Precision psychiatry: The complexity of personalizing antipsychotic dosing

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3 Scopus citations


Recently, Salagre and Vieta commented on the complexity of implementing precision medicine in psychiatry. For 25 years, this author has focused on a circumscribed type of precision medicine: personalized dosing using pharmacokinetic mechanisms to stratified patients. This short communication focuses on personalized dosing of three oral antipsychotics (clozapine, risperidone and paliperidone) and presents their maintenance dosing in a table which provides dose-correction factors generated by pharmacokinetic studies. Inhibitors need dose-correction factors < 1 and inducers need correction factors >1. Clozapine maintenance dosing is based on the dose needed to reach 350 ng/ml (the minimum plasma therapeutic concentration in treatment-resistant schizophrenia). Clozapine maintenance dosing is influenced by 3 levels of complexity: 1) ancestry groups (Asians/Native Americans; Europeans and Blacks), 2) sex-smoking subgroups (lowest dose in female non-smokers and highest in male smokers) and 3) presence/absence of poor metabolizer status (due to genetic and non-genetic causes including co-prescription of inhibitors, obesity or inflammation). Risperidone and paliperidone maintenance dosing are based on the dose needed to reach plasma concentrations of 20–60 ng/ml. Risperidone PMs need approximately half the dose, which can be explained by genetics (CYP2D6 PMs) or co-prescription of CYP2D6 inhibitors. Fluoxetine co-prescription may require one fourth the risperidone maintenance dose. Carbamazepine co-prescription may require twice the risperidone maintenance dose. Although not well studied, two groups may need higher doses of oral paliperidone: Koreans may need 1.5 times higher doses while those taking carbamazepine may need 3 times higher paliperidone maintenance doses. Precision dosing in psychiatry requires using blood levels of individuals.

Original languageEnglish
Pages (from-to)80-85
Number of pages6
JournalEuropean Neuropsychopharmacology
StatePublished - May 2022

Bibliographical note

Funding Information:
JdL acknowledges Lorraine Maw, M.A. from the University of Kentucky Mental Health Research Center at Eastern State Hospital, who helped in editing the article.

Publisher Copyright:
© 2022


  • Antipsychotic agents/administration & dosage
  • Clozapine
  • Drug monitoring
  • Olanzapine
  • Pharmacogenetics
  • Risperidone

ASJC Scopus subject areas

  • Pharmacology
  • Neurology
  • Clinical Neurology
  • Psychiatry and Mental health
  • Biological Psychiatry
  • Pharmacology (medical)


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