Abstract: We included 67 studies with 10,509 participants overall. Of these, 15 studies with 5787 participants used a placebo. Stone clearance: Based on the overall analysis, treatment with an alpha-blocker may result in a large increase in stone clearance (risk ratio (RR) 1.45, 95% confidence interval (CI) 1.36 to 1.55; low-quality evidence). A subset of higher-quality, placebo-controlled trials suggest that the likely effect is probably smaller (RR 1.16, 95% CI 1.07 to 1.25; moderate-quality evidence), corresponding to 116 more (95% CI 51 more to 182 more) stone clearances per 1000 participants. Major adverse events: Based on the overall analysis, treatment with an alpha-blocker may have little effect on major adverse events (RR 1.25, 95% CI 0.80 to 1.96; low-quality evidence). A subset of higher-quality, placebo-controlled trials suggest that alpha-blockers likely increase the risk of major adverse events slightly (RR 2.09, 95% CI 1.13 to 3.86), corresponding to 29 more (95% CI 3 more to 75 more) major adverse events per 1000 participants. Patients treated with alpha-blockers may experience shorter stone expulsion times (mean difference (MD) -3.40 days, 95% CI -4.17 to -2.63; low-quality evidence), may use less diclofenac (MD -82.41, 95% CI -122.51 to -42.31; low-quality evidence), and likely require fewer hospitalisations (RR 0.51, 95% CI 0.34 to 0.77; moderate-quality evidence), corresponding to 69 fewer hospitalisations (95% CI 93 fewer to 32 fewer) per 1000 participants. Meanwhile, the need for surgical intervention appears similar (RR 0.74, 95% CI 0.53 to 1.02; low-quality evidence), corresponding to 28 fewer surgical interventions (95% CI 51 fewer to 2 more) per 1000 participants. A predefined subgroup analysis (test for subgroup differences; P = 0.002) suggests that effects of alpha-blockers may vary with stone size, with RR of 1.06 (95% CI 0.98 to 1.15; P = 0.16; I² = 62%) for stones 5 mm or smaller versus 1.45 (95% CI 1.22 to 1.72; P < 0.0001; I² = 59%) for stones larger than 5 mm. We found no evidence suggesting possible subgroup effects based on stone location or alpha-blocker type. For patients with ureteral stones, alpha-blockers likely increase stone clearance but probably also slightly increase the risk of major adverse events. Subgroup analyses suggest that alpha-blockers may be less effective for smaller (5 mm or smaller) than for larger stones (greater than 5 mm).

Plain-language summary: Based on our latest search of the literature from November 2017, we included 64 studies with 10,509 participants. Of these, 15 studies compared alpha-blockers with placebo with 5787 participants. A placebo is a pill that looks and tastes exactly like the real medication, so participants did not know what they were getting. These were the higher-quality studies, which we trusted more. Based on the subset of higher-quality studies that used a placebo, alpha-blockers likely resulted in more people passing their stones. However, these patients are likely to experience slightly more serious unwanted effects of this medication. People taking alpha-blockers may pass their stones in a shorter time, may use less diclofenac (which is a type of pain medication), and are likely to be admitted to the hospital less often. Meanwhile, the need for surgery for their stones was similar. Upon completing additional analyses, we found that effects of alpha-blockers may be different in people with small (5 mm or smaller) versus larger (larger than 5 mm) stones. It appears that this medication works better in people with larger stones. We could find no difference in how well alpha-blockers work, no matter where in the ureter the stone is stuck or what type of alpha-blocker is used. For patients with stones stuck in the ureter, alpha-blockers likely make passing the stone easier but cause slightly more unwanted effects. It appears that alpha-blockers work better in people with larger (greater than 5 mm) rather than smaller (5 mm or smaller) stones. The quality of the evidence for most outcomes was moderate or low, meaning that we have moderate or low confidence in most of the reported results.