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Drug Metabolism and Pharmacokinetics 2011It is now widely appreciated that drug metabolites, in addition to the parent drugs themselves, can mediate the serious adverse effects exhibited by some new therapeutic... (Review)
Review
It is now widely appreciated that drug metabolites, in addition to the parent drugs themselves, can mediate the serious adverse effects exhibited by some new therapeutic agents, and as a result, there has been heightened interest in the field of drug metabolism from researchers in academia, the pharmaceutical industry, and regulatory agencies. Much progress has been made in recent years in understanding mechanisms of toxicities caused by drug metabolites, and in understanding the numerous factors that influence individual exposure to products of drug biotransformation. This review addresses some of these factors, including the role of drug-drug interactions, reactive metabolite formation, individual susceptibility, and species differences in drug disposition caused by genetic polymorphisms in drug-metabolizing enzymes. Examples are provided of adverse reactions that are linked to drug metabolism, and the mechanisms underlying variability in toxic response are discussed. Finally, some future directions for research in this field are highlighted in the context of the discovery and development of new therapeutic agents.
Topics: Acetaminophen; Animals; Biotransformation; Chemical and Drug Induced Liver Injury; Cytochrome P-450 Enzyme System; Drug Evaluation, Preclinical; Drug Interactions; Drug-Related Side Effects and Adverse Reactions; Humans; Inactivation, Metabolic; Liver; Oxidative Stress; Pharmaceutical Preparations; Safety-Based Drug Withdrawals; Species Specificity
PubMed: 20978360
DOI: 10.2133/dmpk.dmpk-10-rv-089 -
Drug Metabolism and Disposition: the... Dec 2023Drug-metabolizing enzymes and transporters (DMETs) are key regulators of the pharmacokinetics, efficacy, and toxicity of therapeutics. Over the past two decades,...
Drug-metabolizing enzymes and transporters (DMETs) are key regulators of the pharmacokinetics, efficacy, and toxicity of therapeutics. Over the past two decades, significant advancements in in vitro methodologies, targeted proteomics, in vitro to in vivo extrapolation methods, and integrated computational approaches such as physiologically based pharmacokinetic modeling have unequivocally contributed to improving our ability to quantitatively predict the role of DMETs in absorption, distribution, metabolism, and excretion and drug-drug interactions. However, the paucity of data regarding alterations in DMET activity in specific populations such as pregnant individuals, lactation, pediatrics, geriatrics, organ impairment, and disease states such as, cancer, kidney, and liver diseases and inflammation has restricted our ability to realize the full potential of these recent advancements. We envision that a series of carefully curated articles in a special supplementary issue of will summarize the latest progress in in silico, in vitro, and in vivo approaches to characterize alteration in DMET activity and quantitatively predict drug disposition in specific populations. In addition, the supplementary issue will underscore the current scientific knowledge gaps that present formidable barriers to fully understand the clinical implications of altered DMET activity in specific populations and highlight opportunities for multistakeholder collaboration to advance our collective understanding of this rapidly emerging area. SIGNIFICANCE STATEMENT: This commentary highlights current knowledge and identifies gaps and key challenges in understanding the role of drug-metabolizing enzymes and transporters (DMETs) in drug disposition in specific populations. With this commentary for the special issue in , the authors intend to increase interest and invite potential contributors whose research is focused or has aided in expanding the understanding around the role and impact of DMETs in drug disposition in specific populations.
Topics: Pregnancy; Female; Humans; Child; Membrane Transport Proteins; Liver Diseases; Drug Interactions; Inflammation; Metabolic Clearance Rate
PubMed: 37775331
DOI: 10.1124/dmd.123.001453 -
Drug Metabolism and Personalized Therapy Jun 2015Drug-metabolizing enzymes play a major role in the biotransformation and subsequent elimination of most drugs and xenobiotics from the body. Both phase I and phase II... (Review)
Review
Drug-metabolizing enzymes play a major role in the biotransformation and subsequent elimination of most drugs and xenobiotics from the body. Both phase I and phase II enzymes are highly polymorphic. Inter-individual differences in genes coding for drug-metabolizing enzymes are important for understanding variability in drug response and for individualization of drug prescription. The prevalence of genetic polymorphisms in drug metabolism varies widely with ethnicity, and marked differences in the distribution of allelic variants of genes encoding drug-metabolizing enzymes have been documented in populations of different racial origin. This review aimed to summarize the available studies on genetic polymorphisms associated with drug metabolism conducted in Italian populations and to compare the frequency of the various metabolizer phenotypes and most common variant alleles (and resulting genotypes) with corresponding values from other populations. Notably, published data are not extensive, and most studies were performed on relatively low numbers of individuals. In general, the frequency of polymorphisms in the cytochrome P450 (CYP) genes as well as in the investigated phase II enzymes in the Italian population was similar to values reported for other Caucasian populations. However, the prevalence of CYP2D6 gene duplication among Italians was found to be very high, confirming the higher frequency of CYP2D6 ultrarapid metabolizers in the Mediterranean area compared to Northern Europe. It is worth noting that a geographic gradient in the flavin-containing monooxygenase 3 polymorphism distribution was also seen, the Italian population showing higher similarity to other Mediterranean populations than to North Europeans.
Topics: Adult; Aged; Catechol O-Methyltransferase; Cytochrome P-450 Enzyme System; Genotype; Glucuronosyltransferase; Glutathione Transferase; Humans; Italy; Methyltransferases; Middle Aged; N-Terminal Acetyltransferases; Pharmaceutical Preparations; Polymorphism, Genetic; Sulfotransferases
PubMed: 25527811
DOI: 10.1515/dmdi-2014-0028 -
Biomolecules Aug 2021Pregnane X Receptor (PXR) belongs to the nuclear receptors' superfamily and mainly functions as a xenobiotic sensor activated by a variety of ligands. PXR is widely... (Review)
Review
Pregnane X Receptor (PXR) belongs to the nuclear receptors' superfamily and mainly functions as a xenobiotic sensor activated by a variety of ligands. PXR is widely expressed in normal and malignant tissues. Drug metabolizing enzymes and transporters are also under PXR's regulation. Antineoplastic agents are of particular interest since cancer patients are characterized by significant intra-variability to treatment response and severe toxicities. Various PXR polymorphisms may alter the function of the protein and are linked with significant effects on the pharmacokinetics of chemotherapeutic agents and clinical outcome variability. The purpose of this review is to summarize the roles of PXR polymorphisms in the metabolism and pharmacokinetics of chemotherapeutic drugs. It is also expected that this review will highlight the importance of PXR polymorphisms in selection of chemotherapy, prediction of adverse effects and personalized medicine.
Topics: Acetylation; Antineoplastic Agents; Biotransformation; Gene Expression; Humans; Inactivation, Metabolic; Neoplasms; Phosphorylation; Polymorphism, Single Nucleotide; Precision Medicine; Pregnane X Receptor; Protein Domains; Protein Processing, Post-Translational; Sumoylation; Treatment Outcome; Ubiquitination
PubMed: 34439808
DOI: 10.3390/biom11081142 -
Expert Opinion on Drug Metabolism &... Jul 2012The xenobiotic detoxification system, which protects the human body from external chemicals, comprises drug-metabolizing enzymes and transporters whose expressions are... (Review)
Review
INTRODUCTION
The xenobiotic detoxification system, which protects the human body from external chemicals, comprises drug-metabolizing enzymes and transporters whose expressions are regulated by pregnane X receptor (PXR) and the constitutive androstane receptor (CAR). The progress made in a large number of recent studies calls for a timely review to summarize and highlight these key discoveries.
AREAS COVERED
This review summarizes recent advances in elucidating the roles of PXR and CAR in the xenobiotic detoxification system. It also highlights the progress in understanding the regulation of PXR and CAR activity at the post-translational levels, as well as the structural basis for the regulation of these two xenobiotic sensors.
EXPERT OPINION
Future efforts are needed to discover novel agonists and antagonists with species and isoform selectivity, to systematically understand the regulation of PXR and CAR at multiple levels (transcriptional, post-transcriptional and post-translational levels) in response to xenobiotics exposure, and to solve the structures of the full-length receptors, which will be enabled by improved protein expression and purification techniques and approaches. In addition, more efforts will be needed to validate PXR and CAR as disease-related therapeutic targets and thus expand their roles as master xenobiotic sensors.
Topics: Animals; Constitutive Androstane Receptor; Drug Interactions; Gene Expression Regulation; Humans; Inactivation, Metabolic; Ligands; Models, Animal; Pregnane X Receptor; Protein Binding; Protein Processing, Post-Translational; Receptors, Cytoplasmic and Nuclear; Receptors, Steroid; Signal Transduction; Xenobiotics
PubMed: 22554043
DOI: 10.1517/17425255.2012.685237