Differential effect of haloperidol and clozapine on plasma homovanillic acid in elderly schizophrenic patients with or without tardive dyskinesia.
BACKGROUND
Plasma homovanillic acid (HVA) changes in response to a challenge of several days with haloperidol have been found to be predictive of the therapeutic response to haloperidol over a longer period of treatment.


METHODS
Twenty-six elderly women who gave informed consent were divided into two groups, with or without tardive dyskinesia, and subjected to an 80-day washout, after which both the dyskinetic and nondyskinetic group was divided, and half of each group given haloperidol or clozapine.


CONCLUSIONS
The nondyskinetic group had a brief rise in plasma HVA, then a decline. The dyskinetic group had no change in plasma HVA. Neither group challenged with clozapine had any change in plasma HVA.
Andia
I
I
Departamento de Investigacion Neuroquimica, Servicio Vasco de Salud, Zamudio, Vizcaya, Spain.
Zumarraga
M
M
Zabalo
M J
MJ
Bulbena
A
A
Davila
R
R
D000368:Aged; D000369:Aged, 80 and over; D014150:Antipsychotic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D003024:Clozapine / Q000009:adverse effects* / Q000627:therapeutic use; D004409:Dyskinesia, Drug-Induced / Q000097:blood*; D005260:Female; D006220:Haloperidol / Q000009:adverse effects* / Q000627:therapeutic use; D006719:Homovanillic Acid / Q000097:blood*; D006801:Humans; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000378:metabolism*
D014150:Antipsychotic Agents; D003024:Clozapine; D006220:Haloperidol; D006719:Homovanillic Acid