Table 3.

RCTs comparing ondansetron versus placebo in children with acute gastroenteritis and vomiting.

Comparison	Population	Episodes of vomiting	Proportion of children with episodes of vomiting	Admissions to hospital	Treatment-induced adverse effects
Ondansetron (single intravenous) v placebo	36 children aged 6 months to 8 years who had vomited twice within 1 hour. All children were hospitalised for a minimum of 24 hours	Mean number of episodes reported <24 hours after treatment: 2 with ondansetron v 5 with placebo; P = 0.049	<24 hours after treatment: 5/12 (42%) with ondansetron v 10/12 (83%) with placebo; P = 0.04	Not reported	Episodes of diarrhoea:More diarrhoeal episodes with ondansetron than placebo; absolute data not reported; P = 0.013 Other adverse effects:Drowsiness in >90% of children in all groups. Cough in 3/12 (25%) with ondansetron v 0/12 (0%) with placebo
Ondansetron (oral, 8 hourly for 1 or 2 days) v placebo	145 children aged 6 months to 12 years with at least 5 episodes of vomiting in the preceding 24 hours	Mean number of episodes reported. In ED: 0.18 with ondansetron v 0.83 with placebo; P = 0.001; <24 hours after treatment: 0.75 with ondansetron v 0.96 with placebo; P = 0.96	In ED: AR 10/74 (14%) with ondansetron v 25/71 (35%) with placebo; P = 0.004; <24 hours after treatment: AR 27/64 (42%) with ondansetron v 26/56 (46%) with placebo; P = 0.8	Reported to be significantly lower with ondansetron compared with placebo; P = 0.007	Episodes of diarrhoea:Mean number of episodes reported; In ED: 0.7 with ondansetron v 0.61 with placebo; P = 0.622; <24 hours after treatment: 4.7 with ondansetron v 1.37 with placebo; P = 0.002 Other adverse effects:Macular rash, without urticaria or respiratory symptoms, in 1 patient 30 minutes after receiving ondansetron
Ondansetron (single oral) v placebo	215 children aged 6 months to 10 years with non-bloody vomiting within the 4 hours preceding triage, and mild-to-moderate dehydration	Mean number of episodes reported: 0.18 with ondansetron v 0.65 with placebo; RR 0.30, 95% CI 0.18 to 0.50; P < 0.001	During oral rehydration: 15/107 (14%) with ondansetron v 37/107 (35%) with placebo; RR 0.40, 95% CI 0.26 to 0.61; P < 0.001	4/107 (4%) with ondansetron v 5/107 (5%) with placebo; RR 0.80, 95% CI 0.22 to 2.90; P = 1.00	Episodes of diarrhoea:Mean number of episodes reported; post intervention: 1.4 with ondansetron v 0.5 with placebo; P < 0.001 Other adverse effects:No cardiovascular or respiratory events occurred. 1 child in the placebo group developed urticaria

ED, emergency department