A randomised determination of the Effect of Fluvastatin and Atorvastatin on top of dual antiplatelet treatment on platelet aggregation after implantation of coronary drug-eluting stents

The Dynamic Effect of Non-CYP3A4-Metabolized and CYP3A4-Metabolized Statins on Clopidogrel Resistance in Patients With Cerebral Infarction

Objective: To explore the treatment effect of statins used together with clopidogrel on cerebral infarction (CI).

Methods: One hundred and thirty non-clopidogrel resistant patients were divided into a dynamic clopidogrel resistant (DCR) group and a continuous Non clopidogrel resistance (NCR) group. Patients were randomly assigned to AC group (atorvastatin 40 mg/d + clopidogrel, 51 patients) and RC group (rosuvastatin 20 mg/d + clopidogrel, 47 patients). The patient’s platelet aggregation rate (PAR) was measured on visit 0 (baseline), visit 1 (1 week after clopidogrel alone treatment), and visits 2 to 4 (one, three, and 6 months after clopidogrel plus statins treatment). The platelet reactivity index (PRI) was assessed on visits 0, 2, and 4, and clopidogrel thiol metabolite (H4) levels was measured on visits 2 and 4. DNA sequencing was used to determine CYP3A4, CYP2C9, and CYP2C19 genotypes in all patients.

Results: PAR, PRI, and H4 levels, DCR ratio, and the genotype frequencies of CYP2C9*3εC, CYP2C19*2εA, and CYP2C19*3εA of both groups were similar (p > 0.05). CYP2C19εA *2 and *3 were independent risk factors for DCR (p < 0.05).

Conclusion: Clopidogrel combined with atorvastatin does not affect platelet inhibition and does not increase the incidence of DCR. The incidence of DCR in the Chinese population is high and is related to CYP2C19εA.

The Role of Genetic Polymorphism and Other Factors on Clopidogrel Resistance (CR) in an Asian Population with Coronary Heart Disease (CHD)

Clopidogrel is a widely-used antiplatelet drug. It is important for the treatment and prevention of coronary heart disease. Clopidogrel can effectively reduce platelet activity and therefore reduce stent thrombosis. However, some patients still have ischemic events despite taking the clopidogrel due to the alteration in clopidogrel metabolism attributable to various genetic and non-genetic factors. This review aims to summarise the mechanisms and causes of clopidogrel resistance (CR) and potential strategies to overcome it. This review summarised the possible effects of genetic polymorphism on CR among the Asian population, especially CYP2C19 *2 / *3 / *17, where the prevalence rate among Asians was 23.00%, 4.61%, 15.18%, respectively. The review also studied the effects of other factors and appropriate strategies used to overcome CR. Generally, CR among the Asian population was estimated at 17.2-81.6%. Therefore, our overview provides valuable insight into the causes of RC. In conclusion, understanding the prevalence of drug metabolism-related genetic polymorphism, especially CYP2C19 alleles, will enhance clinical understanding of racial differences in drug reactions, contributing to the development of personalised medicine in Asia.

Statins: Pharmacokinetics, Pharmacodynamics and Cost-Effectiveness Analysis

Cardiovascular diseases secondary to atherosclerosis are the primary causes of early death and disability worldwide and dyslipidaemia represents one of the most important modifiable risk factors. Among lipid abnormalities that define it, low-density lipoprotein cholesterol (LDL-C) is the primary target of therapy, since multiple randomized controlled trials have shown the positive impact of its reduction on atherosclerosis development. For their ability to lower LDL-C levels, statins are the most studied drugs in cardiovascular disease prevention, of proven utility in slowing the progression or even determining regression of atherosclerosis. In addition, they have ancillary proprieties, with positive effects on the mechanisms involved in the development of atherosclerosis and cardiovascular morbidity and mortality, the so-called "pleiotropic mechanisms". Although sharing the same mechanism of action, the different chemical and pharmacological characteristics of each kind of statins affect their absorption, bioavailability, plasma protein binding properties, excretion and solubility. In this overview, we analysed pharmacokinetic and pharmacodynamic mechanisms of this class of drugs, specifying the differences among the molecules, along with the economic aspects. Detailed knowledge of characteristics and differences of each kind of available statin could help the physician in the correct choice, based also on patient's clinical profile, of this essential tool with a demonstrated high cost-effectiveness both in primary than in the secondary prevention of cardiovascular disease.

Statins significantly reduce mortality in patients receiving clopidogrel without affecting platelet activation and aggregation: a systematic review and meta-analysis

BACKGROUND

Combination of statins and clopidogrel is frequently administered in patients with coronary artery disease (CAD). They are mainly activated and eliminated in the liver by cytochrome P450 isoenzyme 3A4 (CYP3A4). The aim was to clarify whether the coadministration of clopidogrel and statins attenuate respective efficacy.

METHODS

PubMed, Embase, the Cochrane Library, Web of Science and Clinical Trials. gov were searched for until August 2018. Randomized controlled trials (RCTs) and cohort studies were taken into quality evaluation. Data were pooled using random effect models to estimate standard mean difference (SMD) or risk ratio (RR) with 95% confidence interval (CI).

RESULTS

In total, 28 studies representing 25,267 participants were included. Statins reduce the mortality of patients administered clopidogrel (RR 0.54; 95% CI 0.40,0.74; p = 0.000), no differences were found in platelet aggregation (PA) (SMD 0.02; 95% CI -0.38,0.42; p = 0.920) and the expressions of P-selectin (SMD -0.04; 95% CI -0.14,0.05; p = 0.346), CD40L (SMD 0.09; 95% CI -0.29,0.48; p = 0.633), CD63 (SMD 0.09; 95% CI -0.01,0.19; p = 0.079) and PAC-1 (SMD 0.03; 95% CI -0.08,0.13; p = 0.633). Furthermore, CYP3A4 metabolized or non-CYP3A4 metabolized statins have no discrepancies in PA (SMD 0.13; 95% CI -0.31,0.58; p = 0.556), P-selectin (SMD 0.17; 95% CI -0.16,0.51; p = 0310), death (RR 0.89; 95% CI 0.38,2.07; p = 0.791), except for triglyceride (TG) (SMD -0.19; 95% CI -0.33,-0.06; p = 0.005).

CONCLUSIONS

This meta-analysis confirmed that statins reduce mortality in patients undergoing clopidogrel treatment without affecting platelet activation and aggregation.

Efficacy of Clopidogrel and Clinical Outcome When Clopidogrel Is Coadministered With Atorvastatin and Lansoprazole: A Prospective, Randomized, Controlled Trial

This prospective, randomized, nonblind, controlled trial evaluated the effects of clopidogrel on platelet function upon coadministration with atorvastatin and lansoprazole. One hundred four adult patients with non-ST-segment elevated acute coronary syndrome (NSTE-ACS) who underwent percutaneous coronary intervention (PCI) with drug-eluting stent implantation were included. All patients were treated with standard dual antiplatelet therapy (DAPT) plus rosuvastatin 10  mg daily after the operation. On the sixth day after PCI, patients were randomly divided into 4 groups, Group A: DAPT + atorvastatin 20  mg daily (a change from rosuvastatin to atorvastatin) + lansoprazole 30  mg daily, Group B: DAPT + atorvastatin 20  mg daily (a change from rosuvastatin to atorvastatin), Group C: DAPT + lansoprazole 30  mg daily (continuing to take rosuvastatin), Group D is the control group. Additional drugs were used according to the situation of patients. Platelet function and concentrations of platelet activation markers (granular membrane protein 140 (P-selectin), thromboxane B2 (TXB2), and human soluble cluster of differentiation 40 ligand (sCD40L)) were assessed before randomization and at 15- and 30-day follow-up visits. All patients were maintained on treatment for 6 months and observed for bleeding and ischemic events. A total of 104 patients were enrolled, 27 patients in group A, 26 patients in Group B/C, 25 patients in Group D separately, and all the patients were analyzed. There were no differences in platelet function and the levels of platelet activation markers (P-selectin, TXB2, and sCD40L) among or within the 4 groups at the 3 time points of interest (P > 0.05). In the subsequent 6 months, no significant bleeding events occurred, and 12 patients experienced ischemic events, these results were also not significantly different among the groups (P > 0.05). In patients diagnosed with NSTE-ACS who have had drug-eluting stent implantation, simultaneously administering clopidogrel, atorvastatin, and lansoprazole did not decrease the antiplatelet efficacy of clopidogrel or increase adverse event frequency over 6 months.

Clinical pharmacokinetics and pharmacodynamics of clopidogrel

Acute coronary syndromes (ACS) remain life-threatening disorders, which are associated with high morbidity and mortality. Dual antiplatelet therapy with aspirin and clopidogrel has been shown to reduce cardiovascular events in patients with ACS. However, there is substantial inter-individual variability in the response to clopidogrel treatment, in addition to prolonged recovery of platelet reactivity as a result of irreversible binding to P2Y12 receptors. This high inter-individual variability in treatment response has primarily been associated with genetic polymorphisms in the genes encoding for cytochrome (CYP) 2C19, which affect the pharmacokinetics of clopidogrel. While the US Food and Drug Administration has issued a boxed warning for CYP2C19 poor metabolizers because of potentially reduced efficacy in these patients, results from multivariate analyses suggest that additional factors, including age, sex, obesity, concurrent diseases and drug-drug interactions, may all contribute to the overall between-subject variability in treatment response. However, the extent to which each of these factors contributes to the overall variability, and how they are interrelated, is currently unclear. The objective of this review article is to provide a comprehensive update on the different factors that influence the pharmacokinetics and pharmacodynamics of clopidogrel and how they mechanistically contribute to inter-individual differences in the response to clopidogrel treatment.

Epidemiology of CYP3A4-mediated clopidogrel drug-drug interactions and their clinical consequences

AIMS

Clopidogrel is a prodrug that needs to be activated to inhibit platelet aggregation. The objective of this study was to evaluate the prevalence and clinical consequences of potential drug-drug interactions of clopidogrel with drugs affecting CYP3A4 activity.

METHODS

Co-administrations of clopidogrel together with well-established CYP3A4 inhibitors, CYP3A4 inducers, and atorvastatin were investigated in a population-based pharmacoepidemiological study utilizing data from the national healthcare registers and in more detail from a university hospital register in Finland. The main outcome measures were all-cause mortality and mortality and morbidity related to thrombosis or bleeding.

RESULTS

In the nationwide analysis, 6.1%, 1.0%, and 20.8% of the clopidogrel-treated patients were exposed to concomitant use of CYP3A4 inhibitors, CYP3A4 inducers, and atorvastatin, respectively. In the survival analysis, the adjusted hazard ratio for overall mortality was 2.29 (P < 0.001) for CYP3A4 inducer users and 0.74 (P = 0.003) for atorvastatin users compared with controls (patients receiving clopidogrel without interacting medication). CYP3A4 inhibitor use seemed to prevent from thrombosis: HR 0.67, P < 0.001. The hospitalizations due to bleedings were rarer in atorvastatin and CYP3A4 inhibitor groups compared with controls. Thrombosis complications leading to hospitalizations were more often seen in the atorvastatin group than in the control group.

CONCLUSIONS

No uniform untoward effect of concomitant CYP3A4 inhibitor use on the clinical efficacy of clopidogrel was found. In patients receiving concomitant atorvastatin and clopidogrel, the antithrombotic effect of clopidogrel was moderately attenuated, but the combination significantly reduced the overall mortality. CYP3A4 inhibitors and atorvastatin may reduce bleedings in clopidogrel users.

Cytochrome P450-mediated cardiovascular drug interactions

INTRODUCTION

There are numerous drug-drug interactions (DDIs) related to cardiovascular medications and many of these are mediated via the cytochrome P450 (CYP) system. Some of these may lead to serious adverse events and it is, therefore, essential that clinicians are aware of the important interactions that occur.

AREAS COVERED

An extensive literature search was performed to analyze the CYP-mediated cardiovascular DDIs that lead to a loss of efficacy or potential toxicity. Cardiovascular drugs may be victims or act as perpetrators of DDIs. The paper analyzes CYP-mediated drug interactions concerning anticoagulants, antiplatelet agents, antiarrhythmics, β-blockers, calcium antagonists, antihypertensive medications, lipid-lowering drugs and oral antidiabetic agents.

EXPERT OPINION

Cardiovascular DDIs involving the CYP system are numerous. Additionally, the spectrum of drugs prescribed is constantly changing, particularly with cardiovascular diseases and it is not necessarily the case that drugs that had shown safety earlier will always show safety. Clinicians are encouraged to develop their knowledge of CYP-mediated DDIs so that they can choose safe drug combination regimens, adjust drug dosages appropriately and conduct therapeutic drug monitoring for drugs with narrow therapeutic indices.

Proton pump inhibitors, genetic polymorphisms and response to clopidogrel therapy

Clopidogrel has become part of the mainstay of therapy for acute coronary syndromes and in patients post stenting. Clopidogrel is a pro drug and is metabolised by liver enzymes, particularly CYP2C19, into its active form. A considerable proportion of patients have a poor response to clopidogrel and this may be due to several factors. Genetic polymorphisms involved in clopidogrel's absorption, metabolism and activity at the platelet may interfere with its antiplatelet actions. Further, proton pump inhibitors (PPI) may interfere with clopidogrel's actions by functionally reducing the ability of CYP2C19 to convert clopidogrel to its active metabolite. By attenuating clopidogrel's actions, both polymorphisms and drug interactions may increase the risk of thrombotic events during clopidogrel therapy. This review will explore the current evidence relating to the association between PPIs, genetic polymorphisms and poor response to clopidogrel. Routine genetic testing cannot be recommended for patients receiving dual antiplatelet therapy (DAPT). However, it may have a role for patients with an episode of stent thrombosis, prior to planned high-risk stenting or major bleeding. Regarding concomitant clopidogrel and PPI therapy, it is recommended that only patients with previous gastrointestinal (GI) bleeding or multiple risk factors for GI bleeding should be prescribed gastroprotection. This is due to the uncertainty surrounding the clinical significance of this interaction given the discordant biochemical and clinical data, conflicting results from observational studies and the limitations of the COGENT study. Pantoprazole seems least likely to interact with clopidogrel and most suitable for use in patients receiving DAPT.