Introduction: Therapeutic drug monitoring (TDM) of clozapine is a very useful method for verifying both the correct intake and the interindividual variability of its metabolism, thereby avoiding the risk of toxicity. The purposes of this paper were to discover how many patients using clozapine in common clinical practice have clozapine plasma concentration (PC) levels in the proposed reference range and to identify factors that influence clozapine PC levels.
Methods: Our study included 100 inpatients (diagnosed with schizophrenia or schizoaffective disorder) taking standard doses of clozapine (100-700 mg/day). Clozapine concentration was measured by high-performance liquid chromatography. Correlations between doses and PC levels and the influence of smoking and gender on clozapine PC levels were calculated.
Results: A large number of the patients (67%) had PC levels outside the proposed reference range. The clozapine PC levels were influenced by dose, gender, and cigarette smoking.
Conclusion: The correlations between dose, gender, and cigarette smoking and clozapine PC levels highlighted by our study overlap other research. It was surprising to find such a large number of patients with clozapine PC levels outside the therapeutic range. This result suggests the importance of clozapine TDM due to misunderstood inter- and/or intraindividual variability or misestimated partial therapeutic compliance.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6011879 | PMC |
| http://dx.doi.org/10.2147/NDT.S163839 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Adiponectin, resistin, interleukin-4 and TGF-β2 levels in treatment resistant schizophrenia patients.
Prog Neuropsychopharmacol Biol Psychiatry
December 2024
Department of Psychiatry, Faculty of Medicine, School of Health Sciences, University of Ioannina (UOI), P.O. Box 1186, 45110 Ioannina, Greece. Electronic address:
Background: The aim of the present study was to measure adiponectin, resistin, interleukin-4 and TGF-β levels in first episode, treatment resistant patients with schizophrenia.
Methods: In total, fifty-three treatment-resistant patients were included in the study. In subgroups of these patients, we measured Interleukin-4 (IL-4), Tumor Growth Factor-β2 (TGF-β2), adiponectin and resistin levels at three different timepoints: in the drug-naïve state, after two rounds of treatment with different antipsychotic drugs for a total of 16 weeks and, after clozapine treatment for 12 weeks.
Clozapine/norclozapine plasma level ratio and cognitive functioning in patients with schizophrenia spectrum disorders: a systematic review.
Ther Adv Psychopharmacol
December 2024
Department of Community Mental Health, Mental Health Service Noord-Holland Noord, Alkmaar, The Netherlands.
Background: Extant research on cognitive functioning in treatment-resistant schizophrenia (TRS) is limited and of poor quality. Cognitive impairments in patients with schizophrenia spectrum disorders (SSD) significantly influence quality of life. In patients with TRS, clozapine (CLO) is not consistently associated with improved cognitive functioning.
View Article and Find Full Text PDFPeripheral inflammatory and metabolic markers as potential biomarkers in treatment-resistant schizophrenia: Insights from a Qatari Cohort.
Psychiatry Res
November 2024
Division of Genomics and Precision Medicine, College of Health and Life Sciences, Hamad Bin Khalifa University, Qatar. Electronic address:
Schizophrenia presents significant diagnostic and treatment challenges, particularly in distinguishing between treatment-resistant (TRS) and non-treatment-resistant schizophrenia (NTRS). This cross-sectional study analyzed routine laboratory parameters as potential biomarkers to differentiate TRS, NTRS, and healthy individuals within a Qatari cohort. The study included 31 TRS and 38 NTRS patients diagnosed with schizophrenia, alongside 30 control subjects from the Qatar Biobank.
View Article and Find Full Text PDFTherapeutic drug monitoring vs. pharmacogenetic testing in the context of elevated olanzapine concentrations and prior clozapine intolerability: a case study.
BMC Psychiatry
December 2024
University of California, Irvine, School of Medicine, 1001 Health Sciences Road, Irvine, CA, 92697, USA.
Article Synopsis
- Strong evidence supports therapeutic drug monitoring (TDM) for olanzapine and clozapine, but TDM for olanzapine is often underused despite its effectiveness.
- A case study of a 32-year-old male with schizoaffective disorder demonstrated that while olanzapine dosing revealed high levels indicating poor metabolism, pharmacogenetic tests did not provide useful information about his drug metabolism.
- The conclusion emphasizes the importance of TDM over pharmacogenomic testing for managing medications like olanzapine and clozapine, especially in patients suspected of having altered CYP1A2 metabolism.
How antipsychotics work in schizophrenia: a primer on mechanisms.
CNS Spectr
December 2024
Voluntary Clinical Professor of Psychiatry, University of California, San Diego, CA, USA.
Antipsychotics effective for schizophrenia approved prior to 2024 shared the common mechanism of postsynaptic dopamine D receptor antagonism or partial agonism. Positive psychosis symptoms correlate with excessive presynaptic dopamine turnover and release, yet this postsynaptic mechanism improved positive symptoms only in some patients, and with concomitant risk for off-target motor and endocrine adverse effects; moreover, these agents showed no benefit for negative symptoms and cognitive dysfunction. The sole exception was data supporting cariprazine's superiority to risperidone for negative symptoms.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!