Treatment of Acute Gastroenteritis-Related Emesis with Bimodal Release Ondansetron

Document Type

Conference Proceeding

Publication Date


Publication Title

Acad Emerg Med


Background: There are 179 million cases of acute gastroenteritis (AGI) annually in the USA. In this study we tested a long-acting experimental 24 mg bimodal release ondansetron (BRO) pill which provides early serum levels similar to an 8mg immediate release tablet but sustains levels over 24 hours. We studied whether oral BRO improves 24 hour emesis related outcomes without the use of intravenous (IV) therapy among emergency department (ED) and urgent-care patients with AGI.

Methods: This was a placebo-controlled double-blind randomized trial comparing the effects of BRO with a like-appearing placebo among patients >12 years presenting to 19 EDs and 2 urgent-care centers with symptoms of AGI. Among inclusion criteria were >2 episodes of emesis 4 hours prior to ED arrival, and duration of symptoms ≤ 36 hours. Among exclusion criteria were pregnancy, recent surgery, alcohol abuse, and an EKG QTC> 450ms. The primary endpoint of treatment failure was defined as IV fluids given, vomiting, or rescue anti-emetics 30 minutes-24 hours after the first dose of study medication. Randomization was performed in a 3:2 treatment/placebo ratio after obtaining written consent and before any intervention. Patients with ED treatment success were discharged with a home diary and 3 additional study pills to use as needed. Statistical analyses included the Cochran Mantel Haenszel test and supporting logistic regression analyses. Odds ratios (OR) included 95% confidence intervals.

Results: 321 patients were randomized with a mean age of 29.0 years. The intention to treat (ITT) analysis indicated treatment success of 66% (126/192) in the BRO group vs 54% (70/129) in the placebo group (OR 1.6 (1.02, 2.54) p=0.04). A per-protocol analysis found treatment success of 70% (123/177) vs 55% (67/122) in placebo (OR 1.87 (1.16, 3.02) p=0.01). Baseline nausea was a predictor of outcome (p=0.01) and was more severe in the treatment group. The ITT nausea-adjusted OR in favor of treatment was (1.78 (1.11, 2.86), p=0.02). Finally, the OR for treatment effect in ITT outcomes at 4 days after ED treatment was 1.47 (0.92, 2.35, p=0.10).

Conclusion: This is the first study of AGI-related emesis showing benefit from any ondansetron preparation in adolescents and adults. Further, the study suggests AGI can be treated with a long-acting bimodal release tablet, potentially avoiding the need for IV access and repeat oral dosing.



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