A Cochrane review ¹ included 67 studies with a total of 10509 subjects. The studied alphablockers were tamsulosin, alfuzosin, terazosin, nadftopidil and silodosin.

Stone clearance: Based on the overall analysis, treatment with an alpha-blocker may result in a large increase in stone clearance (RR 1.45, 95% CI 1.36 to 1.55). 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), 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). 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 (MD 3.40 days, 95% CI 4.17 to 2.63), may use less diclofenac (MD 82.41, 95% CI 122.51 to 42.31), and likely require fewer hospitalisations (RR 0.51, 95% CI 0.34 to 0.77), 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), corresponding to 28 fewer surgical interventions (95% CI 51 fewer to 2 more) per 1000 participants.

Stone size: 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) for stones 5 mm or smaller versus 1.45 (95% CI 1.22 to 1.72; P < 0.0001) for stones larger than 5 mm. No evidence suggesting possible subgroup effects based on stone location or alpha-blocker type was found.