Fenfluramine is an indirect agonist of serotonin receptors. Fenfluramine binds to the serotonin transporter, blocking serotonin reuptake. However, fenfluramine also acts to induce non-exocytotic serotonin release; in a mechanism similar to that of methamphetamine in dopamine neurons, fenfluramine binds to VMAT2, disrupting the compartmentalization of serotonin into vesicles and increasing the concentration of cytoplasmic serotonin available for drug-induced release.