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Related Concept Videos

Pharmacogenetics of Drug Metabolism: Overview01:27

Pharmacogenetics of Drug Metabolism: Overview

Genetic polymorphism in drug metabolism is crucial to the inter-individual variability observed in drug responses. Drug metabolism primarily involves the chemical modification of drugs and other xenobiotics to enhance their elimination by increasing their polarity. Two main classes of enzymes mediate this biotransformation process: Phase I enzymes, primarily cytochrome P450s, catalyze oxidation and reduction reactions, while other enzymes, such as esterases, mediate hydrolysis, and Phase II...
Drug toxicity: Idiosyncratic Reactions01:16

Drug toxicity: Idiosyncratic Reactions

Idiosyncratic drug reactions represent abnormal chemical responses that vary significantly among individuals, ranging from extreme sensitivity to low doses to insensitivity to high doses. These reactions often occur due to the drug's covalent binding with serum proteins, forming a foreign hapten that triggers an immunotoxicological response. The variability in drug reactions has a strong pharmacogenetic foundation, with genetic differences crucial in how individuals metabolize drugs. For...
Factors Affecting Drug Biotransformation: Biological01:19

Factors Affecting Drug Biotransformation: Biological

Biological factors significantly impact drug metabolism, influencing drug clearance, efficacy, and potential toxicity.
Species differences: Variations in enzyme systems across species can cause disparities in drug metabolism. For instance, humans may metabolize certain drugs faster than rodents, altering therapeutic effects.
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Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu01:29

Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu

Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes01:28

Pharmacogenetics of Phase I Enzymes: Cytochrome P450 Isozymes

Cytochrome P450 (CYP450) enzymes are a superfamily of heme-containing monooxygenases that play a pivotal role in Phase I drug metabolism by catalyzing oxidation and reduction reactions.These enzymes transform lipophilic xenobiotics into more hydrophilic metabolites, facilitating subsequent Phase II conjugation and eventual excretion. The CYP450 family is classified into families (e.g., CYP1–CYP3) and subfamilies (e.g., CYP2A, CYP2C), based on amino acid sequence homology.CYP450 isoenzymes,...
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Related Experiment Video

Updated: May 30, 2026

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
10:44

Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures

Published on: March 28, 2017

Inter-ethnic differences in xenobiotic metabolism.

A G Renwick

    Environmental Toxicology and Pharmacology
    |July 26, 2011
    PubMed
    Summary
    This summary is machine-generated.

    Understanding ethnic differences in how the body processes substances is crucial for setting safe intake levels. While some differences exist, they generally fall within safety margins for acceptable daily intake (ADI) and tolerable daily intake (TDI).

    Related Experiment Videos

    Last Updated: May 30, 2026

    Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures
    10:44

    Mass Spectrometry and Luminogenic-based Approaches to Characterize Phase I Metabolic Competency of In Vitro Cell Cultures

    Published on: March 28, 2017

    Area of Science:

    • Toxicology
    • Pharmacokinetics
    • Risk Assessment

    Background:

    • Safety assurance procedures aim to establish acceptable daily intake (ADI) or tolerable daily intake (TDI) levels.
    • Research on inter-ethnic differences in xenobiotic metabolism often focuses on the poor metabolizer phenotype.
    • Ethnic variations in metabolism can increase individual risk but may not impact ADI/TDI if recognized.

    Purpose of the Study:

    • To evaluate the significance of inter-ethnic differences in xenobiotic metabolism and sensitivity for safety assurance.
    • To determine if ethnic variations in kinetic parameters affect the calculation of ADI or TDI.
    • To assess the impact of ethnic differences on population variability in internal dose and AUC.

    Main Methods:

    • Review of existing studies on inter-ethnic differences in xenobiotic metabolism and drug metabolizing enzymes.
    • Analysis of data on ethnic variations in kinetic parameters (e.g., internal dose, AUC).
    • Examination of studies on inter-ethnic differences in sensitivity to therapeutic agents.

    Main Results:

    • Ethnic differences in the incidence of poor metabolizer phenotypes are noted but may not affect safety assessments if accounted for.
    • Population differences in mean values and variability of kinetic parameters are of greater importance than incidence of poor metabolizers.
    • Existing data suggest inter-ethnic differences in sensitivity are limited and fall within the standard uncertainty factor of 10 for human variability.

    Conclusions:

    • Inter-ethnic differences in xenobiotic metabolism and sensitivity are generally not substantial enough to alter safety assurance outcomes (ADI/TDI).
    • Focusing on population-level differences in kinetic parameters is more critical for accurate risk assessment than solely on poor metabolizer phenotypes.
    • The established uncertainty factor adequately accounts for observed inter-ethnic variability in human sensitivity.