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#49 Can ondansetron help children vomiting due to gastroenteritis?

In children presenting with vomiting associated with gastroenteritis, what are the benefits and harms of ondansetron?

While most cases of pediatric gastroenteritis are self-limiting, studies from the emergency setting show a single dose of oral ondansetron can help reduce vomiting, the need for IV fluids and admission.  

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Systematic review,1 six Randomized Controlled Trials (RCTs), five in emergency department (ED) and one inpatient745 patients total, oral and IV administration. 
  • Ondansetron statistically significantly improved:  
    • Admission: Ondansetron (7.5% versus placebo 14.6%) Number Needed to Treat (NNT)=14. 
    • Need for IV fluids: (13.9% versus 33.9%) NNT=5. 
    • Continued vomiting in ED(16.9% versus 37.8%) NNT=5. 
  • No change in return to care.  
  • Increased diarrhea (no numbers given).  
An updated Cochrane systematic review2 considered six RCTs (five RCTs from above review) with 777 patients, all in the ED. 
  • Only oral treatments were meta-analyzed and had similar results. 
    • Statistically significant reduction in admission (NNT=17), need for IV rehydration (NNT=5), persistent vomiting (NNT=5) but no reduction in return to care.   
RCT from Iran (176 patients) found no difference in persistent vomiting between ondansetron and placebo, however more on ondansetron were able to tolerate oral rehydration (NNT=7).3  Two RCTs from Thailand and Qatar (76 and 186 patients, respectively) found no statistical difference in vomiting rates between ondansetron and domperidone or metoclopramide.4,5  Context:   
  • Evidence for other medications for vomiting due to gastroenteritis in pediatrics is poor and/or limited.1,6 
    • More recent RCT found dimenhydrinate suppositories helped stop vomiting (NNT=5) but did not reduce admission rates.7   
  • Ondansetron appears cost-effective in ED setting.8,9 
  • An evidence-based review of ondansetron for gastroenteritis by the Canadian Pediatric Society10 recommended: 
    • A single oral dose ondansetron for children (age six months to 12 years):  
      • With mild to moderate dehydration or failed oral rehydration, and 
      • Not predominantly moderate to severe diarrhea.   
  • Ondansetron can be administered IV or orally (dissolving formulations available) 
    • Oral doses example: 2 mg if patient weighs 8-15 kg, 4 mg if 15-30 kg, and  6-8 mg if >30 kg. 
updated apr 21 2015 Adrienne

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  • Erin Wilson NP(F) MSN
  • G. Michael Allan MD CCFP

1. DeCamp LR, Byerley JS, Doshi N, et al. Arch Pediatr Adolesc Med. 2008; 162(9):858-65.

2. Fedorowicz Z, Jagannath VA, Carter B. Cochrane Database Syst Rev. 2011; 9:CD005506. .

3. Golshekan K, Badeli H, Rezaieian S, et al. Iran J Pediatr. 2013; 23(5):557-63.

4. Rerksuppaphol S, Rerksuppaphol L. J Clin Med Res. 2013; 5(6):460-6.

5. Al-Ansari K, Alomary S, Abdulateef H, et al. J Pediatr Gastroenterol Nutr. 2011; 53(2):156-60.

6. Carter B, Fedorowicz Z. BMJ Open. 2012; 2(4). pii: e000622

7. Uhlig U, Pfeil N, Gelbrich G, et al. Pediatrics. 2009; 124:e622–e632.

8. Freedman SB, Steiner MJ, Chan KJ. PLoS Med. 2010; 7(10):e1000350.

9. Hervás D, Armero C, Carrión T, et al. Pediatr Emerg Care. 2012; 28(11):1166-8.

10. Cheng A. Paediatr Child Health. 2011; 16(3):177-9.

Authors do not have any conflicts of interest to declare.