Redux, having been already launched in Europe, was marketed in Canada
and the US for obesity. The (+)-isomer of fenfluramine is obtained by resolution using
d-camphoric acid and ultimate conversion to the HCl salt. The levo-isomer has
significant effects on dopaminerigic neurotransmission, while the dextro-isomer has a
greater anorectic effect because it is more selective on serotonin as a 5-HT agonist
with no dopaminergic or noradenergic activity. Redux inhibits the presynaptic release
of serotonin, is a reuptake inhibitor, a 5-HT1B, receptor agonist, and a postsynaptic 5-HT2C receptor agonist . A dietary reduction in fat intake was thought to proceed via a
CCK A-type receptor agonist activity. Due to the side effects of primary pulmonary
hypertension, brain serotonin neurotoxicity and valvular heart disease, Redux was
withdrawn world wide.
