Prolactin response to dl-fenfluramine in panic disorder

Abstract

The objective of this study was to test the hypothesis that serotonin receptors are hypersensitive in patients with panic disorder. Eleven patients and 12 controls received a single PO dose of 60 mg of dl-fenfluramine at 0900h on a single occasion. Blood samples were collected with an indwelling intravenous catheter at 30-min intervals from 0930h to 1530h and prolactin determined by radioimmunoassay. In both groups, fenfluramine induced a rise in the plasma prolactin concentration from baseline. The patients showed a greater increase in prolactin response than the normal controls. This result is consistent with the hypothesis of increased serotonin receptor function in patients with panic disorder.