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Indigenous Australians face a disproportionately severe burden of chronic disease relative to other Australians, with elevated rates of morbidity and mortality. While genomics technologies are slowly gaining momentum in personalised treatments for many, a lack of pharmacogenomic research in Indigenous peoples could delay adoption. Appropriately implementing pharmacogenomics in clinical care necessitates an understanding of the frequencies of pharmacologically relevant genetic variants within Indigenous populations. We analysed whole-genome sequence data from 187 individuals from the Tiwi Islands and characterised the pharmacogenomic landscape of this population. Specifically, we compared variant profiles and allelic distributions of previously described pharmacologically significant genes and variants with other population groups. We identified 22 translationally relevant pharmacogenomic variants and 18 clinically actionable guidelines with implications for drug dosing and treatment of conditions including heart disease, diabetes and cancer. We specifically observed increased poor and intermediate metabolizer phenotypes in the CYP2C9 (PM:19%, IM:44%) and CYP2C19 (PM:18%, IM:44%) genes.

Dietary supplement use has continued to rise. In addition to supplement-drug interactions, it is prudent to consider how dietary supplements may interact with a patient’s specific pharmacogenetics. Variations in genes associated with CYP 450 enzymes have evidence of impacting drug metabolism and adverse effects. This research was performed to evaluate CYP P450 enzyme activity of the top 15 dietary supplements used in the USA in order to initiate pharmacogenetic considerations specific to commonly used dietary supplements. The most common dietary supplements used in the USA were obtained from the National Health and Nutrition Examination Survey (NHANES). Primary literature detailing supplement CYP P450 activity was compiled from PubMed using MeSH search terms: supplement name(s), cytochrome P450 enzymes, metabolism, and pharmacokinetics. Additional resources utilized for documented CYP enzyme genotypes were the pharmacogenetic databases from Clinical Pharmacogenetics Implementation Consortium and The Pharmacogenomic Variation Consortium. Of the 15 most common dietary supplements used in the USA, 53% (cranberry, echinacea, garlic, ginkgo biloba, ginseng, melatonin, milk thistle, and valerian) exhibit CYP P450 metabolism, with some having possible induction activity as well. Melatonin and garlic are substrates of CYP1A2 and CYP2C19, respectively. Additionally, there is evidence of echinacea having possible CYP3A4 induction activity. CYP P450 activity is an important consideration for any patient but becomes increasingly critical if patients have certain CYP P450 phenotypes that impact metabolism. These popular supplements have the potential for changes in supplement exposure, and adverse effects based on pharmacogenetic profiles. Furthermore, these sites of metabolism are shared with many medications, setting the stage for possibly more profound interactions between medications and supplements. This paper highlights the mechanisms in which dietary supplements may constitute a risk for patients with certain CYP P450 phenotypes. Further research is needed in the area of dietary supplements and their pharmacogenomic implications.

The Pharmacogenomics (PGx) Profile Service was a proof-of-concept project to implement PGx in patient care at Mayo Clinic. Eighty-two healthy individuals aged 18 and older underwent genotyping of CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, SLCO1B1, HLA-B*58:01, and VKORC1. A PGx pharmacist was involved in ordering, meeting with patients, interpreting, reviewing, and documenting results. Ninety three percent were CYP1A2 rapid metabolizers, 92% CYP3A4 normal metabolizers, and 88% CYP3A5 poor metabolizers; phenotype frequencies for CYP2C19 and CYP2D6 varied. Seventy-three percent had normal functioning SLCO1B1 transporter, 4% carried the HLA-B*58:01 risk variant, and 35% carried VKORC1 and CYP2C9 variants that increased warfarin sensitivity. Pre-emptive PGx testing offered medication improvement opportunity in 56% of participants for commonly used medications. A collaborative approach involving a PGx pharmacist integrated within a clinical practice with regards to utility of PGx results allowed for implementation of the PGx Profile Service.

The purpose was to explore the value of high on-treatment platelet reactivity (HTPR) in predicting long-term clinical outcomes for stroke patients. The platelet reactivity was assayed after being treated with either 75 mg clopidogrel or 100 mg aspirin daily with VerifyNow System in stroke patients. HTPR for clopidogrel was defined as PRU ≥ 208, and that for aspirin was defined as ARU ≥ 550. CYP2C19 genotyping was performed using the Sequenom MassARRAY iPLEX platform. The primary endpoint was a composite of recurrent ischemic stroke, transient ischemic attack, myocardial infarction, or ischemic vascular death. The safety endpoint was bleeding. In the clopidogrel group, among 345 patients recruited, 174 of them were categorized as HTPR. A total of 270 patients were followed up for 54 months. There was a significant association between HTPR and the primary endpoint (HRadj 2.13 [95% CI, 1.43–3.15], p

Urine drug testing (UDT) is a tool for monitoring drug use, including oxycodone. While variation in cytochrome P450 (CYP) genes is known to alter oxycodone metabolism, its impact on UDT results of oxycodone and its metabolites has not been well-studied. Here, multivariate analysis was performed on retrospective UDT results of 90,379 specimens collected from 14,684 genotyped patients prescribed oxycodone. Genetic variation in CYP2D6 and CYP2C19 had a significant impact on oxymorphone/oxycodone ratios, with a 6.9-fold difference between CYP2D6 ultrarapid metabolizers (UMs) and poor metabolizers (PMs; p < 10-300) and a 1.6-fold difference between CYP2C19 UMs and PMs (p = 1.50 × 10-4). CYP2D6 variation also significantly impacted noroxycodone/oxycodone ratios (p = 6.95 × 10-38). Oxycodone-positive specimens from CYP2D6 PMs were ~5-fold more likely to be oxymorphone-negative compared to normal metabolizers. These findings indicate that multivariate analysis of UDT data may be used to reveal the real-world impact of genetic and non-genetic factors on drug metabolism.

Isoniazid (INH) is prescribed both for the prophylaxis as well as the treatment of tuberculosis. It is primarily metabolized through acetylation by a highly polymorphic enzyme, N-acetyl transferase 2 (NAT2), owing to which significant variable systemic drug levels have been reported among slow and rapid acetylators. Furthermore, many drugs, like phenytoin, diazepam, triazolam, etc., are known to show toxic manifestation when co-administered with INH and it happens prominently among slow acetylators. Additionally, it is revealed in in vitro inhibition studies that INH carries noteworthy potential to inhibit CYP2C19 and CYP3A4 enzymes. However, CYP inhibitory effect of INH gets masked by opposite enzyme-inducing effect of rifampicin, when used in combination. Thus, distinct objective of this study was to fill the knowledge gaps related to gene-drug-drug interactions (DDI) potential of INH when given alone for prophylactic purpose. Whole body-PBPK models of INH were developed and verified for both slow and fast acetylators. The same were then utilized to carry out prospective DDI studies with CYP2C19 and CYP3A4 substrates in both acetylator types. The results highlighted likelihood of significant higher blood levels of CYP2C19 and CYP3A4 substrate drugs in subjects receiving INH pre-treatment. It was also re-established that interaction was more likely in slow acetylators, as compared to rapid acetylators. The novel outcome of the present study is the indication that prescribers should give careful consideration while advising CYP2C19 and CYP3A4 substrate drugs to subjects who are on prophylaxis INH therapy, and are slow to metabolic acetylation.

Jingyin granules, a marketed antiviral herbal medicine, have been recommended for treating H1N1 influenza A virus infection and Coronavirus disease 2019 (COVID-19) in China. To fight viral diseases in a more efficient way, Jingyin granules are frequently co-administered in clinical settings with a variety of therapeutic agents, including antiviral drugs, anti-inflammatory drugs, and other Western medicines. However, it is unclear whether Jingyin granules modulate the pharmacokinetics of Western drugs or trigger clinically significant herb-drug interactions. This study aims to assess the inhibitory potency of the herbal extract of Jingyin granules (HEJG) against human drug-metabolizing enzymes and to clarify whether HEJG can modulate the pharmacokinetic profiles of Western drug(s) in vivo. The results clearly demonstrated that HEJG dose-dependently inhibited human CES1A, CES2A, CYPs1A, 2A6, 2C8, 2C9, 2D6, and 2E1; this herbal medicine also time- and NADPH-dependently inhibited human CYP2C19 and CYP3A. In vivo tests showed that HEJG significantly increased the plasma exposure of lopinavir (a CYP3A-substrate drug) by 2.43-fold and strongly prolonged its half-life by 1.91-fold when HEJG (3 g/kg) was co-administered with lopinavir to rats. Further investigation revealed licochalcone A, licochalcone B, licochalcone C and echinatin in Radix Glycyrrhizae, as well as quercetin and kaempferol in Folium Llicis Purpureae, to be time-dependent CYP3A inhibitors. Collectively, our findings reveal that HEJG modulates the pharmacokinetics of CYP substrate-drug(s) by inactivating CYP3A, providing key information for both clinicians and patients to use herb-drug combinations for antiviral therapy in a scientific and reasonable way.

Acute coronary syndrome (ACS) carries a high mortality in Uygur populations. Percutaneous coronary intervention (PCI) is a safe treatment for patients with ACS. Clopidogrel reduces the risk for recurrent cardiovascular events after PCI; however, its activity is influenced by cytochrome P450 (CYP450), ATP-binding cassette transporter B1 (ABCB1), and paraoxonase-1 (PON1). To assess the effects of genetic polymorphisms CYP2C19*2, *3, *17, ABCB1 C3435T, and PON1 Q192R along with clinical and demographic factors on variations in responses in Uygur patients following PCI. We enrolled 281 patients with PCI who were treated with clopidogrel and aspirin for at least 12 months and recorded major adverse cardiovascular events (MACE) or bleeding within 1 year. Approximately, 2 mL of peripheral venous blood samples were used for genotype detection. Binary logistic regression with likelihood ratio forward stepwise analysis and redundancy analysis were carried out to identify factors associated with MACE. We analyzed risk factors including age, body mass index, smoking, hypertension, dyslipidemia, gender, alcohol consumption, diabetes mellitus, carriers of ABCB1 C3435T T allele, carriers of PON1 Q192R A allele, metabolizer phenotype of CYP2C19, number of targeted vessels, and number of stents. The CYP2C19 IMs (OR 3.546, 95% CI 1.972–6.375, P = 0.001), CYP2C19 PMs (OR 7.038, 95% CI 1.658–29.880, P = 0.008), and number of targeted vessels (OR 2.033, 95% CI 1.078–3.648, P = 0.026) were significantly associated with MACE. The CYP2C19 IMs, PMs, and the number of targeted vessels are essential factors associated with MACE risk in dual clopidogrel-treated Uygur population with ACS following PCI. These data provide valuable insights into the genetic polymorphisms affecting clopidogrel response among minority groups in China.

Genetic variation in the activation of the prodrug cyclophosphamide (CP) by cytochrome P450 (CYP) enzymes has been shown to influence outcomes. However, CYP are also subject to phenoconversion due to either the effects of comedications or cancer associated down-regulation of expression. The aim of this study was to assess the relationship between CP bioactivation with CYP2B6 and CYP2C19 genotype, as well as CYP2C19 phenotype, in breast cancer patients. CP and the active metabolite levels were assessed in breast cancer patients (n = 34) at cycle 1 and cycle 3 of treatment. Patients were genotyped for a series of SNP known to affect CYP2B6 and CYP2C19 function. The activity of CYP2C19 was also assessed using a probe drug. We found a significant linear gene-dose relationship with CYP2B6 coding SNP and formation of 4-hydroxycyclophosphamide. A possible association with CYP2C19 null genotype at cycle 1 was obscured at cycle 3 due to the substantial intra-individual change in CP bioactivation on subsequent dosing. Comedications may be the cause for this inter-occasion variation in bioactivation of cyclophosphamide and the ensuing phenoconversion may account for the conflicting reports in the literature about the relationship between CYP2C19 genotype and CP bioactivation pharmacokinetics. Trial registration ANZCTR363222 (6/11/2012, retrospectively registered).

Omeprazole is commonly co-prescribed with clopidogrel. Clopidogrel requires bio-activation by cytochrome P450 CYP2C19. Omeprazole may reduce clopidogrel’s antithrombotic efficacy by inhibiting CYP2C19. Studies in Caucasians receiving omeprazole with clopidogrel showed no significant increase in death and myocardial infarction with this drug–drug interaction. There are limited large-scale studies in Asians, who may have a greater prevalence of CYP2C19 loss-of-function polymorphisms. A single centre retrospective cohort study was undertaken based on a review of medication records and prescription data. Patients prescribed clopidogrel from 2009 to 2012 were followed-up with until December 2012 (median:29 months). The primary outcome was all-cause mortality and secondary outcomes were myocardial infarction (MI), cerebrovascular accidents, and subsequent coronary interventions. Of 12,440 patients prescribed clopidogrel, 62%(n = 7714) were on omeprazole (63.8% Chinese, 13.9% Malay, 12.4% Indian, 10.0% others), and 38%(n = 4726) were not on omeprazole or other proton pump inhibitors (62.6% Chinese, 13.5% Malay, 10.7% Indian, 13.2% others). Mortality after co-prescription occurred in 14.3%(n = 1101) of patients, compared to 6.3%(n = 300) of patients prescribed clopidogrel only. Multivariate analysis using propensity score adjusted analysis showed no significant increase in all-cause mortality with co-prescription (adjusted hazards ratio [AHR] 1.13, [95%CI 0.95–1.35]). Patients on co-prescription had a higher risk of subsequent MI (16% vs 3.8%; AHR 2.03 [95%CI 1.70–2.44]), but not of cerebrovascular accidents (5.0% vs 2.0%; AHR 0.98 [95%CI 0.76–1.27]) or coronary interventions (1.7% vs 0.7%; AHR 1.28 [95%CI 0.83–1.96]). The risk of a subsequent MI was higher in the Malay (AHR 2.43 [95%CI 1.68–3.52]) and Chinese (AHR 2.06 [95%CI 1.63–2.60]) population as compared to the Indian (AHR 1.56 [95%CI 1.06–2.31]) population. In conclusion, the use of clopidogrel with omeprazole is associated with an increased risk of MI, but not mortality or stroke, in this multi-ethnic Asian population. These risks appear to vary among different ethnic groups.

Over the past decade, pharmacogenetic testing has emerged in clinical practice to guide selected cardiovascular therapies. The most common implementation in practice is CYP2C19 genotyping to predict clopidogrel response and assist in selecting antiplatelet therapy after percutaneous coronary intervention. Additional examples include genotyping to guide warfarin dosing and statin prescribing. Increasing evidence exists on outcomes with genotype-guided cardiovascular therapies from multiple randomized controlled trials and observational studies. Pharmacogenetic evidence is accumulating for additional cardiovascular medications. However, data for many of these medications are not yet sufficient to support the use of genotyping for drug prescribing. Ultimately, pharmacogenetics might provide a means to individualize drug regimens for complex diseases such as heart failure, in which the treatment armamentarium includes a growing list of medications shown to reduce morbidity and mortality. However, sophisticated analytical approaches are likely to be necessary to dissect the genetic underpinnings of responses to drug combinations. In this Review, we examine the evidence supporting pharmacogenetic testing in cardiovascular medicine, including that available from several clinical trials. In addition, we describe guidelines that support the use of cardiovascular pharmacogenetics, provide examples of clinical implementation of genotype-guided cardiovascular therapies and discuss opportunities for future growth of the field.

Reduced clopidogrel effectiveness in preventing recurrent myocardial ischemia following percutaneous coronary intervention has been demonstrated in CYP2C19 loss-of-function carriers. Less is known about the effect of CYP2C19 genotype on the effectiveness of clopidogrel for stroke prevention, particularly in Caucasians. This is a retrospective cohort study, in which we used the Clalit clinical database to follow genotyped clopidogrel initiators, for up to 3 years. Endpoint was a new primary discharge diagnosis of ischemic stroke; secondary endpoints were new primary discharge diagnoses of coronary angioplasty, myocardial infarction (MI), or a composite endpoint of: stroke, MI, or coronary angioplasty. After 3 years of follow up over 628 clopidogrel initiators, 2 out of 12 (16.7%) poor metabolizers, 9 out of 144 intermediate metabolizers (6.3%), and 29 out of 472 (6.1%) normal/rapid/ultrarapid metabolizers have been newly diagnosed with ischemic stroke. Poor metabolizer status was associated with higher risk for ischemic stroke, marginally significant in univariate analysis and in multivariable models; and higher risk for the composite outcome of stroke, myocardial infarction and coronary angioplasty, HR = 3.32 (1.35-8.17) p = 0.009, 2.86 (1.16-7.06) p = 0.02 (univariate and multivariate analyses, respectively). Poor metabolizer status was associated with higher risk for stroke HR = 5.80 (1.33-25.24) p = 0.019, HR = 4.13 (0.94-18.13) p = 0.06 (univariate and multivariate analyses, respectively) in patients who "survived" the first year, and were in the cohort 1-3 years. Caucasian treated with clopidogrel who are homozygote for the CYP2C19 loss-of function allele might be at increased risk for ischemic stroke, and for the composite outcome of ischemic stroke, myocardial infarction and coronary angioplasty.

Introduction This study describes the frequency of prescription claims for drugs that may interact with Janus kinase (JAK) inhibitors among adult patients with rheumatoid arthritis (RA) in a large US claims database. Methods This observational, retrospective, cross-sectional study of the IBM® MarketScan® Research Commercial and the Medicare Supplemental Database included adults (≥ 18 years) with ≥ 2 outpatient claims 30 or more days apart or ≥ 1 inpatient visit claim with an RA diagnosis between January 1, 2013 and March 31, 2017 (the index period). During the study period, from January 1, 2013 to March 31, 2018, strong organic anion transporter (OAT3) inhibitors, strong cytochrome P450 (CYP) 3A4 inhibitors, and moderate or strong CYP3A4 inhibitors in combination with strong CYP2C19 inhibitors, were identified as drugs with potential for drug–drug interactions (DDIs) with JAK inhibitors approved for RA treatment in the US. Descriptive statistics were conducted. Results A total of 152,853 patients met eligibility criteria. Approximately 76% were women and the median age was 57 years. Of these patients

Prescribing the right medication, at the right dose, to the right patient is the goal of every physician. Pharmacogenomic information is an emerging tool that can be used to deliver precision medicine. In this review, we discuss the pharmacogenomics of available PPIs, racial differences of CYP2C19 and how PPI pharmacogenomics affects the treatment of common gastrointestinal diseases. We also provide practical guidance on when to order pharmacogenomic testing, which test to order, and how to modify treatment based on published guidelines.

Cytochrome P450s (CYPs) are a class of hemoproteins involved in drug metabolism. It has been reported that body composition, proportion of dietary macronutrients, fasting and nutritional status can interfere with the activity of drug-metabolizing CYPs. The present systematic review was conducted to summarize the effect of obesity, weight reduction, macronutrients, fasting and malnutrition on the CYP-mediated drug metabolism. PubMed (Medline), Scopus, Embase and Cochrane Library databases and Google Scholar were searched up to June 2020 to obtain relevant studies. The PRISMA guidelines were employed during all steps. Two reviewers independently extracted the information from the included studies. Studies investigating CYPs activity directly or indirectly through pharmacokinetics of probe drugs, were included. Increase in clearance (CL) or decrease in elimination half-life (t½) and area under the curve (AUC) of probe drugs were considered as increase in CYPs activity. A total of 6545 articles were obtained through searching databases among which 69 studies with 126 datasets fully met the inclusion criteria. The results indicated that obesity might decrease the activity of CYP3A4/5, CYP1A2 and CYP2C9 and increase the activity of CYP2E1. The effect of obesity on CYP2D6 is controversial. Also, weight loss increased CYP3A4 activity. Moreover, CYP1A2 activity was decreased by high carbohydrate diet, increased by high protein diet and fasting and unchanged by malnutrition. The activity of CYP2C19 was less susceptible to alterations compared to other CYPs. The activity of drug-metabolizing CYPs are altered by body composition, dietary intake and nutritional status. This relationship might contribute to drug toxicity or reduce treatment efficacy and influence cost-effectiveness of medical care.

Dual antiplatelet therapy with aspirin and clopidogrel is commonly used for coronary artery disease (CAD) patients undergoing percutaneous coronary intervention to prevent stent thrombosis and ischemic events. However, some patients show high on-treatment platelet reactivity (HTPR) during clopidogrel therapy. Genetic factors such as loss-of-function variants of CYP2C19 are validated to increase the risk of HTPR. Flavin-containing monooxygenase 3 (FMO3) is reported to be associated with potency of platelet responsiveness and thrombosis. This study aimed to explore the association between FMO3 rs1736557 polymorphism and clopidogrel response. Five hundred twenty-two Chinese CAD patients treated with dual antiplatelet therapy were recruited from Xiangya Hospital. After oral administration of 300 mg loading dose (LD) clopidogrel for 12–24 h or 75 mg daily maintenance dose (MD) clopidogrel for at least 5 days, the platelet reaction index (PRI) was determined by vasodilator-stimulated phosphoprotein-phosphorylation assay. FMO3 rs1736557, CYP2C19*2, and CYP2C19*3 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Mean PRI value was significantly higher in CYP2C19 poor metabolizers (PMs) and intermediate metabolizers (IMs) than the extensive metabolizers (EMs) (p

Genetic variability of CYP2C19 may affect safety or efficacy of many clinically important medications as outlined in the clinical pharmacogenetics implementation consortium (CPIC) dosing guidelines. To determine the predictive prevalence of high-risk phenotypes due to CYP2C19 genetic variants collectively in the world population and to establish a correlation how the identified high-risk phenotypes may affect safety or effectiveness of drugs, this study was conducted. Frequency of CYP2C19*2, *3 and *17 alleles were obtained from 1000 Genomes project Phase III in line with Fort Lauderdale principles. Phenotypes were assigned using international standardized consensus terms based on the carrier of characteristics alleles. Association of predicted high-risk phenotypes with the safety or effectiveness of medications was gained from CPIC dosing guidelines. Ultrarapid and poor metabolizers were considered as being as high-risk phenotypes for at least ten clinically important medications. Meta-analysis of the prevalence of high-risk phenotypes showed that it was statistically significant (p

Patients with ischemic stroke are often treated with clopidogrel monotherapy as part of secondary stroke prevention. The prevalence of loss of function (LOF) mutations in the CYP2C19 gene is higher in Asians than in Western populations. Patients with loss of function (LOF) mutations are at risk for poorer secondary outcomes when prescribed clopidogrel. We aimed to determine the cost effectiveness of genotype-guided antiplatelet therapy in an Asian population with the aim of prescribing ticagrelor as an alternative to patients with LOF mutations. Markov models were developed to look at the cost effectiveness of genetic testing of CYP2C19, with patients who screened positive for LOF alleles being switched to ticagrelor compared to universal clopidogrel treatment. Effect ratios were obtained from the literature and incidence rates and costs were obtained from the national data published by the Singapore Ministry of Health. Lifetime costs and quality-adjusted life-years (QALYs) were calculated. The primary endpoints were the incremental cost-effectiveness ratios (ICERs). The prevalence of the LOF mutations was 61% in the population, with 65% of ethnic Chinese, 60% of ethnic Indian, and 53% of ethnic Malay patients having LOF mutations. Based on this prevalence, the overall ICER of genetic testing was S$33,839/QALY with ICERS of S$30,755/QALY, S$33,177/QALY, and S$41,470/QALY for Chinese, Indians, and Malays, respectively. This study suggests that it is cost effective to screen for LOF mutations in the CYP2C19 gene in ischemic stroke populations, with ticagrelor as a substitute for clopidogrel in those with LOF mutations.

Lopinavir-ritonavir combination is being used for the treatment of SARS-CoV-2 infection. A low dose of ritonavir is added to other protease inhibitors to take advantage of potent inhibition of cytochrome (CYP) P450 3A4, thereby significantly increasing the plasma concentration of coadministered lopinavir. Ritonavir also inhibits CYP2D6 and induces CYP2B6, CYP2C19, CYP2C9, and CYP1A2. This potent, time-dependent interference of major hepatic drug-metabolizing enzymes by ritonavir leads to several clinically important drug-drug interactions. A number of patients presenting with acute coronary syndrome and acute heart failure may have SARS-CoV-2 infection simultaneously. Lopinavir-ritonavir is added to their prescription of multiple cardiac medications leading to potential drug-drug interactions. Many cardiology, pulmonology, and intensivist physicians have never been exposed to clinical scenarios requiring co-prescription of cardiac and antiviral therapies. Therefore, it is essential to enumerate these drug-drug interactions, to avoid any serious drug toxicity, to consider alternate and safer drugs, and to ensure better patient care.

While the impact of genetic polymorphisms on the metabolism of various pharmaceuticals is well known, more data are needed to better understand the specific influence of pharmacogenetics on the metabolism of delta 9-tetrahydocannabinol (Δ9-THC). Therefore, the aim of the study was to analyze the potential impact of variations in genes coding for phase I enzymes of the Δ9-THC metabolism. First, a multiplex assay for genotyping different variants of genes coding for phase I enzymes was developed and applied to 66 Δ9-THC-positive blood samples obtained in cases of driving under the influence of drugs (DUID). Genetic and demographic data as well as plasma concentrations of Δ9-THC, 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-Δ9-THC), and 11-nor-9-carboxy-Δ9-THC (Δ9-THC-COOH) were combined and statistically investigated. For cytochrome P450 2C19 (CYP2C19) variants, no differences in analyzed cannabinoid concentrations were found. There were also no differences in the concentrations of Δ9-THC and 11-OH-Δ9-THC for the different allelic CPY2C9 status. We recognized significantly lower Δ9-THC-COOH concentrations for CYP2C9*3 (p = 0.001) and a trend of lower Δ9-THC-COOH concentrations for CYP2C9*2 which did not reach statistical significance (p = 0.068). In addition, this study showed significantly higher values in the ratio of Δ9-THC/Δ9-THC-COOH for the carriers of the CYP2C9 variants CYP2C9*2 and CYP2C9*3 compared with the carriers of the corresponding wild-type alleles. Therefore, an impact of variations of the CYP2C9 gene on the interpretation of cannabinoid plasma concentrations in DUID cases should be considered.

Cytochrome (CYP) P450 enzymes are responsible for metabolism of antiepileptic drugs (AEDs), and encoded by highly polymorphic genes. A case–control study was conducted in Mansoura University Children’s Hospital, Egypt including 100 children with nonlesional epilepsy (50 AEDs responders and 50 resistant cases) and 50 healthy controls. All participants were investigated for frequencies of CYP2C9 (*2&*3) and CYP2C19 (*2&*3) genotypes and alleles using polymerase chain reaction. The current study reported higher frequencies of CYP2C9*2 (CT) genotype and (T) allele among responsive and resistant groups than controls (P

This study focuses on Quantitative structure–activity relationship (QSAR) and in silico pharmacokinetics/ADMET predictions to investigate the structural features and pharmacokinetic/ADMET properties that influenced the antipsychotic activity of some arylpiperazine derivatives as inhibitors of Serotonin Transporter (SERT) for antidepressant agents. Density Functional Theory approach (DFT/B3LYP/6-31G*) via Spartan 14 V1.1.4 software was used for the geometry optimization of the compounds while the Genetic Function Algorithm (GFA) and Multiple Linear Regression Analysis (MLRA) in Material studio software were used for variable selection and development of QSAR models. The statistical analysis and validation parameters of the best model (RTrain2 = 0.944, RTest2 = 0.637, Qcv2 = 0.895, cRp2 = 0.845 and RMSE = 0.100) shows that the model was predictive, reliable, robust and very stable. More so, molecular descriptors; SpMax6_Bhm, VP-3, geomDiameter, RDF35i and E1e were significantly contributed to the observed antipsychotic activities of the compounds with SpMax6_Bhm (37.5%) played a predominant role and positively correlated to the observed antipsychotic property of the compounds. Similarly, the in silico pharmacokinetics/ADMET investigations revealed that the selected compounds portend to be orally bioavailable, highly absorbed by the gastrointestinal system and could permeate into the brain with low ADMET risk. Likewise, all the selected compounds were inhibitors of CYP2C19 and CYP2D6 cytochromes P450 (CYP) enzymes and none of the selected compounds exhibit human ether-a-go-go-related gene (hERG) cardiovascular toxicity. Hence, the model possessed good quality assurance and satisfied OECD Principles for model development. In consequence, the physicochemical and pharmacokinetic parameters/properties derived from this study could be considered when developing other arylpiperazine derivatives with improved activity as antidepressant agents.

Dual antiplatelet therapy (DAT) with clopidogrel and aspirin is not suitable for clopidogrel resistance (CR) patients with aspirin intolerance. To investigate the prevalence of CR in patients with aspirin intolerance after ischemic stroke (IS) and to assess the relationship between CR and CYP2C19, P2Y12 receptor genotypes in patients with aspirin intolerance after IS. We enrolled 126 IS patients with aspirin intolerance from Han Chinese in Shangqiu from January 2016 to November 2018. All IS patients with aspirin intolerance were treated with clopidogrel for 7 days. Adenosine diphosphate-induced platelet inhibition rate was measured by thrombelastography (TEG) mapping assay. The SNPs CYP2C19*2, CYP2C19*3, and P2Y12 receptor (52 G >T) were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Binary logistic regression analyses were performed using SPSS version 20.0. The prevalence of CR in patients with aspirin intolerance after IS was approximately 31.0%. Multivariate regression analysis showed that body weight (OR 1.091 (95% CI 1.031–1.155), p = 0.003), CYP2C19 phenotype intermediate metabolizer (IM) (OR 3.820 (95% CI 1.021–14.288), p = 0.046), and CYP2C19 phenotype poor metabolizer (PM) (OR 14.481 (95% CI 2.791–75.129), p = 0.001) significantly increased the risk of CR and P2Y12 receptors (52 G >T) (OR 3.498 [95% CI 1.251–9.784], p = 0.017) increased the risk of CR. The patients with high body weight, the CYP2C19 phenotypes, and P2Y12 receptor (52 G >T) variant alleles are at risk of CR during clopidogrel treatment in Chinese IS patients with aspirin intolerance. The higher body weight and relevant polymorphisms may help to predict CR in Chinese IS patients with aspirin intolerance.

Fractional doses of proton pump inhibitors (PPIs) more often than once daily (qd) inhibit 24-h acid secretion more effectively than an increase in the standard single daily dose. Although rabeprazole 5 mg qd is covered for prevention of aspirin-induced gastric injury under the Japanese insurance system, it is unclear whether rabeprazole 5 mg twice daily (bid) would more effectively inhibit acid secretion. We compared acid inhibition between rabeprazole 10 mg qd and 5 mg bid in healthy volunteers with different alleles of CYP2C19. Twelve Helicobacter pylori-negative healthy volunteers (CYP2C19 genotypes: extensive metabolizer (EM) (n = 6) and poor metabolizer (PM) (n = 6)) received three kinds of regimen for 7 days under a randomized crossover design: rabeprazole 5 mg qd (5 mg QD), 10 mg qd (10 mg QD), and 5 mg bid (5 mg BID). A 24-hour pH monitoring was conducted before the trial and on day 7 of each regimen. No significant differences in median pH values (4.0 (1.9–5.9)) and (4.4 (2.1–6.5)) or percent time of pH ≥ 4 (50.7% (11.9–86.8%) and 56.8% (19.3–83.9%)) were seen between the 10 mg QD and 5 mg BID regimens. Median pHs and percent time of pH ≥ 4 in CYP2C19 PMs were significantly higher than those in EMs. With 5 mg BID, there was no significant difference in percent-time with pH ≥ 4 between daytime and nighttime, but the 10 mg QD showed a significant difference. Rabeprazole 5 mg bid provided no therapeutic advantage for acid inhibition compared with rabeprazole 10 mg qd, regardless of CYP2C19 genotype status.

Bupropion is hydroxylated to its primary active metabolite hydroxybupropion by cytochrome P450 enzyme CYP2B6. In vitro data suggest the existence of alternative hydroxylation pathways mediated by the highly polymorphic enzyme CYP2C19. However, the impact of its genetic variants on bupropion metabolism in vivo is still under investigation. We report the case of a 28-year-old male Caucasian outpatient suffering from major depressive disorder who did not respond to a treatment with bupropion. Therapeutic drug monitoring revealed very low serum concentrations of both bupropion and hydroxybupropion. Genotyping identified a heterozygous status for the gain-of-function allele with the genotype CYP2C19*1/*17 predicting enhanced enzymatic activity. The present case shows a reduced bupropion efficacy, which may be explained by a reduced active moiety of bupropion and its active metabolite hydroxybupropion, due to alternative hydroxylation pathways mediated by CYP2C19 in an individual with CYP2C19 rapid metabolizer status. The case report thus illustrates the clinical relevance of therapeutic drug monitoring in combination with pharmacogenetics diagnostics for a personalized treatment approach.

High pharmacokinetic variability of voriconazole is mainly explained by CYP2C19 phenotype, but there are still unknown factors affecting the variability. In this study, the effect of solute carrier organic anion transporter family member 2B1 (SLCO2B1) genotype on the pharmacokinetics (PKs) of voriconazole was evaluated in 12 healthy CYP2C19 poor metabolizers after a single administration of voriconazole 200 mg intravenously and orally. In addition, the influence of CYP3A4 enzyme activity was also explored. The oral absorption of voriconazole was decreased and delayed in the subjects with the SLCO2B1 c.*396T>C variant compared to the subjects with wild type. However, the CYP3A activity markers measured in this study did not show significant association with metabolism of voriconazole. The results suggest that the SLCO2B1 c.*396T>C may be associated with the decreased function of intestinal OATP2B1, and it could contribute to interindividual PK variability of voriconazole.

Two phase I studies assessed the drug–drug interaction potential of apalutamide as a substrate and perpetrator. Study A randomized 45 healthy men to single-dose apalutamide 240 mg alone or with strong inhibitors of cytochrome P450 (CYP)3A4 (itraconazole) or CYP2C8 (gemfibrozil). In study B, 23 patients with castration-resistant prostate cancer received probes for CYP3A4 (midazolam), CYP2C9 (warfarin), CYP2C19 (omeprazole), and CYP2C8 (pioglitazone), and transporter substrates for P-glycoprotein (P-gp) (fexofenadine) and breast cancer resistance protein (BCRP)/organic anion transporting polypeptide (OATP) 1B1 (rosuvastatin) at baseline and after repeat once-daily administration of apalutamide 240 mg to steady state. Systemic exposure (area under the plasma concentration–time curve) to single-dose apalutamide increased 68% with gemfibrozil but was relatively unchanged with itraconazole (study A). Apalutamide reduced systemic exposure to midazolam ↓92%, omeprazole ↓85%, S-warfarin ↓46%, fexofenadine ↓30%, rosuvastatin ↓41%, and pioglitazone ↓18% (study B). After a single dose, apalutamide is predominantly metabolized by CYP2C8, and less by CYP3A4. Co-administration of apalutamide with CYP3A4, CYP2C19, CYP2C9, P-gp, BCRP or OATP1B1 substrates may cause loss of activity for these medications. Therefore, appropriate mitigation strategies are recommended.

This study was aimed to investigate the prevalence of CYP2C9*2 (p.430C > T, rs1799853), CYP2C9*3 (p.1075A > C, rs1057910), CYP4F2*3 (p.1297G > A, rs2108622), CYP2C19*2 (p.681G > A, rs4244285), CYP2C19*3 (p.636G > A, rs4986893), CYP2C19*17 (p.1260C > A, rs12248560), ABCB1 (p.3435C > T, rs1045642), CYP2D6*4 (p.1846G > A, rs3892097), SLCO1B1*5 (p.521T > C, rs4149056) and CES1 (p.1168-33A > C, rs2244613) among Tatars and Balkars ethnic groups living in Russia to provide a basis for future clinical studies concerning on understanding of population-level differences in drug response. The study involved 341 apparently healthy, unrelated, and chronic medication-free volunteers of both sexes of ethnic groups of Tatars and Balkars living in Volga and Caucasus regions of Russia. Genotyping was performed using real-time polymerase chain reaction-based methods. The allelic prevalence of studied markers in ethnic groups were compared with Russians as a largest ethnic group in Russia. Statistically significant differences for the following gene polymorphisms were found between both ethnic groups in respect of different markers and with Russians. Our study shows differences in prevalence of the main relevant pharmacogenetic markers in Tatars and Balkars. These findings should be taken into consideration for personalization algorithms development and pharmacogenetics implementation in regions with ethnic minorities as Russia has.

To compare the risk of cardiovascular events between patients with two CYP2C19 loss-of-function alleles who were prescribed ticagrelor or clopidogrel after percutaneous coronary intervention (PCI). Patients with two loss-of-function alleles based on the CYP2C19 genotype were selected from patients enrolled in a retrospective institutional registry. Propensity score matching using logistic regression was performed to adjust for bias between patients prescribed ticagrelor or clopidogrel. Multivariate Cox regression was used to compare the risk of adverse events in the ticagrelor and clopidogrel groups. The primary outcome was the incidence of major adverse cardiac events plus any repeat target vessel revascularization within 12 months after PCI. The safety outcomes were minor and major bleeding events. From 1518 patients carrying two loss-of-function alleles based on the CYP2C19 genotype who underwent PCI, 638 patients treated with ticagrelor or clopidogrel were successfully propensity-score matched. The primary outcome occurred in 25 patients (7.8%) in the ticagrelor group and 47 (14.7%) in the clopidogrel group. The risk of the primary outcome was significantly lower in the ticagrelor group versus the clopidogrel group (HR 0.466, 95% CI 0.286–0.759, p = 0.002). The incidence of major bleeding events did not significantly differ between the ticagrelor and clopidogrel groups (0.3% and 0.9%, respectively), while the ticagrelor group had a higher risk of minor bleeding events (HR 1.959, 95% CI 1.396–2.750, p

Pharmacogenomic biomarker availability of Hungarian Summaries of Product Characteristics (SmPC) was assembled and compared with the information in US Food and Drug Administration (FDA) drug labels of the same active substance (July 2019). The level of action of these biomarkers was assessed from The Pharmacogenomics Knowledgebase database. From the identified 264 FDA approved drugs with pharmacogenomic biomarkers in drug label, 195 are available in Hungary. From them, 165 drugs include pharmacogenomic data disposing 222 biomarkers. Most of them are metabolizing enzymes (46%) and pharmacological targets (41%). The most frequent therapeutic area is oncology (37%), followed by infectious diseases (12%) and psychiatry (9%) (p CYP2D6, CYP2C19, estrogen and progesterone hormone receptor (ESR, PGS). Importantly, US labels present more specific pharmacogenomic subheadings, the level of action has a different prominence, and offer more applicable dose modifications than Hungarians (5% vs 3%). However, Hungarian SmPCs are at 9 oncology drugs stricter than FDA, testing is obligatory before treatment. Out of the biomarkers available in US drug labels, 62 are missing completely from Hungarian SmPCs (p

Many antidepressants, atomoxetine, and several antipsychotics are metabolized by the cytochrome P450 enzymes CYP2D6 and CYP2C19, and guidelines for prescribers based on genetic variants exist. Although some laboratories offer such testing, there is no consensus regarding validated methodology for clinical genotyping of CYP2D6 and CYP2C19. The aim of this paper was to cross-validate multiple technologies for genotyping CYP2D6 and CYP2C19 against each other, and to contribute to feasibility for clinical implementation by providing an enhanced range of assay options, customizable automated translation of data into haplotypes, and a workflow algorithm. AmpliChip CYP450 and some TaqMan single nucleotide variant (SNV) and copy number variant (CNV) data in the Genome-based therapeutic drugs for depression (GENDEP) study were used to select 95 samples (out of 853) to represent as broad a range of CYP2D6 and CYP2C19 genotypes as possible. These 95 included a larger range of CYP2D6 hybrid configurations than have previously been reported using inter-technology data. Genotyping techniques employed were: further TaqMan CNV and SNV assays, xTAGv3 Luminex CYP2D6 and CYP2C19, PharmacoScan, the Ion AmpliSeq Pharmacogenomics Panel, and, for samples with CYP2D6 hybrid configurations, long-range polymerase chain reactions (L-PCRs) with Sanger sequencing and Luminex. Agena MassARRAY was also used for CYP2C19. This study has led to the development of a broader range of TaqMan SNV assays, haplotype phasing methodology with TaqMan adaptable for other technologies, a multiplex genotyping method for efficient identification of some hybrid haplotypes, a customizable automated translation of SNV and CNV data into haplotypes, and a clinical workflow algorithm.

Etravirine is a second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI) for the treatment of human immunodeficiency virus type 1 infection. It is a potent inhibitor of HIV reverse transcriptase and retains activity against wild-type and most NNRTI-resistant HIV. The pharmacokinetic profile of etravirine and clinical data support twice-daily dosing, although once-daily dosing has been investigated in treatment-naïve and treatment-experienced persons. Despite similar pharmacokinetic and pharmacodynamic results compared with twice-daily dosing, larger studies are needed to fully support once-daily etravirine dosing in treatment-naïve individuals. Etravirine is reserved for use in third- or fourth-line antiretroviral treatment regimens, as recommended, for example, in treatment guidelines by the US Department of Health and Human Services—Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents Living with HIV. Etravirine exhibits the potential for bi-directional drug–drug interactions with other antiretrovirals and concomitant medications through its interactions with cytochrome P450 (CYP) isozymes: CYP3A4, CYP2C9, and CYP2C19. This review summarizes the pharmacokinetic and pharmacodynamic parameters of etravirine, with particular attention to information on drug–drug interactions and use in special patient populations, including children/adolescents, women, persons with organ dysfunction, and during pregnancy.

Exogenous progesterone is prescribed for a variety of conditions with endogenous progesterone deficiency, e.g. menstrual alterations, primary or secondary infertility or premenopause. To the best of our knowledge, no pharmacogenetic studies have been published in relation to exogenous progesterone pharmacokinetic safety or progesterone metabolites so far. Candidate-gene study where we evaluated whether five single-nucleotide polymorphisms (CYP2C9*2, *3, CYP2C19*2, *3 and *17) were related to the pharmacokinetics, safety and metabolism of progesterone in 24 healthy volunteers who received a 200-mg progesterone formulation either orally or vaginally. The vaginal formulation had an average AUCt value approximately 18 times greater than the oral formulation. CYP2C19 intermediate metabolizers (IM) consistently showed higher adjusted AUCt and adjusted Cmax than extensive metabolizers (EM) (P

Perform a cost-effectiveness analysis comparing strategies for selecting P2Y12 inhibitors in acute coronary syndrome (ACS). Six strategies for selection of P2Y12 inhibitors in ACS were compared from the US healthcare system perspective: (1) clopidogrel for all (universal clopidogrel); (2) ticagrelor guided by platelet reactivity assay (PRA; clopidogrel + phenotype); (3) ticagrelor use only in CYP2C19 poor metabolizers (genotype + conservative ticagrelor); (4) ticagrelor use in both CYP2C19 intermediate and poor metabolizers (genotype + liberal ticagrelor); (5) ticagrelor use only in patients with CYP2C19 polymorphisms and clopidogrel nonresponse by PRA (genotype + phenotype); and (6) ticagrelor for all (universal ticagrelor). A decision model was developed to model major adverse cardiovascular events and bleeding during 1 year of treatment with a P2Y12 inhibitor. Model inputs were identified from the literature. Lifetime costs were adjusted to 2017 US dollars; quality-adjusted life-years (QALYs) were projected using a Markov model. The primary endpoint was the incremental cost-effectiveness compared to the next best option along the cost-effectiveness continuum. Sensitivity analyses were performed on all model inputs to assess their influence on the incremental cost-effectiveness. In the base case analysis, incremental cost-effectiveness ratios (ICER) for the clopidogrel + phenotype, genotype + liberal ticagrelor, and universal ticagrelor strategies were $12,119/QALY, $29,412/QALY, and $142,456/QALY, respectively. Genotype + conservative ticagrelor and genotype + phenotype were not cost-effective due to second-order dominance. Genotype + liberal ticagrelor compared to clopidogrel + phenotype demonstrated the highest acceptance (97%) at a willingness to pay (WTP) threshold of $100,000/QALY. Cost-effective strategies to personalize P2Y12 inhibition in ACS include clopidogrel +phenotype and genotype + liberal ticagrelor. Universal ticagrelor may be considered cost-effective at a higher WTP threshold ($150,000/QALY). Genotype + liberal ticagrelor exhibited the highest acceptability compared to clopidogrel + phenotype over the widest range of WTP thresholds and may be preferred.

Drug response is subject to an important within- and between-individual variability owing, mainly, to pharmacokinetic and pharmacodynamic factors. Pharmacokinetics includes metabolism by cytochrome P450 (CYP450), major enzymes of phase I reactions that are responsible for the biotransformation of around 60% of the currently approved drugs. CYP450 activity and/or expression are influenced by multiple intrinsic and extrinsic factors, such as drug-drug interactions or genetic polymorphisms. Present phenotyping strategies with xenobiotics used to assess CYP450 activity could be replaced by less invasive procedures using endogenous CYP450 biomarkers. In this work, we review existing knowledge on endobiotics and their ability to characterise variability of the CYP1A2, CYP2C19, CYP2D6 and CYP3A enzymes in humans. To date, it appears that there is a lack of clinical data for the majority of the endogenous compounds described in the literature or some important limitations to allow their use in clinical practice. Additional studies are needed to fill the gap or to identify new candidates, in particular through the use of metabolomics. The use of multivariate models is also a very promising approach to enhance prediction by combining several endogenous phenotyping metrics and other covariates.

Voriconazole is widely recommended for the prevention and treatment of invasive fungal infections in hematopoietic stem cell transplantation patients. However, its use is limited by a narrow therapeutic range and large inter-individual variability. This study aimed to characterize the pharmacokinetics of voriconazole in Chinese hematopoietic stem cell transplantation patients, to explore factors affecting its pharmacokinetic parameters, and to provide recommendations for its optimal dosing regimens. A total of 121 serum concentration samples from 23 patients were retrospectively included. Voriconazole concentrations were detected, and patient clinical data were recorded. Population pharmacokinetic analysis was performed by a non-linear, mixed-effect modeling approach. Goodness-of-fit plots, bootstrap method, prediction-corrected visual predictive check and external validation by an independent group of seven patients were performed to evaluate the final model. A one-compartment model with first-order elimination successfully described the data. The absorption rate constant was fixed at 1.1 h−1 and bioavailability was fixed at 0.895. The typical values for voriconazole clearance and distribution volume were 9.52 L/h and 155 L, respectively. CYP2C19*2 genotype and mycophenolate mofetil combination presented a significant impact on the clearance. Compared with CYP2C19*2 carriers, voriconazole clearance was proven to be higher in CYP2C19*1/*1 patients. A population pharmacokinetic model of voriconazole was successfully established in Chinese hematopoietic stem cell transplantation patients. Based on the final model, CYP2C19*2 genotyping coupled with therapeutic drug monitoring seems to be useful to guide voriconazole dosing and to explain subtherapeutic concentrations in clinical practice.

Background CYP2C19 isoenzyme of cytochrome P450 in the liver catabolises proton pump inhibitors, one of the therapeutics utilized in Helicobacter pylori eradication therapy, and in this way could influence the eradication effectiveness. The isoensyme contributes also to metabolism of endogenous substances, which derivatives are involved in the pathogenesis of peptic ulceration. CYP2C19*2 polymorphism (rs4244285) changing the CYP2C19 function could be relevant in the predisposition to peptic ulcer disease. Methods CYP2C19*2 polymorphism in 197 peptic ulcer patients and 107 healthy subjects of Polish origin by PCR-RFLP method was investigated. Results There were no statistically significant differences in genotypes and alleles frequencies for investigated polymorphism between peptic ulcer patients and healthy individuals. No associations between frequencies of particular CYP2C19 genotypes and alleles and the presence of H. pylori infection in peptic ulcer patients were stated. However, significant association between CYP2C19*2 and gender in H. pylori-infected but not -uninfected peptic ulcer individuals was found. Conclusions Investigated polymorphism is not a risk factor for peptic ulcer in Polish population. Obtained results could suggested there is some interaction between gender, CYP2C19*2 polymorphism, and pathogenesis of H. pylori infection development. However, this hypothesis should be verified in the further studies.

This study sought to explore the relationship between cytochrome P450 2C19 (CYP2C19) *2/*3 polymorphisms and the development of coronary heart disease (CHD), and to evaluate the influence of the single nucleotide polymorphisms (SNPs) on the occurrence of adverse clinical events in CHD patients. A total of 231 consecutive patients candidate for percutaneous coronary intervention genotyped for CYP2C19*2 (681G>A) and *3 (636G>A) polymorphisms were enrolled. The adverse clinical events were recorded during a follow-up period of 14 months. The incidence of CHD, according to coronary angiography, was significantly higher (P=0.025) in CYP2C19*2 carriers group. Stepwise binary logistic regression analysis revealed that among factors that potentially influenced the presence of CHD (age>60 years, gender, BMI, etc.), CYP2C19*2 carriers (OR 1.94, 95% CI: 1.08–3.50, P=0.028) and male gender (OR 2.74, 95% CI: 1.58–4.76, P=0.001) were independent predictors, which were associated with the presence of CHD. The follow-up results showed that the incidence of adverse cardiovascular events within 14 months of discharge was significantly higher in the CYP2C19*2 carriers than in the non-carriers (21.6% vs. 6.3%, P=0.019). The results of the multivariate Cox proportional hazards model showed that CYP2C19*2 loss-of-function was the only independent factor which predicted the coronary events during the follow-up period of 14 months (OR=3.65, 95% CI 1.09–12.25, P=0.036). The adverse impact of CYP2C19*2 polymorphisms was found not only in the risk of the presence of CHD, but also in the adverse cardiovascular events in CHD patients during the follow-up period of 14 months. However the same influence was not found in CYP2C19*3 mutation in Chinese Han population.

Eliminating the Plasmodium vivax malaria parasite infection remains challenging. One of the main problems is its capacity to form hypnozoites that potentially lead to recurrent infections. At present, primaquine is the only drug used for the management of hypnozoites. However, the effects of primaquine may differ from one individual to another. The aim of this work is to determine new measures to reduce P. vivax recurrence, through primaquine metabolism and host genetics. A genetic study of MAO-A, CYP2D6, CYP1A2 and CYP2C19 and their roles in primaquine metabolism was undertaken of healthy volunteers (n = 53). The elimination rate constant (Ke) and the metabolite-to-parent drug concentration ratio (Cm/Cp) were obtained to assess primaquine metabolism. Allelic and genotypic analysis showed that polymorphisms MAO-A (rs6323, 891G>T), CYP2D6 (rs1065852, 100C>T) and CYP2C19 (rs4244285, 19154G>A) significantly influenced primaquine metabolism. CYP1A2 (rs762551, -163C>A) did not influence primaquine metabolism. In haplotypic analysis, significant differences in Ke (p = 0.00) and Cm/Cp (p = 0.05) were observed between individuals with polymorphisms, GG-MAO-A (891G>T), CT-CYP2D6 (100C>T) and GG-CYP2C19 (19154G>A), and individuals with polymorphisms, TT-MAO-A (891G>T), TT-CYP2D6 (100C>T) and AA-CYP2C19 (19154G>A), as well as polymorphisms, GG-MAO-A (891G>T), TT-CYP2D6 (100C>T) and GA-CYP2C19 (19154G>A). Thus, individuals with CYP2D6 polymorphisms had slower primaquine metabolism activity. The potential significance of genetic roles in primaquine metabolism and exploration of these might help to further optimise the management of P. vivax infection.

Lysergic acid diethylamide (LSD) is a classic psychedelic substance that is used recreationally and investigated in psychiatric research. There are no pharmacogenetic studies on LSD. In vitro metabolic studies indicate that several cytochrome P450 (CYP) isoforms (e.g., CYP2D6, CYP1A2, and CYP2C9) are involved in LSD metabolism, but in vivo data are scarce. The present study examined the influence of genetic polymorphisms of CYP genes on the pharmacokinetics and acute effects of LSD in healthy subjects. We identified common genetic variants of CYPs (CYP2D6, CYP1A2, CYP2C9, CYP2C19, and CYP2B6) in 81 healthy subjects who were pooled from four randomized, placebo-controlled, double-blind Phase 1 studies. We found that genetically determined CYP2D6 functionality significantly influenced the pharmacokinetics of LSD. Individuals with no functional CYP2D6 (i.e., poor metabolizers) had longer LSD half-lives and approximately 75% higher parent drug and main metabolite 2-oxo-3-hydroxy LSD area-under-the-curve blood plasma concentrations compared with carriers of functional CYP2D6. Non-functional CYP2D6 metabolizers also exhibited greater alterations of mind and longer subjective effect durations in response to LSD compared with functional CYP2D6 metabolizers. No effect on the pharmacokinetics or acute effects of LSD were observed with other CYPs. These findings indicate that genetic polymorphisms of CYP2D6 significantly influence the pharmacokinetic and subjective effects of LSD. Given the potential therapeutic use of psychedelics, including LSD, the role of pharmacogenetic tests prior to LSD-assisted psychotherapy needs to be further investigated.

Formaldehyde (FA) is a human carcinogen used as formalin in hospital laboratories. We evaluated its association with human chromosomal aberrations (CAs) and the risk/protective role played by several genetic polymorphisms in this relationship, on a cohort of 57 exposed pathologists vs 48 controls. All subjects were assessed for CAs on peripheral blood lymphocytes and genotyped for the most common cancer-associated gene polymorphisms which could be related with the genotoxic outcome: CYP1A1 exon 7 (A>G), CYP1A1*2A (T>C), CYP2C19*2 (G>A), GSTT1 (Positive/Null), GSTM1 (Positive/null), GSTP1 (A>G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPD (A751C), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα − 308 (G>A), IL10 − 1082 (G>A), IL10 − 819 (C>T) and IL6 − 174 (G>C). Air-FA concentration was assessed through personal samplers. The comparison between pathologists and controls showed a significantly higher CAs frequency in pathologists. Significant positive correlations were found between CAs frequency and air-FA concentration while significant associations were found between variation in CAs frequency and the mutated allele for CYP1A1 exon 7 (A>G), CYP2C19*2 (G>A), GSTT1-positive, GSTM1-positive and XRCC1 (G399A). Our study confirms the role of FA as genotoxicity inductor, even in workers chronically exposed to low air-FA levels and reveals the role played by some genetic polymorphisms in this association, highlighting the importance of individual susceptibility biomarkers assessment in occupational health studies.

Dual antiplatelet therapy (DAPT) with clopidogrel plus aspirin within 48 h of acute minor strokes and transient ischemic attacks (TIAs) has been indicated to effectively reduce the rate of recurrent strokes. However, the efficacy of clopidogrel has been shown to be affected by cytochrome P450 2C19 (CYP2C19) polymorphisms. Patients carrying loss-of-function alleles (LoFAs) at a low risk of recurrence (ESRS

Background Early neurological deterioration (END) is common in acute ischemic stroke (IS). However, the underlying mechanisms for END are unclear. The aim of this study was to evaluate the associations of 16 variants in clopidogrel-relevant genes and interactions among these variants with END in acute IS patients receiving clopidogrel treatment. Methods We consecutively enrolled 375 acute IS patients between June 2014 and January 2015. Platelet aggregation was measured on admission and after the 7–10 days of clopidogrel treatment. The 16 variants in clopidogrel-relevant genes were examined using mass spectrometry. The primary outcome was END within the 10 days of admission. Gene-gene interactions were analyzed by generalized multifactor dimensionality reduction (GMDR) methods. Results Among the 375 patients, 95 (25.3%) patients developed END within the first 10 days of admission. Among the 16 variants, only CYP2C19*2 (rs4244285) AA/AG was associated with END using single-locus analytical approach. GMDR analysis revealed that there was a synergistic effect of gene-gene interactions among CYP2C19*2 rs4244285, P2Y12 rs16863323, and GPIIIa rs2317676 on the risk for END. The high-risk interactions among the three variants were associated with the higher platelet aggregation and independent predictor for END after adjusting for the covariates (hazard ratio: 2.82; 95% confidence interval: 1.36–7.76; P = 0.003). Conclusions END is very common in patients with acute IS. The mechanisms leading to END are most likely multifactorial. Interactions among CYP2C19*2 rs4244285, P2Y12 rs16863323, and GPIIIa rs2317676 may confer a higher risk for END. It was very important to modify clopidogrel therapy for the patients carrying the high-risk interactive genotypes. Clinical trial registration information The study described here is registered at http://www.chictr.org/ (unique Identifier: ChiCTR-OCH-14004724). The date of trial registration was May 30, 2014.

Pregnane X receptor (PXR) is a member of nuclear receptor subfamily 1 (NR1I2) that is a transcriptional regulator of several metabolic enzymes involved in clopidogrel metabolism. In this study we identified and evaluated the contributions of single nucleotide polymorphisms (SNPs) in NR1I2 and cytochrome P450 (CYP) 2C19 alleles to clopidogrel resistance (CR) and long-term clinical outcomes in acute ischemic stroke (IS) patients. A total of 634 patients with acute IS were recruited, who received antiplatelet medication (clopidogrel or aspirin) every day and completed a 1-year follow-up. The selected SNPs were genotyped, and platelet function was measured. Modified Rankin Scale (mRS) scores and main adverse cardiovascular and cerebrovascular events (MACCE) were noted to assess the prognosis. We showed that SNPs NR1I2 rs13059232 and CYP2C19 alleles (2*/3*) were related to CR. SNP NR1I2 (rs13059232) was identified as an independent risk factor for the long-term clinical outcomes in the clopidogrel cohorts (P 0.05). Our results suggest that NR1I2 variant (rs13059232) could serve as biomarker for clopidogrel therapy and individualized antiplatelet medications in the treatment of acute IS patients.

Depression is known to be a risk factor for suicide. Currently, the most used antidepressants are selective serotonin reuptake inhibitors (SSRIs). Not all users, however, benefit from them. In such cases, treatment failure can be explained in part by genetic differences. In this study, we investigated the role of pharmacogenetic factors in citalopram-positive completed suicides (n = 349). Since citalopram is metabolized by CYP2C19 and CYP2D6 enzymes, the study population was genotyped for clinically relevant CYP2C19 and CYP2D6 polymorphisms and CYP2D6 copy number variation. To assess genetic differences between suicide cases and Finns in general, Finnish population samples (n = 855) were used as controls. Also, the role of drug interactions among suicide cases was evaluated. We found enrichment of a combined group of genetically predicted poor and ultrarapid metabolizer phenotypes (gMPs) of CYP2C19 among suicide victims compared to controls 0.356 [0.31-0.41] vs. 0.265 [0.24-0.30] (p = 0.0065). In CYP2D6 gMPs, there was no difference between cases and controls when the study population was analyzed as a whole. However, there were significantly more poor metabolizers among females who committed suicide by poisoning compared to female controls. In 8% of all drug poisoning deaths, lifetime drug-drug interaction was evaluated having a contribution to the fatal outcome. From clinical perspective, pharmacogenetic testing prior to initiation of SSRI drug could be beneficial. It may also be useful in medico-legal settings as it may elucidate obscure poisoning cases. Also, the possibility of unintentional drug interactions should be taken into account in drug poisoning deaths.

The mechanisms of early neurologic deterioration (END) and prevention strategies for END are not completely understood. The aim of this study was to investigate the association between CYP2C19*2 variants and END, and the effectiveness of antiplatelet therapy for prevention of END according to CYP2C19*2 genotypes in patients with ischemic stroke (IS). This was a two-center, randomized controlled study. Between August 2009 and December 2011, 570 IS patients were randomly assigned to clopidogrel plus aspirin group (n = 284) or aspirin alone group (n = 286). Platelet aggregation and platelet–leukocyte aggregates were measured before and after 7–10 days of treatment. CYP2C19*2 (rs4244285) genotypes were examined using mass spectrometry. The primary outcome was END during the 10 days of admission. Among the 570 patients, 121 (21.2%) patients suffered from END. Carriers of CYP2C19*2 reduced-function alleles were associated with higher incidence of END (26.8% in carriers vs. 16.6% in noncarriers, P = 0.004). The incidence of END was lower in the clopidogrel plus aspirin group than in the aspirin alone group (17.6 vs. 24.8%, P = 0.032). Stratified analyses revealed that clopidogrel plus aspirin could be more effective in reducing END than aspirin alone for carriers of CYP2C19*2 reduced-function alleles (18.8 vs. 34.9%, P = 0.006). However, there was no significant difference in incidence of END between dual therapy group and monotherapy group for noncarriers (16.7 vs. 16.6%, P = 0.998). Dual therapy with clopidogrel and aspirin may be adequate for prevention of END in carriers of CYP2C19 reduced-function alleles, but not for noncarriers. Our findings may be useful to guide precise antiplatelet therapy, and decrease the risk of END.

Clopidogrel non-responsiveness is multifactorial; several genetic and non-genetic factors may contribute to impaired platelet inhibition. The goal of this study is to determine the effect of the cytochrome P450 CYP2C19*2 polymorphism on the platelet response to clopidogrel in patients with and without diabetes mellitus (DM). We conducted an observational study in patients with coronary artery disease and consequent exposure to clopidogrel therapy (75 mg/day for at least 7 consecutive days). We have analyzed two groups of patients: group I (DM patients) and group II (non-diabetes mellitus patients). Platelet reactivity was assessed by the VerifyNow P2Y12 assay and high on clopidogrel platelet reactivity (HPR) was defined as P2Y12 reaction units (PRU) ≥ 208. Genotyping for CYP2C19*2 polymorphism was performed by PCR-RFLP. We have included 150 subjects (76 DM and 74 non-diabetes mellitus patients). The carriage of CYP2C19*2 allele, in DM patients, was significantly associated to HPR (odds ratio (OR) 4.437, 95% confidence interval (CI) 1.134 to 17.359; p = 0.032). Furthermore, 8.4% of the variability in percent inhibition by clopidogrel could be attributed to CYP2C19*2 carrier status. However, in non-diabetes mellitus patients, there was no significant difference in platelet response to clopidogrel according to the presence or absence of CYP2C19*2 allele carriage (OR 1.260, 95% CI 0.288 to 5.522; p = 0.759). Our study suggests that the carriage of CYP2C19*2 polymorphism, in DM patients, might be a potential predictor of persisting HPR in these high-risk individuals. Clinical Trials.gov NCT03373552 (Registered 13 December 2017)

This randomized double-blind crossover study aimed to investigate the influence of cytochrome P450 (CYP) 2C19 polymorphisms on the antiplatelet effects of prasugrel in patients with non-cardioembolic stroke treated with clopidogrel. Patients received clopidogrel 75 mg/day for > 4 weeks. Subsequently, patients received prasugrel 3.75 mg/day (group A; n = 64) or 2.5 mg/day (group B; n = 65) for 4 weeks followed by a 4 week switched-dose regimen. To assess the influence of CYP2C19 polymorphisms, patients were classified as extensive metabolizers (EMs), intermediate metabolizers (IMs), and poor metabolizers (PMs). The primary endpoint was P2Y12 reaction units (PRU) at the end of each 4 week treatment. A significant reduction in PRU was noted after treatment with prasugrel 3.75 mg/day compared with the pre-dose value (after treatment with clopidogrel) (p

Zolpidem is indicated for the short-term treatment of insomnia and it is predominantly metabolized by CYP3A4, and to a lesser extent by CYP2C19, CYP1A2, and CYP2C9. Therefore, we evaluated the effects of CYP2C19 genetic polymorphisms on the pharmacokinetics of zolpidem in healthy male subjects. Thirty-two male subjects were recruited and all subjects were classified into three groups according to their genotypes: CYP2C19EM (CYP2C19*1/*1, n = 12), CYP2C19IM (CYP2C19*1/*2 or *1/*3, n = 10), and CYP2C19PM (CYP2C19*2/*2, *2/*3 or *3/*3, n = 10). The pharmacokinetic parameters of zolpidem were compared in three CYP2C19 genotype groups after zolpidem administration with or without a CYP3A4 inhibitor at steady-state concentration. Plasma concentrations of zolpidem were determined up to 12 h after drug administration by liquid chromatography-tandem mass spectrometry method. The maximum plasma concentration (Cmax) differed, but mean total area under the plasma concentration–time curve (AUCinf), half-life (t1/2), and apparent oral clearance (CL/F) of zolpidem administered alone did not significantly differ among the three different CYP2C19 genotype groups. Furthermore, when zolpidem was administered with a CYP3A4 inhibitor at steady-state concentration, there were no significant differences in any of the pharmacokinetic parameters of zolpidem in relation to CYP2C19 genotypes. In conclusion, we did not find any evidence for the impact of CYP2C19 genetic polymorphisms on the pharmacokinetic parameters of zolpidem.