How is fenfluramine hydrochloride thought to reduce seizures in Dravet syndrome and Lennox–Gastaut syndrome?

Fenfluramine hydrochloride releases serotonin and may reduce seizures through agonism at brain serotonin receptors, including 5-HT1D, 5-HT2A and 5-HT2C, and action on the sigma-1 receptor, although its precise mechanism in Dravet syndrome and Lennox–Gastaut syndrome is unknown.