Serotonin 5-HT4 receptors play a critical role in the action of fenfluramine to block seizure-induced sudden death in a mouse model of SUDEP

•Fenfluramine is anticonvulsant in the DBA/1 mouse model of SUDEP.•The 5-HT receptor(s) that mediate this action of fenfluramine were examined.•We evaluated if selective 5-HT receptor antagonists could block fenfluramine’s action.•The action of fenfluramine was mediated primarily by 5-HT4 receptors in these mice.•A 5-HT4 receptor agonist was also anticonvulsant in this SUDEP model.