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NCT Number: NCT04240496

Clinical and Genetic Influencing Factors on Clozapine Pharmacokinetics

Clozapine (Clz), an atypical antipsychotic, is the reference medication for patients with treatment-resistant schizophrenia. Due to the high inter-individual variability of its pharmacokinetics and its narrow therapeutic index, a close therapeutic drug monitoring (TDM) of Clz is highly recommended.

Several factors can cause a variation in the pharmacokinetics as age, smoking habits, coffee consumption and drug interaction. Genetic factors related to hepatic expression levels of the cytochrome P450 (CYP), regulate the hepatic clearance of Clz, thereby determine its bioavailability.

The CYP1A2 and CYP2C19 isoenzymes are mainly responsible for the metabolism of several drugs including Clz. It has been demonstrated that there is an interethnic variation in the expression and function of these two isoenzymes. This variation is caused by single nucleotide polymorphisms (SNPs) of genes encoding these proteins.

While the Influence of the different polymorphisms related to CYP1A2 and CYP2C19 have been established especially in Asian and Caucasian populations, no study has examined the impact of these SNPs in the southern Mediterranean populations. Moreover, the impact of these SNPs is very controversial. The present study aims to investigate in Tunisian schizophrenic patients, the influence of genetic (CYP1A2 and CYP2C19 polymorphisms) and non-genetic factors on Clz pharmacokinetics.

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Key information

Conditions

CYP1A2 Polymorphism CYP2C19 Polymorphism Clozapine Mental Disorders Schizophrenia Schizophrenia Spectrum and Other Psychotic Disorders

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of Medecine of Monastir

Monastir, 5000, Tunisia

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Schizophrenic patients receiving clozapine
  • Good adherence to the treatment (clozapine)

Exclusion criteria

  • Patients who were co-prescribed drugs that affected the pharmacokinetics of Clozapine.
  • Patients who presented gastrointestinal disorders disturbing absorption of clozapine.

Treatment and study plan

Determination of plasma concentration of clozapine/ Genotyping

Other

Determination of trough plasma concentration of clozapine (C0) Genotyping of CYP1A2 & CYP2C19

Primary outcomes

  1. Determination of trough plasma concentration of clozapine (C0)

    Time frame: One and a half months

    Technique : HPLC/UV (high-performance liquid chromatography associated with a UV detector)

Secondary outcomes

  1. Determination of the correlation between the presence of CYP1A2*1F (rs762551;-163C> A), CYP1A2*1C (rs2069514;-3860 G> A) and CYP 2C19*2 (rs4244285; 681G>A) and the variability of C0/Daily dose.

    Time frame: One and a half months

    • Technique: PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism)

Sponsors and collaborators

Lead sponsor

University of Monastir

Other

Registry information

Official study title

Clinical and Genetic Influencing Factors on Clozapine Pharmacokinetics in Schizophrenic Patients

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
Jan 27, 2020
Registry last updated
Jan 27, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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