Norfenfluramine, or 3-trifluoromethylamphetamine, is a drug of the amphetamine family which behaves as a serotonin and norepinephrine releasing agent and potent 5-HT2A, 5-HT2B, and 5-HT2C agonist. The action of norfenfluramine on 5-HT2B receptors on heart valves leads to a characteristic pattern of heart failure following proliferation of cardiac fibroblasts on the tricuspid valve, known as cardiac fibrosis.[1] This side effect led to the withdrawal of fenfluramine as an anorectic agent worldwide, and to the withdrawal of benfluorex in Europe,[2] as both fenfluramine and benfluorex form norfenfluramine as an active metabolite. It is a human TAAR1 agonist.[3]
