Pharmacogenetic and pharmacokinetic assays from saliva samples can guarantee personalized drug prescription

Abstract Saliva is widely used for clinical and laboratory analysis. This study proposed to use DNA extracted from saliva for genotyping and pharmacokinetics of piroxicam. A fast and efficient genotyping method was used to determine relevant allelic variants of CYP2C9 (*2 and *3), since genetic factors can influence in non-steroidal anti-inflammatory drugs (NSAIDs) metabolization. DNA Extract All Reagents Kit® was used for DNA extraction and genotyping was performed using TaqMan® GTXpress™ Master Mix, SNP genotyping assays and a Viia7 Real-Time PCR system. Volunteers performed sequential collections of saliva samples before and after taking a single dose of piroxicam (0.25 to 72 h) which were used for pharmacokinetics assays. Piroxicam concentrations were analyzed using LC-MS/MS. Sixty-six percent of volunteers were ancestral homozygous (CYP2C9*1/*1), and 34% showed one or both polymorphisms. Of these 34%, 22 individuals showed CYP2C9*2 polymorphism, 8 CYP2C9*3, and 4 CYP2C9*2/*3. Piroxicam pharmacokinetics were performed in 5 subjects. Areas under the curve (AUC0-t(h*ng/mL)) for CYP2C9*1/*1, *1/*2 and *1/*3 were, respectively, 194.33±70.93, 166 and 303. Maximum concentrations (Cmax(ng/mL)) for these genotypes were respectively 6.46±2.56, 4.3 and 10.2. Saliva sampling was a very effective matrix for both pharmacogenetic and pharmacokinetic tests, ensuring the speed of the procedure and the well-being and agreement of the participants. Once having the knowledge about the slow and fast metabolizers, it is possible to make an adequate prescription in order to avoid the adverse effects of the medication and to guarantee greater analgesic comfort to the patients respectively.

Resumo Saliva é amplamente utilizada para análises clínicas e laboratoriais. Este estudo propôs o uso de DNA extraído da saliva para genotipagem e farmacocinética do piroxicam. Um método de genotipagem rápido e eficiente foi usado para determinar as variantes alélicas clinicamente relevantes de CYP2C9 (* 2 e * 3), uma vez que fatores genéticos podem influenciar nas respostas metabólicas individuais a medicamentos como anti-inflamatórios não esteroides (AINEs). DNA Extract All Reagents Kit® foi usado para extração de DNA e a genotipagem foi realizada usando TaqMan® GTXpress ™ Master Mix, ensaios de genotipagem SNP e um sistema Viia7 Real-Time PCR. Os voluntários realizaram coletas sequenciais de amostras de saliva antes e após a ingestão de uma única dose de piroxicam (0,25 a 72 h) que foram utilizadas para ensaios farmacocinéticos. As concentrações de piroxicam foram analisadas usando LC - MS / MS. Sessenta e seis por cento dos voluntários eram homozigotos ancestrais (CYP2C9 * 1 / * 1) e 34% apresentaram um ou ambos os polimorfismos. Destes 34%, 22 indivíduos apresentaram polimorfismo CYP2C9 * 2, 8 CYP2C9 * 3 e 4 CYP2C9 * 2 / * 3. A farmacocinética do piroxicam foi realizada em 5 indivíduos. As áreas sob a curva (AUC0-t (h * ng / mL)) para CYP2C9 * 1 / * 1, * 1 / * 2 e * 1 / * 3 foram, respectivamente, 194,33±70,93, 166 e 303. Concentrações máximas (Cmax (ng / mL)) para esses genótipos foram, respectivamente, 6,46±2,56, 4,3 e 10,2. A amostra de saliva foi uma matriz muito eficaz tanto para os testes farmacogenéticos quanto para os farmacocinéticos, garantindo a agilidade do procedimento e o bem-estar e concordância dos participantes. Com o conhecimento dos metabolizadores lentos e rápidos, é possível fazer uma prescrição adequada para evitar os efeitos adversos da medicação e garantir maior conforto analgésico aos pacientes respectivamente.

Polymorphism of the CYP2C9 and VKORC1 genes in patients on the public health system of a municipality in Southern Brazil / Polimorfismo dos genes CYO2C9 e VKORC1 em pacientes do Sistema Público de Saúde em um município do Sul do Brasil

Abstract Background Genetic factors can be responsible for part of the populational and interindividual differences observed in warfarin users. Objectives To identify occurrence of polymorphisms of the CYP2C9 and VKORC1 genes in patients taking warfarin and relate these profiles to their medication dosages and the Time in Therapeutic Range (TTR). Methods Monthly interviews were conducted for data collection. Data were collected on demographic characteristics and medications in use, especially warfarin, including reason for prescription and weekly dose. TTR was calculated as the percentage of days with international normalized ratio (INR) between 2 and 3. The CYP2C9 and VKORC1 genes were analyzed at a Human Genetics Laboratory. Results 49 patients (74.2%) had polymorphisms of the CYP2C9 and/or VKORC1 genes; the remaining 17 (25.8%) did not have these polymorphisms. The average weekly dose of warfarin was lower among those who had a polymorphism for any of the genes compared to those who did not, with a significant difference (p = 0.035). The mean TTR was also lower among patients with polymorphism. However, the difference between the two groups was not significant for this variable (p = 0.438). Conclusions An association was observed between the polymorphisms and the warfarin doses taken by the patients. However, there was no association with adverse events or the time spent within the therapeutic range in this sample.

Resumo Contexto Fatores genéticos podem ser responsáveis por parte das diferenças populacionais e interindividuais observadas em usuários de varfarina. Objetivos Identificar a ocorrência de polimorfismo dos genes CYP2C9 e VKORC1 em pacientes em uso de varfarina e relacionar esses perfis com a dose do medicamento e o tempo no intervalo terapêutico. Métodos Foram realizadas entrevistas mensais para a coleta de dados. Foram reunidos dados sobre características demográficas e medicamentos em uso, principalmente sobre varfarina, como motivo da prescrição e dose semanal. O tempo no intervalo terapêutico foi calculado como a porcentagem de dias com razão normalizada internacional entre os valores 2 e 3. Os genes CYP2C9 e VKORC1 foram analisados em laboratório de Genética Humana. Resultados Entre os participantes, 49 pacientes (74,2%) apresentaram polimorfismo dos genes CYP2C9 e/ou VKORC1; os 17 restantes (25,8%) não apresentaram esses polimorfismos. A dose média semanal de varfarina foi menor entre os que apresentaram polimorfismo para algum dos genes em comparação aos que não apresentaram, com diferença significativa (p = 0,035). O tempo no intervalo terapêutico médio também foi menor entre os pacientes com polimorfismo. Porém, não houve diferença significativa entre os dois grupos para essa variável (p = 0,438). Conclusões Foi observada associação entre os polimorfismos e a dose de varfarina utilizada pelos pacientes; no entanto, não houve associação com eventos adversos e o tempo de permanência na faixa terapêutica nessa amostra.

Polymorphism of the CYP2C9 and VKORC1 genes in patients on the public health system of a municipality in Southern Brazil / Polimorfismo dos genes CYO2C9 e VKORC1 em pacientes do Sistema Público de Saúde em um município do Sul do Brasil

Abstract Background Genetic factors can be responsible for part of the populational and interindividual differences observed in warfarin users. Objectives To identify occurrence of polymorphisms of the CYP2C9 and VKORC1 genes in patients taking warfarin and relate these profiles to their medication dosages and the Time in Therapeutic Range (TTR). Methods Monthly interviews were conducted for data collection. Data were collected on demographic characteristics and medications in use, especially warfarin, including reason for prescription and weekly dose. TTR was calculated as the percentage of days with international normalized ratio (INR) between 2 and 3. The CYP2C9 and VKORC1 genes were analyzed at a Human Genetics Laboratory. Results 49 patients (74.2%) had polymorphisms of the CYP2C9 and/or VKORC1 genes; the remaining 17 (25.8%) did not have these polymorphisms. The average weekly dose of warfarin was lower among those who had a polymorphism for any of the genes compared to those who did not, with a significant difference (p = 0.035). The mean TTR was also lower among patients with polymorphism. However, the difference between the two groups was not significant for this variable (p = 0.438). Conclusions An association was observed between the polymorphisms and the warfarin doses taken by the patients. However, there was no association with adverse events or the time spent within the therapeutic range in this sample.

Resumo Contexto Fatores genéticos podem ser responsáveis por parte das diferenças populacionais e interindividuais observadas em usuários de varfarina. Objetivos Identificar a ocorrência de polimorfismo dos genes CYP2C9 e VKORC1 em pacientes em uso de varfarina e relacionar esses perfis com a dose do medicamento e o tempo no intervalo terapêutico. Métodos Foram realizadas entrevistas mensais para a coleta de dados. Foram reunidos dados sobre características demográficas e medicamentos em uso, principalmente sobre varfarina, como motivo da prescrição e dose semanal. O tempo no intervalo terapêutico foi calculado como a porcentagem de dias com razão normalizada internacional entre os valores 2 e 3. Os genes CYP2C9 e VKORC1 foram analisados em laboratório de Genética Humana. Resultados Entre os participantes, 49 pacientes (74,2%) apresentaram polimorfismo dos genes CYP2C9 e/ou VKORC1; os 17 restantes (25,8%) não apresentaram esses polimorfismos. A dose média semanal de varfarina foi menor entre os que apresentaram polimorfismo para algum dos genes em comparação aos que não apresentaram, com diferença significativa (p = 0,035). O tempo no intervalo terapêutico médio também foi menor entre os pacientes com polimorfismo. Porém, não houve diferença significativa entre os dois grupos para essa variável (p = 0,438). Conclusões Foi observada associação entre os polimorfismos e a dose de varfarina utilizada pelos pacientes; no entanto, não houve associação com eventos adversos e o tempo de permanência na faixa terapêutica nessa amostra.

Farmacogenómica de los anticoagulantes orales: la importancia de establecer algoritmos de dosificación en población chilena

There is an important interindividual variability in dose requirement for coumarinic anticoagulants, which could be explained by genetic and non-genetic factors. Among hereditary factors, there are gene polymorphisms that code the therapeutic target and the main enzyme responsible for their metabolism. However, there are other candidate genes that could modulate dose requirements. The is a paucity of pharmacogenomic platforms to determine dose requirements of coumarinics in the Chilean population. Therefore, algorithms considering different variables to adjust individual dosages are required. Herein, we analyze the available evidence about factors that can modify the effects of vitamin K antagonists and that should be incorporated to dosing algorithms.

Verification of accuracy of warfarin stable dose prediction models in Shandong population / 中华医学遗传学杂志

OBJECTIVE@#To compare the accuracy of five warfarin-dosing algorithms and warfarin stable dose model (2.5 mg/day) for Shandong population.@*METHODS@#One hundred and twenty five patients who achieved stable warfarin dose were enrolled. Clinical and genetic data were used to evaluate the value of each algorithm by calculating the percentage of patients whose predicted warfarin dose was within 20% of the actual stable therapeutic dose and mean absolute error (MAE).@*RESULTS@#The frequency of patients with CYP2C9*1/*1, CYP2C9*1/*3 and CYP2C9*1/*2 genotype was 92.00%, 7.20%, 0.80%, respectively. That of VKORC1-1639 AA, AG and GG genotype was 82.40%, 15.20%, 2.40%, respectively. CYP4F2*1/*1, *1/*3, *3/*3 genotype was 50.40%, 39.20%, 10.40%, respectively. With the same genotypes for other loci, patients who carried at least one VKORC1-16398G mutant allele had increased warfarin stable daily dose compared with VKORC1-1639AA. Compared with CYP4F2*1/*1, those carrying at least one CYP4F2*3 mutant allele had warfarin stable daily dose increased by 5.9%-13.00%. The percentage of ideal prediction calculated from IWPC model (59.20%), Huang model (57.60%) and Ohno model (52.80%) were higher than others. The MAE were 0.35 (95%CI: 0.11-0.49), 0.15 (95%CI: 0.10-0.32), 0.39 (95%CI: 0.12-0.51), respectively.@*CONCLUSION@#The polymorphisms of CYP2C9, VKORC1 and CYP4F2 genes can influence the stable dose of warfarin in Shandong population. IWPC algorithm is suitable for guiding the use of warfarin in this population.

Nurse empowerment through Pharmacogenetics / Empoderamento do enfermeiro por meio da Farmacogenética / Empoderamiento del enfermero a través de la farmacogenética

Objective: to verify the existence of elements that justify the use of pharmacogenetics by the Brazilian nurse. Method: this is a quantitative, cross-sectional, observational, descriptive study, whose final sample was 67 individuals. The participants were healthy at the time of the study and reported a history of previous use and the occurrence of adverse effects by drugs commonly used and metabolized by CYP2C9. We collected 4 mL of venous blood for subsequent DNA extraction by salting out method and genotyping of the CYP2C9*2 and CYP2C9*3 polymorphisms, using Polymerase Chain Reaction in real time using Taqman assays. Results: the use of drugs metabolized by CYP2C9 was frequent (more than 75% of the individuals have already used between 2 or 4 of these drugs). Regarding adverse events, there were 19 perceived symptomatic occurrences associated with drugs metabolized by CYP2C9. The allele frequency of the polymorphism * 2 and * 3 in the population studied was 11.1% and 7.5%, respectively, and there was a coincidence between the presence of alleles of low enzyme activity and the occurrence of adverse effects. Conclusion: there are elements that justify the adoption of pharmacogenetics in the nursing care to reduce the occurrence of adverse reactions to drugs metabolized by CYP2C9.

Objetivo: verificar a existência de elementos que justifiquem o uso da farmacogenética pelo enfermeiro brasileiro. Método: trata-se de um estudo quantitativo, do tipo transversal, observacional descritivo, cuja amostra final foi de 67 indivíduos. Os participantes estavam saudáveis no momento do estudo e reportaram histórico de uso prévio e ocorrência de efeitos adversos por fármacos comumente utilizados e metabolizados pela CYP2C9. Coletamos 4 mL de sangue venoso para posterior extração de DNA por método salting out e genotipagem dos polimorfismos CYP2C9*2 e CYP2C9*3 através de Polymerase Chain Reaction em tempo real, utilizando ensaios Taqman. Resultados: o uso de fármacos metabolizados pela CYP2C9 foi frequente (mais de 75% dos sujeitos já utilizaram entre 2 ou 4 desses fármacos). A respeito dos eventos adversos, houve 19 ocorrências sintomáticas percebidas, associadas a fármacos metabolizados pela CYP2C9. A frequência alélica do polimorfismo *2 e *3 na população estudada foi de 11,1% e 7,5%, respectivamente, com coincidência entre a presença dos alelos de baixa atividade enzimática e ocorrência de efeitos adversos. Conclusão: existem elementos que justificam a adoção da farmacogenética no cuidado do enfermeiro com objetivo de redução da ocorrência de reações adversas a fármacos metabolizados pela CYP2C9.

Objetivo: verificar la existencia de elementos que justifiquen el uso de la farmacogenética por parte del enfermero brasileño. Método: se trata de un estudio cuantitativo, transversal, observacional, descriptivo, cuya muestra final fue de 67 individuos. Los participantes estaban sanos en el momento del estudio e informaron un historial de uso previo y la aparición de efectos adversos por fármacos comúnmente utilizados y metabolizados por el CYP2C9. Recolectamos 4 ml de sangre venosa para la posterior extracción de ADN mediante el método de salazón y genotipificación de los polimorfismos CYP2C9 * 2 y CYP2C9 * 3 a través de la reacción en cadena de la polimerasa en tiempo real utilizando ensayos Taqman. Resultados: el uso de drogas metabolizadas por el CYP2C9 fue frecuente (más del 75% de las personas ya han usado entre 2 o 4 de estas drogas). Con respecto a los eventos adversos, hubo 19 casos sintomáticos percibidos asociados con medicamentos metabolizados por el CYP2C9. La frecuencia alélica del polimorfismo * 2 y * 3 en la población estudiada fue de 11.1% y 7.5%, respectivamente, y hubo una coincidencia entre la presencia de alelos de baja actividad enzimática y la aparición de efectos adversos. Conclusión: existen elementos que justifican la adopción de la farmacogenética en el cuidado del enfermero para reducir la aparición de reacciones adversas a los medicamentos metabolizados por el CYP2C9.

Efecto de las variantes de CYP2C9 sobre la dosis de losartán en hipertensos chilenos / Association between cytochrome p4502c9 polymorphisms and losartan dosing in hypertensive patients

Background Losartan is widely used in many clinicals settings. Its dosage is related to the genetic characteristics of CYP2C9 enzymatic activity, which metabolizes losartan to its active form E-3174, responsible for the antihypertensive effect. Aims To identify the frequency of allelic variants CYP2C9*2 and CYP2C9*3 in hypertensive patients and to compare genotypes with a healthy Chilean population. To relate polymorphisms with the losartan dosing to obtain an optimal blood pressure. Material and Methods We studied 30 patients with controlled essential hypertension using losartan with normal liver function, and 202 healthy people. Peripheral blood DNA genotyping was performed by polymerase chain reaction to identify the polymorphisms. Allelic and genotypic frequencies were compared. Results In hypertensive patients, allelic frequencies were 0.85 (CYP2C9*1), 0.05 (CYP2C9*2) and 0.1 (CYP2C9*3). Genotypic frequencies were 73.3% (CYP2C9*1/*1), 6.7% (CYP2C9*1/*2), 16.7% (CYP2C9*1/*3) and 3.3% (CYP2C9*2/3); observing a significantly higher frequency of the allele CYP2C9*3 (p=0.041) and CYP2C9*1/*3 genotype (p=0.04). A non-significant tendency to need a larger dose of losartan was observed with the CYP2C9 * 3 allele, with an odds ratio (OR) of 1.46 (95% confidence intervals (CI) 0.01-18.64). The same tendency was observed with the need to use losartan twice a day, obtaining an OR of 5.88 (CI 0.54 -62.14). Conclusions There could be a relationship between the presence of CYP2C9 polymorphisms and the pathogenesis of hypertension. The presence of CYP2C9*3 is associated with the need for higher doses of losartan, possibly due to a decrease in the conversion of losartan to E-3174.

Estudio de las variantes alélicas CYP2C9*2 y CYP2C9*3 en muestras de población mestiza peruana / Study of the allelic variants CYP2C9*2 and CYP2C9*3 in samples of the Peruvian mestizo population

Resumen Introducción. El citocromo CYP2C9 metaboliza, aproximadamente, el 15 % de los fármacos prescritos. Su gen presenta alelos cuyas frecuencias difieren entre grupos étnicos y poblaciones. Los alelos CYP2C9*2 y CYP2C9*3 dan cuenta de una enzima con actividad disminuida cuya frecuencia no ha sido determinada en la población mestiza peruana. Objetivo. Caracterizar la frecuencia de las variantes *2 (rs1799853) y *3 (rs1057910) del gen CYP2C9 en muestras de población mestiza peruana provenientes de Lima, Tacna y Junín. Materiales y métodos. Se hizo un estudio descriptivo, observacional y prospectivo, con muestreo no probabilístico, por conveniencia e incidental. Se incluyeron 218 sujetos según los criterios de inclusión y exclusión; todos los participantes otorgaron su consentimiento informado. El ADN genómico se obtuvo mediante hisopado de mucosa oral, y la detección de los genotipos para los alelos CYP2C9*2 y CYP2C9*3 se hizo mediante reacción en cadena de la polimerasa (PCR) en tiempo real, utilizando sondas TaqMan™. Resultados. Las variantes de CYP2C9*2 y CYP2C9*3 están presentes en la población mestiza peruana con frecuencias de 0,046 y 0,062, respectivamente. El análisis de las frecuencias genotípicas observadas permitió predecir que la frecuencia de fenotipos metabolismo intermedio sería del 15,13 % (CYP2C9*1/*2: 5,96 %; CYP2C9*1/*3: 9,17 %), y la de fenotipos de metabolismo lento, del 3,22 % (CYP2C9*2/*2: 1,38 %; CYP2C9*3/*3: 1,38 %; CYP2C9*2/*3: 0,46 %). Conclusiones. Se lograron determinar las frecuencias genotípicas y alélicas para las variantes *2 y *3 del gen CYP2C9 en una muestra no probabilística de población mestiza peruana. Las frecuencias obtenidas (0,046 y 0,062, respectivamente) están entre las esperadas para una población mestiza sudamericana con ascendencia amerindia, europea, africana y asiática.

Abstract Introduction: CYP2C9 metabolizes approximately 15% of the prescribed drugs. Its gene has alleles whose frequencies differ between ethnic groups and populations. The alleles CYP2C9*2 and CYP2C9*3 account for an enzyme with decreased activity and their frequencies have not been determined in the Peruvian mestizo population. Objective: To characterize the frequencies of the allelic variants *2 (rs1799853) and *3 (rs1057910) of CYP2C9 gen in the Peruvian mestizo population from Lima, Tacna y Junín. Materials and methods: We conducted an observational, prospective cross-sectional study with non-probabilistic, by convenience, and incidental sampling. We included 218 subjects according to the inclusion and exclusion criteria, all of whom had signed the informed consent. We obtained the genomic DNA from oral mucosa swab. For the detection of the CYP2C9*2 and CYP2C9*3 genotypes, we used real-time-polymerase chain reaction with TaqMan® probes. Results: The genotyping revealed that CYP2C9*2 and CYP2C9*3 variants have low frequencies (0.046 and 0.062, respectively). The frequency of intermediate metabolizers was 15.13% (CYP2C9*1/*2: 5.96%; CYP2C9*1/*3: 9.17%) and that of slow metabolizers was 3.22% (CYP2C9*2/*2: 1.38%; CYP2C9*3/*3: 1.38%; CYP2C9*2/*3: 0.46%). Conclusions: It was possible to determine the genotypic and allelic frequencies for the variants *2 and *3 of the CYP2C9 gene in a non-probabilistic sample of the Peruvian mestizo population. The frequencies obtained (0.046 and 0.062, respectively) corresponded to those expected for a South American mestizo population with Amerindian, European, African and Asian ancestry.

Influência do genótipo do citocromo P450 (CYP2C9) na eficácia clínica do tenoxicam após cirurgias de terceiros molares inferiores / Influence of cytochrome P450 (CYP2C9) genotype on clinical efficacy of tenoxicam after lower third molars surgeries

Atualmente, com os avanços da Farmacogenética, estudos estão demonstrando que a resposta individual de medicamentos pode ser diretamente afetada pela alteração da farmacocinética induzida pela genética de cada paciente, e isto pode induzir à ausência, redução, alteração ou aumento da atividade enzimática associada. Esse fato pode modificar a eficácia clínica de determinados medicamentos e, nos casos de anti-inflamatórios não esteroidais (AINEs), alterar sua capacidade de lidar com a dor e até aumentar a frequência e a gravidade dos efeitos adversos. Este estudo teve como objetivo genotipar e fenotipar o gene CYP2C9 em 89 pacientes saudáveis submetidos à cirurgia de terceiro molar inferior, sob medicação de 20 mg de tenoxicam por dia durante 4 dias, comparando a influência do gene na dor pós-operatória, edema, trismo, quantidade de medicamentos de socorro consumidos pelos pacientes, avaliação global e satisfação do paciente em relação à ingestão do medicamento. Trata-se de um ensaio clínico randomizado, desenvolvido no Departamento de Cirurgia e Traumatologia Bucomaxilofacial da Faculdade de Odontologia de Araçatuba (FOA/UNESP) e na Disciplina de Farmacologia do Departamento Ciências Biológicas da Faculdade de Odontologia de Bauru (FOB/USP). Foi realizado o sequenciamento genético dos participantes do estudo, a fim de verificar polimorfismos do gene CYP2C9, e estes dados foram cruzados com as características pós-operatórias acima mencionadas. Oitenta e nove participantes foram selecionados: 64 (74%) foram incluídos no grupo "Metabolizadores Normais" (CYP2C9 * 1 / * 1) e 25 participantes no grupo "Metabolizadores Intermediários/Lentos" (CYP2C9 * 1 / * 2, * 1 / * 3 e CYP2C9 * 2 / * 3, * 3 / * 3). Não foram encontradas diferenças estatisticamente significantes em todos os parâmetros avaliados. Em relação à dor, apesar dos dois grupos referirem baixos níveis de dor durante o pós-operatório, o grupo "Metabolizadores Normais" apresentou mais dor (p<0,05) nos períodos de 4, 5, 6, 7, 8, 10, 48 e 72 horas de pós-operatório, quando comparado ao ponto de tempo "zero", diferente do grupo "Metabolizadores Intermediários/Lentos" que relatou dor significativa apenas em 6 horas de pós-operatório, quando comparados com o tempo "zero". Na prática clínica, isso significa que indivíduos com atividade anormal do CYP2C9 (metabolizadores intermediários e lentos) apresentam uma exposição aumentada ao tenoxicam e provavelmente mostram níveis mais baixos de dor, mas também mostram provavelmente um risco maior de efeitos colaterais, que incluem sangramento gastrointestinal, distúrbios hemorrágicos e cardiovasculares, sendo provavelmente necessário que a dose habitual do medicamento seja revisada(AU)

One of the most accepted pharmacological protocols on third molar extraction surgeries involves the use of the non-steroidal anti-inflammatory drugs, as tenoxicam. Many studies present that the individual drug response could be directly affected by genetics induced pharmacokinetics alteration. Our study aimed to genotype and phenotype CYP2C9 gene in 89 health patients that were submitted to wisdom teeth surgical removal under medication of tenoxicam, comparing the gene influence on postoperative pain, edema, trismus, amount of rescue medication consumed, global evaluation and patient satisfaction regarding the medication. CYP2C9 gene was screened to evaluate polymorphisms and the genetic characteristics were crossed to aforementioned postoperative findings on a randomized clinical trial. 89 volunteers were splitted in two groups: 64 (74%) Normal Metabolizers (NM) group and 25 (26%) Intermediate/Slow Metabolizers (ISM) group. There were not found statistically significant difference between groups. The NM group referred more pain (p<0,05) at 4, 5, 6, 7, 8, 10, 48 and 72 postoperative hours time points when compared to time zero. In clinical practice it means that individuals with CYP2C9 abnormal activity (ISM) presented an augmented exposition to tenoxicam and referred lower pain levels, but also, they were probably more susceptible to adverse effects(AU)

Effect of iguratimod on diclofenac metabolism by CYP2C9 in rats and human recombinant CYP2C9 yeast cells

Iguratimod (IGU, also known as T-614), a novel disease modifying antirheumatic drug intended to cure patients with rheumatoid arthritis (RA). The purpose of this study is to evaluate the effect of IGU on the pharmacokinetics of CYP2C9 probe drug diclofenac and its metabolite 4′-hydroxy diclofenac in vivo and in vitro. In in vivo experiments, 24 rats were randomly assigned to three groups consisting of the control group (Normal saline), low dose IGU group (10 mg/kg) and high dose IGU group (30 mg/kg). Blood samples were collected from orbital sinuses vein before 1 hour and serial times of giving diclofenac (15 mg/kg) to all the rats. Plasma concentration of diclofenac and its metabolite 4´-hydroxy diclofenac were assayed by high performance liquid chromatography. Pharmacokinetic parameters were assessed by Winnonlin 6.4 pharmacokinetic software. Moreover, in vitro studies were performed in recombinant human CYP2C9 yeast cell system. IGU at low dose showed no significant differences in the pharmacokinetic parameters of diclofenac and 4-hydroxy diclofenac in vivo when compared with control group (p>0.005). However, at the high dose of IGU, the pharmacokinetic parameters of 4´-hydroxy metabolite of diclofenac increase in half-life (T1/2) and mean area under the curve (AUC0→24), while a decrease in mean clearance (CL, mL/h/kg) and volume of distribution Vz (mL/kg). In addition, in in vitro study, high doses of IGU reduces the metabolism rate of diclofenac. IGU at high dose significantly increase the pharmacokinetics parameters of 4´-hydroxy diclofenac in rats. Additionally, it also showed the potent inhibitory effect on diclofenac metabolism in recombinant human CYP2C9 yeast cells.

Clinical Pharmacogenetic Testing and Application: Laboratory Medicine Clinical Practice Guidelines

Pharmacogenetic testing for clinical applications is steadily increasing. Correct and adequate use of pharmacogenetic tests is important to reduce unnecessary medical costs and adverse patient outcomes. This document contains recommended pharmacogenetic testing guidelines for clinical application, interpretation, and result reporting through a literature review and evidence-based expert opinions for the clinical pharmacogenetic testing covered by public medical insurance in Korea. This document aims to improve the utility of pharmacogenetic testing in routine clinical settings.

Bosentan and Rifampin Interactions Modulate Influx Transporter and Cytochrome P450 Expression and Activities in Primary Human Hepatocytes

The incidence of polypharmacy-which can result in drug-drug interactions-has increased in recent years. Drug-metabolizing enzymes and drug transporters are important polypharmacy modulators. In this study, the effects of bosentan and rifampin on the expression and activities of organic anion-transporting peptide (OATP) and cytochrome P450 (CYP450) 2C9 and CYP3A4 were investigated in vitro. HEK293 cells and primary human hepatocytes overexpressing the target genes were treated with bosentan and various concentrations of rifampin, which decreased the uptake activities of OATP transporters in a dose-dependent manner. In primary human hepatocytes, CYP2C9 and CYP3A4 gene expression and activities decreased upon treatment with 20 μM bosentan+200 μM rifampin. Rifampin also reduced gene expression of OATP1B1, OATP1B3, and OATP2B1 transporter, and inhibited bosentan influx in human hepatocytes at increasing concentrations. These results confirm rifampin- and bosentan-induced interactions between OATP transporters and CYP450.

Screening study for genetic polymorphisms affecting pharmacokinetics of talniflumate

Talniflumate is a phthalidyl ester of niflumic acid, which has potent analgesic and anti-inflammatory effects and is widely used to treat inflammatory disorders, such as rheumatoid arthritis. To screen the possible genetic factors affecting the pharmacokinetics (PK) of talniflumate, 23 male Korean volunteers were enrolled from two separate bioequivalence studies. All subjects received 740 mg (two tablets) talniflumate in a standard 2×2 cross-over model in a randomized order. For the genetic study, PK parameters of the reference drug were used. We used Illumina Human610Quad v1.0 DNA Analysis BeadChip for whole genome single nucleotide polymorphism (SNP) analysis and whole genome genotyping data were processed by linear regression analysis for PK parameters. Whole genome analysis revealed 1498 significant SNPs (P < 0.0001) for Cmax, 65 significant SNPs (P < 0.0001) for T(max), and 1491 significant SNPs (P < 0.0001) for AUC(inf). For clinical pharmacological purposes, we selected SNPs from drug metabolizing enzymes and transporters, and analyzed the PK parameters of various genotypes. Two SNPs (rs11165069 from ABCA4 (p=0.00002); rs17847036 from CYP2C9 (p=0.000001)) showed significant associations with talniflumate C(max). In the T(max) group, two SNPs (rs3787555 from CYP24A1 (p=0.00035); rs2275034 from ABCA4 (p=0.000587)) showed significant associations with talniflumate T(max). In the AUC(inf) group, two SNPs (rs11165069 from ABCA4 (p=0.00002); rs12461006 from SLC1A6 (p=0.00008)) exhibited significant associations with talniflumate absorption. These results show that genetic factors could affect the PK parameters, and provide information that may be used in the development of personalized talniflumate therapy.

Relevance of the ancestry for the variability of the Drug-Metabolizing Enzymes CYP2C9, CYP2C19 and CYP2D6 polymorphisms in a multiethnic Costa Rican population / Relevancia de la ancestría para la variabilidad de polimorfismos de las enzimas metabolizadoras de fármacos CYP2C9, CYP2C19 y CYP2D6 en una población multiétnica de Costa Rica

Abstract:CYP2C9, CYP2C19 and CYP2D6 metabolize around 40 % of drugs and their genes vary across populations. The Costa Rican population has a trihybrid ancestry and its key geographic location turns it into a suitable scenario to evaluate interethnic differences across populations. This study aims to describe the diversity of CYP2C9, CYP2C19 and CYP2D6 polymorphisms in Costa Rican populations in the context of their ancestry. A total of 448 healthy individuals were included in the study: Bribri (n= 47), Cabécar (n= 27), Maleku (n= 16), Guaymí (n= 30), Huetar (n= 48), Chorotega (n= 41), Admixed/Mestizos from the Central Valley/Guanacaste (n= 189), and Afro-Caribbeans (n= 50) from Limón. CYP2C9 (alleles *2, *3, *6) and CYP2C19 (*2, *3, *4, *5, *17) genotypes were determined by Real-Time PCR. African, European and Native American ancestry were inferred using 87 ancestry informative markers. The frequency of the decreased activity allele CYP2C9*2 is lower in the self-reported Amerindian groups compared to the admixed population, and the highest frequencies of CYP2C19*2 (null activity) and the CYP2C19*17 (increased activity) were found in the self-reported AfroCaribbean population. Moreover, a frequency of 0.7 % CYP2C9 gPMs in the Admixed population and a variable frequency of CYP2C19 gUMs (0.0-32.6 %, more prevalent in Afro-Caribbeans) in Costa Rican populations, was found. Finally, the following alleles were positively correlated with genomic African ancestry and negatively correlated with genomic Native American ancestry: CYP2D6*5 (null activity), CYP2D6*17 (decreased activity), CYP2D6*29 (decreased activity) and CYP2C19*17 (increased activity). No correlation for CYP2C9 polymorphisms and genomic ancestry was found. Further studies assessing the CYP2C9 and CYP2C19 sequence in these populations, preferentially by sequencing these genes, are warranted. Rev. Biol. Trop. 64 (3): 1067-1076. Epub 2016 September 01.

ResumenCYP2C9, CYP2C19 y CYP2D6 metabolizan aproximadamente el 40 % de los fármacos y los genes que las codifican varían en las distintas poblaciones humanas. La población costarricense posee ancestría trihíbrida y su posición geográfica estratégica la convierten en un escenario idóneo para evaluar la variabilidad interétnica en sus poblaciones multiétnicas. El presente estudio tiene como objetivo describir la diversidad de los polimorfismos CYP2C9, CYP2C19 y CYP2D6 en las poblaciones costarricenses en el contexto de su ancestría. Un total de 448 individuos sanos fueron incluidos: Bribri (n= 47), Cabécar (n= 27), Maleku (n= 16), Guaymí (n= 30), Huetar (n= 48), Chorotega (n= 41), mestizos del Valle Central y Guanacaste (n= 189) y afrocaribeños de Limón (n= 50). Los genotipos CYP2C9 (alelos *2, *3, *6) y CYP2C19 (*2, *3, *4, *5 y *17) fueron determinados mediante PCR tiempo real. Las ancestrías africana, europea y nativa americana fueron inferidas usando 87 marcadores informativos de ancestría. La frecuencia del alelo de actividad disminuida CYP2C9*2 fue menor en los grupos autodefinidos de amerindios que en la población mestiza y las frecuencias más altas de CYP2C19*2 (actividad nula) y CYP2C19*17 (actividad incrementada) se encontraron en la población autodefinida afrocaribeña. Asimismo, se encontró una frecuencia de gPMs CYP2C9 de 0.7 % en la población mestiza y una frecuencia variable de gUMs CYP2C19 (0.0 a 32.6 %, más prevalente en afrocaribeños) en las poblaciones costarricenses. Por último, los siguientes alelos fueron positivamente correlacionados con la ancestría africana y negativamente con la ancestría nativa americana: CYP2D6*5 (actividad nula), CYP2D6*17, CYP2D6*29 (ambos de actividad disminuida) y CYP2C19*17 (actividad incrementada). No se encontró correlación entre los polimorfismos CYP2C9 y la ancestría. Se requieren estudios posteriores que evalúen la secuencia de CYP2C9 y CYP2C19 en estas poblaciones, preferiblemente mediante la secuenciación de estos genes.

Predicción de la sensibilidad a la warfarina con base en polimorfismos de los genes VKORC1 y CYP2C9 en pacientes colombianos / Prediction of sensitivity to warfarin based on VKORC1 and CYP2C9 polymorphisms in patients from different places in Colombia

Introducción. La validación de los factores predictores de la sensibilidad a la warfarina es importante para evitar las hemorragias asociadas con la terapia anticoagulante. En los estudios previos hechos en Colombia con polimorfismos de los genes VKORC1 y CYP2C9 , se reportaban algoritmos con rendimientos diferentes para explicar la variación de las dosis, pero no se evaluaba la predicción de la sensibilidad a la warfarina. Objetivo. Determinar la exactitud del análisis farmacogenético de los polimorfismos *2 y *3 en el gen CYP2C9 y 1639G>A en el gen VKORC1 para predecir la sensibilidad a la warfarina en pacientes del Hospital Militar Central, un centro de referencia que atiende pacientes de diferentes lugares de Colombia. Materiales y métodos. Se recopilaron los datos demográficos y clínicos de 130 pacientes que habían recibido una dosis estable de warfarina durante más de dos meses. Se obtuvieron sus genotipos mediante un análisis de curvas de fusión , y, después de verificar el equilibrio de Hardy-Weinberg de los polimorfismos, se hizo un análisis estadístico con enfoque multivariado y predictivo. Resultados. Se construyó un modelo farmacogenético que explicó el 52,8 % de la variación de la dosis (p<0,001), solo 4 % por encima del rendimiento obtenido con los mismos datos usando el algoritmo del International Warfarin Pharmacogenetics Consortium . El modelo predictivo de sensibilidad logró 77,8 % de exactitud e incluyó como factores la edad (p=0,003), los polimorfismos *2 y *3 (p=0,002) y el polimorfismo 1639G>A (p<0,001). Conclusiones. Estos resultados en una población mestiza colombiana respaldan la validez de la predicción de la sensibilidad a la warfarina basada en los polimorfismos de los genes VKORC1 y CYP2C9.

Introduction: In the search to prevent hemorrhages associated with anticoagulant therapy, a major goal is to validate predictors of sensitivity to warfarin. However, previous studies in Colombia that included polymorphisms in the VKORC1 and CYP2C9 genes as predictors reported different algorithm performances to explain dose variations, and did not evaluate the prediction of sensitivity to warfarin. Objective: To determine the accuracy of the pharmacogenetic analysis, which includes the CYP2C9 *2 and *3 and VKORC1 1639G>A polymorphisms in predicting patients´ sensitivity to warfarin at the Hospital Militar Central , a reference center for patients born in different parts of Colombia. Materials and methods: Demographic and clinical data were obtained from 130 patients with stable doses of warfarin for more than two months. Next, their genotypes were obtained through a melting curve analysis. After verifying the Hardy-Weinberg equilibrium of the genotypes from the polymorphisms, a statistical analysis was done, which included multivariate and predictive approaches. Results: A pharmacogenetic model that explained 52.8% of dose variation (p<0.001) was built, which was only 4% above the performance resulting from the same data using the International Warfarin Pharmacogenetics Consortium algorithm. The model predicting the sensitivity achieved an accuracy of 77.8% and included age (p=0.003), polymorphisms *2 and *3 (p=0.002) and polymorphism 1639G>A (p<0.001) as predictors. Conclusions: These results in a mixed population support the prediction of sensitivity to warfarin based on polymorphisms in VKORC1 and CYP2C9 as a valid approach in Colombian patients.

Clinical Pharmacogenetic Testing and Application: Laboratory Medicine Clinical Practice Guidelines Part 2

Pharmacogenetics is a rapidly evolving field and the number of pharmacogenetic tests for clinical use is steadily increasing. However, incorrect or inadequate implementation of pharmacogenetic tests in clinical practice may result in a rise in medical costs and adverse outcomes in patients. This document suggests guidelines for the clinical application, interpretation, and reporting of pharmacogenetic test results based on a literature review and the collection of evidence-based expert opinions. The clinical laboratory practice guidelines encompass the clinical pharmacogenetic tests covered by public medical insurance in Korea. Technical, ethical, and regulatory issues related to clinical pharmacogenetic tests have also been addressed. In particular, this document comprises the following pharmacogenetic tests: CYP2C9 and VKORC1 for warfarin, CYP2C19 for clopidogrel, CYP2D6 for tricyclic antidepressants, codeine, tamoxifen, and atomoxetine, NAT2 for isoniazid, UGT1A1 for irinotecan, TPMT for thiopurines, EGFR for tyrosine kinase inhibitors, ERBB2 (HER2) for erb-b2 receptor tyrosine kinase 2-targeted therapy, and KRAS for anti-epidermal growth factor receptor drugs. These guidelines would help improve the usefulness of pharmacogenetic tests in routine clinical settings.

Development and Comparison of Warfarin Dosing Algorithms in Stroke Patients

PURPOSE: The genes for cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) have been identified as important genetic determinants of warfarin dosing and have been studied. We developed warfarin algorithm for Korean patients with stroke and compared the accuracy of warfarin dose prediction algorithms based on the pharmacogenetics. MATERIALS AND METHODS: A total of 101 patients on stable maintenance dose of warfarin were enrolled. Warfarin dosing algorithm was developed using multiple linear regression analysis. The performance of all the algorithms was characterized with coefficient of determination, determined by linear regression, and the mean of percent deviation was used to predict doses from the actual dose. In addition, we compared the performance of the algorithms using percentage of predicted dose falling within ±20% of clinically observed doses and dividing the patients into a low-dose group (≤3 mg/day), an intermediate-dose group (3-7 mg/day), and high-dose group (≥7 mg/day). RESULTS: A new developed algorithms including the variables of age, body weight, and CYP2C9 and VKORC1 genotype. Our algorithm accounted for 51% of variation in the warfarin stable dose, and performed best in predicting dose within 20% of actual dose and intermediate-dose group. CONCLUSION: Our warfarin dosing algorithm may be useful for Korean patients with stroke. Further studies to elucidate clinical utility of genotype-guided dosing and find the additional genetic association are necessary.

Influence of genetic polymorphisms and non-genetic factors on the maintenance dose of warfarin / 中华医学遗传学杂志

OBJECTIVE To assess the influence of genetic polymorphisms and non-genetic factors on warfarin maintenance dose variations in order to provide guidance for personalized use of warfarin. METHODS Two hundred patients from outpatient and inpatient with stable international normalized ratio(INR) were recruited. Clinical data and blood samples were collected. Genotypes of 4 genes involved in warfarin metabolic pathways were determined with Sanger sequencing. Based on statistical analysis of warfarin maintenance dosage, a mathematical model was established. RESULTS Among non-genetic factors, the age and height have significant influence in warfarin dosage. The dosage is negatively correlated with age but positively correlated with height. The difference in dosage for between the 20-year-old group and 60-year-old group has reached 1.81 mg/day, and that for between the 140 cm in height and 180 cm in height groups has reached 1.06 mg/day. VKORC1 -1639G/A, CYP2C9 430C/T, CYP2C9 1075A/C and CYP4F2 V433M polymorphisms have significant influence on stable warfarin dosage. The dosage for patients with wild type and mutant genotypes has varied from 0.35 mg/day to 0.84 mg/day. CONCLUSION Non-genetic factors and genetic polymorphisms play important roles in personalized variations of warfarin maintenance dose. The establishment of mathematical models considering multiple factors is helpful in evaluating the safety and effectiveness of warfarin dosage.

Population pharmacokinetic/pharmacodynamic modeling of warfarin by nonlinear mixed effects model / 药学学报

The study aimed to establish a population pharmacokinetic/pharmacodynamic (PPK/PD) model of warfarin. PCR-RFLP technique was used to genotype the CYP2C9 and VKORC1 polymorphisms of 73 patients. RP-HPLC-UV method was used to determine the 190 plasma concentrations of warfarin. Application of NONMEM, the clinical information and 263 international normalized ratio (INR) monitoring data were used to investigate the effect of genetic, physiological, pathological factors, other medication on clearance and anticoagulant response. The final model of warfarin PPK/PD was described as follows: CL = θCL · (WT/60)θWT · θCYP · eηCL (if CYP2C9*1/*1, θCYP = 1; if *1/*3, θCYP = 0.708); EC50 = θEC50 · θVKOR · eηEC50 (if VKORC1- 1639AA, θVKOR = 1; if GA, θVKOR = 2.01; V = θV; K(E0) = θK(E0); Emax = θEmax; E0 = θE0 · eηE0. Among them, the body weight (WT), CYP2C9 and VKORC1 genotype had conspicuous effect on warfarin PK/PD parameters. The goodness diagnosis, Bootstrap, NPDE verification showed that the final model was stable, effective and predictable. It may provide a reference for opitimizing the dose regimen of warfarin.