细胞色素P_(450)2C9基因多态性与药物相互作用

目的:为指导临床合理用药、实现个体化给药提供参考。方法:本文从CYP2C9的基因多态性与代谢表型、代谢底物、代谢酶的诱导和抑制等方面,探讨CYP2C9基因多态性与药物相互作用的关系。结果与结论:CYP2C9作为一种重要的P450系氧化代谢酶,具有基因多态性,参与多种药物的氧化代谢,能被多种药物竞争性抑制,这是造成药物作用个体差异的最重要因素之一,也是发生药物相互作用的原因之一。因此对其研究具有非常重要的临床意义。     

CYP2D6基因多态性及其临床意义

CYP2D6是CYP酶系中重要的一种氧化代谢酶,参与多种药物的代谢.CYP2D6具有基因多态性,使药物代谢在不同种族之间,甚至在同种族不同人群中产生较大的差异,从而影响药物的疗效.因此,深入了解CYP2D6基因的多态性以及对药物代谢的影响,对指导临床合理用药和调整用药方案具有重大意义.     

CYP2D6基因多态性与抗精神病药物的个体化应用

CYP2D6是一种重要的细胞色素P450酶,存在着显著的基因多态性.CYP2D6在抗精神病类药物的代谢中发挥着重要作用,与许多抗精神病药物药动学及药效学的个体间变异存在着密切联系,检测CYP2D6基因型有助于患者抗精神病药物治疗方案的选择和调整,提高用药的安全性和有效性.本文综述CYP2D6基因多态性对抗精神病药物的药动学、不良反应及药物相互作用的影响,探讨了CYP2D6基因型检测在抗精神病个体化治疗中的应用前景.     

CYP2 D6的基因多态性与药物临床应用

CYP2D6是CYP酶系中重要的一种氧化代谢酶,参与多种药物的代谢。 CYP2D6具有基因多态性,这是构成药物代谢个体差异和种族差异的基础,它主要参与心血管类、抗精神病类、镇痛药、以及一些抗癌药物等的代谢。研究 CYP2D6基因多态性与药物代谢个体差异的相关性,有助于减轻药物不良反应,提高治疗效果,实施个体化给药。     

CYP2D6基因多态性及对美托洛尔代谢的影响

CYP2D6是一种重要的P450系氧化代谢酶,主要参与多种重要药物的代谢。CYP2D6基因多态性会引起药物代谢有显著的个体和种族差异。美托洛尔为选择性β1受体阻滞剂,临床应用上存在巨大个体差异,主要在肝脏经多条途径代谢,大约70%的代谢由CYP2D6介导,CPY2D6基因多态性对美托洛尔代谢有较大影响。本文从CYP2D6的基因多态性及它对美托洛尔代谢的影响这两方面作一综述。     

细胞色素P450的基因多态性与药物代谢

细胞色素P450（cytochrome P450，CYP）是重要的药物代谢酶，参与催化多种内源和外源化合物，特别是多种临床药物的生物转化。CYP存在广泛的基因多态性和表型多态性，使其对于各种化合物的代谢存在统计学个体差异。核受体是配体依赖性转录因子超家族，与药物代谢过程中的基因表达调控密切相关，被外源物质活化后诱导或抑制CYP基因的表达。现综述CYP与药物代谢、CYP的基因多态性、CYP表达的诱导机制、核受体及其配体诱导CYP表达及近年研究CYP450的各种实验方法。     

CYP2D6基因多态性及对药物代谢的影响

CYP2D6代谢酶是细胞色素P450家族中的成员之一,是参与Ⅰ相代谢和众多内源性物质和不同药物消除的酶。虽然它在肝脏中的含量大约只占肝脏总量的2%,但在临床上却参与了25%以上的常用药物的代谢活动。在所有参与药物代谢的细胞色素P450基因家族中,CYP2D6是唯一不能被诱导的酶,这种酶具有广泛的多态性,这种多态性对酶的药物代谢功能具有重要影响,CYP2D6的这种多态性和药物代谢功能所表现的对个体活性的差异,在遗传药理学上具有重要意义。本文从CYP2D6基因多态性和它对药物代谢的影响这两方面进行了阐述。     

与细胞色素P_(450)2D6相关的药物相互作用研究

细胞色素P450（CYP）是一组结构和功能相关的超家族基因编码同工酶。人体内参与药物代谢的CYP有17个基因家族，42个亚家族，64个酶。众所周知，在人体内许多因素如遗传因素、年龄、性别、疾病和环境都可以影响CYP的活性。本文着重综述了近年来国内、外文献报道的与CYP2D6相关的药物相互作用。CYP2D6是一种重要的细胞色素药物代谢酶，除参与代谢一些内源性物质和某些环境中毒性化合物外，主要是参与多种药物的代谢。CYP2D6参与代谢的药物占总CYP代谢药物的30％，同时对手性药物的代谢还呈现立体选择性。CYP2D6是临床上重要的肝药酶之一，与之相关的药物相互作用也十分多见。了解CYP2D6的底物以及相关的药物相互作用对临床合理用药具有十分重要的意义。     

CYP2D6基因与药物代谢

细胞色素P 45 0 (CYP)中的CYP2D6酶在抗抑郁药、安定药及某些抗心律失常药的代谢中起重要作用 ,CYP2D6基因位于 2 2号常染色体上为隐性遗传 ,CYP2D6基因呈多态性约有 70余种等位基因变异型 ,也存在特异人群差别 ,因而导致所编码的酶活性不同 ,这些数据有助于理解药物代谢的个体差异、有助于预测药物之间的相互作用。     

细胞色素P4502D6与药物代谢

细胞色素P4502D6（CYP2D6）是一种重要的P450系氧化代谢酶,除参与代谢一些内源性物质和某些环境中毒性化合物外,主要是参怀多种重要药物的代谢,如作用于心血管和中枢神经系统的药物。CYP2D6参与代谢的药物占总P450代谢药物的30％,同时对手性药物的代谢还呈现立体选择性。研究还发现CYP2D6对药物的代谢呈现明显的个体和种族差异,引起这种差异的主要原因是CYP2D6具有的基因多态性,此外还有一些非基因因素,如药物的影响等。目前,CYP2D6的生物学特征已被基本确定,这将十分有助于对CYP2D6的深入研究,从而为临床合理用药提供科学依据。     

Clinical implications of CYP2D6 genetic polymorphism during treatment with antipsychotic drugs

CYP2D6 is described as the most relevant enzyme in the metabolism of many antipsychotic drugs. Its contribution to the interindividual differences in drug response is reviewed here highlighting its role in the kinetics of antipsychotic drugs and the occurrence of drug interactions. The activity of CYP2D6 is inherited as a monogenetic trait and the CYP2D6 gene appears highly polymorphic in humans. The polymorphic alleles may lead to altered activity of the CYP enzymes causing absent, decreased (poor), or increased (ultrarapid) metabolism that in turn influence the disposition of the antipsychotic drugs. Antipsychotic drug biotransformation is mainly determined by genetic factors mediating CYP2D6 gene polymorphism, however the importance of environmental factors (dietary, smoking, diseases, etc.) is also recognized. Additionally, the potential interaction between CYP2D6 and the endogenous metabolism must be taken into consideration. The present review summarizes the relevance of physiological and environmental factors in CYP2D6 hydroxylation capacity, the inhibition of CYP2D6 activity during treatment, the use of drug/metabolite ratio as a tool to evaluate CYP2D6 hydroxylation capacity in a patient, and the relevance of CYP2D6 for drug plasma concentration and for QTc interval lengthening during treatment with antipsychotic drugs.     

Pharmacogenomics of CYP2D6: molecular genetics, interethnic differences and clinical importance

CYP2D6 has received intense attention since the beginning of the pharmacogenetic era in the 1970s. This is because of its involvement in the metabolism of more than 25% of the marketed drugs, the large geographical and inter-ethnic differences in the genetic polymorphism and possible drug-induced toxicity. Many interesting reviews have been published on CYP2D6 and this review aims to reinstate the importance of the genetic polymorphism of CYP2D6 in different populations as well as some clinical implications and important drug interactions.     

Relevance and limits of pharmacogenetics to detect patients at risk of adverse drug reactions

For more than 15 years genetic polymorphism of drug metabolism has been extensively studied. Poor Metabolizer (PM) and Extensive Metabolizer (EM) Slow Acetylators (SA) Rapid Acetylators (RA) phenotype and genotype can be defined for CYP2D6 (Debrisoquine) and N-AT (acetylation). Lists of drugs whose metabolism is CYP2D6 or N-AT dependent have been published. So it is theoretically possible to forecast an adverse drug reaction (ADR) for a specific patient who is given a drug affected by a polymorphism. However, not only PM are at risk of ADRs. When an active or reactive metabolite is produced, EM might be at risk whatever the enzyme involved. Drug interactions must also be taken into account. Competitive inhibition of the metabolism of a drug CYP2D6 dependent provokes not only a blurring effect on phenotyping, leading to a misclassification, but also increases the risk of ADRs. New drug metabolic polymorphism is under scrutiny. Determination of phenotypes and genotypes when possible, development of investigations of drug metabolic capacity at large, in patients exhibiting ADR's, might improve the efficiency of pharmacovigilance to forecast at-risk subjects.     

The unique regulation of brain cytochrome P450 2 (CYP2) family enzymes by drugs and genetics

Cytochrome P450 (CYP) enzymes in the brain may have a role in the activation or inactivation of centrally acting drugs, in the metabolism of endogenous compounds, and in the generation of damaging toxic metabolites and/or oxygen stress. CYPs are distributed unevenly among brain regions, and are found in neurons, glial cells and at the blood-brain interface. They have been observed in mitochondrial membranes, in neuronal processes and in the plasma membrane, as well as in endoplastic reticulum. Brain CYPs are inducible by many common hepatic inducers, however many compounds affect liver and brain CYP expression differently, and some CYPs which are constitutively expressed in liver are inducible in brain. CYP induction is isozyme-, brain region-, cell type- and inducer-specific. While it is unlikely that brain CYPs contribute to overall clearance of xenobiotics, their punctate, region- and cell-specific expression suggests that CNS CYPs may create micro-environments in the brain with differing drug and metabolite levels (not detected or predicted by plasma drug monitoring). Coupled with the sensitivity of CNS CYPs to induction, this may in part account for inter-individual variation in response to centrally acting drugs and neurotoxins, and may have implications for individual variation in receptor adaptation and cross-tolerance to different drugs. In addition, genetic variation in brain CYPs, depending on the type of polymorphism (structural versus regulatory), will alter enzyme activity. These aspects of brain CYP expression regulation and genetic influences are illustrated in this review using mRNA, protein, and enzyme activity data for CYP2D1/6, CYP2E1 and CYP2B1/6 in rat and human brain. The role of CYP-mediated metabolism in the brain, a highly heterogeneous and complex organ, is a new and relatively unexplored field of scientific enquiry. It holds promise for furthering our undestanding of inter-individual variability in response to centrally acting drugs as well as risk for neurological diseases and pathogies.     

Clomipramine, fluoxetine and CYP2D6 metabolic capacity in depressed patients

Cytochrome P450-2D6 may be involved in the metabolism of many drugs such as psychotropic drugs and its genetic polymorphism is responsible for inter-individual differences in the therapeutic effect and toxicity of these drugs. Moreover with the same genetic basis, CYP2D6 metabolic capacity variations are observed. Different factors of variation may be involved, among them the prescribed drugs. The aim of this study was to compare the influence of two types of antidepressants, tricyclic (clomipramine) and serotonergic specific recapture inhibitor (SSRI) (fluoxetine), on the CYP2D6 metabolic capacity of depressed inpatients. The CYP2D6 phenotype (dextromethorphan test) was determined in 56 genotyped (PCR-SSCP) depressed caucasian inpatients with a heterozygous genotype. Forty-five subjects were treated with clomipramine and eleven received fluoxetine. The dextromethorphan metabolic ratio (MR) median was significantly higher in the fluoxetine group (0.255) than in the clomipramine group (0.083, p < 0.014). In this study, fluoxetine involved a greater decrease of CYP2D6 metabolic capacity than clomipramine. Clinical implications and the possible connection between a decreased CYP2D6 activity and adverse drug effects were discussed. Caution should be taken when drugs with a low therapeutic index must be coprescribed in such patients.     

The role of cytochrome P450 pharmacogenomics in chronic non-cancer pain patients

Introduction: Pharmacogenomics is the field that studies an individualized treatment approach for patients’ medication regimen that can impact drug safety, productivity, and personalized health care. Pharmacogenomics characterizes the genetic differences in metabolic pathways which can affect a patient’s individual responses to drug treatments.

Areas covered: The various responses to pharmacological agents are mainly determined by the different types of genetic variants of the CYP450. CYP2D6 polymorphism is well known for its variation in the metabolism of drugs from many therapeutic arenas, including some analgesic drugs such as codeine, hydromorphone, oxycodone and tramadol. Allele combinations determine the phenotypic expression, characterized as either: extensive metabolizer, intermediate metabolizer, ultra-rapid metabolizer and poor metabolizer.

Expert opinion: The Human Genome Project (HGP) revolutionized the future of medicine and the way health care providers approach individualized patient treatment, and chronic pain management is one of those areas. The key findings in the literature appear to be related to the CYP2D6 expression and its high polymorphism influencing the metabolism of opioid medications, and the impact of that on the patient’s therapeutic outcome thus exemplifying the importance of genetic testing for CYP2D6 in the process of physician therapeutic decision making.     

CYP2D6 polymorphism: implications for antipsychotic drug response, schizophrenia and personality traits

The CYP2D6 gene is highly polymorphic, causing absent (poor metabolizers), decreased, normal or increased enzyme activity (extensive and ultrarapid metabolizers). The genetic polymorphism of the CYP2D6 influences plasma concentration of a wide variety of drugs metabolized in the liver by the cytochrome P450 (CYP) 2D6 enzyme, including antipsychotic drugs used for schizophrenia treatment. Additionally, CYP2D6 is involved in the metabolism of endogenous substrates in the brain, and reported to be located in regions such as the cortex, hippocampus and cerebellum, which are impaired in schizophrenia. Moreover, recently we have found that CYP2D6 poor metabolizers are under-represented in a case-control association study of schizophrenia. Furthermore, null CYP2D6 activity in healthy volunteers is associated with personality characteristics of social cognitive anxiety, which may bear some resemblance to milder forms of psychotic-like symptoms. In keeping with this, CYP2D6 may influence, not only variability to drug response, but also vulnerability to disease in schizophrenia patients.     

In vitro evaluation of the interaction potential of irosustat with drug-metabolizing enzymes

Irosustat is a first-generation, irreversible, steroid sulfatase inhibitor currently in development for hormone-dependent cancer therapy. To predict clinical drug-drug interactions between irosustat and possible concomitantly administered medications, the inhibition/induction potential of irosustat with the main drug-metabolizing enzymes was investigated in vitro. The interaction of aromatase inhibitors in the in vitro metabolism of irosustat was also studied. Irosustat inhibited CYP1A2 activity in human liver microsomes through the formation of its desulfamoylated degradation product and metabolite 667-coumarin. CYP1A2 inhibition by 667-coumarin was competitive, with a K(i) of 0.77 μM, a concentration exceeding by only 5-fold the maximal steady-state concentration of 667-coumarin in human plasma with the recommended dose of irosustat. In addition, 667-coumarin metabolites enhanced the inhibition of CYP1A2 activity. Additional clinical interaction studies of irosustat with CYP1A2 substrate drugs are strongly recommended. 667-Coumarin also appeared to be a competitive inhibitor of CYP2C19 (K(i) = 5.8 μM) in human liver microsomes, and this inhibition increased with assessment in human hepatocytes. Inhibition of CYP2C19 enzyme activity was not caused by repression of CYP2C19 gene expression. Therefore, additional mechanistic experiments or follow-up studies with clinical evaluation are recommended. Irosustat neither inhibited CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2D6, CYP2E1, CYP3A4/5, or UDP-glucuronosyltransferase 1A1, 1A4, or 2B7 activities nor induced CYP1A2, CYP2C9, CYP2C19, or CYP3A4/5 at clinically relevant concentrations. Results from human liver microsomes indicated that no changes in irosustat pharmacokinetics in vivo are expected as a result of inhibition of irosustat metabolism in cases of concomitant medication administration or irosustat-aromatase inhibitor combination therapy with letrozole, anastrozole, or exemestane.     

Update: Clinically Significant Cytochrome P-450 Drug Interactions

Recent technologies have resulted in an explosion of information concerning the cytochrome P-450 isoenzymes and increased awareness of life-threatening interactions' with such commonly prescribed drugs as cisapride and some antihistamines. Knowledge of the substrates, inhibitors, and inducers of these enzymes assists in predicting clinically significant drug interactions. In addition to inhibition and induction, microsomal drug metabolism is affected by genetic polymorphisms, age, nutrition, hepatic disease, and endogenous chemicals. Of the more than 30 human isoenzymes identified to date, the major ones responsible for drug metabolism include CYP3A4, CYP2D6, CYP1A2, and the CYP2C subfamily.     

黄酮类化合物对细胞色素P450 CYP1，2E1，3A4和19的影响

黄酮类化合物广泛存在于蔬菜、坚果、水果和饮料及中草药中，可诱导或抑制多种细胞色素P450的活性。本篇综述主要集中回顾黄酮类化合物对于细胞色素P450 CYP1，2E1，3A4和19的影响。归纳总结了该类物质抑制和诱导细胞色素P450的多种机制，如刺激特定的受体、稳定相关mRNA等。并总结了该类物质对细胞色素P450的影响体内和体外水平的研究结果并非总是一致的原因，如体内外的浓度的差异、基因和其他环境因素的影响。由于黄酮类化合物可通过影响细胞色素P450的活性影响药物代谢从而导致药物不良反应和药物相互作用，因此在将该类物质与其他药物合用时应高度重视。