title: Olanzapine and risperidone plasma concentration therapeutic drug monitoring: A feasibility study.
abstract: BACKGROUND
  This study aimed to develop a clinically acceptable method of therapeutic drug monitoring (TDM) for olanzapine and risperidone and to evaluate the feasibility of its implementation.
  
  
  METHODS
  A non-randomised study of inpatients from five Mental Health Trusts was conducted, with a clinical interview at the time of TDM and a subsequent 6-week follow-up review of clinical notes. The TDM intervention comprised: (a) a venous blood sample taken 12 hours post-dose, 7-10 days after drug initiation, and (b) rapid results feedback, with interpretation algorithm guidance.
  
  
  RESULTS
  Thirty-two participants provided samples (19 prescribed olanzapine, 13 risperidone). Twenty-six participants remained on the target drug at study end, with seven experiencing a dose change, for whom only four of the TDM results were confirmed as having been checked. Mean dose increased for olanzapine (0.9 mg/day, range 0-10) and decreased for risperidone (-0.3 mg/day, range -4-3).
  
  
  CONCLUSIONS
  TDM can be implemented as part of routine clinical practice for both drugs. However, the lack of robust supporting evidence for or against antipsychotic TDM has probably led to a lack of enthusiasm for and interest in the results. Nevertheless, the advent of less invasive measures and the targeting of patients who might be more likely to benefit may facilitate uptake.
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Law
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Maria
authors.initials: M
authors.lastname: Gudbrandsen
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Magill
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Isabel
authors.initials: I
authors.lastname: Sweetman
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Diana
authors.initials: D
authors.lastname: Rose
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Sabine
authors.initials: S
authors.lastname: Landau
authors.affiliation: Toxicology Unit, King's College Hospital, London, UK.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Flanagan
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
authors.forename: Anthony S
authors.initials: AS
authors.lastname: David
authors.affiliation: Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK maxine.patel@kcl.ac.uk.
authors.forename: Maxine X
authors.initials: MX
authors.lastname: Patel
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000008:administration & dosage / Q000097:blood*; D001569:Benzodiazepines / Q000008:administration & dosage / Q000097:blood*; D016903:Drug Monitoring / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077152:Olanzapine; D018967:Risperidone / Q000008:administration & dosage / Q000097:blood*; D012559:Schizophrenia / Q000188:drug therapy*; D055815:Young Adult
chemical_list: D014150:Antipsychotic Agents; D001569:Benzodiazepines; D018967:Risperidone; D000077152:Olanzapine
keywords: Antipsychotics; dose; olanzapine; plasma concentration; risperidone; schizophrenia; therapeutic drug monitoring