Sibutramine is an equipotent serotonin and norepinephrine reuptake inhibitor (SNRI), which means it has an equal effect on serotonin (a brain neurotransmitter which generally promotes a calming feeling) and norepinephrine (a stimulant). Research indicates that these brain chemicals have an effect on appetite and satiety.
Sibutramine is used in the management of obesity by increasing the amount of neurotransmitters serotonin and norepinephrine. Sibutramine inhibits the re-uptake of these neurotransmitters by the nerve cells and alters the balance of neurotransmitters within the nerve cells. Unlike other diet drugs (fenfluramine, dexfenfluramine) which increase release of these neurotransmitters from the cells, the action of sibutramine is similar to anti-depressants (fluoxetine) which inhibit reuptake of serotonin.