In children with vomiting related to acute gastroenteritis, are antiemetic medications an effective adjunct to fluid and electrolyte therapy?

Abstract

Acute gastroenteritis continues to be associated with substantial morbidity in developed countries and has a significant mortality rate in developing countries (1,2). Poor nutrition status is associated with an increased risk (3). Dehydration is the most frequent and dangerous complication because of associated electrolyte imbalance and metabolic acidosis (3). Gastroenteritis-related vomiting remains a significant health problem. Prolonged or protracted vomiting is uncomfortable for patients and stressful for their families (1). Gastroenteritis-related vomiting increases the risk of dehydration and electrolyte imbalance, as well as the need for intravenous hydration and hospitalization. Vomiting is not a contraindication to oral rehydration therapy (ORT), but it can interfere with ORT (1,4). Chongbanyatcharoen (5) conducted a survey of physicians who had attended a short course entitled “Practical Approach to Common GI Problems”. At the end of the course, the physicians were surveyed about the possible reasons for failure of ORT. Sixty-one questionnaires were returned. Vomiting was the most common reason identified (86.9%). Preliminary data suggest that the appropriate use of an antiemetic medication can minimize the need for intravenous therapy and also possibly the need for hospital admission (6-8). Given the high incidence of gastroenteri-tis, well-designed, large-scaled, multicentre, double-blind, placebo-controlled, randomized studies are needed to confirm the usefulness of antiemetic medications in the treatment of gastroenteritis-related vomiting. A cost-effectiveness analysis would provide useful information. The decision to use any medication should be evidence based, and should take into consideration the clinical efficacy, potential adverse events and cost of treatment (1). Ondansetron shows promise as a first-line antiemetic medication. Use of ondansetron should be considered when vomiting interferes with ORT. Oral and single-dose ondansetron, rather than intravenous ondansetron, should be used if possible. The medication can be used for both inpatients and outpatients, but only after the patient has been clinically assessed. Prolonged ondansetron treatment is likely unnecessary, and such treatment may result in more diarrheal episodes, as shown in some of the reviewed studies. The medication should be used with caution in children whose diarrhea is a major concern. Although unproven, use of this medication may also result in substantial cost savings by a reduction in the need for intravenous hydration and hospitalization. Other potential cost savings can result from a reduction in time lost from work for parents or time lost from school for children (1). The cost of ondansetron is approximately $5 for 2 mg, $10 for 4 mg and $20 for 10 mg (with a generic form of the 10 mg dose being $10), plus the dispensing fee. Other antiemetic medications, such as metoclopramide, are less efficacious in the treatment of gastroenteritis-induced vomiting and are associated with more adverse events than ondansetron. The adverse effects of metoclo-pramide include restlessness, drowsiness and dizziness, as well as extrapyramidal reactions such as dystonia, akathisia, oculogyric crisis and tardive dyskinesia. In the clinical trials, children who received ondansetron experienced more episodes of diarrhea than children who received placebo. The increase in diarrheal episodes might have resulted from the repeated and prolonged use of ondansetron. Clinicians must balance the proven benefits of antiemetic therapy against the cost and risks of adverse events in patients with gastroenteritis-related vomiting (1). It should be emphasized that antiemetic agents are an effective adjunctive therapeutic agent in children requiring ORT, and their use by no means replaces the need for, nor should remove the emphasis from, the proper application of ORT.