Fenfluramine disrupts the behavioural satiety sequence in rats.

Previous studies have shown that when hungry rats are fed to satiety, the offset of eating is followed by a short period of activity superseded by resting behaviour. Observations of rats consuming wet mash or sucrose confirmed this "behavioural satiety sequence" and showed that the duration of resting was related to the intake of calories rather than of bulk. Fenfluramine reduced the consumption of sucrose and wet mash, but at anorectic and subanorectic doses, fenfluramine also suppressed resting behaviour; the effects of dl- and d-fenfluramine were qualitatively similar. It is argued that the suppression of resting behaviour by fenfluramine is incompatible with an enhancement of satiety.