Population Pharmacokinetics of Sertraline in Psychiatric and Substance Use Disorders.

This study aimed to characterize the population pharmacokinetics of sertraline in Mexican patients with psychiatric and substance use disorders. Fifty-nine patients (13 to 76 years old) treated with doses of sertraline between 12.5 and 100 mg/day were included. Plasma sertraline concentrations were determined in blood samples and five of the main substances of abuse were determined by rapid tests in urine samples. Demographic, clinical, and pharmacogenetic factors were also evaluated. Population pharmacokinetic analysis was performed using NONMEM software with first-order conditional estimation method. A one-compartment model with proportional residual error adequately described the sertraline concentrations versus time. CYP2D6*2 polymorphism and CYP2C19 phenotypes significantly influenced sertraline clearance, which had a population mean value of 66 L/h in the final model. The absorption constant and volume of distribution were fixed at 0.855 1/h and 20.2 L/kg, respectively. The model explained 11.3% of the interindividual variability in sertraline clearance. The presence of the CYP2D6*2 polymorphism caused a 23.1% decrease in sertraline clearance, whereas patients with intermediate and poor phenotype of CYP2C19 showed 19.06% and 48.26% decreases in sertraline clearance, respectively. The model was internally validated by bootstrap and visual predictive check. Finally, stochastic simulations were performed to propose dosing regimens to achieve therapeutic levels that contribute to improving treatment response.

Prevalence of CYP2C19*2 and CYP2C19*3 Allelic Variants and Clopidogrel Use in Patients with Cardiovascular Disease in Trinidad & Tobago.

INTRODUCTION: Trinidad & Tobago has the highest prevalence of cardiovascular disease (CVD) in the Caribbean and clopidogrel is a ubiquitously used treatment. Yet, the extent of genetically mediated clopidogrel resistance is unknown. To determine this, we investigated whether the association between CYP2C19*2 and CYP2C19*3 genetic variants and clopidogrel resistance holds, and calculated the frequencies of these in the Trinidadian CVD population. METHODS: Demographic data, clinical data, and a saliva sample were collected under informed consent from 22 patients with CVD on dual anti-platelet therapy whose biochemical resistance to clopidogrel is known, and a further 162 patients accessing the main public CVD clinic in Trinidad and who are either currently being treated or are likely to be treated with clopidogrel. A polymerase chain reaction (PCR) and restriction enzyme digestion procedure was used to genotype each patient for the CYP2C19*2 and CYP2C19*3 allelic variants. Genotype was compared to known clopidogrel resistance in the 22 patients, and to disease status and clopidogrel usage in the larger cohort. RESULTS: CYP2C19*2 genotype was concordant with clopidogrel resistance. CYP2C19*2 was detected in 61.1% (99/162) of patients and CYP2C19*3 was undetected. Clopidogrel was the most prescribed antiplatelet therapy (42%). A total of 120 people presented with coronary artery disease (CAD) and 52.5% of these (n = 63/120) are currently prescribed clopidogrel. 63.5% (40/63) of patients with CAD who are prescribed clopidogrel carry the CYP2C19*2 allele; ten homozygous and 30 heterozygous. Indian patients comprised 65% of the cohort and were four times more likely to carry the CYP2C19*2 allele than African patients. CONCLUSIONS: A large proportion of Trinidadian patients with CVD who are prescribed or may be prescribed clopidogrel carry genetic variants associated with clopidogrel resistance. These results emphasize the clinical need for further investigation into whether CYP2C19*2 genotype should guide clopidogrel use for the cardiovascular disease population in Trinidad & Tobago. A slide deck is available for this article.

Psychiatric Level 1A evidence pharmacogenomics in a Brazilian admixed cohort and global populations.

Purpose: To compare minor allele frequencies (MAFs) of psychiatric drug response variants in a Brazilian admixed cohort with global populations and other Brazilian groups. Methods: PharmGKB MAFs were gathered from publicly available genetic datasets for Brazil and worldwide. Results: Among 146 variants in CYP2D6 and CYP2C19, 41 were present in Brazil, mostly rare (MAF <1%). 11 variants showed significant MAF differences with large effect sizes compared with global populations. CYP2C19*3 (rs4986893), CYP2C19*17 (rs12248560), CYP2D6*17 (rs28371706-A) and CYP2D6*29 (rs61736512) exhibited higher frequencies in Brazil, with the latter three also differing from other Brazilian groups. Conclusion: This study highlights significant pharmacogenomic diversity in Brazil and globally, underscoring the need for more research in personalized psychiatric drug therapy.

Association of CYP2C19, CYP2D6 and CYP3A4 Genetic Variants on Primaquine Hemolysis in G6PD-Deficient Patients.

In the Amazon, the treatment for Plasmodium vivax is chloroquine plus primaquine. However, this regimen is limited due to the risk of acute hemolytic anemia in glucose-6-phosphate dehydrogenase deficiency. Primaquine is a prodrug that requires conversion by the CYP2D6 enzyme to be effective against malaria. A series of cases were performed at an infectious diseases reference hospital in the Western Brazilian Amazon. The STANDARD G6PD (SD Biosensor®) assay was used to infer G6PD status and real-time PCR to genotype G6PD, CYP2C19, CYP2D6 and CYP3A4. Eighteen patients were included, of which 55.6% had African A- variant (G202A/A376G), 11.1% African A+ variant (A376G), 5.6% Mediterranean variant (C563T) and 27.8% were wild type. CYP2C19, CYP2D6 and CYP3A4 genotyping showed no statistically significant differences in the frequency of star alleles between the groups G6PD deficient and G6PD normal. Elevated levels of liver and kidney markers in the G6PDd patients were observed in gNM, gRM and gUM of CYP2C19 and CYP2D6 (p < 0.05). Furthermore, in this study there was no influence of CYPs on hemolysis. These findings reinforce the importance of studies on the mapping of G6PD deficiency and genetic variations of CYP2C19, CYP2D6 and CYP3A4. This mapping will allow us to validate the prevalence of CYPs and determine their influence on hemolysis in patients with malaria, helping to decide on the treatment regimen.

Distribution of a novel CYP2C haplotype in Native American populations.

The CYP2C19 gene, located in the CYP2C cluster, encodes the major drug metabolism enzyme CYP2C19. This gene is highly polymorphic and no-function (CYP2C19*2 and CYP2C19*3), reduced function (CYP2C19*9) and increased function (CYP2C19*17) star alleles (haplotypes) are commonly used to predict CYP2C19 metabolic phenotypes. CYP2C19*17 and the genotype-predicted rapid (RM) and ultrarapid (UM) CYP2C19 metabolic phenotypes are absent or rare in several Native American populations. However, discordance between genotype-predicted and pharmacokinetically determined CYP2C19 phenotypes in Native American cohorts have been reported. Recently, a haplotype defined by rs2860840T and rs11188059G alleles in the CYP2C cluster has been shown to encode increased rate of metabolism of the CYP2C19 substrate escitalopram, to a similar extent as CYP2C19*17. We investigated the distribution of the CYP2C:TG haplotype and explored its potential impact on CYP2C19 metabolic activity in Native American populations. The study cohorts included individuals from the One Thousand Genomes Project AMR superpopulation (1 KG_AMR), the Human Genome Diversity Project (HGDP), and from indigenous populations living in Brazil (Kaingang and Guarani). The frequency range of the CYP2C:TG haplotype in the study cohorts, 0.469 to 0.598, is considerably higher than in all 1 KG superpopulations (range: 0.014-to 0.340). We suggest that the high frequency of the CYP2C:TG haplotype might contribute to the reported discordance between CYP2C19-predicted and pharmacokinetically verified CYP2C19 metabolic phenotypes in Native American cohorts. However, functional studies involving genotypic correlations with pharmacokinetic parameters are warranted to ascertain the importance of the CYP2C:TG haplotype.

Prediction of the Impact of CYP2C19 Polymorphism on Drug-Drug Interaction between Voriconazole and Tacrolimus Using Physiologically-Based Pharmacokinetic Modelling

Abstract Voriconazole increases tacrolimus blood concentration significantly when coadministrated. The recommendation of reducing tacrolimus to 1/3 in voriconazole package insert seems not to be satisfactory in clinical practice. In vitro studies demonstrated that the magnitude of inhibition depends on the concentration of voriconazole, while voriconazole exposure is determined by the genotype status of CYP2C19. CYP2C19 gene polymorphism challenges the management of drug-drug interactions(DDIs) between voriconazole and tacrolimus. This work aimed to predict the impact of CYP2C19 polymorphism on the DDIs by using physiologically based pharmacokinetics (PBPK) models. The precision of the developed voriconazole and tacrolimus models was reasonable by evaluating the pharmacokinetic parameters fold error, such as AUC0-24, Cmax and tmax. Voriconazole increased tacrolimus concentration immediately in all population. The simulated duration of DDIs disappearance after voriconazole withdrawal were 146h, 90h and 66h in poor metabolizers (PMs), intermediate metabolizers (IMs) and extensive metabolizers(EMs), respectively. The developed and optimized PBPK models in this study can be applied to assit the dose adjustment for tacrolimus with and without voriconazole.

CYP2D6 and CYP2C19 Genes Associated with Tricontinental and Latin American Ancestry of Pe-ruvians.

Precision medicine seeks to individualize the dose from the beginning of phar-macological therapy based on the characteristics of each patient, genes involved in the metabolic phenotype, ethnicity or miscegenation, with the purpose to minimize adverse effects and optimize drug efficacy. The objective was to re-view studies that describe the association of the CYP2D6 and CYP2C19 genes with the tricontinental and Latin American ancestry of Peruvians. A biblio-graphic search was carried out in PubMed/Medline and SciELO, with various descriptors in Spanish and English. The results of this review confirm that the ethnic origin of Peruvians is triconti-nental due to European (mainly Spanish), African and Asian migration, in addi-tion to Latin American migration, being 60.2% mixed, 25.8% Amerindian, 5.9% white, 3.6% African descent, 1.2% Chinese and Japanese descent, and 3.3% unspecified. Studies on CYP2C19*3, CYP2D6*2, *3 and *6 have been reported in Peruvians, and the frequency is similar to that studied in Ecuadori-ans and Colombians. The CYP2C19*3, CYP2D6*3, and CYP2D6*6 alleles found in Peruvians are common in Europeans, Africans, and Asians; while CYP2D6*4 in Africans and CYP2D6*2 related to Asians. In some studies, the ethnic/gene association has not been demonstrated; while others have shown a significant association, which is why further investigation is warranted. It is concluded that the studies on CYP2D6 and CYP2C19 genes associated with the tricontinental and Latin American ancestry of Peruvians are little, and ac-cording to what has been investigated, the CYP2C19*3, CYP2D6*2, *3, *4 and *6 alleles have more related to their ancestry.

Qualidade de vida, sintomas de depressão e adesão ao tratamento em pacientes com trantorno depressivo maior / Quality of life, depression symptoms and adherence to treatment in patients with major depressive disorder / Calidad de vida, síntomas depresión y adhesión al tratamiento en pacientes con trastorno depresivo mayor

Introdução:Pacientes com depressão maior geralmente respondem ao tratamento com medicamentos antidepressivos, no entanto em 10% a 30% dos casos há apenas uma resposta parcial ou nenhuma resposta, entre os fatores que podem influenciar encontra-se o perfil das enzimas hepáticas metabolizadoras dos antidepressivos, tal como a CYP2C19.Objetivo:Caracterizar os indivíduos quanto ao perfil genético dospolimorfismos CYP2C19*2 ou CYP2C19*17 em pacientes com transtorno depressivo maior (TDM) tratados com citalopram ou escitalopram e compará-los em relação a adesão ao tratamento, sintomas de depressão e qualidade de vida.Metodologia:Trata-se de um estudo transversal realizado com 29 pacientes com TDM. Amostras de sangue foram coletadas para genotipagem de CYP2C19 por discriminação alélica TaqMan®. Após caracterização do perfil genético, os indivíduos foram comparados quanto aos dados demográfico e socioeconômico, adesão ao tratamento (TestedeMorisky-Green),sintomas de depressão (escala de Hamilton) e qualidade de vida (WHOQoL-BREF).Resultados:Quatro pacientes (13.8%) apresentaram polimorfismo para CYP2C19*2 e 10 pacientes (34.4%) para CYP2C19*17, com maior prevalência de CYP2C19*17 (p>0.05). Nenhuma associação significativa de características socioeconômicas, demográficas e clínicas entre os genótipos do CYP2C19.No TestedeMorisky-Green, aadesão moderada ao tratamento foi predominante nos pacientes CYP2C19*2 e CYP2C19*17 (p>0.05). Não foi observada associação entre sintomas de depressão e polimorfismos genéticos (p>0.05). Uma associação significativa entre o genótipo polimórfico CC do CYP2C19*17 com a satisfação com a saúde, enquanto o genótipo CT foi associado ao estado "nem satisfeito/nem insatisfeito" (p<0.05). A maioria dos indivíduos CYP2C19*2 e CYP2C19*17 relatou "necessidade de melhorar" em relação aos domínios de qualidade de vida físico, psicológico, social e ambiental (p>0.05).Conclusões:Os pacientes apresentaram maior prevalência do polimorfismo CYP2C19*17, com moderada adesão ao tratamento. Alguns pacientes, mesmo sob efeito da medicação, apresentaram sintomas de depressão moderado a intenso e relataram uma indefinição na satisfação da sua qualidade de vida (AU).

Introduction:Patients with major depression usually respond to treatment with antidepressant drugs, however in 10% to 30% of cases there is only a partial response or no response, among the factors that can influence is the profile of liver enzymes metabolizing antidepressants, such as CYP2C19.Objective:To characterize the individuals regarding the genetic profile ofCYP2C19*2or CYP2C19*17 polymorphisms in patients with major depressive disorder (MDD) treated with citalopram or escitalopram, and to compare themaccording to treatment adherence, symptoms of depression and quality of life.Methodology:This is cross-sectionalstudy carried out with 29 patients with MDD. Blood samples were collected for CYP2C19 genotyping by TaqMan® allelic discrimination. After characterization of the genetic profile, the individuals were compared regarding the demographic and socioeconomic data, treatment adherence (Morisky-GreenTest), symptoms of depression (Hamilton scale) and quality of life (WHOQoL-BREF).Results:Four patients showed (13.8%) CYP219*2 and 10 patients (34.4%) CYP219*17 polymorphisms.,withhigher prevalence of CYP219*17 (p>0.05). No association between socioeconomic, demographic, and clinical features with CYP2C19 genotypes was observed. In Morisky-GreenTest, moderate adherence to treatment was predominant for CYP2C19*2 and CYP219*17 patients (p>0.05). No statistically significant association was observed between symptoms of depression and genetic polymorphisms (p>0.05). A significant association between polymorphic CC genotype of CYP219*17 with health satisfaction, while the CT genotype was associated with "neither satisfied/nor dissatisfied" status (p<0.05). Most of the CYP2C19*2 and CYP2C19*17 subjects reported "need to improve" or "regular" regarding physical, psychological, social, and environmental domainsof quality of life(p>0.05).Conclusions:The patients showed a higher prevalence of CYP219*17 polymorphism, with moderate treatment adherence. Some subjects, even under the effect of the medication, presented moderate to intense symptoms of depression, and reported a lack of definition in the satisfaction of their quality of life (AU).

Introducción:Los pacientes con depresión mayor responder al tratamiento con antidepresivos, en 10% al 30% de los casos existe una respuesta parcial o nula, entre los factores que pueden influir se encuentra el perfil de enzimas hepáticas metabolizadoras de antidepresivos, como CYP2C19.Objetivo: Caracterizar a los individuos en cuanto al perfil genético depolimorfismos CYP2C19 *2 o CYP2C19 * 17 en pacientes con trastorno depresivo mayor (TDM) tratados con citalopram o escitalopram y compararlos en relaciónpara la adherencia al tratamiento, síntomas de depresión y la calidad de vida.Metodología: Estudio transversalcon 29 pacientes con TDM. Se recogieron muestras de sangre para la determinación del genotipo CYP2C19 mediante discriminación alélica TaqMan®, los individuos fueron comparados en cuanto a los datosdemográficosy socioeconómicos, adherencia (Prueba de Morisky-Green), síntomas de depresión (escala de Hamilton) y calidad de vida (WHOQoL-BREF).Resultados: Cuatro pacientes (13,8%) con polimorfismo CYP2C19*2 y 10 (34,4%) con CYP2C19 * 17,(p> 0,05). No existe una asociación significativa de las características socioeconómicas, demográficas y clínicas con los genotipos CYP2C19. La adherencia moderada al tratamiento fue predominante en los pacientes con CYP2C19*2 y CYP2C19*17 (p> 0,05). No hubo asociación entre síntomas de depresión y polimorfismos genéticos (p> 0.05). Una asociación significativa entre el genotipo polimórfico CYP2C19 * 17 CC con la satisfacción con la salud, mientras que el genotipo CT se asoció con el estado "ni satisfecho / no insatisfecho" (p <0.05). La mayoría de CYP2C19 * 2 y CYP2C19 * 17 individuos informaron "necesidad de mejorar" en relación con los dominios físico, psicológico, social y ambientalde calidad de vida(p> 0,05).Conclusiones: Los pacients mostraron una mayor prevalencia del CYP2C19 * 17, con adherencia moderada al tratamiento, síntomas de depresión moderada a intensay informaron una falta de definición en la satisfacción de su calidad de vida (AU).

Variants *1, *2, *3 and *17 of CYP2C19 Cytochrome among Helicobacter Pylori Carriers from Manaus, Amazonas State, Brazil.

OBJECTIVE: The objective of the present study was to estimate the frequency of CYP2C19 cytochrome variants *1, *2, *3 and *17 among Helicobacter pylori carriers from Manaus, Amazonas state, who were treated at Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD). METHODS: From the 78 recruited individuals who underwent upper gastrointestinal endoscopy with biopsy and histopathological test, 50 tested positive for H. pylori. Peripheral blood was collected from this group and CYP2C19 *2, *3 and *17 alleles were genotyped using qPCR. RESULTS: Of the 50 H. pylori + individuals, 22 were male and 28 were female. Their age varied from 18 to 67 years old, with the mean age being 40.24. Racial groups were classified by self-declaration, based on the official Instituto Brasileiro de Geografia e Estatística (IBGE) categories: 16% (8) were white, 78% (39) were brown, 4% (2) were black, and 2% (1) were indigenous. H. pylori infection was classified using the system of crosses, with 30% (15) of infections being classified as mild (+), 30% (15) as moderate (++), and 40% (20) as severe (+++). The CYP2C19 genotype results showed an allelic frequency of 11% for *2 (20% of the subjects), 6% for *3 (10% of the subjects) and 17% for *17 (30% of the subjects). Based on the phenotypic profiles, the individuals were classified as poor metabolizers (PM, 10%), intermediate metabolizers (IM, 2%), extensive metabolizers (EM, 58%) and ultra-rapid metabolizers (UM, 20%). CONCLUSIONS: Even though the percentage of allele *3 was higher than expected, the percentage of allele *17, a possible contributor to H. pylori eradication failure, was also significant. The population that self-declared as brown showed a unique genotypic pattern, unlike any other population described in previous studies. Our results show that small populations may have genetic particularities that are relevant to therapeutic outcomes.
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Enantioselective inhibition of human CYP2C19 by the chiral pesticide ethofumesate: Prediction of pesticide-drug interactions in humans.

Ethofumesate is a chiral herbicide that may display enantioselective behavior in humans. For this reason, the enantioselective potential of ethofumesate and its main metabolite ethofumesate-2-hydroxy to cause pesticide-drug interactions on cytochrome P450 forms (CYPs) has been evaluated by using human liver microsomes. Among the evaluated CYPs, CYP2C19 had its activity decreased by the ethofumesate racemic mixture (rac-ETO), (+)-ethofumesate ((+)-ETO), and (-)-ethofumesate ((-)-ETO). CYP2C19 inhibition was not time-dependent, but a strong inhibition potential was observed for rac-ETO (IC50 = 5 ± 1 µmol L-1), (+)-ETO (IC50 = 1.6 ± 0.4 µmol L-1), and (-)-ETO (IC50 = 1.8 ± 0.4 µmol L-1). The reversible inhibition mechanism was competitive, and the inhibition constant (Ki) values for rac-ETO (2.6 ± 0.4 µmol L-1), (+)-ETO (1.5 ± 0.2 µmol L-1), and (-)-ETO (0.7 ± 0.1 µmol L-1) were comparable to the Ki values of strong CYP2C19 inhibitors. Inhibition of CYP2C19 by ethofumesate was enantioselective, being almost twice higher for (-)-ETO than for (+)-ETO, which indicates that this enantiomer may be a more potent inhibitor of this CYP form. For an in vitro-in vivo correlation, the Food and Drug Administration's (FDA) guideline on the assessment of drug-drug interactions used in the early stages of drug development was used. The FDA's R1 values were estimated on the basis of the obtained ethofumesate Ki and distribution volume, metabolism, unbound plasma fraction, gastrointestinal and dermal absorption data available in the literature. The correlation revealed that ethofumesate probably inhibits CYP2C19 in vivo for both chronic (oral) and occupational (dermal) exposure scenarios.

Evaluation of CYP2C19 Gene Polymorphisms in Patients with Acid Peptic Disorders Treated with Esomeprazole.

BACKGROUND: CYP2C19 is a highly polymorphic gene that encodes an enzyme with the same name and whose function is associated with the metabolism of many important drugs, such as proton pump inhibitors (such as esomeprazole, which is used for the treatment of acid peptic disease). Genetic variants in CYP2C19 alter protein function and affect drug metabolism. This study aims to genotypically and phenotypically characterize the genetic variants in the CYP2C19 gene in 12 patients with acid peptic disorders and different therapeutic profiles to proton pump inhibitor (PPI) drugs. The patients were randomly selected from a controlled, randomized and blinded clinical pilot trial of 33 patients. We determined the presence and frequency of single nucleotide polymorphisms (SNPs) within exons 1-5 and 9, the intron-exon junctions, and a fragment in the 3' UTR region of the CYP2C19 gene using Sanger sequencing. Undescribed polymorphisms were analyzed by free online bioinformatics tools to evaluate the potential molecular effects of these genetic variants. RESULTS: We identified nine polymorphisms, six of which had no reported functions. One of these genetic variants, with a functional impact, not yet reported (p.Arg132Trp) was predicted by bioinformatic tools as potentially pathogenic. This finding suggests that p.Arg132Trp could be related to poor metabolizers of drugs metabolized by CYP2C19. CONCLUSION: We identified the genotype spectrum of variants in CYP2C19. The genotype spectrum of variants in CYP2C19 could predict the treatment response and could support to evaluate clinical efficacy in patients treated with esomeprazole.

Clinical treatment for hepatitis C reverses CYP2C19 inhibition.

AIMS: Infection by the hepatitis C virus (HCV) generates inflammatory response selectively modulating cytochrome P450 protein (CYP) activities. This study assessed the effect of chronic hepatitis C on CYP2C19 activity in patients with HCV. METHODS: Patients with HCV infection (n = 23) at different fibrosis stages were allocated into groups 1 (F0/F1 and F2, mild to moderate fibrosis) and 2 (F3 and F4, advanced fibrosis stages). Phase 1 was conducted before the treatment with direct-acting antivirals (DAAs) and phase 2 after the sustained virological response. Participants were administered 2 mg of a single oral dose of omeprazole (OME) as probe drug in both phases. Metabolic ratios (MRs) (plasma samples collected at 4 h after OME administration) were calculated by dividing plasma concentrations of 5-hydroxyomeprazole by OME. RESULTS: The MRs for group 1 were 0.45 (0.34-0.60, 90% confidence interval) and 0.69 (0.50-0.96) for phases 1 and 2, respectively, while the MRs for group 2 were 0.25 (0.21-0.31) and 0.41 (0.30-0.56) for phases 1 and 2, respectively. MRs were different (P < .05) between phases 1 and 2 for both groups, as well as between groups 1 and 2 in phase 1, but not in phase 2 (P > .05). CONCLUSIONS: Both groups presented different MRs before and after treatment with DAAs, evidencing that CYP2C19 inhibition during inflammation was at least partially reversed after DAA treatment. Groups 1 and 2 were also found to be different in phase 1 but not phase 2, showing that CYP2C19 metabolic activity does not differ between groups after DAA treatment.

Impact of Plasmodium vivax malaria and antimalarial treatment on cytochrome P450 activity in Brazilian patients.

AIMS: To investigate the impact of Plasmodium vivax malaria and chloroquine-primaquine chemotherapy on CYP2D6 and CYP2C19 activity in patients from the Brazilian Amazon. METHODS: Adult patients (n = 30) were given subtherapeutic doses of CYP2D6 and CYP2C19 phenotypic probes metoprolol (10 mg) and omeprazole (2 mg) in three different stages of vivax malaria illness: acute disease (study phase 1), post chemotherapy (phase 2) and convalescence (stage 3). Plasma concentrations of probes and CYP-hydroxylated metabolites (α-OH metoprolol and 5-OH omeprazole) were measured using LC/MS/MS. Two pharmacokinetic metrics were used to estimate CYP activity: (a) ratio of plasma concentrations of probe/metabolite at 240 minutes after administration of the probes and (b) ratio of areas under the time-concentration curves for probe/metabolite (AUC0-12h ). For statistical analysis, the pharmacokinetic metrics were normalized to the respective values in phase 3. Taqman assays were used for CYP2D6 and CYP2C19 genotyping. Cytokines levels were measured using cytometric bead array. RESULTS: Both pharmacokinetic metrics for metoprolol and omeprazole, and plasma concentrations of cytokines IL-6, IL-8 and IL-10 varied significantly across the three study phases (ANOVA P < 0.0001). Post hoc tests showed greater metoprolol:α-OH metoprolol ratios in phases 1 and 2 compared to phase 3, larger omeprazole:5-OH omeprazole ratios in phase 1 than in phases 2 and 3, and higher circulating IL-6, IL-8 and IL-10 in phase 1 than in phases 2 and 3. CONCLUSION: P. vivax malaria and treatment altered CYP2D6 and CYP2C19 metabolic phenotypes. CYP2C19 inhibition is attributed to a higher level of circulating proinflammatory cytokines, while suppression of CYP2D6 is ascribed mainly to chloroquine exposure.

CYP2C19 polymorphisms and outcomes of Escitalopram treatment in Brazilians with major depression.

Escitalopram (ESC), a selective serotonin reuptake inhibitor indicated for the treatment of depression and anxiety disorders, is primarily metabolized by cytochrome P450 (CYP) 2C19, which is a highly polymorphic enzyme known to cause inter-individual differences in pharmacokinetics. We hypothesized that CYP2C19 polymorphisms are associated with major depressive disorder (MDD) remission in patients treated with ESC in the long term. Thirty-one patients with MDD receiving chronic treatment with ESC monotherapy or combination therapy with other antidepressants (mirtazapine and bupropion), in naturalistic conditions, were included in the study. For comparison of genotype and phenotype frequencies, a group of 126 healthy subjects was also included. The CYP2C19∗2, CYP2C19∗3, and CYP2C19∗17 polymorphisms were analyzed by RFLP-PCR genotyping. The CYP2C19 genotypes and phenotypes were similar in patient and healthy subject groups. Four phenotypes were found in the healthy subject group: ultra-rapid (UM; 28%), extensive (EM; 52%), intermediate (IM; 17%), and poor metabolizers (PM; 3%). The patient group showed the UM (22.5%), EM (55%), and IM (22.5%) phenotypes. The UM patients had significantly higher ESC doses than both EM and IM patients (20.7 ± 4.5, 15.7 ± 3.8, and 14.0 ± 3.3 mg/day, respectively; p = 0.0041). Furthermore, all patients using ESC in combination with mirtazapine or bupropion antidepressants (ESC plus mirtazapine or bupropion) were UM metabolizers, suggesting that the ∗17 ultra-rapid allele seems to be the factor responsible for lower response to ESC, even at higher doses. The CYP2C19 UM phenotype is associated with higher ESC doses and antidepressant combinations for symptom remission in MDD patients.

The CYP2C19*2 and CYP2C19*17 Polymorphisms Influence Responses to Clozapine for the Treatment of Schizophrenia.

INTRODUCTION: Clozapine (CLZ) is the gold standard drug for treatment-refractory schizophrenia (TRS). However, approximately 30% of patients partially respond to CLZ, defining this subset with super refractory schizophrenia (SRS). Alterations in enzyme activity may affect CLZ responses; the CYP3A4, CYP1A2 and CYP2C19 genes are primarily responsible for CLZ metabolism. OBJECTIVE: The aim of this study was to assess if CYP2C19 variants were associated with TRS or SRS. METHODS: CYP2C19*2 loss-of-function and CYP2C19*17 gain-of-function polymorphism genotype testing were performed in 108 individuals undergoing pharmacological treatment for TRS or SRS. DNA was extracted and polymorphisms were analyzed by polymerase chain reaction (PCR) and sequencing. RESULTS: CYP2C19*17 had positive correlations with SRS and lower Brief Psychiatric Rating Scale (BPRS) scores for TRS. In addition, CYP2C19*2 was associated with lower CLZ dosages for TRS. CONCLUSION: These results show that CYP2C19*2 and CYP2C19*17 polymorphisms influence CLZ responses during schizophrenia treatment.

Association of CYP2C19*2 polymorphism with clopidogrel resistance among patients with high cardiovascular risk in Northeastern Mexico.

Objective: Oral antiplatelet drugs are a key to modern pharmacotherapy in cardiovascular atherothrombotic diseases. Clopidogrel (CLO) constitutes the main preventive treatment of atherothrombosis. However, a considerable inter-individual variation in CLO response has been documented, resulting in suboptimal therapy and an increased risk of recurrent adverse effects in some patients. The enzyme CYP2C19 has been reported to be the CYP isoform that activates CLO to its active metabolite. Several single nucleotide polymorphisms in the CYP2C19 gene have been identified as strong predictors of CLO-impaired pharmacological response. At least 16 variants have been associated with changes in CYP2C19 activity. Materials and Methods: The following research was composed of a total of 102 subjects with high cardiovascular risk in the northeast of Mexico, with a maintenance dose of 75 mg of CLO per day. The platelet reactivity was measured with VerifyNow P2Y12 assay, while the presence of CYP2C19*2 was identified by real-time polymerase chain reaction. Results: Patients were categorized by CYP2C19 metabolizer status based on *2 genotypes using the common consensus star allele nomenclature as normal metabolizer (G/G), intermediate metabolizer (G/A), and poor metabolizer (A/A), respectively. The phenotype frequency for CYP2C19*2 was 74.5% (G/G), 21.6% (G/A), and 3.9% (A/A). The subjects with the A allele presented ≥235 P2Y12 reaction unit levels, classifying them how poor metabolizer. The prevalence of reduced CLO effectiveness was associated with the presence of CYP2C19*2 polymorphism among Mexican patients. Conclusion: The presence of the CYP2C19*2 allele is related to resistance to the antiplatelet effect of CLO (p = 0.003).

Objetivo: Los antiplaquetarios orales son clave en la farmacoterapia moderna de las enfermedades aterotrombóticas cardiovasculares. Clopidogrel (CLO) constituye el principal tratamiento preventivo de aterotrombosis (AT). Sin embargo, se ha documentado una considerable variación interindividual en la respuesta a CLO, lo que da como resultado una terapia subóptima y mayor riesgo de efectos adversos en algunos pacientes. La enzima CYP2C19 es la isoforma CYP que activa CLO a su metabolito activo. Se han identificado varios polimorfismos de un solo nucleótido en el gen CYP2C19 como fuertes predictores de respuesta farmacológica alterada a CLO. Al menos 16 variantes se han asociado con cambios en la actividad de CYP2C19. Método: Se reclutaron un total de 102 sujetos con alto riesgo cardiovascular del noreste de México, con dosis de mantenimiento de 75 mg de CLO/día. La reactividad plaquetaria se midió con el ensayo Verify Now P2Y12, la presencia de CYP2C19*2 se identificó mediante polymerase chain reaction en tiempo real. Resultado: Los pacientes fueron clasificados por el estado metabolizador CYP2C19*2 utilizando nomenclatura consenso, como metabolizador normal (G/G), metabolizador intermedio (G/A) y metabolizador pobre (A/A), respectivamente. La frecuencia del fenotipo para CYP2C19*2 fue 74.5% (G/G), 21.6% (G/A) y 3.9% (A/A). Los sujetos con alelo A presentaron ≥235 niveles P2Y12 reaction unit, clasificándolos como metabolizadores deficientes. La prevalencia de eficacia reducida a CLO se asoció con la presencia del polimorfismo CYP2C19*2 en pacientes mexicanos. Conclusiones: La presencia del alelo CYP2C19*2 se relaciona con resistencia al efecto antiagregante plaquetario del CLO (p = 0.003).

Association of CYP2C19*2 polymorphism with clopidogrel resistance among patients with high cardiovascular risk in Northeastern Mexico / Asociación del polimorfismo CYP2C19*2 con resistencia a clopidogrel en pacientes con alto riesgo cardiovascular en el noreste de México

abstract Objective: Oral antiplatelet drugs are a key to modern pharmacotherapy in cardiovascular atherothrombotic diseases. Clopidogrel (CLO) constitutes the main preventive treatment of atherothrombosis. However, a considerable inter-individual variation in CLO response has been documented, resulting in suboptimal therapy and an increased risk of recurrent adverse effects in some patients. The enzyme CYP2C19 has been reported to be the CYP isoform that activates CLO to its active metabolite. Several single nucleotide polymorphisms in the CYP2C19 gene have been identified as strong predictors of CLO-impaired pharmacological response. At least 16 variants have been associated with changes in CYP2C19 activity. Materials and Methods: The following research was composed of a total of 102 subjects with high cardiovascular risk in the northeast of Mexico, with a maintenance dose of 75 mg of CLO per day. The platelet reactivity was measured with VerifyNow P2Y12 assay, while the presence of CYP2C19*2 was identified by real-time polymerase chain reaction. Results: Patients were categorized by CYP2C19 metabolizer status based on *2 genotypes using the common consensus star allele nomenclature as normal metabolizer (G/G), intermediate metabolizer (G/A), and poor metabolizer (A/A), respectively. The phenotype frequency for CYP2C19*2 was 74.5% (G/G), 21.6% (G/A), and 3.9% (A/A). The subjects with the A allele presented ≥235 P2Y12 reaction unit levels, classifying them how poor metabolizer. The prevalence of reduced CLO effectiveness was associated with the presence of CYP2C19*2 polymorphism among Mexican patients. Conclusion: The presence of the CYP2C19*2 allele is related to resistance to the antiplatelet effect of CLO (p = 0.003).

Resumen Objetivo: Los antiplaquetarios orales son clave en la farmacoterapia moderna de las enfermedades aterotrombóticas cardiovasculares. Clopidogrel (CLO) constituye el principal tratamiento preventivo de aterotrombosis (AT). Sin embargo, se ha documentado una considerable variación interindividual en la respuesta a CLO, lo que da como resultado una terapia subóptima y mayor riesgo de efectos adversos en algunos pacientes. La enzima CYP2C19 es la isoforma CYP que activa CLO a su metabolito activo. Se han identificado varios polimorfismos de un solo nucleótido en el gen CYP2C19 como fuertes predictores de respuesta farmacológica alterada a CLO. Al menos 16 variantes se han asociado con cambios en la actividad de CYP2C19. Método: Se reclutaron un total de 102 sujetos con alto riesgo cardiovascular del noreste de México, con dosis de mantenimiento de 75 mg de CLO/día. La reactividad plaquetaria se midió con el ensayo Verify Now P2Y12, la presencia de CYP2C19*2 se identificó mediante polymerase chain reaction en tiempo real. Resultado: Los pacientes fueron clasificados por el estado metabolizador CYP2C19*2 utilizando nomenclatura consenso, como metabolizador normal (G/G), metabolizador intermedio (G/A) y metabolizador pobre (A/A), respectivamente. La frecuencia del fenotipo para CYP2C19*2 fue 74.5% (G/G), 21.6% (G/A) y 3.9% (A/A). Los sujetos con alelo A presentaron ≥235 niveles P2Y12 reaction unit, clasificándolos como metabolizadores deficientes. La prevalencia de eficacia reducida a CLO se asoció con la presencia del polimorfismo CYP2C19*2 en pacientes mexicanos. Conclusiones: La presencia del alelo CYP2C19*2 se relaciona con resistencia al efecto antiagregante plaquetario del CLO (p = 0.003).

Personalized therapy for Helicobacter pylori: CYP2C19 genotype effect on first-line triple therapy.

BACKGROUND: Triple therapy efficacy against Helicobacter pylori is low worldwide, and thus, alternatives must be sought to improve eradication. The aim of the present study was to determine CYP2C19 genetic polymorphism effect on H pylori eradication. METHODS: A randomized, single-blinded clinical trial including 133 participants was carried out. H pylori infection was confirmed by histologic and microbiologic test. Antibiotic susceptibility to amoxicillin and clarithromycin was performed. CYP2C19 polymorphisms *1, *2, and *3 were analyzed by real-time PCR (Roche ®), and nested PCR for CYP2C19*17 polymorphisms. Participants were randomized into two groups for different H pylori therapies, one with standard omeprazole doses and another with omeprazole doses depending on CYP2C19 polymorphism. H pylori eradication was verified by stool antigen tests (Meridian ®). RESULTS: The most common CYP2C19 polymorphism was *1/*1 in 54.9% of the participants followed by *17/*17 in 21.1%. Triple therapy efficacy with standard omeprazole doses versus personalized therapy based on CYP2C19 polymorphism by ITT analysis was 84% (95% CI: 0.73-0.91) vs 92.2% (95% CI: 0.82-0.97) (P = 0. 14), respectively. The efficacy by PP analysis was 92.1% (95% CI: 0.82-0.97) vs 100% (95% CI: 0.92-0.01) (P = 0.027), respectively. CONCLUSIONS: The most frequent polymorphism was extensive PPI metabolizers (62.4%). Effectiveness of guided therapies by susceptibility test was good, yet they can be further improved by customized therapy based on CYP genotype. Therefore, high PPI (80 mg/d) doses are recommended for H pylori eradication therapies in Colombia. ClinicalTrials.gov ID: NCT03650543.

Correspondence between the CYP2C19 and CYP3A4 genotypes with the inferred metabolizer phenotype by omeprazole administration in Mexican healthy children.

WHAT IS KNOWN AND OBJECTIVE: CYP2C19 genotypes presumably allow the prediction of the metabolizer phenotypes: poor (PMs), extensive (EMs) and ultra-rapid (UMs). However, evidence from previous studies regarding this predictive power is unclear, which is important because the benefits expected by healthcare institutions and patients are based on this premise. Therefore, we aimed to complete a formal evaluation of the diagnostic value of CYP2C19 and CYP3A4 genes for predicting metabolizer phenotypes established by omeprazole (OME) administration in 118 healthy children from Jalisco (western Mexico). METHODS: The genotypes for CYP3A4*1B and CYP2C19*2, *3, *4, *5 and *17 alleles were determined. CYP2C19 and CYP3A4 phenotypes were obtained after 20 mg OME administration and HPLC quantification in plasma to estimate the Hydroxylation Index (HI = OME/HOME) and Sulfonation Index (SI = OME/SOME), respectively. RESULTS AND DISCUSSION: The distribution of genotypes and phenotypes for CYP2C19 and CYP3A4 was similar to previous studies in Mexico and Latin America. We estimated the CYP2C19 UM, EM and PM phenotype frequency in 0.84%, 96.61% and 2.54%, respectively. Although differences in the HI distribution were observed between CYP2C19 genotypes, they showed a poor diagnostic ability to predict the CYP2C19 metabolizer phenotype. Similarly, the number of CYP2C19 and CYP3A4 functional alleles was correlated with the HI distribution, but also their diagnostic ability to predict the CYP2C19 phenotype was poor. WHAT IS NEW AND CONCLUSION: The CYP2C19 phenotype is not predicted by the number of functional alleles of CYP2C19 and CYP3A4 genes. Phenotyping is still the most valuable alternative to dose individualization for CYP2C19 substrate drugs.

Impact of CYP2D6 on venlafaxine metabolism in Trinidadian patients with major depressive disorder.

AIM: This study aimed to assess the impact of CYP2D6 and CYP2C19 variation on venlafaxine (VEN) at steady state in patients from Trinidad and Tobago of Indian and African descent with major depressive disorder. PATIENTS & METHODS: Patients were phenotyped with dextromethorphan, genotyped for CYP2D6 and CYP2C19, and metabolic ratios for VEN obtained at 2-week intervals. RESULTS: Of 61 patients, 55 were genotyped and phenotyped and 47 completed 8 weeks of VEN treatment. The majority of patients had metabolic ratios for VEN that were consistent with those for dextromethorphan and genotype-predicted phenotype using activity scores. One subject presented with a novel no-function allele, CYP2D6*99. No correlations were observed with CYP2C19 genotype. CONCLUSION: CYP2D6 genotype analysis provides valuable information to individualize drug therapy with VEN.