Detrol la has tolterodine in it. What is that?

Detrol = tolterodine. It is an ancholinergic and thus relaxes smooth muscle ; thus prescribed as treatment of an overactive bladder, to control involuntary bladder contractions which can cause urinary incontinence ;/or to increase functional bladder capacity ; thus reduce urinary frequency or number of yimes you have to get up at night to urinate.
Anticholinergic. Tolterodine is an anticholinergic which relaxes the smooth muscle of the bladder, resulting in the therapeutic effects along with other muscles, causing the side effects.