Use of glyceryl trinitrate patches in patients with ureteral stones: a randomized, double-blind, placebo-controlled...

To report a randomized, double-blind, placebo-controlled trial of glyceryl trinitrate (GTN) patches. The primary outcome measure was stone passage at 6 weeks. GTN is a potent smooth muscle relaxant that may offer benefit by both reducing pain and facilitating ureteral stone passage.

Fifty consecutive patients, with a single radiopaque calculus less than 10 mm, were randomized to receive a 6-week course of patches containing either 5 mg GTN or placebo. Patients used a diary to record pain episodes during the 6-week study period and were reviewed weekly with x-ray imaging. Analysis was by intention to treat.

Twenty-six patients were randomized to the GTN group and 24 to the placebo group. Seven patients in the GTN group discontinued therapy because of headaches. One patient in the placebo group discontinued because of a skin reaction to the patches. No serious adverse events were recorded. No difference was observed in the stone-free rate at 6 weeks (18 patients in each group), interval to stone passage (median GTN 11.5 days versus placebo 13 days), or interventions performed (5 patients each). Although the GTN group reported fewer pain episodes (median 3.5 versus 6.0), this did not achieve statistical significance.

Our preliminary results did not demonstrate a significant advantage in using GTN compared with placebo, with regard to the stone-free rate at 6 weeks, interval to stone passage, or number of episodes of pain experienced.