For large renal stones, which intervention can facilitate passage by relaxing the ureter?

• A. Osmotic Diuretics
• B. Proton Pump Inhibitors
• C. Beta Blockers
• D. Alpha Blockers (e.g., Tamsulosin)

Answer: (D)

Relaxing the ureter’s smooth muscle helps a stone move through the urinary tract more easily. Alpha-adrenergic blockade, as with tamsulosin, relaxes the distal ureter by blocking alpha receptors, reducing ureteral tone and spasms, and often increasing the chance that a lodged or relatively large stone will pass spontaneously. This approach—medical expulsive therapy—targets the mechanism that makes passage difficult in many stones, especially those in the distal ureter, and can shorten time to passage and lessen pain. Other options don’t act on ureteral smooth muscle: osmotic diuretics mainly boost urine flow without altering ureter tone, proton pump inhibitors have no role in stone expulsion, and beta blockers don’t provide the necessary ureteral relaxation.