CompletedNot Applicable

Clinical and Genetic Influencing Factors on Clozapine Pharmacokinetics

Tunisia51 participantsStarted 2019-10-17

Plain-language summary

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.

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

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.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Determination of trough plasma concentration of clozapine (C0)

Timeframe: One and a half months

Trial details

NCT IDNCT04240496

SponsorUniversity of Monastir

Sponsor typeOTHER

Study typeINTERVENTIONAL

Primary completion2019-12-14

View on ClinicalTrials.gov More CYP1A2 Polymorphism trials