Inhibition of gastric emptying by peripheral and central fenfluramine in rats: correlation with anorexia

Rats treated acutely with i.p. fenfluramine showed a profound inhibition of emptying of a chow meal from the stomach. This inhibition was attenuated by previous chronic treatment with fenfluramine. Tolerance to the gastric slowing occurred with as few as 2-4 prior injections, a time course which closely matches tolerance to the anorectic effects of the drug. Cerebroventricular injections of fenfluramine and norfenfluramine in anorectic doses also inhibited gastric emptying.