The tablet given to help a stone pass matched placebo in 1,136 patients. Where it still earns its place is narrower

A patient sent home to pass a ureteric stone is usually sent home with a tablet. The tablet is meant to relax the smooth muscle of the ureter and let the stone through. In 2015 a trial designed to settle whether it does reported that it does not, and the finding has been absorbed unevenly ever since — partly because the question the trial answered is narrower than the way the drug is used.

What SUSPEND tested#

SUSPEND, published in the Lancet, recruited adults aged 18 to 65 undergoing expectant management for a single ureteric stone identified on computed tomography at 24 UK hospitals. Participants were randomly assigned, masked, to tamsulosin 400 micrograms, nifedipine 30 mg or placebo daily for up to four weeks, with minimisation on centre, stone size and stone location. The primary outcome was the proportion needing no further intervention for stone clearance within four weeks.

Of 1,167 randomised, 1,136 were included in the primary analysis. No difference appeared between active treatment and placebo, or between the two drugs. The confidence intervals are the part worth dwelling on: they are narrow enough to exclude the size of benefit the earlier meta-analyses had claimed, not merely too wide to detect it.

Four in five people passed the stone without further treatment whatever they were given. That figure is itself the most useful thing in the trial for a patient in pain, and it is rarely the number they are quoted.

The question the Korean trial asked instead#

A prospective randomised controlled trial published in the Korean Journal of Urology enrolled 88 patients with a single proximal ureteric stone and tested tamsulosin in a setting SUSPEND excluded: not instead of an intervention, but after one. All patients had extracorporeal shockwave lithotripsy; the treatment group then received tamsulosin 0.2 mg once daily.

• Stone-free: 37 of 44 patients (84.1 percent) on tamsulosin against 29 of 44 (65.9 percent) on no medication, P = 0.049.
• Mean time to clearance of fragments: 10.0 days against 13.2 days, P = 0.012.
• No statistically significant difference in analgesic requirement or pain score.
• One patient on tamsulosin had transient dizziness, which resolved on its own.

These are not competing answers to one question. SUSPEND asked whether a drug lets a whole stone pass without an operation. The Korean trial asked whether it clears fragments faster after the stone has already been broken. A ureter emptying gravel is a different mechanical problem from a ureter obstructed by a single stone, and it is reasonable for a smooth-muscle relaxant to help with one and not the other.

Which stones move, and how you would know#

Whether a stone passes depends more on the stone than on the tablet, and a Korean series in Urology quantified which measurement predicts it. Reviewing 328 patients with symptomatic ureteric stones under 10 mm on axial computed tomography images, all treated with alpha-blockers for two weeks and rescanned, the authors compared several measurements against outcome.

Expulsion occurred in 44.1 percent of 145 upper ureteric stones and 69.4 percent of 183 lower ureteric stones. Transverse diameter, longitudinal diameter, ureteric diameter and the ureter-to-stone ratio were all significantly lower in patients whose stone passed — but on logistic regression only the longitudinal diameter, measured on the coronal reconstruction, remained a significant independent predictor, in both upper stones (odds ratio 0.580, P = 0.040) and lower stones (odds ratio 0.415, P = 0.012).

A stone is not a sphere. The axial slice measures it across; the coronal reconstruction measures it along the axis it has to travel. That the second is the one that predicts passage is intuitive after the fact and was not what routine reporting measured.

What is being tried next#

A network meta-analysis published in BMC Urology in 2025 pooled 19 studies of 2,414 participants with distal ureteric stones, comparing combination regimens against an alpha-blocker alone. Alpha-blocker with a PDE-5 inhibitor gave an odds ratio for expulsion of 2.7 (95% CI 1.80 to 4.05), with a corticosteroid 2.7 (1.81 to 4.13) and with phytotherapy 3.10 (1.62 to 5.92). The PDE-5 combination also shortened expulsion time by a mean of 3.8 days and reduced analgesia use.

Those odds ratios are measured against an alpha-blocker alone, which SUSPEND indicates is close to placebo for whole-stone passage. A combination that beats a comparator of unproven value has not thereby been shown to beat no treatment, and the analysis excluded upper ureteric stones and post-shockwave use. The authors call for further study, which is the correct reading.

What a Korean patient should take from this#

The strongest single fact is not about a drug. Around four in five people with a single ureteric stone managed expectantly avoid further intervention within four weeks, with or without medication. Expulsive therapy is not the reason most stones pass.

Where the evidence still supports a tablet is narrower than the prescription pattern: after shockwave lithotripsy, to clear fragments sooner, on Korean trial data in a small cohort at a Korean dose. A tablet offered on that basis is defensible. A tablet offered as the thing that will make a whole stone pass is offering the patient credit for something their own ureter was going to do.