In this double blind randomized placebo-controlled trial from New Delhi, India, 170 children (age 3 mo to 5 y) with acute diarrhea with vomiting and some dehydration were randomized equally to receive either single dose of oral ondansetron or placebo in addition to standard management of dehydration according to World Health Organization guidelines. Failure of oral rehydration therapy (ORT), administration of unscheduled intravenous fluids, and amount of oral rehydration solution intake in 4 hours were the primary outcomes. Failure of ORT was significantly less in children receiving ondansetron compared with those receiving placebo (31% vs 62%; P<0.001; RR 0.50, 95% CI 0.35, 0.72). The oral rehydration solution consumption was significantly more in the ondansetron group (645 mL vs 554 mL; mean difference 91 mL; 95% CI: 35, 148 mL). Patients in the ondansetron group also showed faster rehydration, lesser number of vomiting episodes, and better caregiver satisfaction. The authors concluded that a single oral dose of ondansetron, given before starting ORT to children <5 years of age having acute diarrhea and vomiting, results in better oral rehydration.

Relevance: Clinical experience suggests that vomiting is often a significant barrier to successful oral rehydration therapy (ORT) in children with acute gastroenteritis. Vomiting can result in reluctance among family members/caregivers to administer adequate quantity of oral fluid; it sometimes impels physicians to prescribe intravenous fluids to avoid the delays associated with oral rehydration; and it also creates difficulties for individual children to accept oral rehydration salt (ORS) solution in appropriate amounts. Available systematic reviews suggest that anti-emetic therapy administered in conjunction with ORS solution (ORS) may enhance the efficacy of ORT [1-4]. Against this background, the recent trial by Danewa, et al. [5] comparing oral ondansetron versus placebo for management of dehydration among children with diarrhea having associated vomiting, is a significant value addition to existing literature. The authors identified some of the lacunae in existing knowledge [1] and addressed these. Table I summarizes the main features of the trial.

Table I  Summary of the Trial

Critical appraisal: Critical appraisal of the trial [5] adapting various standard tools [6,7] is summarized in Table II. The trial fulfilled all criteria for low risk of bias. It is interesting to note that children in the ondansetron group could take 75 mL/kg fluid over 4 hours. Incidentally this is the exact target volume for children with ‘some dehydration’. In contrast, those in the placebo group could take an average of 63.7 mL/kg in the same duration. This means that in real world situations, children having vomiting are unable to accept the required volume of ORS solution. While this readily explains why nearly two-thirds of children in the placebo group required another round of ORT or intravenous fluids, it also suggests that current protocols recommending 75 mL/kg ORS solution may be chasing a futile goal in such children. The issue is somewhat complicated by the fact that majority of participants in this trial were infants receiving breast milk. Since the number of breastfeeding infants in each group and estimation of number/volume of feeds was not measured, its implications are unclear.

Table II: Critical Appraisal of The Trial 

On the other hand, if children were able to take 75 mL/kg ORS solution within 4 hours, why did some require intravenous fluids? This issue gains even more importance considering that all the previous trials and systematic reviews on this subject reported statistically significant reduction in the need for intravenous rehydration. The absence of this finding here [5] necessitates updating current systematic reviews.

1. Fedorowicz Z, Jagannath VA, Carter B. Anti-emetics for reducing vomiting related to acute gastroenteritis in children and adolescents. Cochrane Database Syst Rev 2011;9:CD005506.

2. Carter B, Fedorowicz Z. Antiemetic treatment for acute gastroenteritis in children: An updated Cochrane systematic review with meta-analysis and mixed treatment comparison in a Bayesian framework. BMJ Open. 2012;19:2.

3. Freedman SB, Pasichnyk D, Black KJ, Fitzpatrick E, Gouin S, Milne A, et al. Gastroenteritis therapies in developed countries: Systematic review and meta-analysis. PLoS One. 2015;10:e0128754.

4. Freedman SB, Ali S, Oleszczuk M, Gouin S, Hartling L. Treatment of acute gastroenteritis in children: An overview of systematic reviews of interventions commonly used in developed countries. Evid Based Child Health. 2013;8: 1123-37.

5. Danewa AS, Shah D, Batra P, Bhattacharya SK, Gupta P. Oral ondansetron in management of dehydrating diarrhea with vomiting in children aged 3 months to 5 years: A　randomized controlled trial. J Pediatr. 2015; Dec 1. pii: S0022-3476(15)01165-8.

6. Centre for Evidence-Based Medicine. Critical Appraisal Tools. Available: from: http://www.cebm.net/critical-appraisal/. Accessed January 14, 2016.

7. Cochrane Risk of Bias Tool. Available from: http://ohg.cochrane.org/sites/ohg.cochrane.org/files/uploads/Risk%20of%20bias%20assessment%20tool.pdf. Accessed January 14, 2016.

8. Roslund G, Hepps TS, McQuillen KK. The role of oral ondansetron in children with vomiting as a result of acute gastritis/gastroenteritis who have failed oral rehydration therapy: A randomized controlled trial. Ann Emerg Med. 2008;52:22-9.

9. Freedman SB, Adler M, Seshadri R, Powell EC. Oral ondansetron for gastroenteritis in a pediatric emergency department. N Engl J Med. 2006;354: 1698-1705.

10. Yilmaz HL, Yildizdas RD, Sertdemir Y. Clinical trial: oral ondansetron for reducing vomiting secondary to acute gastroenteritis in children – a double-blind randomized study. Aliment Pharmacol Ther. 2010;31:82-91.

11. Ramsook C, Sahagun-Carreon I, Kozinetz CA, Moro-Sutherland D. A randomized clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Ann Emerg Med. 2002;39:397-403.

12. Rerksuppaphol S, Rerksuppaphol L. Efficacy of intravenous ondansetron to prevent vomiting episodes in acute gastroenteritis: A randomized, double blind, and controlled trial. Pediatr Rep. 2010;2:e17.

13. Ondansetron side effects. Available from: http://www.drugs.com/sfx/ondansetron-side-effects.html. Accessed January14, 2016.

14. Freedman SB, Uleryk E, Rumantir M, Finkelstein Y. Ondansetron and the risk of cardiac arrhythmias: A systematic review and post marketing analysis. Ann Emerg Med. 2014;64:19-25.

15. Moazzam MS, Nasreen F, Bano S, Amir SH. Symptomatic sinus bradycardia: A rare adverse effect of intravenous ondansetron. Saudi J Anaesth. 2011;5:96-7.

16. Moffett PM, Cartwright L, Grossart EA, O’Keefe D, Kang CS. Intravenous ondansetron and the QT interval in adult emergency department patients: An observational study. Acad Emerg Med. 2016;23:102-5.

17. The Comprehensive Resource for Physicians, Drug and Illness Information. Available from: http://www.rxmed. com/b.main/b2.pharmaceutical/b2.1.monographs/CPS- %20Monographs/CPS-%20(General%20Monographs-%20Z)/ZOFRAN.html. Accessed January 14, 2016.

18. Guarino A, Ashkenazi S, Gendrel D, Lo Vecchio A, Shamir R, Szajewska H; European Society for Pediatric Gastroenterology, Hepatology, and Nutrition; European Society for Pediatric Infectious Diseases. European Society for Pediatric Gastroenterology, Hepatology, and Nutrition/European Society for Pediatric Infectious Diseases evidence-based guidelines for the management of acute gastroenteritis in children in Europe: Update 2014. J Pediatr Gastroenterol Nutr. 2014;59:132-52.

Joseph L Mathew
Department of Pediatrics, PGIMER, Chandigarh, India.
Email: [email protected]

Vomiting associated with acute gastroenteritis is a distressing symptom for children and their parents. Persistent vomiting is also one of the main causes of failure of oral rehydration therapy and need for intravenous rehydration. Decision of using antiemetic drugs should be guided by their efficacy, side effects and cost. A cochrane review published in 2011 and a systemic review published in 2012 concluded that use of ondansetron when compared to placebo increased the proportion of patients with cessation of vomiting (RR 1.44, 95% CI 1.29, 1.61), reduced the need of immediate hospitalization (RR 0.40, 95% CI 0.19, 0.83) and need for intravenous rehydration (RR 0.41, 95% CI 0.29, 0.59) [1,2]. All studies done so far were done in emergency department, in children with persistent vomiting and mild to moderate dehydration. There is lack of evidence from ambulatory settings, in children with vomiting and no dehydration, and in children with moderate to severe acute malnutrition. Most of studies have used a single dose. Studies have also reported prolongation of diarrhea in children who received ondansetron [1]. There is also some concern regarding prolongation of QT interval in patients with potential electrolyte abnormalities who receive intravenous ondansetron [3].

In the present study, authors evaluated the role of a single dose of oral ondansetron in facilitating successful rehydration of under-five children. This study also reported similar efficacy by demonstrating lesser failure of ORT (31% vs 62%) and lesser need of intravenous fluids. This study is most probably the first double–blind randomized placebo controlled trial on this topic from a developing country. Present study confirms efficacy of single oral dose of ondansetron on cessation of vomiting, resulting in better oral rehydration and parents’ satisfaction. At present there is lack of evidence for repeated doses, use in ambulatory settings, and in children with malnutrition.

1. Fedorowicz Z, Jagannath VA, Carter B. Anti-emetics for reducing vomiting related to acute gastroenteritis in children and adolescents. Cochrane Database Syst Rev. 2011;9:CD005506.

2. Carter B, Fedorowicz Z. Anti-emetic treatment of acute gastroenteritis in children: An updated Cochrane systematic review with meta-analysis and mixed treatment comparison in a Bayesian framework. BMJ Open. 2012;2:e000622.

3. FDA. FDA Drug Safety Communication: Abnormal heart rhythms may be associated with use of Zofran (ondansetron). Available from: http://www.fda.gov/Drugs/DrugSafety/ucm271913.htm. Accessed January 10, 2015.

Oral rehydration therapy (ORT) has been the cornerstone of all the diarrhea treatment protocols since 1970s. However, in this era of indiscriminate use of antibiotics and other drugs, ORT is being grossly underused. One of the major barriers to ORT is vomiting which makes pediatricians prefer intravenous fluids many a times only for parental reassurance. Literature suggests that wealthier family children are 1.5 times less likely to receive oral rehydration salt (ORS) solution. Till ORS is made more palatable, we have to rely on other cost-effective strategies to promote its use.

In this study, the authors have carried out a systematic randomized controlled trial (RCT), and supported the use of single dose of ondansetron in acute diarrhea with vomiting for successful delivery of ORT. However, lack of follow-up to see readmission rates or assessment for worsening of diarrhea, as reported in previous studies, has not been done.

In the Indian context, it could be an excellent step to scale up ORS use as motivating parents and even healthcare providers to give ORT despite vomiting is not easy, and traditional antiemetics have been marred with side effects. However, we should resist from a tendency to jump to this drug as it was originally intended for severe vomiting in chemotherapy and post-operative patients. More robust studies are needed to address the concerns of safety and benefit in ambulatory settings, and in select group of children such as those with severe malnutrition and other co-morbities.