Ondansetron to Help Children With Cholera Rehydrate Successfully With Oral Rehydration Solution

INTERVENTION: Standard cholera care Standard cholera care plus oral ondansetron CONDITION: ; Cholera Cholera PRIMARY OUTCOME: Oral rehydration failure, defined as initiation of clinically necessary, unplanned intravenous fluids. SECONDARY OUTCOME: Adverse events and serious adverse events, including symptoms potentially related to cardiac arrhythmia. Cumulative volume of oral rehydration solution consumed. Length of hospital stay. Number of vomiting episodes. Time to clinical rehydration. Total volume of intravenous fluids administered INCLUSION CRITERIA: Age 6 months to 17 years. Suspected or confirmed cholera. Active vomiting, defined as at least one episode within the preceding 4 hours. No or some dehydration according to WHO/GTFCC criteria.