Influences of different proton pump inhibitors on the anti-platelet function of clopidogrel in relation to CYP2C19 genotypes

Toward building a comprehensive human pan-genome: The SEN-GENOME project

The human reference genome (GRCh38), primarily sourced from individuals of European descent, falls short in capturing the vast genetic diversity across global populations. Efforts to diversify the reference genome face challenges in accessibility and representation, exacerbating the scarcity of African genomic data crucial for studying diseases prevalent in these populations. Sherman et al. proposed constructing reference genomes tailored to distinct human sub-populations. Their African Pan-Genome initiative highlighted substantial genetic variation missing from the GRCh38 human reference genome, emphasizing the necessity for population-specific genomes. In response, local initiatives like the Senegalese Genome project (SEN-GENOME) have emerged to document the genomes of historically overlooked populations. SEN-GENOME embodies community-driven decentralized research. With meticulous recruitment criteria and ethical practices, it aims to sequence 1,000 genomes from 31 ethnolinguistic groups, in the fourteen administrative regions of Senegal, fostering local genomic research tailored to the region. The key to SEN-GENOME's success is its commitment to local governance of data, capacity building, and integration with broader pan-genome projects in Africa. Despite the complexities of data harmonization and sharing, our collaborative efforts are aligned with common goals, ensuring steady progress toward a comprehensive human pan-genome. We invite and welcome collaboration with other research entities to achieve this shared vision. In summary, local initiatives such as SEN-GENOME are pivotal in bridging genomic disparities, offering pathways to equitable and inclusive genomic research. Collaborative endeavors guided by a collective vision for human health will propel us toward a more encompassing understanding of the human genome and better health through genomic medicine.

A network meta-analysis: evaluating the efficacy and safety of concurrent proton pump inhibitors and clopidogrel therapy in post-PCI patients

Introduction

The objective of this research was to evaluate the risk of major adverse cardiovascular events (MACEs) associated with the use of various proton pump inhibitors (PPIs) in combination with clopidogrel in patients who underwent percutaneous coronary intervention (PCI).

Methods

To accomplish this, we analyzed data from randomized controlled trials and retrospective cohort studies sourced from key electronic databases. These studies specifically examined the effects of different PPIs, such as lansoprazole, esomeprazole, omeprazole, rabeprazole, and pantoprazole, when used in conjunction with clopidogrel on MACEs. The primary focus was on the differential impact of these PPIs, while the secondary focus was on the comparison of gastrointestinal (GI) bleeding events in groups receiving different PPIs with clopidogrel vs. a placebo group. This study's protocol was officially registered with INPLASY (INPLASY2024-2-0009).

Results

We conducted a network meta-analysis involving 16 studies with a total of 145,999 patients. Our findings indicated that rabeprazole when combined with clopidogrel, had the lowest increase in MACE risk (effect size, 1.05, 95% CI: 0.66-1.66), while lansoprazole was associated with the highest risk increase (effect size, 1.48, 95% CI: 1.22-1.80). Esomeprazole (effect size, 1.28, 95% CI: 1.09-1.51), omeprazole (effect size, 1.23, 95% CI: 1.07-1.43), and pantoprazole (effect size, 1.38, 95% CI: 1.18-1.60) also significantly increased MACE risk. For the secondary outcome, esomeprazole (effect size, 0.30, 95% CI: 0.09-0.94), omeprazole (effect size, 0.34, 95% CI: 0.14-0.81), and pantoprazole (effect size, 0.33, 95% CI: 0.13-0.84) demonstrated an increased potential for GI bleeding prevention.

Conclusions

In conclusion, the combination of lansoprazole and clopidogrel was found to significantly elevate the risk of MACEs without offering GI protection in post-PCI patients. This study is the first network meta-analysis to identify the most effective regimen for the concurrent use of clopidogrel with individual PPIs.

Systematic Review Registration

https://inplasy.com/inplasy-2024-2-0009/, identifier (INPLASY2024-2-0009).

An update on oral antiplatelet drug interactions with proton pump inhibitors: what are the risks?

INTRODUCTION

Aspirin and anti-P2Y12 are widely prescribed in cardiovascular patients, often in combination with proton pump inhibitors (PPIs) to limit the risk of upper gastrointestinal bleedings. The potential interaction between PPIs and antiplatelet agents has been widely discussed, but doubts remain as to whether PPIs may reduce the cardiovascular protection provided by aspirin, prasugrel, ticagrelor, and clopidogrel.

AREAS COVERED

Many pharmacokinetic (PK) and pharmacodynamic (PD) studies have confirmed the interaction, especially between PPIs and clopidogrel, but with uncertain consequences on clinical outcomes. Therefore, we aimed to summarize the evidence for the widespread combined use of oral antiplatelet drugs and PPIs, to outline the current evidence supporting or opposing drug-drug interaction, and to discuss the clinical implications of such interactions.

EXPERT OPINION

A large body of evidence describes the PK/PD interaction of antiplatelet drugs with PPIs and its potential role in increasing clinical cardiovascular adverse events, but no solid clinical data have confirmed these effects. In the light of the published studies, there seems to be no restriction on the choice of PPI with aspirin, prasugrel, and/or ticagrelor. The choice of a PPI with no (or minimal) interference with the hepatic cytochrome P450 2C19 is preferred in patients receiving clopidogrel.

Rebound Acid Hypersecretion after Withdrawal of Long-Term Proton Pump Inhibitor (PPI) Treatment-Are PPIs Addictive?

Proton pump inhibitors (PPIs) are widely used in the long-term treatment of gastroesophageal reflux disease (GERD) and other upper gastrointestinal disorders, such as the healing of peptic ulcers and/or prophylactic treatment of peptic ulcers. PPIs are also widely used as symptomatic treatment in patients with functional dyspepsia. One of the adverse effects of the long-term use of PPI is rebound acid hypersecretion (RAHS), which can occur after the withdrawal of PPI therapy due to a compensatory increase in gastric acid production. Mechanisms of the RAHS have been well established. Studies have shown that pentagastrin-stimulated acid secretion after the discontinuation of PPIs increased significantly compared to that before treatment. In healthy volunteers treated with PPIs, the latter induced gastrointestinal symptoms in 40-50% of subjects after the discontinuation of PPI therapy but after stopping the placebo. It is important for practicing physicians to be aware and understand the underlying mechanisms and inform patients about potential RAHS before discontinuing PPIs in order to avoid continuing unnecessary PPI therapy. This is important because RAHS may lead patients to reuptake PPIs as symptoms are incorrectly thought to originate from the recurrence of underlying conditions, such as GERD. Mechanisms of RAHS have been well established; however, clinical implications and the risk factors for RAHS are not fully understood. Further research is needed to facilitate appropriate management of RAHS in the future.

Insight into Risk Factors, Pharmacogenetics/Genomics, and Management of Adverse Drug Reactions in Elderly: A Narrative Review

The European Medicine Agency (EMA) has defined Adverse Drug Reactions (ADRs) as "a noxious and unintended response to a medicine", not including poisoning, accidental, or intentional overdoses. The ADR occurrence differs based on the approach adopted for defining and detecting them, the characteristics of the population under study, and the research setting. ADRs have a significant impact on morbidity and mortality, particularly among older adults, and represent a financial burden for health services. Between 30% and 60% of ADRs might be predictable and preventable, emerging as a result of inappropriate prescription, drug chemistry inherent toxicity, cell-specific drug toxicity, age- and sex-related anomalies in drug absorption, distribution, metabolism, and elimination (ADME), and drug-drug interactions (DDIs) in combination therapies or when a patient is treated with different drugs for concomitant disorders. This is particularly important in chronic diseases which require long-term treatments. Rapid developments in pharmacogenetics/genomics have improved the understanding of ADRs accompanied by more accurate prescriptions and reduction in unnecessary costs. To alleviate the burden of ADRs, especially in the elderly, interventions focused on pharmaceutical principles, such as medication review and reconciliation, should be integrated into a broader assessment of patients' characteristics, needs, and health priorities. Digital health interventions could offer valuable solutions to assist healthcare professionals in identifying inappropriate prescriptions and promoting patient adherence to pharmacotherapies.

Drug-Drug-Gene Interactions in Cardiovascular Medicine

Cardiovascular disease remains a leading cause of both morbidity and mortality worldwide. It is widely accepted that both concomitant medications (drug-drug interactions, DDIs) and genomic factors (drug-gene interactions, DGIs) can influence cardiovascular drug-related efficacy and safety outcomes. Although thousands of DDI and DGI (aka pharmacogenomic) studies have been published to date, the literature on drug-drug-gene interactions (DDGIs, cumulative effects of DDIs and DGIs) remains scarce. Moreover, multimorbidity is common in cardiovascular disease patients and is often associated with polypharmacy, which increases the likelihood of clinically relevant drug-related interactions. These, in turn, can lead to reduced drug efficacy, medication-related harm (adverse drug reactions, longer hospitalizations, mortality) and increased healthcare costs. To examine the extent to which DDGIs and other interactions influence efficacy and safety outcomes in the field of cardiovascular medicine, we review current evidence in the field. We describe the different categories of DDIs and DGIs before illustrating how these two interact to produce DDGIs and other complex interactions. We provide examples of studies that have reported the prevalence of clinically relevant interactions and the most implicated cardiovascular medicines before outlining the challenges associated with dealing with these interactions in clinical practice. Finally, we provide recommendations on how to manage the challenges including but not limited to expanding the scope of drug information compendia, interaction databases and clinical implementation guidelines (to include clinically relevant DDGIs and other complex interactions) and work towards their harmonization; better use of electronic decision support tools; using big data and novel computational techniques; using clinically relevant endpoints, preemptive genotyping; ensuring ethnic diversity; and upskilling of clinicians in pharmacogenomics and personalized medicine.

Rates of Divergent Pharmacogenes in a Psychiatric Cohort of Inpatients with Depression-Arguments for Preemptive Testing

Background: The international drug agencies annotate pharmacogenes for many years. Pharmacogenetic testing is thus far only established in few settings, assuming that only few patients are actually affected by drug-gene interactions. Methods: 108 hospitalized patients with major depressive disorder were genotyped for CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, NAT2, DPYD; VKORC1 and TMTP. Results: We found 583 (mean 5.4, median 5) divergent phenotypes (i.e., divergent from the common phenotypes considered normal, e.g., extensive metabolizer) in the 12 analyzed pharmacokinetic genes. The rate for at least one divergent phenotype was 100% in our cohort for CYP, but also for all 12 important pharmacogenes: patients had at least two divergent phenotypes. Compared to a large Danish cohort, CYP2C9 NM and IM status, CYP2C19 UM, CYP2D6 UM and DYPD (GAS 0, 1, 2) genotypes differed statistical significantly. For CYP2D6 and CYP2C19, 13% of the patients were normal metabolizers for both enzymes in our cohort, but this value was 27.3% in the Danish cohort, which is a highly significant difference (p < 0.0001). Conclusion: Divergent phenotypes in pharmacogenes are not the exception, but the rule. Patients with divergent phenotypes seem more prone for hospitalization, emphasizing the need for pre-emptive testing to avoid inefficacy and adverse drug effects in all patients.

The Safety of Long-Term Proton Pump Inhibitor Use on Cardiovascular Health: A Meta-Analysis

Introduction: Proton pump inhibitors (PPIs) are one of the most prescribed classes of drugs worldwide as a first-line treatment of acid-related disorders. Although adverse effects are rare and rapidly reversible after a short exposure, concerns have been recently raised about a greater toxicity on cardiovascular health after a longer exposure, especially when combined with clopidogrel. We aimed to evaluate the safety of long-term PPI use on cardiovascular health in patients with known atheromatous cardiovascular disease. Methods: A literature search was conducted in the PubMed, Embase, and Cochrane Library databases and grey literature in April 2022. Articles published between 2014 and 2022 were considered relevant if they were designed as randomized controlled trials (RCTs) that included post hoc analyses or prospective observational studies and if they investigated clinical cardiovascular outcomes associated with PPI use for 6 months or more in patients suffering from cardiovascular disease requiring antiplatelet agent therapy and/or coronary angioplasty. Statistical analyses were performed using RevMan 5.4 software (Computer program, the Cochrane Collaboration, 2020, London, UK). The risk of bias was assessed using the Cochrane risk-of-bias tool for the RCTs and the Newcastle−Ottawa scale for the observational studies. Results: A total of 10 full-text articles involving 53,302 patients were included. Substantial heterogeneity was found among the 10 included studies. The primary analysis showed no significant differences between the PPI group and the control group for the risks of major adverse cardiovascular events (MACEs), all-cause death (ACD), or target vessel revascularization (TVR) using a random-effects model (OR 1.15, 95% CI 0.98−1.35, p = 0.08, I2 = 73%; OR 1.24, 95% CI 0.94−1.65, p = 0.13, I2 = 63%; and OR 1.19, 95% CI 0.76−1.87, p = 0.45, I2 = 61%, respectively). The primary analysis yielded similar results for the risks of myocardial infarction (MI), stroke, and cardiovascular death (CVD) using a fixed-effects model (OR 0.98, 95% CI 0.88−1.09, p = 0.66, I2 = 0%; OR 1.02, 95% CI 0.90−1.17, p = 0.73, I2 = 0%; and OR 1.04, 95% CI 0.94−1.16, p = 0.44, I2 = 35%, respectively). Likewise, a subgroup analysis based on eight randomized controlled trials failed to identify any association between PPI use and the risks of MACEs, MI, stroke, TVR, ACD, or CVD using a fixed-effects model (overall pooled OR 1.01, 95% CI 0.96−1.06; p = 0.66; I2 = 0%). The pulled data from the two included observational studies (OS) demonstrated a significantly increased risk of MACEs in the PPI group (OR 1.42, 95% CI [1.29−1.57], p <0.001; I2 = 0%). In another subgroup analysis, no evidence of an increased risk of adverse cardiovascular events in the co-therapy PPI/clopidogrel versus clopidogrel alone groups was found with the exception of the risk of ACD (OR 1.50, 95% CI 1.23−1.82, p = 0.001, I2 = 0%). Nevertheless, after performing a sensitivity analysis reaching heterogeneity I2 = 0%, the co-prescription of PPIs and clopidogrel was at increased risk of MACEs (p < 0.001), CVD (p = 0.008), and TVR (p < 0.001) but remained statistically non-significant for the risk of MI (p = 0.11). Conclusions: The overall results of this meta-analysis showed that long-term PPI use was not associated with an increased risk of adverse cardiovascular events. However, inconsistent results were found for combined PPI/clopidogrel therapy. These results should be considered with caution in light of the significant heterogeneity, the limited number of included studies, and the lack of adjustment for potential confounders.

Physiologically Based Pharmacokinetic (PBPK) Modeling of Clopidogrel and Its Four Relevant Metabolites for CYP2B6, CYP2C8, CYP2C19, and CYP3A4 Drug–Drug–Gene Interaction Predictions

The antiplatelet agent clopidogrel is listed by the FDA as a strong clinical index inhibitor of cytochrome P450 (CYP) 2C8 and weak clinical inhibitor of CYP2B6. Moreover, clopidogrel is a substrate of—among others—CYP2C19 and CYP3A4. This work presents the development of a whole-body physiologically based pharmacokinetic (PBPK) model of clopidogrel including the relevant metabolites, clopidogrel carboxylic acid, clopidogrel acyl glucuronide, 2-oxo-clopidogrel, and the active thiol metabolite, with subsequent application for drug–gene interaction (DGI) and drug–drug interaction (DDI) predictions. Model building was performed in PK-Sim^® using 66 plasma concentration-time profiles of clopidogrel and its metabolites. The comprehensive parent-metabolite model covers biotransformation via carboxylesterase (CES) 1, CES2, CYP2C19, CYP3A4, and uridine 5′-diphospho-glucuronosyltransferase 2B7. Moreover, CYP2C19 was incorporated for normal, intermediate, and poor metabolizer phenotypes. Good predictive performance of the model was demonstrated for the DGI involving CYP2C19, with 17/19 predicted DGI AUC_last and 19/19 predicted DGI C_max ratios within 2-fold of their observed values. Furthermore, DDIs involving bupropion, omeprazole, montelukast, pioglitazone, repaglinide, and rifampicin showed 13/13 predicted DDI AUC_last and 13/13 predicted DDI C_max ratios within 2-fold of their observed ratios. After publication, the model will be made publicly accessible in the Open Systems Pharmacology repository.

Influence of daily versus alternate-day dosing of vonoprazan on intragastric pH, serum gastrin, and the antiplatelet function of clopidogrel : Influence of alternate-day dosing of vonoprazan

BACKGROUND

Vonoprazan, a potassium-competitive acid blocker, inhibits gastric acid secretion and attenuates the antiplatelet function of clopidogrel more potently than esomeprazole. We investigated whether alternate-day dosing of vonoprazan might avoid this interaction with clopidogrel while providing sufficient gastric acid inhibition.

METHODS

Following 24 h of pH monitoring (control regimen), 12 healthy volunteers received three regimens (clopidogrel-only regimen: clopidogrel 75 mg daily [q.d.]; vonoprazan alternate-day regimen: vonoprazan 10 mg every other day [q.o.d.] + clopidogrel 75 mg q.d.; vonoprazan daily regimen: vonoprazan 10 mg q.d. + clopidogrel 75 mg q.d.) for 14 days in a randomized open-label crossover manner. Intragastric pH monitoring was performed for 24 h on day 13 in the clopidogrel-only and vonoprazan q.d. regimens and for 48 h on days 13 and 14 in the vonoprazan q.o.d. regimen. Serum gastrin and inhibition of platelet aggregation (IPA) were measured before the commencement of pH monitoring in each regimen.

RESULTS

Twelve volunteers completed the study. Equivalent median IPA values in the q.o.d. and q.d. regimens were measured (21.8% and 25%, respectively) and were significantly lower than that with the clopidogrel-only regimen (40.8%). The median pH4 holding time ratio for the vonoprazan q.o.d. regimen (49.7%) was superior to that of the clopidogrel-only regimen (18.4%), but was significantly inferior to that of the vonoprazan q.d. regimen (77.0%; p < 0.01).

CONCLUSION

Alternate-day administration of vonoprazan could not prevent the interaction between vonoprazan and clopidogrel, and acid inhibition was inferior to that with vonoprazan daily administration. Alternate-day administration of vonoprazan thus appears to be of questionable clinical utility.

SAFETY OF LONG-TERM PROTON PUMP INHIBITORS: FACTS AND MYTHS

BACKGROUND

Proton pump inhibitors (PPIs) are one of the most prescribed drugs in the world. Frequent use and long-term maintenance of these drugs drew the attention of researchers for sporadic adverse effects reports.

OBJECTIVE

The purpose of this narrative review is to discuss appropriate data and causality related to these adverse events and PPIs.

METHODS

A narrative review was conducted by systematizing information about safety and adverse events on PPIs from 2015 to 2020. A structured search on Pubmed was performed to identify systematic reviews and meta-analysis investigating the following situations: a) gastric cancer; b) micronutrients deficiency; c) acid rebound; d) infections; e) fractures; f) dementia; g) kidney disease; and h) sudden death and cardiovascular changes.

RESULTS

Recent studies have potentially associated PPIs with some adverse events as osteoporosis-related fractures. There are also reports of intestinal infections, including Clostridium difficile, besides poor vitamins absorption and minerals such as vitamin B12, magnesium, and iron. Furthermore, there are some dementia, pneumonia, kidney disease, myocardial infarction, and stroke reports. For kidney diseases, studies consistently suggest that the use of PPI may be associated with an increased risk of adverse kidney events, especially in the elderly, with long-term PPI use and pre-existing kidney disease. Another additional question is whether chronic PPI use would also lead to the onset of gastric cancer. The abrupt discontinuation of PPIs is also related to increased gastric acid production above pre-PPI treatment levels; this phenomenon is called acid rebound.

CONCLUSION

The key to mitigate adverse effects is the rational use of PPIs at the lowest effective dose and in the shortest possible duration. Although these adverse effects have a potential clinical impact, their causal association is still subject to validation.

Vertebral artery dissection and associated ruptured intracranial pseudoaneurysm successfully treated with coil assisted flow diversion: A case report and review of the literature

Dissecting intracranial pseudoaneurysms (IPs) are associated with a high incidence of rupture and poor neurologic outcomes. Lesions in the posterior circulation are particularly malignant and pose even greater management challenges. Traditional management consists of microsurgical vessel sacrifice with or without bypass. Flow diversion (FD) in the setting of subarachnoid hemorrhage (SAH) represents a reconstructive treatment option and can be paired with coil embolization to promote more rapid thrombosis of the lesion. We report a case of a ruptured dissecting vertebral artery (VA) IP successfully acutely treated with coil-assisted FD. A 53-year-old male presented with a right V4 dissection spanning the origin of the posterior inferior cerebellar artery and associated ruptured V4 IP. The patient was treated with coil-assisted FD. Oral dual-antiplatelet therapy (DAPT) was initiated during the procedure, and intravenous tirofiban was used as a bridging agent. Immediate obliteration of the IP was achieved, with near-complete resolution of the dissection within 48 h. The patient made a complete recovery, and angiography at 6 weeks confirmed total IP obliteration, reconstruction of the VA, and a patent stent. The use of FD and DAPT in the setting of acute SAH remains controversial. We believe that coil-assisted FD in carefully selected patients offers significant advantages over traditional microsurgical and endovascular options. The risks posed by DAPT and potential for delayed thrombosis with FD can be effectively mitigated with planning and the development of protocols. We discuss the current literature in the context of our case and review the challenges associated with treating these often devastating lesions.

Interaction between Omeprazole and Gliclazide in Relation to CYP2C19 Phenotype

The antidiabetic drug gliclazide is partly metabolized by CYP2C19, the main enzyme involved in omeprazole metabolism. The aim of the study was to explore the interaction between omeprazole and gliclazide in relation to CYP2C19 phenotype using physiologically based pharmacokinetic (PBPK) modeling approach. Developed PBPK models were verified using in vivo pharmacokinetic profiles obtained from a clinical trial on omeprazole-gliclazide interaction in healthy volunteers, CYP2C19 normal/rapid/ultrarapid metabolizers (NM/RM/UM). In addition, the association of omeprazole cotreatment with gliclazide-induced hypoglycemia was explored in 267 patients with type 2 diabetes (T2D) from the GoDARTS cohort, Scotland. The PBPK simulations predicted 1.4–1.6-fold higher gliclazide area under the curve (AUC) after 5-day treatment with 20 mg omeprazole in all CYP2C19 phenotype groups except in poor metabolizers. The predicted gliclazide AUC increased 2.1 and 2.5-fold in intermediate metabolizers, and 2.6- and 3.8-fold in NM/RM/UM group, after simulated 20-day dosing with 40 mg omeprazole once and twice daily, respectively. The predicted results were corroborated by findings in patients with T2D which demonstrated 3.3-fold higher odds of severe gliclazide-induced hypoglycemia in NM/RM/UM patients concomitantly treated with omeprazole. Our results indicate that omeprazole may increase exposure to gliclazide and thus increase the risk of gliclazide-associated hypoglycemia in the majority of patients.

Use of Clopidogrel and Proton Pump Inhibitors Alone or in Combinations in Persons with Diabetes in Denmark; Potential for CYP2C19 Genotype-Guided Drug Therapy

Background: Clopidogrel and proton pump inhibitors (PPIs) are among the most used drugs in Denmark for which there exists pharmacogenomics (PGx)-based dosing guidelines and FDA annotations. In this study, we further scrutinized the use of clopidogrel and PPIs when prescriptions were redeemed from Danish Pharmacies alone or in combination in the Danish population and among persons with diabetes in Denmark. The focus deals with the potential of applying PGx-guided antiplatelet therapy taking both drug–drug interactions (DDI) and drug–gene interactions (DGI) into account. Methods: The Danish Register of Medicinal Product Statistics was the source to retrieve consumption data. Results: The consumption of PPIs and clopidogrel in terms of prevalence (users/1000 inhabitants) increased over a five-year period by 6.3% to 103.1 (PPIs) and by 41.7% to 22.1 (clopidogrel), respectively. The prevalence of the use of clopidogrel and PPIs in persons with diabetes are 3.8 and 2.1–2.8 times higher compared to the general population. When redeemed in combination, the prevalence increased to 4.7. The most used combination was clopidogrel and pantoprazole. Conclusions: The use of clopidogrel and PPIs either alone or in combination is quite widespread, in particular among the elderly and persons with diabetes. This further supports the emerging need of accessing and accounting for not only DDI but also for applying PGx-guided drug therapy in clinical decision making for antiplatelet therapy with clopidogrel having a particular focus on persons with diabetes and the elderly.

Intermittent concurrent use of clopidogrel and proton pump inhibitors did not increase risk of adverse clinical outcomes in Chinese patients with coronary artery disease

BACKGROUND

Proton pump inhibitors (PPIs) are frequently prescribed to patients with coronary heart disease (CHD) under antiplatelet therapy to prevent gastrointestinal (GI) bleeding. However, its clinical impact is still under debate, especially in Asian population. This study was undertaken to explore the effects of concurrent use of clopidogrel and PPIs on the clinical outcomes in Chinese patients with CHD in secondary prevention.

METHODS

A single-center retrospective study was conducted in 638 patients with CHD on consecutive clopidogrel therapy for at least 1 year. After 18-month follow-up, adverse clinical events were collected. Cox regression was used to calculate hazard ratios (HR) and 95% confidence interval (CI) for the effect of PPI use on the outcomes. A total of 638 patients were recruited from 2014 to 2015 in this study, among whom 201 were sustained PPI users, 188 were intermittent PPI users and the remaining 249 were non-PPI users.

RESULTS

Compared with sustained PPI users, intermittent use of PPIs was associated with a lower risk of stroke, major adverse cardiac events (MACE) and net adverse clinical event (NACE) (stroke: adjusted HR: 0.109, 95% CI 0.014-0.878, p = 0.037; MACE: adjusted HR: 0.293, 95% CI 0.119-0.722; p = 0.008; NACE: adjusted HR: 0.357, 95% CI 0.162-0.786, p = 0.011). Subgroup analysis further revealed the benefit of intermittent PPI use was significant in male CHD patients over 60 years old, with hypertension or chronic kidney disease, and undergoing percutaneous coronary intervention during hospitalization.

CONCLUSION

The current findings suggest that the intermittent concurrent use of PPIs and clopidogrel is not associated with an increased risk of 18-month adverse clinical outcomes, and intermittent use of PPIs is associated with a lower rate of MACE and NACE.

Optimising Seniors' Metabolism of Medications and Avoiding Adverse Drug Events Using Data on How Metabolism by Their P450 Enzymes Varies with Ancestry and Drug-Drug and Drug-Drug-Gene Interactions

Many individuals ≥65 have multiple illnesses and polypharmacy. Primary care physicians prescribe >70% of their medications and renew specialists’ prescriptions. Seventy-five percent of all medications are metabolised by P450 cytochrome enzymes. This article provides unique detailed tables how to avoid adverse drug events and optimise prescribing based on two key databases. DrugBank is a detailed database of 13,000 medications and both the P450 and other complex pathways that metabolise them. The Flockhart Tables are detailed lists of the P450 enzymes and also include all the medications which inhibit or induce metabolism by P450 cytochrome enzymes, which can result in undertreatment, overtreatment, or potentially toxic levels. Humans have used medications for a few decades and these enzymes have not been subject to evolutionary pressure. Thus, there is enormous variation in enzymatic functioning and by ancestry. Differences for ancestry groups in genetic metabolism based on a worldwide meta-analysis are discussed and this article provides advice how to prescribe for individuals of different ancestry. Prescribing advice from two key organisations, the Dutch Pharmacogenetics Working Group and the Clinical Pharmacogenetics Implementation Consortium is summarised. Currently, detailed pharmacogenomic advice is only available in some specialist clinics in major hospitals. However, this article provides detailed pharmacogenomic advice for primary care and other physicians and also physicians working in rural and remote areas worldwide. Physicians could quickly search the tables for the medications they intend to prescribe.

Drug-drug-gene interactions and adverse drug reactions

The economic and health burden caused by adverse drug reactions has increased dramatically in the last few years. This is likely to be mediated by increasing polypharmacy, which increases the likelihood for drug–drug interactions. Tools utilized by healthcare practitioners to flag potential adverse drug reactions secondary to drug–drug interactions ignore individual genetic variation, which has the potential to markedly alter the severity of these interactions. To date there have been limited published studies on impact of genetic variation on drug–drug interactions. In this review, we establish a detailed classification for pharmacokinetic drug–drug–gene interactions, and give examples from the literature that support this approach. The increasing availability of real-world drug outcome data linked to genetic bioresources is likely to enable the discovery of previously unrecognized, clinically important drug–drug–gene interactions.

Asia-Pacific working group consensus on non-variceal upper gastrointestinal bleeding: an update 2018

Non-variceal upper gastrointestinal bleeding remains an important emergency condition, leading to significant morbidity and mortality. As endoscopic therapy is the 'gold standard' of management, treatment of these patients can be considered in three stages: pre-endoscopic treatment, endoscopic haemostasis and post-endoscopic management. Since publication of the Asia-Pacific consensus on non-variceal upper gastrointestinal bleeding (NVUGIB) 7 years ago, there have been significant advancements in the clinical management of patients in all three stages. These include pre-endoscopy risk stratification scores, blood and platelet transfusion, use of proton pump inhibitors; during endoscopy new haemostasis techniques (haemostatic powder spray and over-the-scope clips); and post-endoscopy management by second-look endoscopy and medication strategies. Emerging techniques, including capsule endoscopy and Doppler endoscopic probe in assessing adequacy of endoscopic therapy, and the pre-emptive use of angiographic embolisation, are attracting new attention. An emerging problem is the increasing use of dual antiplatelet agents and direct oral anticoagulants in patients with cardiac and cerebrovascular diseases. Guidelines on the discontinuation and then resumption of these agents in patients presenting with NVUGIB are very much needed. The Asia-Pacific Working Group examined recent evidence and recommends practical management guidelines in this updated consensus statement.

Prevalence of poor biological response to clopidogrel

The existence of poor biological response to clopidogrel has been shown in some patients. Despite the increasing number of studies, this phenomenon remains difficult to quantify. We performed a systematic review to estimate the prevalence of poor biological response to clopidogrel and investigate the factors known to modulate this. An exhaustive search was performed. Altogether 171 publications were identified, providing data for a total of 45,664 subjects. The estimated prevalence of poor biological response to clopidogrel ranged from 15.9% to 49.5% according to the platelet function assay employed. The assays most frequently used were light transmittance aggregometry (LTA), the vasodilator-stimulated phosphoprotein (VASP) assay and the Verify -now® assay. For all these assays, higher cut-off values were associated with a lower prevalence of poor biological response to clopidogrel. However, when choosing a fixed cut-off point for each assay, the prevalence of poor biological response to clopidogrel was highly variable suggesting that other factors could modulate poor biological response to clopidogrel. Finally, none of the studied factors could apparently explain the variability of poor biological response to clopidogrel. This meta-analysis shows that the prevalence of poor biological response depends on the assay employed, the cut-off value and on various unidentified additional factors.

Comparative Study of Effects of Vonoprazan and Esomeprazole on Antiplatelet Function of Clopidogrel or Prasugrel in Relation to CYP2C19 Genotype

Drug-drug interaction between antiacid and antiplatelet agents has not been fully elucidated. Vonoprazan, a new potassium competitive acid blocker, has been available in Japan. CYP2C19 and CYP3A4 are involved in the metabolism of clopidogrel, prasugrel, esomeprazole, and vonoprazan. Using a P2Y12 assay, we compared the effects of vonoprazan and esomeprazole on the antiplatelet functions of clopidogrel or prasugrel in 31 healthy Japanese volunteers (14 CYP2C19 homo-extensive (homo-EMs), nine hetero-extensive (hetero-EMs), and eight poor metabolizers (PMs)). Vonoprazan decreased the median inhibition of platelet aggregation (IPA) values of clopidogrel and prasugrel more potently than esomeprazole (P < 0.001 for clopidogrel and P = 0.011 for prasugrel). The same tendencies were observed when stratified by CYP2C19 genotype groups (P = 0.004 in homo-EMs, 0.033 in hetero-EMs, and 0.043 in PMs). Vonoprazan attenuated the antiplatelet function of clopidogrel more potently than esomeprazole. Esomeprazole did not affect that of prasugrel irrespective of CYP2C19 genotype.

East Asian perspective on the interaction between proton pump inhibitors and clopidogrel

Both proton pump inhibitors (PPIs) and clopidogrel are widely prescribed in the Asia-Pacific population. PPIs are the mainstay therapeutic agents for prophylaxis against aspirin gastropathy and for acid-related disorders including gastroesophageal reflux disease. They are also co-prescribed with oral anticoagulant agents and with dual-antiplatelet therapy for the treatment and prevention of gastrointestinal bleeding. Clopidogrel belongs to the drug class of thienopyridines and is currently the most widely prescribed oral anticoagulant agent either alone or in combination with aspirin. Platelet inhibition by clopidogrel is prone to significant inter-individual variability and is believed to be affected by several factors such as genetics and drug-drug interactions. Since it was first reported in 2009, the potential for drug-drug interactions between PPIs and clopidogrel has remained headline news, and its significance in clinical practice is the subject of an ongoing debate. For East Asian patients in particular, the clinical relevance of the interaction between PPIs and clopidogrel remains unclear because of conflicting data, as well as underrepresentation of East Asian subjects in landmark trials. Increased CYP2C19 genetic polymorphisms in individuals from Asia-Pacific countries only fuel the confusion. Recent studies in East Asian cohorts suggests that the potential of PPIs to attenuate the efficacy of clopidogrel could be minimized by the use of newer PPIs with weaker affinity for the CYP2C19 isoenzyme, namely, pantoprazole, dexlansoprazole, and rabeprazole. This review aims to help clinicians choose the most appropriate PPI for co-prescription with clopidogrel in patients from Asia-Pacific countries.

Pharmacogenetics of drug-drug interaction and drug-drug-gene interaction: a systematic review on CYP2C9, CYP2C19 and CYP2D6

Currently, most guidelines on drug-drug interaction (DDI) neither consider the potential effect of genetic polymorphism in the strength of the interaction nor do they account for the complex interaction caused by the combination of DDI and drug-gene interaction (DGI) where there are multiple biotransformation pathways, which is referred to as drug-drug-gene interaction (DDGI). In this systematic review, we report the impact of pharmacogenetics on DDI and DDGI in which three major drug-metabolizing enzymes - CYP2C9, CYP2C19 and CYP2D6 - are central. We observed that several DDI and DDGI are highly gene-dependent, leading to a different magnitude of interaction. Precision drug therapy should take pharmacogenetics into account when drug interactions in clinical practice are expected.

Influence of low-dose proton pump inhibitors administered concomitantly or separately on the anti-platelet function of clopidogrel

Proton pump inhibitors (PPIs) at low doses can effectively prevent gastrointestinal bleeding due to aspirin and are widely used in Japan for gastroprotection in patients taking anti-platelet agents. We examined the influence of different PPIs at low doses administered concomitantly or separately on anti-platelet functions of clopidogrel. In 41 healthy Japanese volunteers with different CYP2C19 genotypes who took clopidogrel 75 mg in the morning alone, or with omeprazole 10 mg, esomeprazole 10 mg, lansoprazole 15 mg, or rabeprazole 10 mg, either concomitantly in the morning or separately in the evening, we measured the inhibition of platelet aggregation (IPA, %) using VerifyNow P2Y12 assay at 4 h after the last clopidogrel dose on Day 7 of each regimen. IPA by clopidogrel with rabeprazole administered at lunchtime, approximately 4 h after clopidogrel, was also measured. Mean IPAs in those concomitantly receiving omeprazole, esomeprazole, lansoprazole or rabeprazole (47.2 ± 21.1%, 43.2 ± 20.2%, 46.4 ± 18.8%, and 47.3 ± 19.2%, respectively) were significantly decreased compared with those receiving clopidogrel alone (56.0%) (all ps < 0.001). This decrease was observed when PPIs were administered separately in the evening. However, IPA by clopidogrel with rabeprazole administered at lunchtime was 51.6%, which was markedly similar to that of clopidogrel alone (p = 0.114). All tested PPIs reduce the efficacy of clopidogrel when administered concomitantly. Our preliminary data suggest that administration of rabeprazole 4 h following clopidogrel may minimize potential drug-drug interactions.

Combination Use of Clopidogrel and Proton Pump Inhibitors Increases Major Adverse Cardiovascular Events in Patients With Coronary Artery Disease: A Meta-Analysis

BACKGROUND

Published data indicated that combination use of clopidogrel and proton pump inhibitors (PPIs) may increase the incidence of major adverse cardiovascular events (MACEs). This has been a highly controversial topic for years.

DESIGN

The present study was performed to evaluate whether combination therapy of clopidogrel and PPIs is associated with increased risk of MACEs than with clopidogrel alone in patients with coronary artery disease.

METHODS

A systematic search of MEDLINE, EMBASE, and the Cochrane Library was conducted for studies recording the occurrence of MACEs in patients with exposure to concomitant use of clopidogrel and PPIs up to February 2015. Odds ratios (ORs) were combined using a random-effects model.

RESULTS

Patients receiving combination therapy with PPIs and clopidogrel were at significantly increased risk of MACEs (OR: 1.42; 95% confidence interval [CI]: 1.30-1.55). Adding a PPI to clopidogrel treatment was associated with a higher rate of MACE occurrence in rapid metabolizers (RMs, *1/*1) of CYP2C19 (OR: 1.42; 95% CI: 1.12-1.81), but there was no obviously increased rate (OR: 1.43; 95% CI: 0.89-2.28) in decreased metabolizers (with 1 or 2 loss-of-function allele). The increased risk of MACEs was similar in 4 classes of PPIs (omeprazole, lansoprazole, esomeprazole, and pantoprazole), but rabeprazole (OR: 1.03; 95% CI: 0.55-1.95) wasn't.

CONCLUSION

The combination use of clopidogrel and certain types of PPIs (omeprazole, lansoprazole, esomeprazole, pantoprazole) increases the risk of MACE in patients with coronary artery disease. Only in the RMs of CYP2C19, PPIs were associated with significantly increased MACE in patients coadministered with clopidogrel.

Snapshot of the prescribing practice for the clopidogrel and esomeprazole coprescription and cost evaluation of the application guidelines

The antiplatelet clopidogrel and the proton pump inhibitor esomeprazole demonstrate a pharmacokinetic interaction through CYP2C19 that could translate into clinical inefficacy of clopidogrel. No medical consensus as to their coprescription has been reached, and different guidelines are available. We evaluated the prescribing practices at the Geneva University Hospitals (HUG) by measuring whether the coprescription was staggered as suggested by experts. We estimated the financial impact of different implementation guidelines. We used the HUG electronic patient records to follow the physicians' prescriptions and the administration by nurses from January 2013 to April 2014. We performed a time series analysis to assess 15 years of proton pump inhibitors (PPIs) and antiplatelet drug use. “Extra costs” were calculated assuming that clopidogrel or esomeprazole would replace prasugrel or ticagrelor and pantoprazole or ranitidine, respectively. Only 10.8% of the patient medical orders for the clopidogrel and esomeprazole coprescription specified to stagger the administration, 12.6% specified a concomitant coprescription, and 76.6% had no clear information. A high rate of 49.6% of the nurses staggered the clopidogrel and esomeprazole coprescription when no clear information was given. We found a statistically significant decrease in clopidogrel use after the publication of the OCLA (Omeprazole–CLopidogrel–Aspirin) study and a significant increase in the trend of esomeprazole. Alternative treatments to avoid this interaction are cost ineffective or offer therapeutic options of lesser quality. We observed a high rate of 56.2% of the clopidogrel and esomeprazole coprescription in our hospital and can therefore not ignore the PK/PD interaction. The most common prescription practice was to not specify the time frame of administration, which was translated by nurses in 49.6% of the cases to a scheduled staggered coprescription of clopidogrel and esomeprazole. As long as no consensus has been reached, the medical orders time frame information should be mandatory to allow a clear and harmonious staggering strategy.

Proton pump inhibitors and other disease-based factors in the recurrence of adverse cardiovascular events following percutaneous coronary angiography: A long-term cohort

BACKGROUND

Dual aspirin-clopidogrel antiplatelet therapy (DAPT) has been shown to decrease the risk of adverse cardiac events after percutaneous coronary intervention (PCI). Proton pump inhibitors (PPIs) are used in these patients to decrease the risk of gastrointestinal bleeding and several studies have reported potential interaction and conflicting clinical outcomes with their use. We aim to assess the effect of different PPIs and other factors on the recurrence of cardiovascular (CV) events in patients following PCI.

METHODS

We performed a retrospective cohort on patients who underwent PCI in the last 5 years and were discharged with or without PPIs. Strict inclusion criteria were adopted, outcome measures were defined, and patient follow up up to 2 years was collected.

RESULTS

Out of 740 patients, 453 (61.2 %) had received PPIs and 287 (38.8 %) were discharged without PPIs. Ninety-five (12.8 %) patients were readmitted due to adverse CV events. Statistically, there was no significant difference in the recurrence of CV events with the use of different PPIs (p = 0.384) and PPI use had an overall protective effect (p = 0.009, HR 0.58 (CI 0.39-0.88). Patients with history of diabetes mellitus (p = 0.048) had an increased risk of adverse CV events.

CONCLUSION

We conclude that pharmacokinetic interaction between PPIs and antiplatelet therapy is not associated with adverse CV events. A comprehensive, multicenter, open-label trial including all PPI subclasses and patient and disease-based factors is warranted for a fair evaluation.

Proton Pump Inhibitors in Cardiovascular Disease: Drug Interactions with Antiplatelet Drugs

Aspirin and P2Y₁₂ receptor antagonists are widely used across the spectrum of cardiovascular diseases. Upper gastrointestinal complications, including ulcer and bleeding, are relatively common during antiplatelet treatment and, therefore, concomitant proton pump inhibitor (PPI) treatment is often prescribed.PPIs provide gastroprotection by changing the intragastric milieu, essentially by raising intragastric pH. In recent years, it has been heavily discussed whether PPIs may reduce the cardiovascular protection by aspirin and, even more so, clopidogrel. Pharmacodynamic and pharmacokinetic studies suggested an interaction between PPIs and clopidogrel, and subsequent clinical studies were conducted to evaluate the clinical impact of this interaction. More recently, it was reported that PPIs may also attenuate the antiplatelet effect of aspirin. This may be clinically important, because a fixed combination of aspirin and a PPI (esomeprazole) has recently been approved and because aspirin is the most widely used drug in patients with cardiovascular disease. The antiplatelet effect of the new P2Y₁₂ receptor antagonists, ticagrelor and prasugrel, seems less influenced by PPI co-treatment.Given the large number of patients treated with antithrombotic drugs and PPIs, even a minor reduction of platelet inhibition potentially carries considerable clinical impact. The present book chapter summarizes the evidence regarding the widespread use of platelet inhibitors and PPIs in combination. Moreover, it outlines current evidence supporting or opposing drug interactions between these drugs and discusses clinical implications.

Differential impact of selective serotonin reuptake inhibitors on platelet response to clopidogrel: a randomized, double-blind, crossover trial

STUDY OBJECTIVE

To assess the effect of two selective serotonin reuptake inhibitors (SSRIs), fluvoxamine and citalopram, that markedly differ in their level of cytochrome P450 (CYP) 2C19 inhibition, on the laboratory response to clopidogrel, a prodrug requiring metabolism by the CYP system, and especially CYP2C19, to produce its active form.

DESIGN

Randomized, double-blind, crossover trial.

SETTING

Clinical research unit of an academic medical center.

SUBJECTS

Fifteen healthy male volunteers.

INTERVENTION

All subjects received clopidogrel as a 300-mg loading dose on day 1, followed by 75 mg/day on days 2 and 3. Platelet function was tested at baseline and then after clopidogrel treatment on day 3. After a washout period of 2 weeks, subjects were randomly assigned in a double-blind manner to receive either citalopram 20 mg/day or fluvoxamine 100 mg/day for 7 days. On day 5, platelet function was tested while receiving the SSRI treatment alone; then, a 300-mg clopidogrel loading dose was administered, followed by clopidogrel 75 mg/day on days 6 and 7. Platelet function was then reassessed on day 7 while receiving the combination of the SSRI and clopidogrel. The treatment protocol was then repeated after a washout period of 2 weeks in all subjects with the other SSRI.

MEASUREMENTS AND MAIN RESULTS

The antiplatelet effects of fluvoxamine and citalopram and their interactions with clopidogrel were assessed. The response to these three drugs was assessed by light transmittance aggregometry and vasodilator-stimulated phosphoprotein phosphorylation, reporting P2Y12 receptor reactivity. Both fluvoxamine and citalopram tended to reduce adenosine diphosphate-induced aggregation: 80.8 ± 3.4% at baseline, 67.3 ± 6.3% while receiving citalopram, and 65.8 ± 6.4% while receiving fluvoxamine. All subjects had a good laboratory response to clopidogrel, with a mean aggregation of 23.5 ± 3.2% and a mean platelet reactivity index of 47.7 ± 3.9% (p<0.001 compared with baseline for both methods). Laboratory response to clopidogrel was significantly attenuated in the presence of fluvoxamine compared with the response in the presence of citalopram as tested both by aggregometry (32.3 ± 4.2% vs 23.4 ± 3%, p=0.04) and by vasodilator-stimulated phosphoprotein phosphorylation (52.7 ± 5.1% vs 35.9 ± 4.2%, p=0.02).

CONCLUSION

Fluvoxamine attenuated the laboratory response to clopidogrel, possibly through inhibition of CYP2C19, whereas citalopram did not affect this response. These potential drug interactions should be taken into consideration in the selection of the appropriate antidepressant agent for patients who are treated with clopidogrel.

Effects of the CYP2C19 genetic polymorphism on gastritis, peptic ulcer disease, peptic ulcer bleeding and gastric cancer

BACKGROUND

The CYP2C19 genotype has been found to be an important factor for peptic ulcer healing and H. pylori eradication, influencing the efficacy of proton pump inhibitors (PPIs) and the pathogenesis of gastric cancer. The aim of this study was to investigate clinical correlations of the CYP2C19 genotype in patients with gastritis, peptic ulcer disease (PUD), peptic ulcer bleeding (PUB) and gastric cancer in Thailand.

MATERIALS AND METHODS

Clinical information, endoscopic findings and H. pylori infection status of patients were assessed between May 2012 and November 2014 in Thammasat University Hospital, Thailand. Upper GI endoscopy was performed for all patients. Five milliliters of blood were collected for H. pylori serological diagnosis and CYP2C19 study. CYP2C19 genotypes were determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis (RFLP) and classified as rapid metabolizer (RM), intermediate metabolizer (IM) or poor metabolizer (PM).

RESULTS

A total of 202 patients were enrolled including 114 with gastritis, 36 with PUD, 50 with PUB and 2 with gastric cancer. Prevalence of CYP2C19 genotype was 82/202 (40.6%) in RM, 99/202 (49%) in IM and 21/202 (10.4%) in PM. Overall H. pylori infection was 138/202 patients (68.3%). H. pylori infection was demonstrated in 72% in RM genotype, 69.7% in IM genotype and 47.6% in PM genotype. Both gastric cancer patients had the IM genotype. In PUB patients, the prevalence of genotype RM (56%) was highest followed by IM (32%) and PM(12%). Furthermore, the prevalence of genotype RM in PUB was significantly greater than gastritis patients (56% vs 36%: p=0.016; OR=2.3, 95%CI=1.1-4.7).

CONCLUSIONS

CYP2C19 genotype IM was the most common genotype whereas genotype RM was the most common in PUB patients. All gastric cancer patients had genotype IM. The CYP2C19 genotype RM might be play role in development of PUD and PUB. Further study in different population is necessary to verify clinical usefulness of CYP2C19 genotyping in development of these upper GI diseases.

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.

Clinical outcomes associated with proton pump inhibitor use among clopidogrel-treated patients within CYP2C19 genotype groups following acute myocardial infarction

We examined clinical outcomes with proton pump inhibitors (PPI) use within CYP2C19 genotype groups during clopidogrel treatment following acute myocardial infarction (AMI). 2062 patients were genotyped for CYP2C19*2 and *17 variants in TRIUMPH. 12 month clinical outcomes were analyzed among patients discharged on clopidogrel within CYP2C19*2 carrier, CYP2C19*17 carrier, and CYP2C19*1 homozygote genotype groups. PPI use was not associated with a difference in mortality. Among clopidogrel-treated Caucasians following AMI, PPI use was associated with a significantly higher rate of cardiac rehospitalization (HR 1.62, 95% CI 1.19-2.19; P=0.002) compared with no PPI use. PPI users who were carriers of the CYP2C19*17 variant experienced significantly higher rates of cardiac rehospitalization (HR 2.05, 95% CI 1.26-3.33; P=0.003), carriers of the CYP2C19*2 variant had a trend toward increased 1-year cardiac rehospitalization (HR 1.69, 95% CI 0.95-2.99; P=0.07), while no significant differences were observed among CYP2C19*1 homozygotes. These results indicate that the risks associated with PPI use among clopidogrel-treated Caucasian post-MI patients are impacted by CYP2C19 genotype, and suggest knowledge of genotype may be useful for personalizing PPI use among patients following AMI to reduce rehospitalization.

Genetic and nongenetic factors influencing the response to clopidogrel

The antiplatelet drug clopidogrel is a commonly prescribed therapy in patients with acute coronary syndrome. However, its clinical efficacy is hampered by a wide inter-patient response variability, with over 30% of patients treated with this drug experiencing an inadequate antiplatelet response. There are growing evidences that clopidogrel response variability is associated with cytochrome P450 (CYP) enzyme genetic polymorphisms, primarily CYP2C19 which is responsible for the conversion of clopidogrel into its active metabolite. All of the CYP2C19 polymorphism data suggest that carriers of allele *2 or *17 are at greater risk of ischemic or bleeding events, particularly in patients with acute coronary syndrome undergoing percutaneous coronary intervention. Yet, CYP2C19 status explains only 12% of clopidogrel response variability, indicating that genetic variants other than CYP2C19 might be important. Clopidogrel undergoes intestinal efflux via P-glycoprotein, encoded by the ABCB1 gene. The C3435T polymorphism in this gene affects the bioavailability of clopidogrel, however, its effects on clinical outcomes are inconclusive. Similarly, a polymorphism in the gene encoding PON1, a rate-limiting enzyme for clopidogrel bioactivation, also affects the response to clopidogrel. Among nongenetic factors, an adverse drug interaction between proton pump inhibitors and clopidogrel is often reported, but evidence is inconclusive. A genetic test to identify potential responders to clopidogrel might be useful. However, the use of such tests is currently limited because they focus mainly on CYP2C19 loss-of-function alleles, and there is no empirical evidence yet for genotype-guided clopidogrel therapy.

Pharmacodynamic effects of cilostazol versus clopidogrel in stented patients under proton pump inhibitor co-administration: the ACCEL-PARAZOL study

AIM

Proton pump inhibitor (PPI) therapy has been shown to attenuate the antiplatelet effects of clopidogrel. The aim of this study was to compare the antiplatelet effects of cilostazol versus clopidogrel in patients co-administered a PPI.

METHODS

We enrolled PPI-naïve stented patients treated with standard clopidogrel and aspirin therapy for at least six months (n=100). The patients were randomly assigned to receive either cilostazol at a dose of 100mg twice daily (CILO group) or clopidogrel at a dose of 75mg daily (CLPD group) in addition to lansoprazole (30mg daily). The platelet aggregation (PA) determined using light transmittance aggregometry and the platelet reactivity index (PRI) obtained using a vasodilator-stimulated phosphoprotein phosphorylation assay were measured before randomization and at the 14-day follow-up visit. The primary endpoint was the PRI value at follow-up.

RESULTS

At follow-up, the CLPD group showed similar values of PRI as the CILO group (66.9±14.0% vs. 63.1±14.1%; mean difference: 3.9%; 95% confidence interval of difference: -1.7% to 9.4%; p=0.174). However, the 6μg/mL collagen- and 0.5mg/mL arachidonic acid-induced PA values in the CLPD group were higher than those observed in the CILO group (mean differences: 9.8% to 11.1%; all p values ＜0.001). CYP2C19 loss-of-function allele carriage was the major contributing factor associated with the PRI level in the absence of lansoprazole treatment (with a gene-dose effect); this association was not observed in the subjects receiving lansoprazole co-administration in the CLPD group.

CONCLUSIONS

During lansoprazole co-administration, cilostazol treatment achieves a more favorable platelet function profile than clopidogrel therapy. The use of combination treatment with cilostazol and aspirin deserves further attention with respect to the management of stable stented patients requiring PPI co-administration.

Aspirin decreases systemic exposure to clopidogrel through modulation of P-glycoprotein but does not alter its antithrombotic activity

Decreased oral clopidogrel absorption caused by induction of intestinal permeability glycoprotein (P-gp) expression after aspirin administration was observed in rats. This study evaluated the effect of aspirin coadministration on the pharmacokinetics/pharmacodynamics of clopidogrel in humans. A single 75-mg dose of clopidogrel was orally administered before and after 2 and 4 weeks of once-daily 100-mg aspirin administration in 18 healthy volunteers who were recruited based on CYP2C19 and PON1 genotypes. Plasma concentrations of clopidogrel and its active metabolite, H4, and relative platelet inhibition (RPI) were determined. The P-gp microRNA miR-27a increased by up to 7.67-fold (P = 0.004) and the clopidogrel area under the concentration-time curve (AUC) decreased by 14% (P > 0.05), but the AUC of H4 remained unchanged and RPI increased by up to 15% (P = 0.002) after aspirin administration. These findings indicate low-dose aspirin coadministration may decrease clopidogrel bioavailability but does not decrease its efficacy.

Factors affecting carisoprodol metabolism in pain patients using urinary excretion data

Carisoprodol is a skeletal muscle relaxant prescribed to treat pain. Carisoprodol is metabolized to meprobamate, an active metabolite with anxiolytic effects, by the genetically polymorphic CYP2C19 enzyme. Concomitant use of CYP2C19 substrates or inhibitors may alter carisoprodol metabolism, with therapeutic and/or toxic implications for effectively treating patients with pain. This was a retrospective analysis of urinary excretion data collected from patients with pain from March 2008 to May 2011. Carisoprodol and meprobamate urine concentrations were measured by liquid chromatography-tandem mass spectrometry, and the metabolic ratio (MR) of meprobamate to carisoprodol concentrations was determined in 14,965 subjects. The MR geometric mean and 95% confidence interval (95% CI) of the young group (105, 95% CI = 99.1-113) were ∼47.4% higher than the middle-aged group (71.9, 95% CI = 70-73.8) and nearly two times higher than the elderly group (54.4, 95% CI = 51.3-57.6). Females had a 20.7% higher MR compared with males. No significant change in the MR was observed with overall CYP2C19 inhibitor or substrate use. However, evaluation of individual inhibitors showed co-administration with esomeprazole or fluoxetine was associated with a 31.8 and 24.6% reduction in MR, respectively, compared with controls (P < 0.05). Omeprazole did not significantly affect the MR. Patient-specific factors such as age, sex and co-medications may be important considerations for effective carisoprodol therapy.

Increased risk for developing major adverse cardiovascular events in stented Chinese patients treated with dual antiplatelet therapy after concomitant use of the proton pump inhibitor

BACKGROUND

Some clinical studies have demonstrated that the proton pump inhibitor (PPI) could decrease clopidogrel platelet response and increase major adverse cardiovascular events (MACE) in white or black subjects. However, that remains to be determined in Chinese patients. In this study, we sought to determine whether there could be an increased risk for developing MACE after concomitant use of dual antiplatelet therapy (DAT) and a PPI in Chinese patients treated with percutaneous coronary intervention (PCI) and stenting.

METHODS

This study was a 5-year, single-center, retrospective cohort analysis of eligible patients (n = 6188) who received DAT and a PPI concomitantly (defined as PPI users) before discharge and/or 12-month follow-up after discharge as compared with those who received DAT alone (also defined as non-PPI users, n = 1465). The incidence of recurrent MACE, such as myocardial infarction (MI), definite stent thromboses (ST), or cardiovascular death, was compared between the PPI users and non-users.

RESULTS

PPI users had a significantly higher incidence of the MACE than non-users (13.9% vs. 10.6%; adjusted HR: 1.33; 95% CI: 1.12 - 1.57, P = 0.007). Stratified analysis revealed that concurrent use of DAT and a PPI was associated with a significantly increased risk for developing ST compared with DAT alone (1% vs. 0.4%; adjusted HR: 2.66, 95% CI: 1.16 - 5.87, P = 0.012). However, there were no significant differences in the risk of MI, cardiovascular death and other adverse events, regardless of combination of clopidogrel and a PPI.

CONCLUSIONS

The study further suggests that concomitant use of DAT and a PPI may be associated with an increased risk for developing MACE, in particular definite ST, in Chinese PCI patients after discharge as compared with use of DAT alone.

Antiplatelet drug interactions with proton pump inhibitors

INTRODUCTION

Non-aspirin antiplatelet agents (e.g., clopidogrel, prasugrel, ticagrelor) are commonly prescribed for the prevention of recurrent cardiovascular events among patients with acute coronary syndromes (ACS) and/or those undergoing percutaneous coronary intervention (PCI). In addition, combination therapy with proton pump inhibitors (PPIs) is often recommended to attenuate gastrointestinal bleeding risk, particularly during dual antiplatelet therapy (DAPT) with clopidogrel and aspirin. Importantly, a pharmacological interaction between clopidogrel and some PPIs has been proposed based on mutual CYP450-dependent metabolism, but available evidence is inconsistent.

AREAS COVERED

This article provides an overview of the currently approved antiplatelet agents and PPIs, including their metabolic pathways. Additionally, the CYP450 isoenzyme at the center of the drug interaction, CYP2C19, is described in detail, and the available evidence on both the potential pharmacological interaction and influence on clinical outcomes are summarized and evaluated.

EXPERT OPINION

Although concomitant DAPT and PPI use reduces clopidogrel active metabolite levels and ex vivo-measured platelet inhibition, the influence of the drug interaction on clinical outcomes has been conflicting and largely reported from non-randomized observational studies. Despite this inconsistency, a clinically important interaction cannot be definitively excluded, particularly among patient subgroups with higher overall cardiovascular risk and potentially among CYP2C19 loss-of-function allele carriers.

Proton pump inhibitors and potential interactions with clopidogrel: an update

Clopidogrel, an antiplatelet agent, is increasingly prescribed for patients with recent stroke, myocardial infarction, acute coronary syndrome, and/or patients post-coronary stent insertion to prevent recurrent cardiovascular events. Since clopidogrel can increase the risk of gastrointestinal hemorrhage, co-administration of proton pump inhibitors (PPIs) has been recommended, particularly in patients at high risk. In 2009, the FDA issued warnings about potential interactions between clopidogrel and PPIs, given the fact that both drugs are metabolized via the cytochrome P450 pathway. Prior studies have demonstrated significant reduction in platelet inhibition when PPI therapy is administered to subjects on clopidogrel therapy. Two meta-analyses were published in 2010 and 2011, the first suggesting association of PPIs with adverse cardiovascular events when observational studies were examined, but noting that the results were limited by the presence of significant heterogeneity. The second meta-analysis did not find a significant increase in the risk of adverse primary events (which included all cause mortality, cardiovascular death, myocardial infarction, or stroke), and concluded that analysis of the data from two randomized controlled trials yielded a risk difference of zero. An updated literature search was performed to assess clinical studies describing interactions between PPIs and clopidogrel published from 2011-2012. The majority of these studies did not show significant interactions when primary cardiac outcomes were considered. More importantly, the newer data demonstrated that PPI usage independently was a risk factor for adverse CV outcomes, since most PPI users were older patients who were more likely to have concomitant co-morbid conditions. Two updated reviews also concluded that the presence of confounding factors likely explained differences in results between studies, and that there were no significant differences in effects on clopidogrel between individual proton pump inhibitors. Overall, clinicians can assure their patients that combination therapy is safe when indicated in a patient at high risk of GI bleeding, but they should also stop PPI therapy if it is not clinically indicated.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

Individualized therapy for gastroesophageal reflux disease: potential impact of pharmacogenetic testing based on CYP2C19

The main therapeutic agent for gastroesophageal reflux disease (GERD) is a proton pump inhibitor (PPI). Plasma levels and the acid inhibitory effect of PPIs depend on the activity of cytochrome P450 (CYP) 2C19, which is polymorphic. Genotypes of CYP2C19 are classified into three groups: rapid metabolizers (RMs: *1/*1), intermediate metabolizers (IMs: *1/*X), and poor metabolizers (PMs: *X/*X), where *1 and X represent the wild type and the mutant allele, respectively. RMs include ultra-rapid metabolizers, who possess the CYP2C19*17 allele. The pharmacokinetics and pharmacodynamics of PPIs differ among different CYP2C19 genotype groups. Plasma PPI levels and intragastric pH values during PPI treatment are lowest in the RM group, intermediate in the IM group, and highest in the PM group. These CYP2C19-genotype-dependent differences in the pharmacokinetics and pharmacodynamics of PPIs influence the healing and recurrence of GERD during PPI treatment, suggesting the need for CYP2C19 genotype-based tailored therapy for GERD. CYP2C19 pharmacogenetics should be taken into consideration for the personalization of PPI-based therapy. However, the clinical usefulness of CYP2C19 genotype testing in GERD therapy should be verified in clinical studies.

[Proton pump inhibitors and clopidogrel: a hazardous association?]

Proton pump inhibitors (PPI) and antiplatelet agents, especially aspirin and clopidogrel, are among the most prescribed medications worldwide. Their co-administration is justified by the increased risk of gastrointestinal bleeding related to the antiplatelet therapy. The issue of the interaction between PPI and clopidogrel has been raised with the emergence of the concept of "high on-clopidogrel platelet reactivity" (or "clopidogrel resistance") together with the discovery of the role of CYP2C19 isoform in the pharmacokinetics of those two medications. Indeed, CYP2C19 is involved in the conversion of the clopidogrel pro-drug into its active metabolite and is involved in the metabolisation of PPI into inactive metabolites, acting as substrates/inhibitors of CYP2C19. Despite their heterogeneity, most pharmacodynamic studies have shown a decreased clopidogrel antiplatelet effect when associated to PPI, especially those with the highest CYP2C19 inhibiting activity (omeprazole, lansoprazole, rabeprazole). On the other hand, clinical studies are inconclusive. Retrospective studies have shown an increased risk of major cardiovascular events or mortality when clopidogrel and PPI are associated in comparison with clopidogrel alone, particularly in the patients with the higher cardiovascular risk. However, the two prospective randomized studies published so far did not find any interaction and confirmed the benefit of PPI on the gastrointestinal bleeding. As a conclusion, as the clinical studies are not conclusive, the French health authorities have recently removed the alert about this interaction. PPI and clopidogrel can thus be co-prescribed.

Potential savings of harmonising hospital and community formularies for chronic disease medications initiated in hospital

Background

Hospitals in Canada manage their formularies independently, yet many inpatients are discharged on medications which will be purchased through publicly-funded programs. We sought to determine how much public money could be saved on chronic medications if hospitals promoted the initiation of agents with the lowest outpatient formulary prices.

Methods

We used administrative databases for the province of Ontario to identify patients initiated on a proton pump inhibitor (PPI), angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) following hospital admission from April 1^st 2008-March 31^st 2009. We assessed the cost to the Ontario Drug Benefit Program (ODB) over the year following initiation and determined the cost savings if prescriptions were substituted with the least expensive agent in each class.

Results

The cost for filling all PPI, ACE inhibitor and ARB prescriptions was $ 2.48 million, $968 thousand and $325 thousand respectively. Substituting the least expensive agent could have saved $1.16 million (47%) for PPIs, $162 thousand (17%) for ACE inhibitors and $14 thousand (4%) for ARBs over the year following discharge.

Interpretation

In a setting where outpatient prescriptions are publicly funded, harmonising outpatient formularies with inpatient therapeutic substitution resulted in modest cost savings and may be one way to control rising pharmaceutical costs.

Evaluation of six proton pump inhibitors as inhibitors of various human cytochromes P450: focus on cytochrome P450 2C19

Six proton pump inhibitors (PPIs), omeprazole, lansoprazole, esomeprazole, dexlansoprazole, pantoprazole, and rabeprazole, were shown to be weak inhibitors of cytochromes P450 (CYP3A4, -2B6, -2D6, -2C9, -2C8, and -1A2) in human liver microsomes. In most cases, IC₅₀ values were greater than 40 μM, except for dexlansoprazole and lansoprazole with CYP1A2 (IC₅₀ = ∼8 μM) and esomeprazole with CYP2C8 (IC₅₀ = 31 μM). With the exception of CYP2C19 inhibition by omeprazole and esomeprazole (IC₅₀ ratio, 2.5 to 5.9), there was no evidence for a marked time-dependent shift in IC₅₀ (IC₅₀ ratio, ≤ 2) after a 30-min preincubation with NADPH. In the absence of preincubation, lansoprazole (IC₅₀ = 0.73 μM) and esomeprazole (IC₅₀ = 3.7 μM) were the most potent CYP2C19 inhibitors, followed by dexlansoprazole and omeprazole (IC₅₀ = ∼7.0 μM). Rabeprazole and pantoprazole (IC₅₀ = ≥ 25 μM) were the weakest. A similar ranking was obtained with recombinant CYP2C19. Despite the IC₅₀ ranking, after consideration of plasma levels (static and dynamic), protein binding, and metabolism-dependent inhibition, it is concluded that omeprazole and esomeprazole are the most potent CYP2C19 inhibitors. This was confirmed after the incubation of the individual PPIs with human primary hepatocytes (in the presence of human serum) and by monitoring their impact on diazepam N-demethylase activity at a low concentration of diazepam (2 μM). Data described herein are consistent with reports that PPIs are mostly weak inhibitors of cytochromes P450 in vivo. However, two members of the PPI class (esomeprazole and omeprazole) are more likely to serve as clinically relevant inhibitors of CYP2C19.

Effects of proton pump inhibitors on platelet function in patients receiving clopidogrel: a systematic review

BACKGROUND

There is considerable debate regarding the negative impact of concomitant proton pump inhibitor (PPI) therapy on the antiplatelet efficacy of clopidogrel.

AIM

The aim of this study was to perform a systematic review of studies that have evaluated the platelet function of patients receiving clopidogrel alone compared with those receiving both clopidogrel and PPIs.

METHODS

We searched MEDLINE, EMBASE and the Cochrane Controlled Trials Register in February 2011 for randomized and non-randomized studies that reported platelet function results in patients taking clopidogrel, with or without PPIs.

RESULTS

Our review included 19 studies (13 trials and 6 observational studies) involving 4693 patients. There was considerable heterogeneity in the study designs, patient characteristics, laboratory tests of platelet function, and drug exposure (dose and duration of PPI and clopidogrel). There was some evidence against omeprazole, with five of nine studies demonstrating a significant interaction with clopidogrel. The available platelet function data on esomeprazole (six studies) or pantoprazole (six studies) did not demonstrate a significant interaction. Of the six studies that statistically analysed platelet function data with omeprazole compared with pantoprazole, three showed a significantly greater interaction between omeprazole and clopidogrel, whereas three studies with limited sample sizes were unable to find a significant difference in the effects of omeprazole and pantoprazole.

CONCLUSION

Platelet function studies do not demonstrate a clear or consistent interaction between clopidogrel and PPIs. These studies are difficult to interpret given the lack of information on drug exposure (dose and duration), variation in laboratory methodology and lack of genetic information. Consequently, platelet function data are of uncertain clinical relevance in determining the risk of an adverse cardiovascular interaction between PPIs and clopidogrel. Clinicians should continue to clinically assess the gastrointestinal risk of the patients and make their prescribing decision for PPIs based on any anticipated benefits in reducing risk of peptic ulcers and gastrointestinal haemorrhage.

Effects of PPIs and an H2 blocker on the antiplatelet function of clopidogrel in Japanese patients under dual antiplatelet therapy

AIM

Dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is essential after percutaneous coronary intervention (PCI). Clopidogrel is a prodrug and changed into active metabolite by cytochrome p450 enzymes (CYPs), especially CYP2C19. Proton pump inhibitors (PPIs) are used for the prevention of aspirin-induced gastrointestinal bleeding. PPIs are also metabolized by CYP2C19, although the degree of its contribution is dependent on the kind of PPI. Omeprazole, a PPI, has been reported to weaken the antiplatelet effects of clopidogrel. Famotidine, a histamine receptor type 2 (H2) blocker, could also be an alternative to PPIs. The aim of this study was to evaluate the effects of PPIs and an H2 blocker on the antiplatelet function of clopidogrel.

METHODS

Patients receiving DAPT due to prior PCI, who took either omeprazole or rabeprazole, were enrolled (n=25). The initial PPI was changed to the other PPI as a crossover study. In another study, patients undergoing DAPT without taking PPIs or H2 blockers were enrolled (n=30) and famotidine was added.

RESULTS

Platelet aggregability when taking omeprazole was higher than when taking rabeprazole, evaluated by an optical aggregometer using collagen as a stimulus (p=0.0051) and by the VerifyNow P2Y12 assay (p=0.0060). Platelet aggregability when taking rabeprazole was comparable to that in control patients (n=15). Concomitant use of famotidine had no effect.

CONCLUSION

Omeprazole significantly reduced the antiplatelet effect of clopidogrel and this effect on clopidogrel was stronger than that of rabeprazole. Concomitant use of famotidine had no effect on the antiplatelet effect of clopidogrel.

Genetic determinants of platelet response to clopidogrel

Antiplatelet agents are the mainstay treatment in the prevention and management of atherothrombotic complications. However, a substantial interpatient variability in response to clopidogrel has been reported. Furthermore, patients with coronary artery disease and lesser platelet inhibition in response to clopidogrel are at increased risk for cardiovascular events. Clopidogrel after absorption requires two-step oxidation by the hepatic cytochrome P450 to generate its active metabolite. Polymorphisms of genes encoding the cytochrome enzymes and P-glycoprotein involved in clopidogrel absorption are regarded as major determinants of the interindividual variability in the clopidogrel-induced platelet inhibition. In our review we discuss the prevalence and clinical significance of various alleles of the genes: CYP2C19 and ABCB1 in the setting of coronary artery disease. Allele CYP2C19*2 is associated with excess of ischaemic events including myocardial infarction and stent thrombosis. On the other hand, CYP2C19*17 allele poses a serious threat of bleeding. Data concerning the prognostic value of genetic variant 3435C→T of ABCB1 remain inconclusive.