Overflow incontinence is most appropriately treated with which agent?

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

Answer: (B)

Overflow incontinence happens when the bladder can’t empty properly, so urine leaks as the bladder overfills. To address this, you want to boost detrusor (bladder muscle) contraction to improve emptying. Bethanechol is a muscarinic agonist that stimulates the detrusor to contract, promoting voiding and reducing retention, which directly treats the underlying problem of overflow.

The other options don’t address detrusor contraction: tamsulosin helps relieve outlet obstruction by relaxing bladder neck/prostate but doesn’t fix an underactive detrusor; finasteride shrinks the prostate to reduce obstruction but isn’t an acute treatment for detrusor weakness; oxybutynin is an antimuscarinic that reduces bladder activity and would worsen overflow by impairing emptying.