Which medication is commonly used to treat overactive bladder?

• A. Oxybutynin
• B. Atropine
• C. Bethanechol
• D. Dicyclomine

Answer: (A)

Overactive bladder is driven by involuntary detrusor muscle contractions. The main treatment approach is to dampen these contractions by blocking acetylcholine at muscarinic receptors in the bladder, especially the M3 subtype. Oxybutynin is an antimuscarinic medication that does exactly this, reducing detrusor overactivity and lowering urgency, frequency, and urge incontinence.

Common side effects come from anticholinergic action—dry mouth, constipation, blurred vision, and potential cognitive effects in older patients. The other drugs listed work differently: bethanechol is a muscarinic agonist that increases bladder contractions to treat urinary retention, atropine is a nonselective antimuscarinic used to reduce secretions or as an antidote, and dicyclomine is an antispasmodic for GI cramps. Thus, oxybutynin best fits the goal of treating overactive bladder.