To the Editor.—
The increase in homovanillic acid (HVA) concentration in rat plasma occurring after treatment with neuroleptic drugs has been found to be largely of central nervous system origin,1 although basal levels derive from both the periphery and the central nervous system.2 The findings on the effect of neuroleptic drugs on plasma HVA level in humans have not been entirely consistent. Pickar et al3 failed to demonstrate an acute neuroleptic drug-induced increase in plasma HVA level in schizophrenic patients, and Davis et al4 originally were unable to detect this effect in subjects studied six hours after treatment. Recently, this latter group reported that an increase did occur 24 hours after treatment.5 They administered haloperidol intramuscularly at 11 AM (0.2 mg/kg) and later, at 6 PM, orally (10 mg). The level of HVA in plasma was determined before administration of haloperidol and again the next
Davila R, ZUMARRAGA M, Perea K, Andia I, Friedhoff AJ. Elevation of Plasma Homovanillic Acid Level Can Be Detected Within Four Hours After Initiation of Haloperidol Treatment. Arch Gen Psychiatry. 1987;44(9):837–838. doi:10.1001/archpsyc.1987.01800210089014
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