Tamsulosin works no better than placebo on small kidney stones, but does improve passage of more large kidney stones than placebo does. The results of this large clinical trial evaluating tamsulosin versus placebo were published online Friday in Annals of Emergency Medicine ("Distal Ureteric Stones and Tamsulosin: A Double-Blind, Placebo-Controlled, Randomized, Multi-Center Trial (The DUST Trial)").

"Kidney stones bring more than a million Americans a year to emergency departments because they are excruciatingly painful," said lead study author Jeremy Furyk, MBBS, MPH and TM of The Townsville Hospital in Townsville, Queensland, Australia. "The news on small kidney stones isn't positive, but tamsulosin appears to offer benefit to those unlucky people whose kidney stones are really big."

Within 28 days of a visit to the , passage occurred in 87 percent of patients treated with tamsulosin and 81.9 percent of those treated with placebo, a difference not considered significant. However, 83.3 percent of patients treated with tamsulosin whose kidney stones measured between 5 and 10 millimeters in length passed their stones, compared to only 61 percent of those who were treated with .

"For patients with small kidney stones, time seems to be the one sure cure," said Dr. Furyk. "However, when treating patients with large kidney stones, emergency physicians should definitely consider tamsulosin."