Silodosin may aid the passage of a unilateral distal ureteral stone 4 to 10 mm in diameter, a new study suggests.

Researchers found an 8 mg daily dose to be “well tolerated and beneficial” for up to 4 weeks of treatment. Results were similar for men and women.

The distal ureter is an area of interest for medical expulsive therapy with alpha-blockers such as silodosin because the location contains the highest concentration of alpha-1 adrenergic receptors. “The mechanism of action of silodosin presumably includes blockage of the alpha-adrenergic receptors, thereby relaxing the ureter and potentially providing a spasmolytic effect,” according to lead investigator Roger L. Sur, MD, of the University of California, San Diego, and colleagues.

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Silodosin performed no better than placebo, however, at eliminating ureteral stones generally, including medial and proximal stones, according to results published online by European Urology. There were also no significant advantages in patient use of pain relievers, emergency room visits, or hospital admissions.

The study was a randomized, double-blind, placebo-controlled trial conducted over 4 weeks at 27 locations in the U.S. from 2010 to 2012. The researchers studied 239 men and women with a single ureteral stone 4 to 10 mm in diameter; 6 discontinued due to adverse effects, which included retrograde ejaculation, nausea, dizziness, headache, and nasal congestion. Most effects were considered mild and unrelated to treatment, however.

Use of selective alpha-blockers for medical expulsive therapy is cost-effective compared with some other therapies for ureteral stones. Both the American Urological Association and the European Association of Urology list alpha blockers among recommended treatments. The researchers suggested future studies investigate the treatment of mid and proximal ureteral stones, larger stones, and the efficacy of silodosin versus tamsulosin.


  1. Sur, R, et al. Published online by European Urology, 2015; doi: 10.1016/j.eururo.2014.10.049.