Jeremy S Furyk, Robert A Meek, Diana Egerton‐Warburton

Nausea and vomiting is a common and distressing presenting complaint in emergency departments (ED). The aetiology of nausea and vomiting in EDs is diverse and drugs are commonly prescribed. There is currently no consensus as to the optimum drug treatment of nausea and vomiting in the adult ED setting. To provide evidence of the efficacy and safety of antiemetic medications in the management of nausea and vomiting in the adult ED setting. We searched the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 8), MEDLINE (OvidSP) (January 1966 to August 2014), EMBASE (OvidSP) (January 1980 to August 2014) and ISI Web of Science (January 1955 to August 2014). We also searched relevant clinical trial registries and conference proceedings. We included randomized controlled trials (RCTs) of any drug in the treatment of nausea and vomiting in the treatment of adults in the ED. Study eligibility was not restricted by language or publication status. Two review authors independently performed study selection, data extraction and assessment of risk of bias in included studies. We contacted authors of studies to obtain missing information if required. We included eight trials, involving 952 participants, of which 64% were women. Included trials were generally of adequate quality, with six trials at low risk of bias, and two trials at high risk of bias. Three trials with 518 participants compared five different drugs with placebo; all reported the primary outcome as mean change in visual analogue scale (VAS) (0 to 100) for nausea severity from baseline to 30 minutes. Trials did not routinely report other primary outcomes of the change in nausea VAS at 60 minutes or number of vomiting episodes. Differences in mean VAS change from baseline to 30 minutes between placebo and the drugs evaluated were: metoclopramide (three trials, 301 participants; mean difference (MD) -5.27, 95% confidence interval (CI) -11.33 to 0.80), ondansetron (two trials, 250 participants; MD -4.32, 95% CI -11.20 to 2.56), prochlorperazine (one trial, 50 participants; MD -1.80, 95% CI -14.40 to 10.80), promethazine (one trial, 82 participants; MD -8.47, 95% CI -19.79 to 2.85) and droperidol (one trial, 48 participants; MD -15.8, 95% CI -26.98 to -4.62). The only statistically significant change in baseline VAS to 30 minutes was for droperidol, in a single trial of 48 participants. No other drug was statistically significantly superior to placebo. Other included trials evaluated a drug compared to "active controls" (alternative antiemetic). There was no convincing evidence of superiority of any particular drug compared to active control. All trials included in this review reported adverse events, but they were variably reported precluding meaningful pooling of results. Adverse events were generally mild, there were no reported serious adverse events. Overall, the quality of the evidence was low, mainly because there were not enough data. In an ED population, there is no definite evidence to support the superiority of any one drug over any other drug, or the superiority of any drug over placebo. Participants receiving placebo often reported clinically significant improvement in nausea, implying general supportive treatment such as intravenous fluids may be sufficient for the majority of people. If a drug is considered necessary, choice of drug may be dictated by other considerations such as a person's preference, adverse-effect profile and cost. The review was limited by the paucity of clinical trials in this setting. Future research should include the use of placebo and consider focusing on specific diagnostic groups and controlling for factors such as intravenous fluid administered.