Effect of clozapine on 5-HIAA excretion in urine and CSF of psychotic patients and on serotonin metabolism in rat brain.

In a clinical study and with experiments in rats Clozapine showed a sedative effect, which diminished during the treatment, and indicated a development of tolerance. 5-HIAA in urine and CSF of patients was elevated after 10 days of treatment. 5-HT and 5-HIAA were elevated in the brains of rats in acute experiments as well as in chronic experiments.