Silodosin to Facilitate Passage of Ureteral Stones: A Multi-institutional, Randomized, Double-blinded, Placebo-controlled Trial

Background Using a selective α-blocker for medical expulsive therapy (MET) is a cost-effective treatment approach widely used for ureteral stones. Objective To evaluate the efficacy of silodosin, a selective α-1a receptor antagonist, in this setting. Design, setting, and participants This was a multicenter, phase 2 study conducted in adult patients with a unilateral ureteral calculus of 4–10mm. Of 239 patients in the safety population, six discontinued due to adverse events. Intervention Patients were randomized 1:1 to receive silodosin 8mg or placebo for up to 4 wk. Outcome measurements and statistical analysis The primary outcome was spontaneous stone passage, analyzed using logistic regression. Secondary outcomes included time to stone passage, emergency room (ER) visits, hospital admissions, analgesic use, and incidence and severity of pain. Results and limitations No significant differences between the silodosin and placebo groups were observed for passage rate of all stones (52% vs 44%, respectively; p =0.2). However, silodosin achieved a significantly greater rate of distal ureter stone passage than placebo ( p =0.01). Significant differences were not observed for ER visits, hospital admission, or use of analgesics. The number of patients in the intent-to-treat population was slightly below the calculated sample size (232 vs 240) and sample sizes were not calculated for subgroup analyses. Conclusions This is among the first prospective, randomized, multi-institutional trials to examine the efficacy of a selective α-1a antagonist as MET in patients with ureteral calculi and did not demonstrate a benefit to the entire ureter. However, silodosin was found to be well tolerated and beneficial in facilitating the passage of distal ureteral stones, warranting additional future studies on distal stone elimination. Patient summary In this report, we looked at the efficacy of silodosin for the treatment of ureteral stones. We found that silodosin increased passage of distal ureteral stones.