Prospective Evaluation of Ondansetron for Undifferentiated Nausea andVomiting in the Prehospital Setting

Abstract

Objective. To evaluate the change in nausea scales andincidence of vomiting with the use of ondansetron in the treatment of nausea andvomiting in the prehospital setting. Methods. Data were prospectively collected on all emergency medical service patients who received ondansetron for undifferentiated nausea andvomiting during a 6-month study period. Added outcome measures for this study were verbal quantitative (scale of 1–10) andqualitative “nausea scales,” incidence of vomiting prior to andafter administration of ondansetron, andadverse events. Patients who had this additional data collected andones who did not were compared. Changes in the “nausea scales” andincidence of vomiting before andafter administration andcorrelation among these measures were also compared. There was no control or placebo group. Results. Ondansetron was administered to 952 patients of 20,054 patients transported during this time period (5%); of these 472 had at least some of the outcome measures documented. There were minimal differences in the two cohorts; 198 patients had paired before andafter quantitative “nausea scales” documented: 7.6 ± 2.4 and4.6 ± 3.1, respectively (Δ = 2.9, 95% CI: 2.5–3.4); 447 patients had a qualitative change in nausea level documented: 0.4% “a lot worse,” 1.3% “a little worse,” 34% “unchanged,” 40% “a little better,” and25% “a lot better”; 187 patients had all three measures documented with a Pearson correlation coefficient of 0.63 between the change in the quantitative scale andthe qualitative scale (95% CI: 0.14–0.20, R 0.39). In 462 patients, vomiting decreased from 60% to 30% (Wilcoxon signed ranks test p < 0.001). The Pearson correlation coefficients for the change in vomiting incidence with the qualitative andquantitative “nausea scales” were poor: 0.012 (95% CI: −0.015 to 0.039, R 0.00014) and0.051 (95% CI: −0.032 to 0.118, R 0.00026), respectively. There were no reported adverse events. Conclusions. Ondansetron appears to be moderately effective in decreasing nausea andvomiting in undifferentiated prehospital patients. Additional controlled trials may be needed to compare it with other antiemetics.