoterodine is related to tolterodine by producing the same active substance that acts on the bladder, but potentially at higher and more effective levels. So, a patient who has a poor response to tolterodine may still obtain a good response to fesoterodine. This study will help find out if this is what happens.