Oxybutynin is an anticholinergic and antispasmodic agent used to treat overactive bladder (OAB) and urinary urgency or incontinence. It works by blocking muscarinic M3 receptors on the detrusor muscle of the bladder, reducing involuntary detrusor contractions and increasing bladder capacity. This parasympathetic blockade decreases the urge to void and reduces episodes of urge incontinence. Because muscarinic receptors are found throughout the body (salivary glands, GI tract, eyes, sweat glands, CNS), systemic anticholinergic side effects are common and clinically significant.