Which therapy is used for decreased detrusor muscle activity (bladder atony)?

Which therapy is used for decreased detrusor muscle activity (bladder atony)?

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

Answer: (C)

Bladder atony means the detrusor muscle isn’t contracting well enough to empty the bladder. The treatment goal is to stimulate the detrusor to contract. Bethanechol is a direct muscarinic (parasympathetic) agonist that acts on the M3 receptors in the bladder wall, increasing detrusor smooth muscle contraction and facilitating urination. This makes it the best choice for underactive detrusor or postoperative urinary retention due to bladder atony. Other options don’t provide that stimulatory effect on the detrusor: an alpha-1 blocker helps with urine flow by relaxing the bladder outlet but doesn’t enhance detrusor contraction; a 5-alpha-reductase inhibitor reduces prostate size with no direct impact on detrusor activity; a muscarinic antagonist would actually reduce detrusor contractions and worsen retention. Bethanechol is specifically used to overcome underactive bladder by promoting bladder emptying, though it can have cholinergic side effects (salivation, sweating, abdominal cramps, bradycardia) and is used with caution in certain conditions.

Bladder atony means the detrusor muscle isn’t contracting well enough to empty the bladder. The treatment goal is to stimulate the detrusor to contract. Bethanechol is a direct muscarinic (parasympathetic) agonist that acts on the M3 receptors in the bladder wall, increasing detrusor smooth muscle contraction and facilitating urination. This makes it the best choice for underactive detrusor or postoperative urinary retention due to bladder atony.

Other options don’t provide that stimulatory effect on the detrusor: an alpha-1 blocker helps with urine flow by relaxing the bladder outlet but doesn’t enhance detrusor contraction; a 5-alpha-reductase inhibitor reduces prostate size with no direct impact on detrusor activity; a muscarinic antagonist would actually reduce detrusor contractions and worsen retention. Bethanechol is specifically used to overcome underactive bladder by promoting bladder emptying, though it can have cholinergic side effects (salivation, sweating, abdominal cramps, bradycardia) and is used with caution in certain conditions.