The assessment and clinical implications of haloperidol acute-dose, steady-state, and withdrawal pharmacokinetics.
In order to evaluate comprehensively haloperidol pharmacokinetics under fixed-dose treatment conditions, psychiatric patients were studied after treatment with an acute dose, during maintenance therapy, and after withdrawal from haloperidol following steady-state conditions. After single doses, haloperidol appeared rapidly in serum, achieving peak concentration at a mean of 4.5 hours. The range of observed elimination half-life was broad, between 8.5 and 66.6 hours, with a mean of 19.5 hours. Under conditions of chronic dosing, serial measurements of steady-state serum concentration revealed intrapatient coefficients of variation between 2 and 72%. The mean for all patients was 26.4%. Body clearance decreased nonsignificantly, and elimination half-life increased significantly after chronic dosing compared with kinetic parameters determined after a single dose. The concentration of haloperidol in serum obtained at 8 hours after a single dose correlated most strongly (r = 0.73; p < 0.0001) with steady-state concentration resulting from chronic dosing. A value of 4 ng/ml or lower determined 8 hours after a single oral dose of 0.2 mg/kg identified patients who did not accumulate haloperidol during chronic dosing of 0.4 mg/kg per day above a presumed therapeutic range for haloperidol of 5 to 15 ng/ml. The implications of these data for the clinical use of haloperidol are discussed.
Khot
V
V
Neuropsychiatry Branch, National Institute of Mental Health Neuroscience Center, Saint Elizabeths, Washington, DC.
DeVane
C L
CL
Korpi
E R
ER
Venable
D
D
Bigelow
L B
LB
Wyatt
R J
RJ
Kirch
D G
DG
D000328:Adult; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D016903:Drug Monitoring; D005260:Female; D006207:Half-Life; D006220:Haloperidol / Q000008:administration & dosage* / Q000009:adverse effects / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate / Q000502:physiology; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000097:blood / Q000188:drug therapy*; D012565:Schizophrenic Psychology; D013375:Substance Withdrawal Syndrome / Q000097:blood*
D006220:Haloperidol