The effects of D-fenfluramine on mood and performance, and on neuroendocrine indicators of 5-HT function

D-fenfluramine has multiple actions which enhance 5-HT transmission and make it a useful neuroendocrine challenge agent, but little is known of its effects on mood or performance. In this study, two doses (15 and 30 mg) and placebo were administered to six male and six female healthy volunteers according to a double blind, cross-over design. Blood was sampled and self-ratings completed pre- and hourly up to 5 h post-challenge. Performance tests were administered pre- and at 2 and 4 h. Plasma concentrations of prolactin and cortisol decreased after all treatments at 1 h and then increased post-drug to a peak at 4 h. Body temperature showed a similar pattern. D-fenfluramine was well tolerated with few side effects. It caused only minor sedation and little psychomotor impairment but there was some decrement in episodic memory. The 30 mg dose produced a mild anxiolytic and anti-aggressive action.