title: The usefulness of monitored therapy using Clozapine concentration in the blood serum for determining drug dose in Polish schizophrenic patients.
abstract: BACKGROUND
  The aim of the study is to evaluate the advisability of systematic monitoring of clozapine (CLO) concentration in serum during treatment of schizophrenia in Polish psychiatric patients.
  
  
  METHODS
  The concentration of CLO and its metabolites: norclozapine (NCLO) and clozapine N-oxide (CLO-NO) in serum obtained from 107 patients suffering from schizophrenia was determined by high performance liquid chromatography (HPLC) method. There were two groups of patients. In the first group of patients (n=95) the concentration of drug and its metabolites was determined by one-time testing. Correlations were tested using the test statistics. In the second group of patients (n=12), 51 samples of serum were provided by the same patient in different time spans (from 6days to 14 months after the beginning of the treatment).
  
  
  RESULTS
  Concentrations of CLO and its metabolites in blood serum do not always show a linear dependence on the applied dose for individual patients.
  
  
  CONCLUSIONS
  The high volatility of CLO concentrations in blood serum of patients treated with identical doses of the drug confirmed the validity of the monitored therapy.
authors: Department of Biochemistry and Clinical Chemistry, Medical University, Warszawa, Poland.
authors: Jadwiga
authors: J
authors: Piwowarska
authors: Department of Psychiatry, Medical University, Warszawa, Poland. Electronic address: maria.radziwon@wum.edu.pl.
authors: Maria
authors: M
authors: Radziwoń-Zaleska
authors: Department of Biochemistry and Clinical Chemistry, Medical University, Warszawa, Poland.
authors: Martyna
authors: M
authors: Dmochowska
authors: Department of Biochemistry and Clinical Chemistry, Medical University, Warszawa, Poland.
authors: Ewa
authors: E
authors: Szepietowska
authors: Department of Psychiatry, Medical University, Warszawa, Poland.
authors: Halina
authors: H
authors: Matsumoto
authors: Department of Biochemistry and Clinical Chemistry, Medical University, Warszawa, Poland.
authors: Grażyna
authors: G
authors: Sygitowicz
authors: Institute of Pharmacology, Polish Academy of Sciences, 31-343 Kraków, Smętna street 12, Poland.
authors: Andrzej
authors: A
authors: Pilc
authors: Department of Biochemistry and Clinical Chemistry, Medical University, Warszawa, Poland.
authors: Jacek
authors: J
authors: Łukaszkiewicz
mesh_terms: D000328:Adult; D014150:Antipsychotic Agents / Q000097:blood* / Q000627:therapeutic use*; D003024:Clozapine / Q000097:blood* / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D016903:Drug Monitoring / Q000379:methods / Q000639:trends*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011044:Poland / Q000453:epidemiology; D012559:Schizophrenia / Q000097:blood* / Q000188:drug therapy / Q000453:epidemiology
chemical_list: D014150:Antipsychotic Agents; D003024:Clozapine
keywords: Clozapine; Clozapine N-oxide; Norclozapine; Schizophrenia; Therapeutic drug monitoring