title: Differential effect of haloperidol and clozapine on plasma homovanillic acid in elderly schizophrenic patients with or without tardive dyskinesia.
abstract: 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.
authors.affiliation: Departamento de Investigacion Neuroquimica, Servicio Vasco de Salud, Zamudio, Vizcaya, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Andia
authors.forename: M
authors.initials: M
authors.lastname: Zumarraga
authors.forename: M J
authors.initials: MJ
authors.lastname: Zabalo
authors.forename: A
authors.initials: A
authors.lastname: Bulbena
authors.forename: R
authors.initials: R
authors.lastname: Davila
mesh_terms: 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*
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine; D006220:Haloperidol; D006719:Homovanillic Acid