 The result of the increased serotonergic and noradrenergic neurotransmission is a feeling of fullness and reduced appetite.The combination of fenfluramine with phentermine, a norepinephrine–dopamine releasing agent acting primarily on norepinephrine, results in a well-balanced serotonin–norepinephrine releasing agent with weaker effects of dopamine release.The elimination half-life of fenfluramine has been reported as ranging from 13 to 30 hours.