Prochlorperazine versus promethazine for uncomplicated nausea and vomitingin the emergency department: A randomized, double-blind clinical trial

Study objective: Nausea and vomiting related to gastritis or gastroenteriti s are common complaints in the emergency department. The most effective ant iemetic agent is yet undetermined. This study was conducted to compare the efficacy of prochlorperazine versus promethazine for uncomplicated nausea a nd vomiting in the ED. Methods: The study was a randomized, double-blind comparison of prochlorper azine (Compazine) and promethazine (Phenergan) for acute ED treatment of ga stritis or gastroenteritis. We studied patients 18 years or older with pres umed uncomplicated gastritis or gastroenteritis who presented to 2 academic EDs. Patients were randomly assigned to receive either prochlorperazine, 1 0 mg intravenously, or promethazine, 25 mg intravenously. Visual analog sca le readings of patient comfort were obtained at baseline and at 30- and 60- minute intervals. The primary endpoint was degree of relief at 30 and 60-mi nutes. Secondary endpoints were time to complete relief, need for further a ntiemetic medication (treatment failures), and side effects. Statistical an alysis was performed using the Mann-Whitney U test for nonparametric analys is and repeated-measures analysis of variance (ANOVA). Results: Eighty-four patients were enrolled in the study; 42 received proch lorperazine and 42 received promethazine. There were no differences in demo graphics in the 2 groups. At baseline (time 0), there was no difference in symptoms (P=.23). At 30 and 60 minutes after receiving medication, prochlor perazine worked significantly better than promethazine (P=.004 and P<.001 u sing nonparametric analysis). Using repeated-measures ANOVA, there was a si gnificant difference in symptoms over time for both groups (P<.001) and a s ignificant difference in prochlorperazine versus promethazine (P=.002). Tim e to complete relief was significantly shorter with prochlorperazine (P=.02 1). There were significantly fewer treatment failures with prochlorperazine (P=.03, 9.5% versus 31%, difference 21%, 95% confidence interval 5 to 38). There was no difference in incidence of extrapyramidal effects. Prochlorpe razine caused significantly fewer complaints of sleepiness (P=.002. 38% ver sus 71%, difference 33%, 95% confidence interval 13 to 53; P=.002). Conclusion: Prochlorperazine works significantly better than promethazine f or relieving symptoms of nausea and vomiting more quickly and completely in ED patients with uncomplicated nausea and vomiting.