Chronic fenfluramine administration: some cerebral effects.

Human cerebral function was monitored electrophysiologically during sleep over a period of months before, during, and after the intake of fenfluramine, 40-120 mg/day. Effects included dose-related reduction of paradoxical sleep, increase of intra-sleep restlessness, and changes in E.E.G. slow-wave sleep. It is hypothesized that weight loss may be associated with increase of the last. Grinding of teeth (bruxism) also was noted.Long-term studies make it possible to demonstrate changing central effects with time, including tolerance phenomena. Withdrawal abnormalities are related to the time taken for the drug to be eliminated-in the present case reaching a maximum four days after withdrawal.