Which medication is used for overactive bladder?

• A. Finasteride
• B. Bethanechol
• C. Oxybutynin
• D. Tamsulosin

Answer: (C)

Overactive bladder happens when the detrusor muscle contracts too readily, causing urgent, frequent urges to urinate and sometimes leakage. The main treatment approach is to calm those involuntary bladder contractions. Medications that block acetylcholine at the bladder’s muscarinic receptors—antimuscarinics—do this effectively. Oxybutynin is a classic antimuscarinic used to treat urge incontinence and overactive bladder. By blocking those receptors on the detrusor muscle, it reduces spontaneous contractions, increases bladder capacity, and lessens urgency and frequency.

Bethanechol would actually stimulate bladder contractions, potentially worsening symptoms. Finasteride targets prostate size and is used for BPH symptoms, not detrusor overactivity. Tamsulosin helps with urine flow in BPH by relaxing the bladder neck and prostate, not addressing detrusor overactivity. Side effects of oxybutynin can include dry mouth, constipation, and other anticholinergic effects, which is useful to anticipate in management.