Date: 18 November 2012
Case Scenario: A fouryear-old child presents with a one day history of vomiting. They are otherwise healthy, immunized, no fever, no rash, no recent travel, no abdominal pain, no cough and no sick contacts.

Background on Dehydration in Children: Dehydration in children is a common presentation to the emergency department. A main cause of dehydration in this age group is gastroenteritis which is characterized by acute onset diarrhea with or without nausea, vomiting, fever and abdominal pain. The scope of the problem was quantified by Glass in 1991. This study showed the following:

  • 20-40 million episodes of diarrhea in children each year in the USA
  • resulting in 2-4 million physician visits per year
  • 10% of all hospital admissions of children < 5 yrs old





Goldman et al Pediatrics in 2008 published a helpful table describing the degree of dehydration in children ranging from mild, moderate to severe.

Most cases of gastroenteritis are mild , self-limiting and can be treated effectively with oral rehydration. For more information on visit this site on Oral Rehydration Therapy. The Canadian Pediatric Society also has a algorithm for oral rehydration (see below).

Question: What can we use to prevent vomiting/IV fluids/admissions in children with gastroenteritis?

Reference: DeCamp LR et al. Use of antiemetic agents in acute gastroenteritis: A systematic review and meta-analysis. Arch Pediatr Adolesc Med. 2008 Sep;162(9):858-65

  • Populations: Children with vomiting from gastroenteritis
  • Intervention:  Antiemetic medications    
  • Control: Placebo
  • Outcome: Further vomiting, requirement of intravenous fluids, admission to hospital, return to the emergency department and episodes of diarrhea

Authors’ Conclusions: “Ondansetron is the only antiemetic agent with consistent, proven efficacy in reducing vomiting from gastroenteritis. Other antiemetic drugs have not demonstrated consistent effectiveness and, therefore, should not be used. In addition, moderately ill children presenting to the ED who were treated with ondansetron have a decreased risk of receiving IVF and a decreased need for immediate hospital admission.”

Results: There were eleven articles that met the inclusion criteria: ondansetron (n = 6), domperidone (n = 2), trimethobenzamide (n = 2), pyrilamine-pentobarbital (n = 2), metoclopramide (n = 2), dexamethasone (n = 1), and promethazine (n = 1). A meta-analysis of 6 randomized, double-masked, placebo-controlled trials of ondansetron was performed.

  • Prevent Admission NNT=14 (95% CI 9-44)

  • Prevent IVF NNT=5 (95% CI 4-8)

  • Prevent Further Emesis NNT=5 (95%CI 4-7)

BEEM Comments: Ondansetron, given orally, is an effective anti-emetic in children experiencing vomiting secondary to gastroenteritis. Doses should be given as needed for vomiting and regular dosing (i.e. every eight hours) of ondansetron should be avoided to prevent worsening diarrhea and return to the emergency department.

EBM Information: Search strategies are always important in systematic reviews. You want researchers to cast a wide net and be exhaustive in their efforts. This study did do an extensive search but there was a significant weakness. They limited the strategy to identify only english language studies. Whether or not this had an impact on the results and conclusions are unknow.

Cochrane traditionally does and excellent job in searching for articles to include. These researchers usually check everything including hand searches of medical meetings and phone calls to experts who have published in the area.

While the english language restriction is a limitation to this 2008 publication there have been other systematic reviews which agree with the conclusions of this study. These include a Cochrane review from 2011 and a BMJ update from the same authors in 2012.

If you want to cut the knowledge translation window down to less than one year consider coming to SkiBEEM 2013 February 4th to 6th at SilverStar, BC.  Dr. Anthony Crocco our Peds BEEM guru will be updating the topic of gastroenteritis in children.

BEEM Bottom Line: Ondansetron is an effective anti-emetic preventing further vomiting, intravenous fluids and admissions for children with gastroenteritis.

Case Resolution: The four-year-old was given 0.1mg/kg of ondansetron orally. They were observed for one hour with a trial of oral rehydration therapy. There was no further vomiting.

For more information about dosing, which is typically between 0.1-0.15mg/kg, check out the Ondansetron dosing in pediatric gastroenteritis: a prospective cohort, dose-response study by Freedman et al 2010 in the journal of Paediatric Drugs.

KEENER KONTEST: Last weeks winner was Alex Zozula a medical student from Washington University in St. Louis. He correctly identified the Hitch Hiker’s Guide to the Galaxy coined the phrase “Don’t Panic”. He even knew that the second rule was “bring a towel”. Which is also good advice for emergency medicine…once the bleeding stops.

What is the NNT with ondansetron to prevent further vomiting in children?

Email your answer to TheSGEM@gmail.com or go to the Contact Us link at the top of the home page. Use “Keener Kontest” in the subject line. First one to email me the correct answer will win a cool skeptical prize.

Happy Thanksgiving to all the American SGEM listeners. Check out the YouTube Video celebrating this holiday.

Remember to be skeptical of anything you learn, even if you heard it on the Skeptics’ Guide to Emergency Medicine.