Tolterodine is an antimuscarinic drug that is used for symptomatic treatment of urinary incontinence. It is characterized by uninhibited bladder contractions causing an uncontrollable urge to void. Urinary frequency, urge incontinence and nocturnal incontinence occur. Abnormal bladder contractions that coincide with the urge to void can be measured by urodynamic studies. Treatment is bladder retraining, pelvic floor therapy or with drugs that inhibit bladder contractions such as oxybutinin and tolterodine. Tolterodine acts on M2 and M3 subtypes of muscarinic receptors whereas older antimuscarinic treatments for overactive bladder act more specifically on M3 receptors. Tolterodine, although it acts on all types of receptors, has fewer side effects than oxybutynin as tolterodine targets the bladder more than other areas of the body. This means that less drug needs to be given daily and so there are fewer side effects.