About Flavoxate Muscarinic antagonist(anticholinergic ) Flavones and their glycosides, Muscle relaxant, systemic urinary tract antispasmodic. Mechanism of Action of Flavoxate This is a direct antagonist drug which act on muscarinic acetylcholine receptors in innervated organs especially in bladder. Its anticholinergic-parasympatholytic action reduces the tonus of smooth muscle in the bladder and relaxing the involuntary muscle that is found in the wall of the bladder. This effectively reduce the number of required voids, urge incontinence episodes, urge severity and improving retention, facilitating increased volume per void.