Role of Antiemetic Drugs for the Treatment of Acute Gastroenteritis in Children

Rachel C. Vreeman


Pediatr Health. 2009;3(4):337-341. 

In This Article

Evidence for the Use of Antiemetics in Children with Acute Gastroenteritis & Vomiting

Ondansetron is a 5-hydroxytryptamine antagonist that has been used in children as young as 1 month of age for treating postoperative or chemotherapy-associated nausea and vomiting.[21] Scientific evidence supports the use of ondansetron for children with AGE and vomiting;[18,19,20] in fact, it is the only antiemetic medication for which multiple randomized, controlled trials support its benefit.[22,23] In a meta-analysis by DeCamp et al., children who received ondansetron were less likely to have ongoing vomiting, to be prescribed intravenous fluids or to be admitted to the hospital from the emergency department.[22] However, the incidence of diarrhea increased in children receiving ondansetron. A Cochrane systematic review by Alhashimi et al. further examined the four randomized, controlled trials comparing antiemetics with placebo in children and adolescents under 18 years of age who had vomiting due to AGE.[23] This review concluded that the limited evidence did favor the use of ondansetron and metoclopramide to reduce the number of episodes of vomiting in children with AGE.[23] These reviews supplant older assessments that did not find sufficient evidence to recommend the use of ondansetron.[24]

Both oral and intravenous ondansetron have been shown to be effective for decreasing persistent vomiting, the use of intravenous fluid and hospital admissions in children with vomiting. In one trial, oral ondansetron stopped vomiting within the first 4 h for 67% of patients and in the first 24 h for 58% of patients.[25] When five studies evaluating the risk of persistent emesis in the emergency department were pooled,[25,26,27,28,29] ondansetron significantly reduced the risk of further vomiting.[22] The number of children who would need to be treated (NNT) with ondansetron to prevent one child from having further emesis was only five.[22] In five studies examining the risk for hospital admission for children receiving ondansetron,[25,26,27,28,29] the risk of admission was significantly less, with an NNT suggesting that only 14 children would need to be treated with ondansetron to prevent one admission. Four studies examined the risk of receiving intravenous fluid in onsansetron-treated patients,[25,26,29,30] and the pooled estimate of relative risk from these studies found a significant decrease in the need for intravenous fluids in patients treated with ondansetron.

The use of ondansetron for AGE is not without adverse effects. Multiple studies reported that children who were given ondansetron had an increased incidence of diarrhea.[25,26,30] However, some studies did not find any increase in diarrheal events.[27,29] The increase in diarrhea is hypothesized to be a result of retained fluids and toxins that would have otherwise been eliminated through vomiting.

Metoclopramide for vomiting related to AGE has been evaluated in 96 hospitalized children in two studies. The evidence supporting metoclopramide for AGE-related vomiting is equivocal. One small study examined both ondansetron and metoclopramide compared with placebo and reported a higher proportion of patients without vomiting over 24 h in both the ondansetron and metoclopramide groups.[30] More patients in the ondansetron group had no vomiting compared with patients in the metoclopramide group.[30] This study found more episodes of diarrhea for both the children who received ondansetron and the children who received metoclopramide (compared with placebo).[30] Another, much older study found metoclopramide to be more effective than placebo at reducing nausea and vomiting and did not report any adverse events.[31] These studies were limited by small sample sizes and lower quality, limiting the support for the use of metoclopramide for AGE.

While there are existing, older studies evaluating domperidone, trimethobenzamide, pyrilamine-pentobarbital, dexamethasone and promethazine, these studies have small sample sizes, low methodological quality and reveal inconsistent results.[28,32,33,34] Therefore, meta-analyses have not been conducted to evaluate these antiemetics, nor can their use be recommended, particularly in the light of increased concerns regarding the safety of these medications for children. The US FDA currently recommends against promethazine for children younger than 2 years old owing to concerns of serious adverse effects including sedation and extrapyramidal reactions.[101]


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