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Published on: March 28, 2017
Effects of CYP2C19 genetic polymorphisms on atomoxetine pharmacokinetics
Chang-Ik Choi1, Jung-Woo Bae, Yun-Jeong Lee
1From the *School of Pharmacy, Sungkyunkwan University, Suwon; †College of Pharmacy, Keimyung University, Daegu; and ‡College of Pharmacy, Dankook University, Cheonan, Republic of Korea.
Genetic variations in CYP2C19 significantly impact atomoxetine pharmacokinetics. Poor metabolizers exhibit altered drug and metabolite levels, affecting treatment efficacy and safety in ADHD patients.
Area of Science:
- Pharmacogenomics
- Drug Metabolism
- Clinical Pharmacology
Background:
- Atomoxetine, a selective norepinephrine reuptake inhibitor, treats attention-deficit/hyperactivity disorder (ADHD).
- Its metabolism involves cytochrome P450 enzymes, specifically CYP2D6 and CYP2C19.
- Genetic variations in these enzymes can influence drug response.
Purpose of the Study:
- To investigate the impact of CYP2C19 genetic polymorphisms on atomoxetine pharmacokinetics.
- To analyze the influence on atomoxetine and its key metabolites: 4-hydroxyatomoxetine and N-desmethylatomoxetine.
Main Methods:
- Forty subjects with varying CYP2C19 genotypes (all carrying CYP2D6*1/*10) received a single 40-mg oral dose of atomoxetine.
- Plasma concentrations of atomoxetine and metabolites were quantified using high-performance liquid chromatography with tandem mass spectrometry.
- Samples were collected for up to 24 hours post-administration.
Main Results:
- CYP2C19 poor metabolizers (PM) showed significantly higher atomoxetine maximum plasma concentration (Cmax) and AUC0-∞, with decreased oral clearance compared to extensive (EM) and intermediate metabolizers (IM).
- Atomoxetine half-life was significantly prolonged in PMs.
- 4-hydroxyatomoxetine levels were elevated in PMs, while N-desmethylatomoxetine levels were reduced.
Conclusions:
- CYP2C19 genetic polymorphisms significantly alter atomoxetine pharmacokinetics.
- These findings highlight the importance of considering CYP2C19 genotype for personalized atomoxetine dosing in ADHD treatment.
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