Please use this identifier to cite or link to this item:
Title: Dopamine D 2/3 receptor occupancy following dose reduction is predictable with minimal plasma antipsychotic concentrations : an open-label clinical trial
Authors: Nakajima, Shinichiro
Uchida, Hiroyuki
Bies, Robert R.
Caravaggio, Fernando
Suzuki, Takefumi
Plitman, Eric
Mar, Wanna
Gerretsen, Philip
Pollock, Bruce G.
Mulsant, Benoit H.
Mamo, David
Graff-Guerrero, Ariel
Keywords: Antipsychotic drugs
Issue Date: 2015
Publisher: Oxford University Press
Citation: Nakajima, S., Uchida, H., Bies, R. R., Caravaggio, F., Suzuki, T., Plitman, E., ... & Mamo, D. C. (2015). Dopamine D 2/3 receptor occupancy following dose reduction is predictable with minimal plasma antipsychotic concentrations: an open-label clinical trial. Schizophrenia Bulletin, 42(1), 212-219.
Abstract: Background: Population pharmacokinetics can predict antipsychotic blood concentrations at a given time point prior to a dosage change. Those predicted blood concentrations could be used to estimate the corresponding dopamine D 2/3 receptors (D 2/3 R) occupancy by antipsychotics based on the tight relationship between blood and brain pharmacokinetics. However, this 2-step prediction has never been tested. Methods. Two blood samples were collected at separate time points from 32 clinically stable outpatients with schizophrenia (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition; mean ± SD age: 60.1±7.3 years) to measure plasma concentrations of olanzapine or risperidone at baseline. Then, subjects underwent a dose reduction of olanzapine or risperidone and completed a [ 11 C]-raclopride positron emission tomography scan to measure D 2/3 R occupancy in the putamen. The plasma concentration at the time of the scan was predicted with the 2 samples based on population pharmacokinetic model, using NONMEM. D 2/3 R occupancy was then estimated by incorporating the predicted plasma concentration in a hyperbole saturation model. The predicted occupancy was compared to the observed value. Results. The mean (95% CI) prediction errors for the prediction of D 2/3 R occupancy were −1.76% (−5.11 to 1.58) for olanzapine and 0.64% (−6.18 to 7.46) for risperidone. The observed and predicted D 2/3 R occupancy levels were highly correlated ( r = 0.67, P = .001 for olanzapine; r = 0.67, P = .02 for risperidone). Conclusions. D 2/3 R occupancy levels can be predicted from blood drug concentrations collected prior to dosage change. Although this 2-step model is subject to a small degree of error, it could be used to select oral doses aimed at achieving optimal D 2/3 R occupancy on an individual basis.
Appears in Collections:Scholarly Works - FacM&SPsy

Files in This Item:
File Description SizeFormat 
  Restricted Access
572.25 kBAdobe PDFView/Open Request a copy

Items in OAR@UM are protected by copyright, with all rights reserved, unless otherwise indicated.