厄贝沙坦和吡格列酮在大鼠体内的药动学相互作用

目的:建立同时测定大鼠血浆中厄贝沙坦、吡格列酮的HPLC法,探讨厄贝沙坦与吡格列酮联用时有无显著的药动学相互作用。方法:大鼠分为A、B、C3组,A组按30mg.kg-1服用厄贝沙坦,B组按4.5mg.kg-1服用吡格列酮,C组为联合给药组,按30mg.kg-1服用厄贝沙坦,按4.5mg.kg-1服用吡格列酮,采用HPLC法同时测定不同时间点厄贝沙坦和吡格列酮的血药浓度,计算药动学参数。结果:与2种药物分别使用的情况相比,厄贝沙坦组在联用时的ρmax、AUC存在有显著性差异。结论:厄贝沙坦与吡格列酮在联用时,存在显著的药动学相互作用。     

黄芪注射液对格列喹酮在糖尿病大鼠体内药动学的影响

目的:研究黄芪注射液对格列喹酮在糖尿病大鼠体内的药动学的影响。方法:将10只糖尿病大鼠随机分为2组,A组作为对照组单独灌胃给予120 mg.kg-1的格列喹酮混悬水溶液;B组作为实验组给予黄芪注射液(8 mL.kg-1)5 min后,灌胃给予格列喹酮混悬水溶液(120 mg.kg-1)。于给药后不同时间点采集血样,采用HPLC-荧光检测器测定格列喹酮的血药浓度,绘制药时曲线,用DAS 2.0计算药动参数,并对主要药动学参数进行统计学分析。结果:格列喹酮单用或与黄芪注射液合用后,其在糖尿病大鼠体内的药动学过程均符合二室模型,但合用后格列喹酮Cl/F较单用时显著性减小(P<0.01),Cmax、t1/2β和AUC较单用时显著性增大(P<0.01)。结论:黄芪注射液可降低格列喹酮经肝药酶CYP2C9的代谢,从而提高了格列喹酮的生物利用度,提示糖尿病患者在两药合用时应降低格列喹酮的用药剂量。     

他汀类药物的药动学及与其他药物的相互作用

综述了他汀类药物的药动学性质及与其他药物的药动学相互作用。他汀类药物的单一疗法耐受性良好,不良反应发生率低,但与其他药物联用时,可能发生药动学相互作用,从而降低药物疗效或增强药物毒副作用。     

瑞格列奈片与其他药物的相互作用及不良反应研究

瑞格列奈片属格列奈类药物之一,是一种新型促胰岛素分泌剂．作用在胰岛β细胞膜上ATP敏感的钾离子通道起效快、半衰期短．不良反应发生率低于磺脲类药物．可单独或与二甲双胍,基础胰岛素等联合使用。但与其它药物联用时．可能发生与酶及转运体相关的药动学相互作用。瑞格列奈可致低血糖．视觉异常。胃肠道反应。肝酶异常及过敏反应等不良反应,本文就瑞格列奈与其他药物的相互作用及不良反应作一概述。     

氨氯地平与其他药物的相互作用研究进展

氨氯地平属于第三代钙离子拮抗剂（CCB）,主要用于心脑血管疾病的治疗。近期的研究发现,氨氯地平与多种药物存在相互作用,这些相互作用主要体现在药动学和药效学两个方面。药动学相互作用主要与肝药酶CYP450以及转运体P-gP（P-糖蛋白）有关。氨氯地平是CYP450和P-gp的底物,影响肝药酶或P-gp活性的药物,如抗病毒药物利托那韦、抗真菌药物伊曲康唑以及大环内酯内抗生素他克莫司等均可改变氨氯地平的药动学特征。药效学相互作用主要表现办疗效的改变,他汀类药物、血管紧张素转化酶抑制剂（ACEI）药物以及血管紧张素Ⅱ受体拮抗剂（ARB）等与氨氯地平具有协同作用,而氯吡格雷等其他药物与氨氯地平合用时,氨氯地平的疗效降低甚至失效。本文就近年来关于氨氯地平的相互作用研究做一综述。     

非磺酰脲类促泌药(格列奈类药物)对2型糖尿病的治疗作用

2型糖尿病患者胰岛素早相分泌缺失,是疾病发生、发展的重要原因之一,尤其与大血管并发症密切相关,非磺酰脲类促泌药(格列奈类药物)能够恢复胰岛素早相分泌,模拟胰岛素分泌的生理模式,临床疗效好,安全性高。本文从格列奈类药物的药理特性、药代动力学特点等方面作进一步的论述,评价格列奈类药物在2型糖尿病中的治疗地位。     

细胞色素P4502C9基因多态性对健康人体内格列喹酮药代动力学的影响

目的研究细胞色素CYP2C9基因多态性对中国人体内格列喹酮药物代谢动力学的影响。方法用RELP-PCR方法对38名健康受试者进行CYP2C9基因多态性检测,并按不同CYP2C9基因型进行分组,用高效液相色谱-荧光检测法测定受试者体内格列喹酮的血药浓度并计算相应的药代动力学参数,比较不同基因型受试者间药代动力学参数的差异。结果在38名健康受试者中,发现3名CYP2C9*1/*3杂合突变型个体与35名CYP2C9*1/*1野生型个体;未发现CYP2C9*3/*3纯合突变型个体。随机抽取的17名野生型个体与3名杂合突变型个体在给予格列喹酮60 mg后,发现杂合突变型个体AUC0-t、AUC0-∞、CL/F分别相当于野生型个体的1.854,1.787,0.554倍。结论 CYP2C9基因多态性对格列喹酮的药代动力学有显著影响,CYP2C9*1/*3突变型个体临床应适当调整给药剂量。     

复方盐酸二甲双胍格列吡嗪片在健康人体的药动学

目的:研究复方盐酸二甲双胍格列吡嗪片在健康中国人体内的药动学特征。方法:12位受试者(男女各半)在不同试验周期分别口服不同盐酸二甲双胍、格列吡嗪制剂。用HPLC-UV方法测定血浆中盐酸二甲双胍及格列吡嗪浓度。结果:试验所得各药动学参数与文献报道基本一致。经过统计学分析,复方盐酸二甲双胍格列吡嗪片中二成分与单独服用盐酸二甲双胍片及格列吡嗪片相比主要药动学参数差异无显著性,多剂量服药与单次服药相比主要药动学参数差异无显著性。结论:复方盐酸二甲双胍格列吡嗪片中两组分之间在体内不存在相互作用,多剂量服药与单次服药相比其体内药物动力学过程不发生改变。     

吡格列酮和罗格列酮的人体药动学差异评价

目的:研究噻唑烷二酮类代表药物吡格列酮、罗格列酮的人体药动学个体化特征,评价给药方案个体化对策。方法:37例健康志愿者先后参加了吡格列酮和罗格列酮口服制剂的2项人体生物利用度试验,记录血药浓度数据并进行药动学研究,考察人体药动学参数的变异性,并通过多元逐步回归分析研究采血时间点血药浓度与药品暴露的相关性。结果:吡格列酮及罗格列酮的人体药动学存在明显的个体差异,吡格列酮平均AUC、t1/2的RSD分别为48.66%～54.04%、61.31%～72.54%,罗格列酮分别为35.37%～48.72%、24.98%～30.10%。多元逐步回归分析显示,4～8h血药浓度与AUC呈良好相关性(r>0.9,P<0.01)。结论:该类药物的人体药动学存在明显个体差异,临床实施个体化给药有助于提高疗效。     

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.     

Drug-drug and food-drug pharmacokinetic interactions with new insulinotropic agents repaglinide and nateglinide

This review describes the current knowledge on drug-drug and food-drug interactions with repaglinide and nateglinide. These two meglitinide derivatives, commonly called glinides, have been developed for improving insulin secretion of patients with type 2 diabetes mellitus. They are increasingly used either in monotherapy or in combination with other oral antihyperglycaemic agents for the treatment of type 2 diabetes. Compared with sulfonylureas, glinides have been shown to (i) provide a better control of postprandial hyperglycaemia, (ii) overcome some adverse effects, such as hypoglycaemia, and (iii) have a more favourable safety profile, especially in patients with renal failure.The meal-related timing of administration of glinides and the potential influence of food and meal composition on their bioavailability may be important. In addition, some food components (e.g. grapefruit juice) may cause pharmacokinetic interactions. Because glinides are metabolised via cytochrome P450 (CYP) 3A4 isoenzyme, they are indeed exposed to pharmacokinetic interactions. In addition to CYP3A4, repaglinide is metabolised via CYP2C8, while nateglinide metabolism also involves CYP2C9. Furthermore, both compounds and their metabolites may undergo specialised transport/uptake in the intestine, another source of pharmacokinetic interactions. Clinically relevant drug-drug interactions are those that occur when glinides are administered together with other glucose-lowering agents or compounds widely coadministered to diabetic patients (e.g. lipid-lowering agents), with drugs that are known to induce (risk of lower glinide plasma levels and thus of deterioration of glucose control) or inhibit (risk of higher glinide plasma levels leading to hypoglycaemia) CYP isoenzymes concerned in their metabolism, or with drugs that have a narrow efficacy : toxicity ratio.Pharmacokinetic interactions reported in the literature appear to be more frequent and more important with repaglinide than with nateglinide. Rifampicin (rifampin) reduced repaglinide area under the plasma concentration-time curve (AUC) by 32-85% while it reduced nateglinide AUC by almost 25%. Reported increases in AUCs with coadministration of drugs inhibiting CYP isoenzymes never exceeded 80% for repaglinide (except with ciclosporin and with gemfibrozil) and 50% for nateglinide. Ciclosporin more than doubled repaglinide AUC (+144%), a finding that should raise caution when using these two drugs in combination. The most impressive pharmacokinetic interaction was reported with combined administration of gemfibrozil (a strong CYP2C8 inhibitor) and repaglinide (8-fold increase in repaglinide AUC). Although no studies have been performed in patients with type 2 diabetes, the latter combination should be avoided in clinical practice.     

CYP-mediated clozapine interactions: how predictable are they?

Despite the introduction of newer drugs, the atypical antipsychotic clozapine remains the most effective drug in psychotic patients who are resistant to treatment with conventional agents. Optimal therapeutic responses to clozapine have been reported with serum concentrations between 350 microg/L and 1000 microg/L. Clozapine is frequently combined with other drugs to enhance efficacy and reduce adverse reactions but pharmacokinetic interactions can have a significant impact on drug response. The majority of the interactions with clozapine are reported to be mediated by cytochrome P450 (CYP) enzymes. CYP1A2 has a major role in the oxidative metabolism of clozapine, with a minor contribution from CYP3A4, and possibly CYP2D6, CYP2C9 and CYP2C19. Interactions mediated by potent CYP1A2 inhibitors (such as fluvoxamine) or inducers (like cigarette smoke) appear to be consistent, predictable and usually clinically significant. There are many case reports of interactions between clozapine and weak CYP1A2 inhibitors or inducers which are also potent inhibitors or inducers of CYP3A4 or CYP2D6. Researchers often explain these observations on the basis of the CYP1A2 involvement. In addition, there are case reports of clinically significant interactions between clozapine and drugs that are not substrates, inhibitors or inducers of CYP1A2. These interactions are difficult to predict and may not be consistent, as reflected by the conflicting literature reports. Further research to elucidate individual differences in clozapine metabolism, with the potential to detect the dominant roles of CYPs other than CYP1A2, may assist us in predicting these interactions.     

Clinically significant drug interactions with antidepressants in the elderly

Pharmacological treatment of depression in old age is associated with an increased risk of adverse pharmacokinetic and pharmacodynamic drug interactions. Elderly patients may have multiple disease states and, therefore, may require a variety of other drugs. In addition to polypharmacy, other factors such as age-related physiological changes, diseases, genetic constitution and diet may alter drug response and, therefore, predispose elderly patients to adverse effects and drug interactions. Antidepressant drugs currently available differ in their potential for drug interactions. In general, older compounds, such as tricyclic antidepressants (TCAs) and monoamine oxidase inhibitors (MAOIs), have a higher potential for interactions than newer compounds, such as selective serotonin reuptake inhibitors (SSRIs) and other relatively novel agents with a more specific mechanism of action. In particular, TCAs and MAOIs are associated with clinically significant pharmacodynamic interactions with many medications frequently prescribed to elderly patients. Moreover, TCAs may be susceptible to pharmacokinetic interactions when given in combination with inhibitors or inducers of the cytochrome P450 (CYP) isoenzymes involved in their metabolism. Because of a more selective mechanism of action, newer antidepressants have a low potential for pharmacodynamic drug interactions. However, the possibility of the serotonin syndrome should be taken into account when drugs affecting serotonergic transmission, such as SSRIs, venlafaxine or nefazodone, are coadministered with other serotonergic agents. Newer agents have a differential potential for pharmacokinetic interactions because of their selective effects on CYP isoenzymes. Within the group of SSRIs, fluoxetine and paroxetine are potent inhibitors of CYP2D6, while fluvoxamine predominantly affects CYP1A2 and CYP2C19 activity. Therefore, these agents should be closely monitored or avoided in elderly patients treated with substrates of these isoforms, especially those with a narrow therapeutic index. On the other hand, citalopram and sertraline have a low inhibitory activity on different drug metabolising enzymes and appear particularly suitable in an elderly population. Among other newer antidepressants, nefazodone is a potent inhibitor of CYP3A4 and its combination with substrates of this isoform should be avoided.     

Inhibition of CYP2C9 by natural products: insight into the potential risk of herb-drug interactions

Abstract

Due to the rapidly increasing global interest in the use of herbs, phytomedicines and other natural products as medical or complementary remedies, concerns about the clinical medication safety have drawn much attention worldwide. Particularly, many natural ingredients exhibit inhibitory effects on cytochrome P450 (CYP) enzymes, which are the most important Phase I metabolism enzymes in liver. CYP2C9 is one of the most abundant CYP enzymes and responsible for the metabolism of over 15% clinical drugs, including oral sulfonylurea hypoglycemics, nonsteroidal anti-inflammatory agents, selective cyclooxygenase-2 inhibitors, antiepileptics, angiotensin II receptor inhibitors and anticoagulants. Diclofenac (4’-hydroxylase) and tolbutamide (methylhydroxylation) are widely used as probe substrates for CYP2C9. To date, numerous natural products have been reported to have the capabilities of inhibiting the catalytic activity of CYP2C9 and further influencing the pharmacokinetic and pharmacodynamic behaviors of drugs that are mainly metabolized by CYP2C9, leading to potential herb-drug interactions. Moreover, some fatal adverse interactions may occur for drugs with a narrow therapeutic window when they are coadministered with a CYP2C9 inhibitor, especially irreversible inactivators. For the purpose of better understanding the interactions of natural products with CYP2C9, we comprehensively reviewed the characteristics of CYP2C9, the natural ingredients that inhibit CYP2C9, the related research approaches and strategies, the types of inhibition and the underlying mechanisms.     

Effect of genetic polymorphisms in cytochrome p450 (CYP) 2C9 and CYP2C8 on the pharmacokinetics of oral antidiabetic drugs: clinical relevance

Type 2 diabetes mellitus affects up to 8% of the adult population in Western countries. Treatment of this disease with oral antidiabetic drugs is characterised by considerable interindividual variability in pharmacokinetics, clinical efficacy and adverse effects. Genetic factors are known to contribute to individual differences in bioavailability, drug transport, metabolism and drug action. Only scarce data exist on the clinical implications of this genetic variability on adverse drug effects or clinical outcomes in patients taking oral antidiabetics. The polymorphic enzyme cytochrome P450 (CYP) 2C9 is the main enzyme catalysing the biotransformation of sulphonylureas. Total oral clearance of all studied sulphonylureas (tolbutamide, glibenclamide [glyburide], glimepiride, glipizide) was only about 20% in persons with the CYP2C9*3/*3 genotype compared with carriers of the wild-type genotype CYP2C9*1/*1, and clearance in the heterozygous carriers was between 50% and 80% of that of the wild-type genotypes. For reasons not completely known, the resulting differences in drug effects were much less pronounced. Nevertheless, CYP2C9 genotype-based dose adjustments may reduce the incidence of adverse effects. The magnitude of how doses might be adjusted can be derived from pharmacokinetic studies. The meglitinide-class drug nateglinide is metabolised by CYP2C9. According to the pharmacokinetic data, moderate dose adjustments based on CYP2C9 genotypes may help in reducing interindividual variability in the antihyperglycaemic effects of nateglinide. Repaglinide is metabolised by CYP2C8 and, according to clinical studies, CYP2C8*3 carriers had higher clearance than carriers of the wild-type genotypes; however, this was not consistent with in vitro data and therefore further studies are needed. CYP2C8*3 is closely linked with CYP2C9*2. CYP2C8 and CYP3A4 are the main enzymes catalysing biotransformation of the thiazolidinediones troglitazone and pioglitazone, whereas rosiglitazone is metabolised by CYP2C9 and CYP2C8. The biguanide metformin is not significantly metabolised but polymorphisms in the organic cation transporter (OCT) 1 and OCT2 may determine its pharmacokinetic variability. In conclusion, pharmacogenetic variability plays an important role in the pharmacokinetics of oral antidiabetic drugs; however, to date, the impact of this variability on clinical outcomes in patients is mostly unknown and prospective studies on the medical benefit of CYP genotyping are required.     

药物相互作用的临床意义

阿片类物质已经被证实在临床上能与多种药物发生相互作用,多数是药代动力学上的相互作用,也有部分药物是在药效学方面发生的相互作用。药代动力学上的相互作用包括对肝药酶P450的抑制或诱导。药效学上的相互作用包括对中枢神经系统附加的抑制作用。抑制肝药酶活性的药物能引起血浆中药物浓度的增高,易导致过量或中毒。诱导肝药酶活性的药物能加速药物的代谢,降低血浆中药物浓度和药物有效性;对阿片物质来说,可能导致戒断症状。药效学的相互作用发生在同时使用抑制呼吸的药物（如苯二氮卓艹类药物）和丁丙诺啡或美沙酮的情况下,两者共同滥用可导致死亡。本文还讨论了HIV和阿片治疗之间相互作用的例子,这种相互作用可导致依从性降低以及较差的临床结局。苯二氮卓艹类药物与可加强心血管效应的药物之间的相互作用也需要被考虑到。     

Drug-drug interaction of antifungal drugs

This article reviews the in vitro metabolic and the in vivo pharmacokinetic drug-drug interactions with antifungal drugs, including fluconazole, itraconazole, micafungin, miconazole, and voriconazole. In the in vitro interaction studies, the effects of antifungal drugs on specific activities of cytochrome P450s (CYPs), including CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4, in human liver microsomes are compared to predict the possibility of drug interactions in vivo. Fluconazole, micafungin, and voriconazole have lower inhibitory effects on CYP3A4 activities than itraconazole and miconazole, and IC(50) and/or K(i) values against CYP2C9 and CYP2C19 activities are the lowest for miconazole, followed by voriconazole and fluconazole. In in vivo pharmacokinetic studies, it is well known that itraconazole is a potent clinically important inhibitor of the clearance of CYP3A4 substrates, and fluconazole and voriconazole are reported to increase the blood or plasma concentrations of not only midazolam and cyclosporine (CYP3A4 substrates) but also of phenytoin (CYP2C9 substrate) and/or omeprazole (CYP2C19/CYP3A4 substrate). On the other hand, no inhibition of CYP activities except for CYP3A4 activity by micafungin is observed in vitro, and the blood concentrations of cyclosporine and tacrolimus are not affected by coadministration of micafungin in vivo, suggesting that micafungin would not cause clinically significant interactions with drugs that are metabolized by CYPs via the inhibition of metabolism. Miconazole is a potent inhibitor of all CYPs investigated in vitro, although there are few detailed studies on the clinical significance of this except for CYP2C9. Therefore the differential effects of these antifungal drugs on CYP activities must be considered in the choice of antifungal drugs in patients receiving other drugs.     

Pharmacokinetic factors in the adverse cardiovascular effects of antipsychotic drugs

Antipsychotics may cause serious adverse cardiovascular effects, including prolonged QT interval and sudden death. This review considers antipsychotic-induced cardiovascular events from three perspectives: high-risk drugs, high-risk individuals and high-risk drug interactions. Pharmacokinetic drug interactions involving the cytochrome P450 (CYP) enzymatic pathway and pharmacodynamic interactions leading to direct cardiotoxic effects are discussed. Original reports on antipsychotic-induced drug interactions are reviewed, with consideration of management guidelines.The literature was reviewed from 1 January 1966 to 1 February 2002. The literature search revealed only 12 original articles published on antipsychotic drug interactions leading to cardiovascular adverse events. Only 4 of the 12 reports were prospective studies; the remainder were either retrospective or anecdotal.Although poor study designs preclude a definitive statement, it appears that pharmacokinetic interactions primarily involved the CYP2D6 and CYP3A4 enzymatic pathways. Those involving the CYP2D6 isozyme included interactions with tricyclic antidepressants, selective serotonergic reuptake inhibitors and beta-blockers. Among these drug interactions, tricyclic antidepressants were most likely to reach clinical significance because of their limited therapeutic index. Drug interactions related to the CYP3A4 pathway were generally less severe, and involved high-potency antipsychotics coadministered with inhibitors such as clarithromycin.Strategies are discussed for the management of adverse cardiovascular events related to antipsychotic drug interactions, including the use of an algorithm. Large, randomised, placebo-controlled studies with strict inclusion criteria are needed to determine the role that antipsychotics play in QT prolongation and sudden death.     

CYP450与药物相互作用

目的 探讨细胞色素P450（CYP450）与药物相互作用的关系.方法 检索国内外数据库中与药物相互作用的相关文献,并查阅相关书籍,总结CYP450酶与药物相互作用的关系.结果 CYP450与药物相互作用关系最密切的是酶系统,凡参与代谢的酶都与药物相互作用有关,其中最主要的是CYP1 A2,2C9,2C19,2D6,3A4.结论 充分了解药物的药理及药代动力学特点,当与可能发生相互作用的药物合用时,应密切监测患者的情况,必要时进行药物剂量调整或换用其他药物.     

Drug interactions with smoking.

PURPOSE: The mechanisms for drug interactions with smoking and clinically significant pharmacokinetic and pharmacodynamic drug interactions with smoking are reviewed. SUMMARY: Polycyclic aromatic hydrocarbons (PAHs) are some of the major lung carcinogens found in tobacco smoke. PAHs are potent inducers of the hepatic cytochrome P-450 (CYP) isoenzymes 1A1, 1A2, and, possibly, 2E1. After a person quits smoking, an important consideration is how quickly the induction of CYP1A2 dissipates. The primary pharmacokinetic interactions with smoking occur with drugs that are CYP1A2 substrates, such as caffeine, clozapine, fluvoxamine, olanzapine, tacrine, and theophylline. Inhaled insulin's pharmacokinetic profile is significantly affected, peaking faster and reaching higher concentrations in smokers compared with nonsmokers, achieving significantly faster onset and higher insulin levels. The primary pharmacodynamic drug interactions with smoking are hormonal contraceptives and inhaled corticosteroids. The most clinically significant interaction occurs with combined hormonal contraceptives. The use of hormonal contraceptives of any kind in women who are 35 years or older and smoke 15 or more cigarettes daily is considered contraindicated because of the increased risk of serious cardiovascular adverse effects. The efficacy of inhaled corticosteroids may be reduced in patients with asthma who smoke. CONCLUSION: Numerous drug interactions exist with smoking. Therefore, smokers taking a medication that interacts with smoking may require higher dosages than nonsmokers. Conversely, upon smoking cessation, smokers may require a reduction in the dosage of an interacting medication.