Third, we have another prospective trial published in JAMA Internal Medicine, this one split into two phases, an initial “patient-reported” passage phase followed by a “CT follow-up” phase.5 Approximately half of the 512 patients were enrolled in each phase, with the overall results broadly consistent with the other trials. Patient-reported passage was similar as were all secondary measures of resource utilization, subsequent urological intervention, and disability. There was a 6 percent absolute advantage from tamsulosin with regard to radiological evidence of stone passage during the CT follow-up phase. However, unlike the prior studies, there was no benefit observed with regard to stone passage for stones greater than 5 mm in size, and instead, the subgroup favoring tamsulosin in this cohort related to stone location. The few upper ureteral stones enrolled were observed to have a higher passage rate with tamsulosin than with placebo.
Explore This IssueACEP Now: Vol 37 – No 08 – August 2018
Finally, the last bit of evidence comes from a study presented at the 33rd Annual Congress of the European Association of Urology in April and is not yet available in manuscript.6 These authors aimed primarily to evaluate the effect of MET on stone passage specifically focused on the subgroups previously identified for possible benefit. This observational study of 3,127 patients whose stone passage was compared via multivariate analysis showed no associated benefit for MET regardless of stone size or location.
Conclusion: Limited to No Benefit from Tamsulosin
The long story made short: Any benefit from tamsulosin for ureterolithiasis is small and fleeting. When multiple trials fail to consistently show benefit from a specific treatment, this does not eliminate the possibility of a beneficial effect, but the expected effect size should be quite small. Tamsulosin and other alpha-blockers are generally well-tolerated but do have rare adverse effects, particularly in older adults. As the expected benefit diminishes, the risk-benefit ratio converges to unity and the value of this treatment vanishes.
The most recent publication from the European Association of Urology on this topic, published back in 2016, held the view that any benefit, if one were likely, would be restricted to ureteral stones greater than 5 mm in size.7 This is a similar conclusion to the recently updated Cochrane review.8 As these guidelines and reviews continue to be updated, I expect any recommendations for the use of MET to further narrow or disappear entirely. As always, generalizing aggregate data from trials to an individual clinical scenario is imprecise, and it remains reasonable to offer tamsulosin on a case-by-case basis. If any benefit is to be derived, it appears those with larger, proximal ureteral stones are the best candidates for therapy. That said, the strength of the evidence is limited, and it may be conclusively found that the use of tamsulosin has no benefit at all.