Risperidone is associated with blunting of D-fenfluramine evoked serotonergic responses in schizophrenia.
The high 5-HT affinity of some atypical antipsychotic agents is thought to contribute to their clinical efficacy. We examined central 5-HT responses in two groups of ten schizophrenic patients by measuring serum prolactin and cortisol responses to the neuroendocrine challenge D-fenfluramine. One group of patients with schizophrenia was tested after a 2-week neuroleptic free period. A similar group were tested after a mean of 12 weeks treatment with the atypical antipsychotic risperidone. A significant elevation of baseline serum prolactin levels, consistent with dopaminergic antagonism was seen after risperidone treatment. Significantly reduced 5-HT mediated serum prolactin responses were seen in risperidone treated patients. D-fenfluramine evoked serum prolactin responses were positively correlated with positive but not negative schizophrenic symptoms for all 20 patients. Risperidone treatment was associated with a significant functional in-vivo 5-HT antagonism similar to clozapine. 5-HT antagonism may contribute to the efficacy of risperidone against positive schizophrenic symptoms.
Jones
H
H
Division of Psychiatry, Homerton Hospital, London.
Curtis
V A
VA
Wright
P A
PA
Lucey
J V
JV
D000328:Adult; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D005277:Fenfluramine; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D011388:Prolactin / Q000097:blood; D011569:Psychiatric Status Rating Scales; D018967:Risperidone / Q000627:therapeutic use*; D012559:Schizophrenia / Q000188:drug therapy* / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D017367:Selective Serotonin Reuptake Inhibitors; D013997:Time Factors
D014150:Antipsychotic Agents; D005277:Fenfluramine; D006854:Hydrocortisone; D011388:Prolactin; D018967:Risperidone; D012701:Serotonin; D017367:Selective Serotonin Reuptake Inhibitors