Therapeutic drug monitoring of olanzapine and cytochrome P450 genotyping in non-smoking subjects.

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Therapeutic drug monitoring of olanzapine and cytochrome P450 genotyping in non-smoking subjects.

Ther Drug Monit. 2019 Aug 14;:

Authors: Miroshnichenko II, Pozhidaev IV, Ivanova SA, Baymeeva NV

Abstract
BACKGROUND: The relationship between a daily dose of olanzapine, its serum concentration, and the genotype of young non-smoking males treated for schizophrenia or schizophreniform disorder was investigated in day-to-day clinical practice. Pharmacogenetics was also examined for the selected patients.
METHODS: A total of 49 participants were recruited as in-patients at the Mental Health Research Center (Moscow, Russia). Inclusion criteria were patients who had been diagnosed with schizophrenia or schizoaffective disorder (following DSM-IV guidelines) and were being treated with OLZ. A prospective, observational, open-study design was implemented. In line with the literature, patients were only included if they attained steady-state OLZ concentrations lasting for at least 8 days. An LC-MS/MS method was developed for analyzing OLZ in human serum. The single cytochrome P450 polymorphisms were genotyped using an amplifier Real-Time PCR System following standard protocols.
RESULTS: Evidence indicating that CYP2D6 polymorphism has a significant (p=0.046) effect on the pharmacokinetics of olanzapine was obtained, confirming the beneficial effects of therapeutic drug monitoring for olanzapine.
CONCLUSION: TDM should therefore be used as a standard care during olanzapine therapy. TDM is also useful in assessing adherence and may have a role in limiting olanzapine dosage geared at minimizing the risk of long-term toxicity.

PMID: 31425442 [PubMed - as supplied by publisher]