Ritanserin attenuates anorectic, endocrine and thermic responses to d-fenfluramine in human volunteers.

This study investigated the role of the 5-HT2/1C receptor antagonist ritanserin on d-fenfluramine (d-FF) induced changes in food intake, prolactin (PRL) secretion and oral temperature in 12 healthy male volunteers. The study was double blind and placebo controlled. Food intake was measured using an automated food dispenser. d-FF (30 mg) significantly reduced fat intake. While ritanserin (5 mg) had no effect when given alone it abolished the d-FF induced reduction in fat intake. In addition, ritanserin abolished the d-FF induced rise in PRL and oral temperature. The results suggest that 5-HT2 or 5-HT1C receptors mediate the effects of d-fenfluramine on appetite, prolactin secretion and temperature in humans.