Ondansetron is increasingly administered to children suffering from concussion-associated nausea/vomiting. We examined the association between ondansetron administration and post-concussion symptoms in children at 1 week and 1 month following the concussion.

This was a secondary analysis of data collected prospectively in a cohort study conducted in nine pediatric emergency departments (EDs) (5P study). Participants were children ages between 5 and 17.99 years who sustained a concussion in the previous 48 hours. For the current study, only 5P participants who reported nausea and/or vomiting in the ED were eligible. The exposure of interest was ondansetron administration; the comparison group included all other participants. The primary outcome was an increase in at least three symptoms of the Post-Concussion Symptom Inventory score at 1 week and 1 month following trauma.

Among the 3,063 children included in the 5P study, 1805 (59%) reported nausea and provided data at 1 week and/or 1 month. Among them, 132 (7%) received ondansetron. Multivariable logistic regression adjusted for confounders did not show an association between ondansetron use and the risk of persistent post-concussion symptoms at 1 week (OR: 1.13 [95% CI: 0.86-1.49]), but it was associated with a higher risk at 1 month (OR: 1.33 [95% CI: 1.05-1.97]).

In children presenting to the ED with an acute concussion, ondansetron use was associated with a higher risk of persistent post-concussion symptoms at 1 month. Although this may be related to the limitations of the design, it highlights the importance of evaluating this association using a randomized clinical trial.