Oxybutynin

Oxybutynin is a nonselective antimuscarinic, also called an anticholinergic, with additional direct antispasmodic activity on bladder smooth muscle. It blocks muscarinic receptors on the detrusor, reducing involuntary contractions, increasing bladder capacity, and delaying the initial urge to void. Its target pattern is overactive bladder: urinary urgency, increased frequency, and urge urinary incontinence. A patient who leaks after a sudden, difficult-to-defer urge has a different pattern from a patient who leaks mainly when coughing, laughing, or lifting. Oxybutynin reduces involuntary bladder contractions; it does not strengthen the pelvic floor or correct stress incontinence. The same parasympathetic blockade that relaxes the detrusor also affects salivary glands, bowel smooth muscle, the eye, sweat glands, and the central nervous system. That explains why a useful bladder effect can occur alongside dry mouth, constipation, blurred vision, reduced sweating, sedation, or confusion. Bladder training, timed voiding, fluid and caffeine management, and pelvic floor muscle training remain first-line measures for overactive bladder. When symptoms persist, a prescriber may add an antimuscarinic such as oxybutynin or choose a beta-3 agonist. Current guidance generally favors beta-3 agonists over antimuscarinics...