The effect of ondansetron on persisting vomitin in children with gastro-enteritis presenting at primary care out of hours service.

INTERVENTION: Weight‐based dose of oral ondansetron added to oral rehydration therapy. CONDITION: General practice, Gastroenteritis, Children, Nausea , Cost‐effectiveness ; ; PRIMARY OUTCOME: The proportion of children that continue to vomit within the first 4 hours after presentation at the OHS with acute gastro‐enteritis.; ; SECONDARY OUTCOME: Cessation of vomiting, the number of vomiting episodes during ORT, referral to a (pediatric) emergency department), intravenous rehydration, hospital admission rate and duration, healthcare use and costs. A vomiting episode will be recorded by the parent when a forceful expulsion of stomach contents occurs. Episodes separated by no more than two minutes will be counted as a single episode. Nonproductive retching, spilling of oral contents, and drooling are not considered vomiting. Cessation of vomiting will be noted at the time of a vomiting episode after which no more than 1 vomiting episode is noted during a period of at least 1 day. INCLUSION CRITERIA: 1. Aged 6 months to 6 years; 2. At least four reported episodes of vomiting or diarrhoea during the last twenty‐four hours preceding presentation 3. At least one reported episode of vomiting within the four hours preceding presentation; 4. Diagnosed with AGE by a general practitioner at the OHS. 5. Parental written informed consent.