CYP2D6

CYP2D6 encodes a cytochrome P450 monooxygenase that is predominantly expressed in the liver and catalyzes oxidative biotransformation reactions involved in xenobiotic clearance and endogenous substrate metabolism[1][2]. Mechanistically, CYP2D6 mediates hydroxylation, demethylation, and dealkylation reactions that contribute to the metabolism or activation of approximately 25% of clinically used drugs, including antidepressants, antipsychotics, β-blockers, and opioid prodrugs[1][2][3]. Therefore, CYP2D6 represents a major determinant of pharmacokinetic variability and drug response across patient populations[2][3]. In disease-relevant and translational research settings, CYP2D6 genetic polymorphisms produce extensive interindividual differences in enzyme activity, generating poor, intermediate, normal, and ultrarapid metabolizer phenotypes that directly influence therapeutic efficacy and adverse drug reactions[2][3]. Compared with related cytochrome P450 isoforms, CYP2D6 exhibits marked genotype-dependent functional variability and a relatively selective substrate profile, making it a central model for pharmacogenomic investigations and precision medicine studies[1][2]. For experimental applications, selective substrates and inhibitors are widely used to characterize CYP2D6-dependent metabolism, evaluate drug-drug interactions, and define genotype-phenotype relationships during drug development and clinical pharmacology research[1][2].