Robust evidence lacking to show clear-cut benefits of using tamsulosin
Renal colic is a common presentation at emergency departments. Stone expulsion probability — and time to expulsion — depend heavily on the stone size and location. If we could improve the rate and shorten the time to passage of kidney stones with appropriate medical therapy, it would potentially reduce ED return visits, reduce the number of invasive procedures, lower health care costs, and perhaps most importantly, produce better outcomes and increase patient satisfaction.
The pathophysiologic basis for this treatment is that alpha antagonists inhibit contraction of ureteral muscles responsible for ureterospasm, thereby allowing for an increased rate of stone propagation as well as reduce discomfort. Alpha 1-adrenergic receptors are concentrated in the distal ureter and, as a result, distal stones would theoretically benefit the most. As you can see in Table 1, since 2007, there have been at least five major studies evaluating the use of tamsulosin in renal colic. However, only one of the studies was conducted with rigor and produced results that could claim any kind of demonstrable benefit from the use of tamsulosin.
Here’s a synopsis of these studies:
Singh et al: The quality of the studies that were reviewed were poor. Randomization, blinding, and follow-up all were sub-optimal. This is an excellent example of systematic reviews and meta-analyses being only as good as the sum of their original studies. The bottom line: Poor studies in a meta review = weak conclusions.
Hermanns T et al: In this study the time to passage data was missing for one-third of the patients. In addition, it should be noted that this was an outpatient study, and that the majority of the stones were <5 mm.
Rerre RM et al: In this study, there was no placebo group, no blinding, and the mean stone size was small (3.6 mm).
Ali-Ansari et al: This was the only randomized trial to show a benefit to using tamsulosin. However, it is unclear if these patients were, in fact, ED patients; the primary outcome is not clear, and it’s unusual that the patients in this study were discharged on parenteral diclofenac. In addition, the passage rate of stones <5 mm in this study was 69% in the placebo group, which is considerably lower than what is often quoted in other studies.
Vincendeau S et al: The biggest issue with this study is that all the patients were admitted to urology, which is not the standard of management of ureteral stones.
Clearly, none of the studies are ideal, and there is disagreement in the literature about the benefits of using tamsulosin. We still lack a large, randomized, dose-controlled trial on patients presenting to the ED with renal colic.
As of now, the best evidence does not show a significant benefit in the use of tamsulosin in renal colic to facilitate stone passage. With a cost of about $3 a pill and a largely benign (or rare) list of adverse effects (not well documented in studies to date), patients may appreciate a discussion with health care providers of the evidence to date and shared decision-making about tamsulosin as an adjunct to standard supportive care.