Absence of QT prolongation after administration of a 24-mg bimodal-release ondansetron pill (RHB-102).

Abstract

Prospective data evaluating the effect of ondansetron on the corrected QT (QTc) interval is lacking in emergency department clinical use. As part of a randomized trial of a 24-mg bimodal-release ondansetron (RHB-102) pill, we tested the effect of RHB-102 compared to placebo on QTc change. This was a planned safety outcome analysis within a multicenter, double-blind, placebo-controlled trial. The trial compared the effects of RHB-102 among patients ≥12years who presented to 21 centers with symptoms of acute gastroenteritis. Patients with an initial baseline electrocardiogram as well as a follow-up electrocardiogram 4h later were included in the analysis. The safety endpoint for this analysis was the change from baseline in QTc interval at 4h, the median time at which ondansetron serum level peaks. A total of 147 patients were included with a mean baseline QTc in the RHB-102 and placebo arms of 410 and 406ms, respectively. There was no difference in the change in QTc at 4h post-study drug administration between the RHB-102 (+4, 95% CI 1-8ms) and placebo group (+5, 95% CI 1-9ms). In the RHB-102 arm, 6.6% of patients had a QTc change >30ms and in the placebo arm 3.6% (p=0.48). No patient in either arm had a QTc change >60ms after study drug administration. In patients with normal baseline QTc, 24-mg bimodal-release ondansetron did not prolong the QTc in comparison to placebo.