The Study of Tamsulosin for Urolithiasis in the Emergency Department

The Study of Tamsulosin for Urolithiasis in the Emergency Department (STONE) was initiated at a single site with 109 participants who were randomized from 2008 to 2009. This first phase allowed an assessment of the feasibility of recruitment and provided the opportunity to determine the rate of stone passage in the placebo group. The primary outcome was not analyzed at the end of phase 1. The second phase of the study was conducted from 2013 to 2016 at 6 emergency department recruiting sites, including the original site in phase 1. The data from participants enrolled in both phases were analyzed together.

Eligible patients were randomized to either tamsulosin at a dose of 0.4 mg daily or a matching placebo in a 1:1 allocation. Both treatments consisted of identically encapsulated pills with identical packaging (1 bottle with 30 capsules per patient). Neither the participant nor the study staff knew to which group the participant was randomized. The randomization sequence was generated using the simple urn method, stratified by site. Study participants were contacted by telephone to collect data at 2, 7, 15, 20, 29, and 90 days after randomization. Study participants enrolled in the second phase were also asked to undergo a follow-up CT scan after the 28-day treatment period to determine whether their stone had passed based on this imaging modality.