About Tolterodine Tartarate Anticholinergic ( antimuscarinic), Treat urinary incontinence. Mechanism of Action of Tolterodine Tartarate Tolterodine tartrate is a specific muscarinic receptor (M3 receptor) antagonist. It blocks muscarinic receptors which can be found on the muscle cells of the bladder wall. It prevents the action of acetyl choline on these receptors. Acetylcholine acting on these receptors causes the muscle in the bladder wall to contract, and the bladder to empty. By preventing this, Tolterodine helps the muscle in the bladder wall to relax. This reduces unstable, involuntary contractions of the bladder, and thereby increases the capacity of the bladder to hold urine. This in turn reduces the need to pass urine. Stimulation of muscarinic receptors causes the bladder to contract and empty. Tolterodine relax the involuntary muscle in the wall of the bladder.