Chronic haloperidol or fluphenazine: effects on dopamine metabolism in brain, cerebrospinal fluid and plasma of Cercopithecus aethiops (vervet monkey).

Chronic treatment with haloperidol for 3 to 5 weeks (0.5 mg/kg, daily) resulted in significant increases of homovanillic acid (HVA) content in dorsal and orbital frontal cortex and in cingulate cortex. No change in HVA was seen in the olfactory cortex, basal ganglia, cisternal cerebrospinal fluid or plasma of animals chronically treated with haloperidol. Treatment with a single weekly dose of fluphenazine decanoate (5 mg/kg) for 3 weeks resulted in increased HVA levels in all the above brain regions, cisternal cerebrospinal fluid and plasma. Moreover, the fluphenazine-treated group had a significantly higher incidence of extrapyramidal side effects than the haloperidol-treated group. It is concluded that chronically increased dopamine metabolite production in the basal ganglia but not in cortex is reflected by increases in the HVA level of cerebrospinal fluid and plasma and is accompanied by severe extrapyramidal side effects.