الملخص
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.
الموضوعات
Humans , Pharmacogenetics , Vitamin K , Vitamin K/antagonists & inhibitors , Warfarin , Chile , Dose-Response Relationship, Drug , Vitamin K Epoxide Reductases/genetics , Cytochrome P-450 CYP2C9/genetics , Genotype , Anticoagulantsالملخص
OBJECTIVE: In this study, the relationship between osteoporotic vertebral fractures and 9041 Guanine/Adenine and 3673 Guanine/Adenine polymorphisms related to the vitamin K epoxide reductase complex subunit-1 (VKORC1) gene in postmenopausal women with osteoporosis was investigated. METHOD: DNA was isolated from blood samples collected from 150 women with postmenopausal osteoporosis. Genotyping of the two polymorphic regions (9041 Guanine/Adenine and 3673 Guanine/Adenine) in VKORC1 was performed using polymerase chain reaction-restriction fragment length polymorphism analysis. The presence of radiographic fractures among the 150 patients was ascertained by using the Genant method. RESULT: At least one fracture was detected in 98 patients, and no fracture was observed in 52 patients on radiological images. We found no association between the 9041 Guanine/Adenine (p=0.283) and 3673 Guanine/Adenine (p=0.232) polymorphisms of the VKORC1 gene and the development of secondary postosteoporotic fractures in our study. CONCLUSION: There was no relationship between osteoporotic vertebral fracture and VKORC1 gene polymorphism in a postmenopausal Turkish population.
الموضوعات
Humans , Female , Middle Aged , Aged , Polymorphism, Genetic/genetics , Osteoporosis, Postmenopausal/genetics , Spinal Fractures/genetics , Osteoporotic Fractures/genetics , Vitamin K Epoxide Reductases/genetics , Turkey , Bone Density , Pilot Projects , Retrospective Studies , Genetic Association Studies , Gene Frequency/geneticsالملخص
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.
الموضوعات
Anticoagulants/therapeutic use , Antidepressive Agents/therapeutic use , Antimetabolites, Antineoplastic/therapeutic use , Antitubercular Agents/therapeutic use , Arylamine N-Acetyltransferase/genetics , Coronary Artery Disease/drug therapy , Cytochrome P-450 CYP2C19/genetics , Cytochrome P-450 CYP2C9/genetics , Cytochrome P-450 CYP2D6/genetics , Depressive Disorder/drug therapy , Genotype , Isoniazid/therapeutic use , Laboratories, Hospital/standards , Methyltransferases/genetics , Pharmacogenomic Testing/methods , Platelet Aggregation Inhibitors/therapeutic use , Pulmonary Embolism/drug therapy , Ticlopidine/analogs & derivatives , Tuberculosis/drug therapy , Vitamin K Epoxide Reductases/genetics , Warfarin/therapeutic useالموضوعات
Humans , Warfarin/administration & dosage , Acenocoumarol/administration & dosage , Polymorphism, Genetic , Aryl Hydrocarbon Hydroxylases/genetics , Polymorphism, Single Nucleotide , Dose-Response Relationship, Drug , Vitamin K Epoxide Reductases/genetics , Genotype , Anticoagulants/administration & dosageالملخص
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.
الموضوعات
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Warfarin/pharmacokinetics , Polymorphism, Single Nucleotide , Vitamin K Epoxide Reductases/genetics , Cytochrome P-450 CYP2C9/genetics , Anticoagulants/pharmacokinetics , Warfarin/administration & dosage , Warfarin/adverse effects , Algorithms , Ethnicity/genetics , Colombia , International Normalized Ratio , Dose-Response Relationship, Drug , Alleles , Genetic Association Studies , Geography, Medical , Hemorrhage/chemically induced , Hemorrhage/prevention & control , Anticoagulants/administration & dosage , Anticoagulants/adverse effectsالملخص
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.
الموضوعات
Aged , Female , Humans , Male , Middle Aged , Algorithms , Anticoagulants/administration & dosage , Cytochrome P-450 CYP2C9/genetics , Dose-Response Relationship, Drug , Genotype , International Normalized Ratio , Linear Models , Multivariate Analysis , Pharmacogenetics , Regression Analysis , Republic of Korea , Stroke/drug therapy , Vitamin K Epoxide Reductases/genetics , Warfarin/administration & dosageالملخص
Background: The dose of oral anticoagulants (OAC) shows great variability among patients. Pharmacogenetic studies have shown that common variants in genes CYP2C9 (*2 and *3) and VKORC1 (-1639G>A) are associated with lower requirements of OAC. Aim: To study the association between average maintenance doses of oral anticoagulant therapy required to maintain a stable INR and CYP2C9 and VKORC1 gene variants in Chilean adults. Material and Methods: Prospective study of patients on anticoagulant treatment and with a stable international normalized ratio (INR) for prothrombin time for at least three months. Patients were classified as having high or low acenocoumarol or warfarin requirements. Peripheral blood DNA genotyping was performed by polymerase chain reaction and restriction fragment polymorphism or sequencing and electrophoresis. Results: The study included 185 patients, 125 on acenocoumarol and 60 on warfarin. Patients with VKORC1-1639A allele were more likely to require lower doses of both drugs than patients with the G allele (Odds ratio [OR] for acenocoumarol 9.06, and OR for warfarin = 18.7). There was no association between CYP2C9*2 and*3 and acenocoumarol or warfarin requirements. Conclusions: There is an association between VKORC1-1639A variant and anticoagulant doses.
الموضوعات
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Anticoagulants/administration & dosage , /genetics , Polymorphism, Genetic/genetics , Vitamin K Epoxide Reductases/genetics , Acenocoumarol/administration & dosage , Administration, Oral , Chile , Dose-Response Relationship, Drug , Gene Frequency/genetics , Genetic Variation/genetics , Genotype , International Normalized Ratio , Prospective Studies , Prothrombin Time , Warfarin/administration & dosageالملخص
A 73-yr-old Korean man with permanent atrial fibrillation visited outpatient clinic with severely increased International Normalized Ratio (INR) values after taking a usual starting dosage of warfarin to prevent thromboembolism. We found out later from his blood tests that he had hyperthyroidism at the time of treatment initiation. His genetic analysis showed CYP2C9*1/*3 and VKORC1+1173TT genotypes. We suspect that both hyperthyroidism and genetic variant would have contributed to his extremely increased INR at the beginning of warfarin therapy. From this case, we learned that pharmacogenetic and thyroid function test might be useful when deciding the starting dosage of warfarin in patients with atrial fibrillation.