Which medication class is commonly used to facilitate passage of distal ureteral stones?

• A. Alpha-1 adrenergic blockers
• B. Beta-blockers
• C. Calcium channel blockers
• D. Diuretics

Answer: (A)

Relaxation of the distal ureter smooth muscle to ease stone passage is achieved with alpha-1 adrenergic blockers. These drugs, such as tamsulosin, block the alpha-1 receptors in the distal ureter, reducing smooth muscle tone and spasms. With less clamping of the ureter, urine flow and peristaltic propulsion can carry the stone along more easily, improving the chances that a distal ureteral stone will pass spontaneously. They’re frequently used in medical expulsive therapy for small distal stones to shorten symptoms and time to passage.

Beta-blockers don’t affect ureteral smooth muscle in a way that promotes stone passage. Diuretics mainly alter urine volume rather than ureteral tone, and calcium channel blockers can relax smooth muscle but are not as effective or commonly used for facilitating distal ureteral stone passage.