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Eljilany I, Elarref M, Shallik N, Elzouki AN, Bader L, El-Bardissy A, Abdelsamad O, Al-Badriyeh D, Cavallari LH, Elewa H. Genetic and Non-Genetic Factors Impact on INR Normalization in Preprocedural Warfarin Management. PHARMACOGENOMICS & PERSONALIZED MEDICINE 2021; 14:1069-1080. [PMID: 34483679 PMCID: PMC8409603 DOI: 10.2147/pgpm.s322743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/09/2021] [Indexed: 12/01/2022]
Abstract
Background Annually, 10% of warfarin patients will likely need to stop warfarin prior to elective surgery to achieve a baseline international normalization ratio (INR) level (INR ≤ 1.2) at the time of the procedure. This study explores the influence of genetic and non-genetic factors on INR normalization in the Arab (major part of Near Eastern) population in preprocedural warfarin management. Methods An observational prospective cohort study was designed to recruit Arab patients taking warfarin and scheduled for an elective procedure. Two INR readings were recorded. DNA extraction and genotyping of variants in CYP2C9*2, CYP2C9*3, CYP4F2*3, VKORC1*2, and FII (rs5896) and FVII (rs3093229) genes using real-time polymerase chain reaction were performed. Results Data from 116 patients were included in the analysis. CYP2C9 and VKORC1 genetic variants carriers required lower maintenance dose compared to non-carriers. The analysis showed that ciprofloxacin, antiplatelet medications, and INR index (INR at visit 1) are the only factors associated with the INR decline rate. Also, the proportion of CYP2C9*3 carriers with normal INR (≤1.2) on the day of surgery was significantly lower than those with wild-type genotype (28% vs 60%, p=0.013). In addition, heparin bridging, INR target, and Sudanese nationality are significant predictors of INR normalization (≤1.2) on the day of the procedure. Conclusion Despite the confirmed effect of genetic factors on warfarin maintenance dose, the study was not able to find a significant effect of any genetic factor on the rate of INR normalization possibly due to the small sample size. Index INR and interacting medications showed to be significant predictors of INR decline rate.
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Affiliation(s)
- Islam Eljilany
- College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Mohamed Elarref
- Department of Anesthesia, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Nabil Shallik
- Department of Anesthesia, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar.,Department of Anesthesia, Faculty of Medicine, Tanta University, Tanta, Egypt.,Department of Clinical Anesthesia, College of Medicine, Qatar University, Doha, Qatar.,Department of Clinical Anesthesia, Weill Cornell Medical College, Doha, Qatar
| | - Abdel-Naser Elzouki
- Department of Medicine, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar.,Department of Internal Medicine, College of Medicine, Qatar University, Doha, Qatar.,Department of Internal Medicine, Weill Cornell Medical College, Doha, Qatar
| | - Loulia Bader
- College of Pharmacy, QU Health, Qatar University, Doha, Qatar
| | - Ahmed El-Bardissy
- Department of Pharmacy, Hamad General Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Osama Abdelsamad
- Department of Pharmacy, Al Wakra Hospital, Hamad Medical Corporation, Doha, Qatar
| | | | - Larisa H Cavallari
- Department of Pharmacotherapy and Translation Research, Center for Pharmacogenomics and Precision Medicine, College of Pharmacy, University of Florida, Gainesville, FL, USA
| | - Hazem Elewa
- College of Pharmacy, QU Health, Qatar University, Doha, Qatar.,Department of Pharmacy, Al Wakra Hospital, Hamad Medical Corporation, Doha, Qatar.,Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha, Qatar
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GERDAN V. Akılcı ilaç kullanımı: Varfarin. EGE TIP DERGISI 2021. [DOI: 10.19161/etd.863730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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3
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Gao S, Bell EC, Zhang Y, Liang D. Racial Disparity in Drug Disposition in the Digestive Tract. Int J Mol Sci 2021; 22:1038. [PMID: 33494365 PMCID: PMC7865938 DOI: 10.3390/ijms22031038] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 12/13/2022] Open
Abstract
The major determinants of drug or, al bioavailability are absorption and metabolism in the digestive tract. Genetic variations can cause significant differences in transporter and enzyme protein expression and function. The racial distribution of selected efflux transporter (i.e., Pgp, BCRP, MRP2) and metabolism enzyme (i.e., UGT1A1, UGT1A8) single nucleotide polymorphisms (SNPs) that are highly expressed in the digestive tract are reviewed in this paper with emphasis on the allele frequency and the impact on drug absorption, metabolism, and in vivo drug exposure. Additionally, preclinical and clinical models used to study the impact of transporter/enzyme SNPs on protein expression and function are also reviewed. The results showed that allele frequency of the major drug efflux transporters and the major intestinal metabolic enzymes are highly different in different races, leading to different drug disposition and exposure. The conclusion is that genetic polymorphism is frequently observed in different races and the related protein expression and drug absorption/metabolism function and drug in vivo exposure can be significantly affected, resulting in variations in drug response. Basic research on race-dependent drug absorption/metabolism is expected, and FDA regulations of drug dosing adjustment based on racial disparity are suggested.
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Affiliation(s)
- Song Gao
- Department of Pharmaceutical Science, College of Pharmacy and Health Sciences, Texas Southern University, 3100 Cleburne Street, Houston, TX 77004, USA; (E.C.B.); (Y.Z.); (D.L.)
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Yu WY, Sun X, Wadelius M, Huang L, Peng C, Ma WL, Yang GP. Influence of APOE Gene Polymorphism on Interindividual and Interethnic Warfarin Dosage Requirement: A Systematic Review and Meta-Analysis. Cardiovasc Ther 2017; 34:297-307. [PMID: 27062534 DOI: 10.1111/1755-5922.12186] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Warfarin is the most extensively used coumarin anticoagulant. It has been shown that the anticoagulant effect of warfarin is associated with genetic variation. Apolipoprotein E (ApoE) is a possible candidate to influence the maintenance dose of warfarin. ApoE affects the vitamin K cycle by mediating the uptake of vitamin K into the liver. The vitamin K cycle is the drug target of warfarin. However, the association between genetic variants of the APOE gene and warfarin dose requirement is still controversial. METHODS Revman 5.3 software was used to analyze the relationship between APOE genotypes and warfarin dose requirements. RESULTS In our meta-analysis, the E2/E2 genotype was significantly associated with warfarin dose. E2/E2 patients required 12% (P = 0.0002) lower mean daily warfarin dose than E3/E3 carriers. In addition, subgroup analysis showed that Asians with the E4/E4 genotype tended to need lower warfarin maintenance doses, while the African American E4/E4 carriers needed slightly higher doses than E3/E3 carriers; however, these subgroups were very small. CONCLUSION This is the first meta-analysis of the association between APOE genotypes and warfarin dose. APOE E2/E2 might be one of the factors affecting warfarin dose requirements. The effect of APOE may vary between ethnicities.
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Affiliation(s)
- Wan-Ying Yu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xue Sun
- Center of Clinical Pharmacology, the Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mia Wadelius
- Department of Medical Sciences, Clinical Pharmacology and Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Lihua Huang
- Center for Medical Experiments, Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Chen Peng
- Institute of Pharmacy & Pharmacology, University of South China, Hengyang, Hunan, China
| | - Wan-le Ma
- Center of Clinical Pharmacology, the Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Guo-Ping Yang
- Center of Clinical Pharmacology, the Third Xiangya Hospital, Central South University, Changsha, Hunan, China.
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5
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Jin NZ, Gopinath SC. Potential blood clotting factors and anticoagulants. Biomed Pharmacother 2016; 84:356-365. [DOI: 10.1016/j.biopha.2016.09.057] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 09/06/2016] [Accepted: 09/15/2016] [Indexed: 12/20/2022] Open
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Wiwanitkit V. Pharmacogenomic Effect of Cytochrome P450 2C9 Polymorphisms in Different Populations. Clin Appl Thromb Hemost 2016; 12:219-22. [PMID: 16708125 DOI: 10.1177/107602960601200211] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Presently, warfarin sodium or coumadin is the therapeutic drug of choice for maintenance anticoagualtion therapy. One of several factors underlying the variability in warfarin dose response in the patients receiving this oral anticoagulant is a genetic predisposition, especially the CYP2C9 polymorphisms. The pharmacogenomic effect of CYP2C9 polymorphisms is assessed in different racial populations. A retrospective review was performed with an electronic search engine on this topic to get the data for further meta-analysis. A significant correlation between population ethnicity and gene frequencies was detected in this study. A significant low frequency of CYP2C9 variants among the Asian can be demonstrated. The clinical correlation between CYP2C9 polymorphism and warfarin metabolism was also assessed. Four available case-control reports were selected for this meta-analysis. CYP2C9 variants are strongly associated with low-dose warfarin requirement. In summary, the CYP2C9 variants strongly affect the warfarin dose requirement. This phenomenon is ethnically dependent. Due to the high variant frequency among whites in the West, the investigation for CYP2C9 might be useful for this population, not the Asians, whose variant frequency is very low.
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Affiliation(s)
- Viroj Wiwanitkit
- Department of Laboratory Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
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Abohelaika S, Wynne H, Avery P, Kamali F. Influence of CYP2C9 polymorphism on the fall in International Normalized Ratio in patients interrupting warfarin therapy before elective surgery. J Thromb Haemost 2015; 13:1436-40. [PMID: 26010205 DOI: 10.1111/jth.13014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 05/13/2015] [Indexed: 01/19/2023]
Abstract
BACKGROUND Patients on warfarin are normally required to stop treatment for a fixed number of days prior to an invasive procedure. However, the anticoagulant activity of warfarin subsides at different rates among different patients. OBJECTIVES The aim of this study was to investigate the potential influence of CYP2C9 polymorphism on the variable rate of fall in the International Normalized Ratio (INR) in patients withdrawing from warfarin treatment prior to elective surgery. PATIENTS/METHODS One hundred and fifty-two patients aged 43-93 years were recruited. Demographic data on age, height, weight, gender, daily warfarin dose, indication for anticoagulation therapy, medical diagnosis, surgical operation planned and concomitant medication were recorded. A blood sample was taken for later CYP2C9 genotyping. RESULTS For patients with two CYP2C9 variant alleles (CYP2C9*2*2 or CYP2C9*2*3), the odds of having an INR of ≥ 1.5 before the planned day of surgery were 8.64 times greater (95% confidence interval [CI] 2.25-33.25) than for other patients. Multiple regression analysis revealed that the rate of fall in the INR was reduced in the presence of two CYP2C9 variant alleles, as well as increasing patient age, weight and number of comorbidities, and increased with increasing initial INR (F5,132 = 242.9, P < 0.0001), all of which accounted for ~ 90% of the interindividual variability in the fall in INR. CONCLUSION A genotype-guided protocol to tailor warfarin withdrawal according to an individual patient's CYP2C9 genotype could reduce cancellation or delays of planned procedures, and could also be beneficial when transitioning patients from warfarin to one of the new oral anticoagulants.
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Affiliation(s)
- S Abohelaika
- Institute of Cellular Medicine, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
| | - H Wynne
- Department of Older People's Medicine, Newcastle upon Tyne Hospitals, NHS Foundation Trust, Freeman Hospital, Newcastle upon Tyne, UK
| | - P Avery
- School of Mathematics and Statistics, Newcastle University, Newcastle upon Tyne, UK
| | - F Kamali
- Institute of Cellular Medicine, Newcastle University Institute for Ageing, Newcastle University, Newcastle upon Tyne, UK
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Abohelaika S, Wynne H, Cope L, Kamali F. The impact of genetics on the management of patients on warfarin awaiting surgery. Age Ageing 2015; 44:721-2. [PMID: 25758405 DOI: 10.1093/ageing/afv027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 01/09/2015] [Indexed: 11/13/2022] Open
Abstract
Two older patients with atrial fibrillation, receiving warfarin for thromboembolic prophylaxis, with a target range of 2.0-3.0, were significantly over anticoagulated prior to elective intervention, in spite of having adhered to the standard protocol of 5 days of warfarin interruption. Neither patient had any abnormality of liver function nor was taking any interacting drug known to inhibit warfarin metabolism or affect sensitivity to warfarin. Both had variant cytochrome P2C9 (CYP2C9) alleles which reduce the metabolic capacity of the CYP2C9 enzyme responsible for the metabolism of the S-warfarin enantiomer. Need for preoperative administration of vitamin K or postponement of an operation because of an INR >1.5 could be explained by variant alleles for CYP2C9 and age.
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Affiliation(s)
- Salah Abohelaika
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Hilary Wynne
- Department of Older People's Medicine, Newcastle upon Tyne Hospitals NHS Foundation Trust, Freeman Hospital, Freeman Road, High Heaton, Newcastle upon Tyne NE7 7DN, UK
| | - Lance Cope
- Department of Radiology, South Tyneside NHS Foundation Trust, South Tyneside District Hospital, Tyne and Wear NE34 0PL, UK
| | - Farhad Kamali
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
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Oldenburg J, Müller CR, Rost S, Watzka M, Bevans CG. Comparative genetics of warfarin resistance. Hamostaseologie 2013; 34:143-59. [PMID: 24287886 DOI: 10.5482/hamo-13-09-0047] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/25/2013] [Indexed: 11/05/2022] Open
Abstract
Warfarin and other 4-hydroxycoumarin-based oral anticoagulants targeting vitamin K 2,3-epoxide reductase complex subunit 1 (VKORC1) are administered to humans, mice and rats with different purposes in mind - to act as pesticides in high-dosage baits for killing rodents, but also to save lives when administered in low dosages as antithrombotic drugs in humans. However, high-dosage warfarin used to control rodent populations has resulted in numerous mutations causing warfarin resistance. Currently, six single missense mutations in mice, 12 distinct missense mutations in rats, as well as compound heterozygous or homozygous mutations with up to six distinct missense mutations per Vkorc1 allele have been described. Warfarin resistance missense mutations for human VKORC1 have also been found world-wide, but differ characteristically from those in rodents. In humans, 26 distinct mutations have been characterized, but occur only rarely either in heterozygous or, even rarer, in homozygous form. In this review, we summarize the known VKORC1 missense mutations causing warfarin and other 4-hydroxycoumarin drug resistance, identify genomics databases as new sources of data, explore possible underlying genetic mechanisms, and summarize similarities and differences between warfarin resistant VKORC1 variants in humans and rodents.
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Affiliation(s)
- J Oldenburg
- Prof. Dr. Johannes Oldenburg, Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund Freud Str. 25, 53105 Bonn, Germany, E-mail: , Tel. +49/(0)228/287 51 75, Fax +49/(0)228/287 51 76
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Sattar A, Willman JE, Kolluri R. Possible warfarin resistance due to interaction with ascorbic acid: Case report and literature review. Am J Health Syst Pharm 2013; 70:782-6. [DOI: 10.2146/ajhp110704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Adil Sattar
- School of Medicine, Southern Illinois University, Springfield
| | - Jane E. Willman
- Kindred Hospital Springfield; at the time of writing she was Clinical Pharmacist, St. John’s Hospital, Springfield
| | - Raghu Kolluri
- Vascular Medicine and Vascular Laboratory, Prairie Educational Research Co-operative and Prairie Heart Institute, Springfield
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11
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Retraction notice. VKORC1 gene analysis of some Iranian sensitive patients to warfarin. Pak J Biol Sci 2013; 13:906. [PMID: 23413520 DOI: 10.3923/pjbs.2010.906.910] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Population pharmacokinetic modelling of S-warfarin to evaluate the design of drug–drug interaction studies for CYP2C9. J Pharmacokinet Pharmacodyn 2012; 39:147-60. [DOI: 10.1007/s10928-011-9235-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 12/15/2011] [Indexed: 11/27/2022]
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Shrif NEMA, Won HH, Lee ST, Park JH, Kim KK, Kim MJ, Kim S, Lee SY, Ki CS, Osman IM, Rhman EA, Ali IA, Idris MNA, Kim JW. Evaluation of the effects of VKORC1 polymorphisms and haplotypes, CYP2C9 genotypes, and clinical factors on warfarin response in Sudanese patients. Eur J Clin Pharmacol 2011; 67:1119-30. [PMID: 21590310 DOI: 10.1007/s00228-011-1060-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2011] [Accepted: 04/28/2011] [Indexed: 12/27/2022]
Abstract
OBJECTIVE African populations, including the Sudanese, are underrepresented in warfarin pharmacogenetic studies. We designed a study to determine the associations between the polymorphisms and haplotype structures of CYP2C9 and VKORC1 and warfarin dose response in Sudanese patients, one of the most genetically diverse populations in Africa. MATERIAL AND METHODS The effect of the CYP2C9 polymorphisms (*2, *3, *5, *6, *8, *9, and *11), 20 VKORC1 tag SNPs and haplotypes, and clinical covariates were comprehensively assessed in 203 Sudanese warfarin-treated patients. RESULTS Patients with the CYP2C9*2,*5,*6, or *11 variant required a daily warfarin dose that was 21% lower than those with CYP2C9*1/*1 (4.7 vs 5.8 mg/day, P < 0.001). SNPs around the VKORC1 and POL3S genes were divided into two haplotype blocks in Sudanese populations. According to multiple linear regression results, rs8050984, rs7294, and rs7199949 in the VKORC1 and POL3S genes (P <0.001, <0.001, <0.001, respectively), CYP2C9 genotype (*2, *5, *6, *11; P < 0.001), body weight (P = 0.04), target INR (P = 0.007), and concurrent medications (P = 0.029) could explain about 36.7% of the total warfarin dose variation. CONCLUSION Our data revealed that VKORC1 and CYP2C9 polymorphisms are important factors that influence warfarin dose response in Sudanese patients. Our data suggest that combinations of the SNPs may improve predictions of warfarin dose requirements.
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Affiliation(s)
- Nassr Eldin M A Shrif
- Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, #50 Ilwon-dong, Gangnam-gu, Seoul 135-710, South Korea
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Pharmacogénétique et antivitamine K aujourd’hui : un débat ouvert. Rev Med Interne 2010; 31:361-8. [DOI: 10.1016/j.revmed.2009.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 06/03/2009] [Accepted: 07/08/2009] [Indexed: 11/22/2022]
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Ethnic differences in the population pharmacokinetics and pharmacodynamics of warfarin. J Pharmacokinet Pharmacodyn 2009; 37:3-24. [PMID: 19941044 DOI: 10.1007/s10928-009-9138-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 11/07/2009] [Indexed: 10/20/2022]
Abstract
Ethnic differences in warfarin maintenance doses have been documented amongst the three major Asian ethnic groups (Chinese, Malay and Indian) in Singapore. Studies have shown that cytochrome P450 2C9 (CYP2C9) polymorphisms alone did not entirely account for these differences. Recent reports suggest that VKORC1 (subunit of vitamin K epoxide reductase) haplotypes are more predictive of warfarin response. Population pharmacokinetic/pharmacodynamic (PK/PD) modelling techniques were employed to characterise the PK and PD of warfarin in a healthy volunteer study of 16 Chinese and Indian subjects following a single 25 mg dose of warfarin. To further investigate the underlying differences in warfarin response, a semi-mechanistic modelling approach (using an indirect response model for PCA activity) incorporating the vitamin K cycle was attempted using population methods with Bayesian inference. All eight Indian subjects had H7H7 VKORC1 haplotypes and three had either *2/wt or *3/wt CYP2C9 genotypes. Six Chinese subjects had H1H1 VKORC1 haplotypes and one had H1H7. All Chinese subjects were homozygous wt/wt for CYP2C9. Simulations to steady state were performed to examine warfarin response in subjects with different CYP2C9 and VKORC1 polymorphisms. The presence of a single *2 or *3 CYP2C9 allele reduced mean [SE (standard error)] S-warfarin clearance by 35% from 0.276 (0.04) to 0.180 (0.11) l/h. Subjects with VKORC1 haplotype groups of H7H7 had increased mean (SE) C (50,S) (concentration of S-warfarin required to achieve 50% of maximum effect) of 479 (7.3) compared to 206 (6.7) ng/ml in subjects with the H1H1 groups. For subjects with the H1H7 haplotype, mean (SE) C (50,S) increased 1.4 times to 288 (1.3) ng/ml compared to subjects with H1H1 haplotypes. Steady state simulations showed that whilst CYP2C9 polymorphisms affect the PK of warfarin, VKORC1 haplotypes may be better predictors of warfarin response. Since 90% of Chinese subjects had the VKORC1 H1 haplotype and 100% of Indian subjects the H7 haplotype in this study, ethnic differences in warfarin response in this study appear to be linked to differences in VKORC1 haplotypes.
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Pautas E, Moreau C, Gouin-Thibault I, Golmard JL, Mahé I, Legendre C, Taillandier-Hériche E, Durand-Gasselin B, Houllier AM, Verrier P, Beaune P, Loriot MA, Siguret V. Genetic Factors (VKORC1, CYP2C9, EPHX1, and CYP4F2) Are Predictor Variables for Warfarin Response in Very Elderly, Frail Inpatients. Clin Pharmacol Ther 2009; 87:57-64. [DOI: 10.1038/clpt.2009.178] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Ghadam P, Sharifian R, Farsangi ZJ, Kianmehr Z, Lak M. CYP2C9 gene analysis of some Iranian hypersensitive patients to warfarin. Pak J Biol Sci 2009; 12:1160-1163. [PMID: 19899329 DOI: 10.3923/pjbs.2009.1160.1163] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
For the first time in this study, the pharmacogenetic effects of CYP2C9 polymorphism on warfarin sensitivity in some Iranian patients who are on warfarin treatment were shown. The study group consisted of clinically sensitive patients (21 patients) and the control group (37 adult patients). For detection of CYP2C9*2 and CYP2C9*3 variants, a protocol based on restriction fragment length polymorphism based polymerase chain reaction with Eco47I and KpnI was used. In clinically sensitive patients about 81% and in normal response patients about 24.3% carried variant genotypes.
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Affiliation(s)
- P Ghadam
- Department of Biology, Faculty of Basic Sciences, Alzahra University, Tehran, Iran
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Eckman MH, Greenberg SM, Rosand J. Should we test for CYP2C9 before initiating anticoagulant therapy in patients with atrial fibrillation? J Gen Intern Med 2009; 24:543-9. [PMID: 19255811 PMCID: PMC2669861 DOI: 10.1007/s11606-009-0927-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 11/24/2008] [Accepted: 01/20/2009] [Indexed: 11/26/2022]
Abstract
BACKGROUND Genetic variants of the warfarin sensitivity gene CYP2C9 have been associated with increased bleeding risk during warfarin initiation. Studies also suggest that such patients remain at risk throughout treatment. OBJECTIVE Would testing patients with non-valvular atrial fibrillation (AF) for CYP2C9 before initiating warfarin improve outcomes? DESIGN Markov state transition decision model. SETTING Ambulatory or inpatient settings necessitating new initiation of anticoagulation. PATIENTS The base case was a 69-year-old man with newly diagnosed non-valvular AF. Interventions included: (1) warfarin, (2) aspirin, or (3) no antithrombotic therapy without genetic testing; and genetic testing followed by (4) aspirin or (5) no antithrombotic therapy in those with culprit CYP2C9 alleles. MEASURES Quality-adjusted life years (QALYs). RESULTS In the base case, testing and treating patients with CYP2C9*2 and/or CYP2C9*3 with aspirin rather than warfarin was best (8.97 QALYs). However, warfarin without genetic testing was a close second (8.96 QALYs), a difference of roughly 5 days. Sensitivity analyses demonstrated that genetic testing followed by aspirin was best for patients at lower risk of embolic events. Warfarin without testing was preferred if the rate of embolic events was greater than 5% per year, or the risk of major bleeding while receiving warfarin was lower. CONCLUSION For patients at average risk for ischemic stroke due to AF and at average risk for major hemorrhage, treatment based on genetic testing offers no benefit compared to warfarin initiation without testing. The gain from testing may be larger in patients at lower risk of embolic events or at greater risk of bleeding.
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Affiliation(s)
- Mark H Eckman
- Division of General Internal Medicine and Center for Clinical Effectiveness, University of Cincinnati Medical Center, University of Cincinnati (MHE), PO Box 670535, Cincinnati, OH 45267-0535, USA.
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Sadrai S, Ghadam P, Sharifian R, Nematipour E, Kianmehr Z, Shahriari S. Pharmacokinetic Analysis of Warfarin in Iranian Warfarin Sensitive Patients. INT J PHARMACOL 2008. [DOI: 10.3923/ijp.2008.149.152] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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20
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Lee JH, Lee KS, Kim DS, Lee HS, Choi SI, Cho YG. Evaluation of CoaguChek® XS for Measuring Prothrombin Time in Patients Receiving Long-term Oral Anticoagulant Therapy. Ann Lab Med 2007; 27:177-81. [DOI: 10.3343/kjlm.2007.27.3.177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Jae Hyeon Lee
- Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea
| | - Kyoung Suk Lee
- Division of Cardiology, Internal Medicine (Division of Cardiology), Chonbuk National University Medical School, Jeonju, Korea
- Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea
| | - Dal Sik Kim
- Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea
- Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea
| | - Hye Soo Lee
- Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea
- Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea
| | - Sam Im Choi
- Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea
- Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea
| | - Yong Gon Cho
- Department of Laboratory Medicine, Chonbuk National University Medical School, Jeonju, Korea
- Research Institute of Clinical Medicine, Chonbuk National University, Jeonju, Korea
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21
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Mousny M, Banse X, Wise L, Everett ET, Hancock R, Vieth R, Devogelaer JP, Grynpas MD. The genetic influence on bone susceptibility to fluoride. Bone 2006; 39:1283-9. [PMID: 16920415 DOI: 10.1016/j.bone.2006.06.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Revised: 06/13/2006] [Accepted: 06/19/2006] [Indexed: 11/22/2022]
Abstract
INTRODUCTION The influence of genetic background on bone architecture and mechanical properties is well established. Nevertheless, to date, only few animal studies explore an underlying genetic basis for extrinsic factors effect such as fluoride effect on bone metabolism. MATERIALS AND METHODS This study assessed the effect of increasing fluoride doses (0 ppm, 25 ppm, 50 ppm, 100 ppm) on the bone properties in 3 inbred mouse strains that demonstrate different susceptibilities to developing enamel fluorosis (A/J a "susceptible" strain, 129P3/J a "resistant" strain and SWR/J an "intermediate" strain). Fluoride concentrations were determined in femora and vertebral bodies. Bone mineral density was evaluating through DEXA. Finally, three-point bend testing of femora, compression testing of vertebral bodies and femoral neck-fracture testing were performed to evaluate mechanical properties. RESULTS Concordant with increasing fluoride dose were significant increases of fluoride concentration in femora and vertebral bodies from all 3 strains. Fluoride treatment had little effect on the bone mineral densities (BMD) in the 3 strains. Mechanical testing showed significant alterations in "bone quality" in the A/J strain, whereas moderate alterations in "bone quality" in the SWR/J strain and no effects in the 129P3/J strain were observed. CONCLUSION The results suggest that genetic factors may contribute to the variation in bone response to fluoride exposure and that fluoride might affect bone properties without altering BMD.
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Affiliation(s)
- M Mousny
- Orthopaedic Research Laboratory, Cliniques Universitaires Saint-Luc, Catholic University of Louvain, Brussels, Belgium
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22
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Wadelius M, Pirmohamed M. Pharmacogenetics of warfarin: current status and future challenges. THE PHARMACOGENOMICS JOURNAL 2006; 7:99-111. [PMID: 16983400 DOI: 10.1038/sj.tpj.6500417] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Warfarin is an anticoagulant that is difficult to use because of the wide variation in dose required to achieve a therapeutic effect, and the risk of serious bleeding. Warfarin acts by interfering with the recycling of vitamin K in the liver, which leads to reduced activation of several clotting factors. Thirty genes that may be involved in the biotransformation and mode of action of warfarin are discussed in this review. The most important genes affecting the pharmacokinetic and pharmacodynamic parameters of warfarin are CYP2C9 (cytochrome P(450) 2C9) and VKORC1 (vitamin K epoxide reductase complex subunit 1). These two genes, together with environmental factors, partly explain the interindividual variation in warfarin dose requirements. Large ongoing studies of genes involved in the actions of warfarin, together with prospective assessment of environmental factors, will undoubtedly increase the capacity to accurately predict warfarin dose. Implementation of pre-prescription genotyping and individualized warfarin therapy represents an opportunity to minimize the risk of haemorrhage without compromising effectiveness.
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Affiliation(s)
- M Wadelius
- Department of Medical Sciences, Clinical Pharmacology, Uppsala University Hospital, Uppsala, Sweden.
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Abstract
Vitamin K antagonists (coumarins) are widely-used oral anticoagulants for the prevention of venous thromboembolism and strokes. Wide inter-individual variation in dose response and frequent bleeds characterize the initiation of coumarin therapy. Over the past 10 years both genetic and nongenetic determinants of coumarin dose response have been identified. A comprehensive pharmacogenetics approach to warfarin therapy has the potential to improve the safety and efficiency of warfarin initiation.
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Affiliation(s)
- Deepak Voora
- Washington University School of Medicine, Departments of Medicine and of Pathology, St. Louis, MO 63110, USA
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24
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Chern HD, Ueng TH, Fu YP, Cheng CW. CYP2C9 polymorphism and warfarin sensitivity in Taiwan Chinese. Clin Chim Acta 2006; 367:108-13. [PMID: 16413010 DOI: 10.1016/j.cca.2005.11.026] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Revised: 11/24/2005] [Accepted: 11/26/2005] [Indexed: 11/21/2022]
Abstract
BACKGROUND Warfarin prevents thromboembolism in patients with prosthetic heart valvular replacement. Cytochrome P4502C9 (CYP2C9) is polymorphic in human and is principally responsible for the metabolism of warfarin. However, known CYP2C9 polymorphisms cannot entirely account for the low dose requirement of warfarin in Chinese-Taiwanese receiving mitral valve replacement. We screened a new polymorphism of CYP2C9 and investigated its role in warfarin sensitivity. METHODS We examined warfarin dose requirements in 239 Chinese-Taiwanese patients who had attended a cardiac surgery clinic in National Taiwan University Hospital. DNA samples were obtained from 106 Chinese-Taiwanese (37 patients and 69 unrelated healthy controls), and healthy control subjects of Caucasians (n=28) and African-Americans (n=28). Four out of those 37 patients were poor metabolizers of warfarin, and their DNA were subjected to sequencing analysis. Moreover, CYP2C9 genotyping analyses were performed using PCR-RFLP analysis. The chi2 test and Fisher's exact test were used to compare the differences of the allelic frequency and genotype. The association between warfarin dose requirement and genetic polymorphism of CYP2C9 was also analysed. RESULTS The mean daily warfarin dose was 3.11+/-1.62 mg for the maintenance of the international normalized ratio of 2 to 3 in 239 patients. A single nucleotide substitution from G to C was found in this study. This SNP, G-65/C, is in intron 3, 65 base pairs upstream of exon 4. The allelic frequencies of C-65 in healthy controls were 0.125, 0.058 and approximately 0 with respect to African-American, Chinese-Taiwanese and Caucasian, implying inter-ethnic variations of the C-65 allele. In addition, patients who were carrier of either the heterozygous or homozygous C-65 variant received half of the usual warfarin dose. CONCLUSION The novel intronic G-65/C mutation appears to be inter-racially different in allelic frequency, and that the anticoagulation was affected in response to warfarin sensitivity in Chinese-Taiwanese patients receiving mitral valve replacement.
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Affiliation(s)
- Herng-Der Chern
- Graduate Institute of Clinical Pharmacy, College of Medicine, National Taiwan University, Taipei, Taiwan
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25
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Wadelius M, Chen LY, Downes K, Ghori J, Hunt S, Eriksson N, Wallerman O, Melhus H, Wadelius C, Bentley D, Deloukas P. Common VKORC1 and GGCX polymorphisms associated with warfarin dose. THE PHARMACOGENOMICS JOURNAL 2005; 5:262-70. [PMID: 15883587 DOI: 10.1038/sj.tpj.6500313] [Citation(s) in RCA: 335] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We report a novel combination of factors that explains almost 60% of variable response to warfarin. Warfarin is a widely used anticoagulant, which acts through interference with vitamin K epoxide reductase that is encoded by VKORC1. In the next step of the vitamin K cycle, gamma-glutamyl carboxylase encoded by GGCX uses reduced vitamin K to activate clotting factors. We genotyped 201 warfarin-treated patients for common polymorphisms in VKORC1 and GGCX. All the five VKORC1 single-nucleotide polymorphisms covary significantly with warfarin dose, and explain 29-30% of variance in dose. Thus, VKORC1 has a larger impact than cytochrome P450 2C9, which explains 12% of variance in dose. In addition, one GGCX SNP showed a small but significant effect on warfarin dose. Incorrect dosage, especially during the initial phase of treatment, carries a high risk of either severe bleeding or failure to prevent thromboembolism. Genotype-based dose predictions may in future enable personalised drug treatment from the start of warfarin therapy.
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Affiliation(s)
- M Wadelius
- Department of Medical Sciences, Clinical Pharmacology, University Hospital, Uppsala, Sweden.
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26
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Kohnke H, Sörlin K, Granath G, Wadelius M. Warfarin dose related to apolipoprotein E (APOE) genotype. Eur J Clin Pharmacol 2005; 61:381-8. [PMID: 15952022 DOI: 10.1007/s00228-005-0936-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Accepted: 04/13/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Warfarin is an anticoagulant which acts through interference with the recycling of vitamin K in the liver, leading to reduced activation of several clotting factors. Apolipoprotein E plays a central role in the uptake of the lipid-soluble vitamin K. The apolipoprotein E (APOE) alleles E2, E3 and E4 encode the three major isoforms of apolipoprotein E. The aim of this project was to evaluate whether variation in the APOE gene influences warfarin dose. METHODS We genotyped APOE in 183 warfarin-treated patients. Information about warfarin dose, prothrombin time, age, gender, body weight, treatment indication and duration, other diseases and concurrent medication was taken from the patients' medical records. Cytochrome P450 2C9 genotyping had been performed previously, and patients were stratified according to CYP2C9 genotype. RESULTS Patients homozygous for APOE*E4 tended to receive higher warfarin doses than others. Among CYP2C9 extensive metabolisers, APOE*E4 homozygous patients received significantly higher warfarin doses than patients with one or no E4 alleles; 56.9 compared with 34.3 and 34.6 mg/week, (Bonferroni corrected P=0.008 and 0.007, respectively). APOE genotype explains 6% of warfarin dose variance among CYP2C9 extensive metabolisers (analysis of variance, P=0.009). CONCLUSION Previous studies have shown that individuals carrying the APOE*E4 allele have a faster uptake of lipoproteins into the liver and lower levels of circulating vitamin K than others. It is therefore plausible that patients carrying E4 alleles have an enhanced uptake of vitamin K into the liver and require higher doses of warfarin to compensate for this.
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Affiliation(s)
- Hugo Kohnke
- Department of Medical Sciences, Clinical Pharmacology, University Hospital, 75185, Uppsala, Sweden
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Yang DT, Robetorye RS, Rodgers GM. Home prothrombin time monitoring: a literature analysis. Am J Hematol 2004; 77:177-86. [PMID: 15389909 DOI: 10.1002/ajh.20161] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The anticoagulant activity of warfarin sodium is monitored by the prothrombin time (PT) using the international normalized ratio (INR). Standard oral anticoagulant therapy monitoring requires frequent patient visits to physicians' offices and/or laboratories to optimize warfarin dosage. Home PT monitoring by patients can increase testing frequency and may thus decrease complications associated with oral anticoagulant therapy. Clinical studies suggest that home PT monitoring is more effective than uncoordinated management and is as effective as care through specialized anticoagulation clinics for keeping INRs within a therapeutic range. There are accurate and reliable instruments available, but paramount to the success of home PT monitoring is sound patient selection, appropriate patient training, and consistent quality control.
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Affiliation(s)
- David T Yang
- Department of Pathology, University of Utah Health Sciences Center, Salt Lake City, Utah 84132, USA
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28
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Wadelius M, Sörlin K, Wallerman O, Karlsson J, Yue QY, Magnusson PKE, Wadelius C, Melhus H. Warfarin sensitivity related to CYP2C9, CYP3A5, ABCB1 (MDR1) and other factors. THE PHARMACOGENOMICS JOURNAL 2003; 4:40-8. [PMID: 14676821 DOI: 10.1038/sj.tpj.6500220] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The required dose of the oral anticoagulant warfarin varies greatly, and overdosing often leads to bleeding. Warfarin is metabolised by cytochrome P450 enzymes CYP2C9, CYP1A2 and CYP3A. The target cell level of warfarin may be dependent on the efflux pump P-glycoprotein, encoded by the adenosine triphosphate-binding cassette gene ABCB1 (multidrug resistance gene 1). Genetic variability in CYP2C9, CYP3A5 and ABCB1 was analysed in 201 stable warfarin-treated patients using solid-phase minisequencing, pyrosequencing and SNaPshot. CYP2C9 variants, age, weight, concurrent drug treatment and indication for treatment significantly influenced warfarin dosing in these patients, explaining 29% of the variation in dose. CYP3A5 did not affect warfarin dosing. An ABCB1 haplotype containing the exon 26 3435T variant was over-represented among low-dose patients. Thirty-six patients with serious bleeding complications had higher prothrombin time international normalised ratios than 189 warfarin-treated patients without serious bleeding, but there were no significant differences in CYP2C9, CYP3A5 or ABCB1 genotypes and allelic variants.
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Affiliation(s)
- M Wadelius
- Department of Medical Sciences, Clinical Pharmacology, University Hospital, Uppsala, Sweden.
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29
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Yip SP, Lee SY, To SST, Wong ML. Improved Real-Time PCR Assay for Homogeneous Multiplex Genotyping of Four CYP2C9 Alleles with Hybridization Probes. Clin Chem 2003; 49:2109-11. [PMID: 14633897 DOI: 10.1373/clinchem.2003.023622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kohn MH, Pelz HJ, Wayne RK. Locus-specific genetic differentiation at Rw among warfarin-resistant rat (Rattus norvegicus) populations. Genetics 2003; 164:1055-70. [PMID: 12871915 PMCID: PMC1462631 DOI: 10.1093/genetics/164.3.1055] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Populations may diverge at fitness-related genes as a result of adaptation to local conditions. The ability to detect this divergence by marker-based genomic scans depends on the relative magnitudes of selection, recombination, and migration. We survey rat (Rattus norvegicus) populations to assess the effect that local selection with anticoagulant rodenticides has had on microsatellite marker variation and differentiation at the warfarin resistance gene (Rw) relative to the effect on the genomic background. Initially, using a small sample of 16 rats, we demonstrate tight linkage of microsatellite D1Rat219 to Rw by association mapping of genotypes expressing an anticoagulant-rodenticide-insensitive vitamin K 2,3-epoxide reductase (VKOR). Then, using allele frequencies at D1Rat219, we show that predicted and observed resistance levels in 27 populations correspond, suggesting intense and recent selection for resistance. A contrast of F(ST) values between D1Rat219 and the genomic background revealed that rodenticide selection has overwhelmed drift-mediated population structure only at Rw. A case-controlled design distinguished these locus-specific effects of selection at Rw from background levels of differentiation more effectively than a population-controlled approach. Our results support the notion that an analysis of locus-specific population genetic structure may assist the discovery and mapping of novel candidate loci that are the object of selection or may provide supporting evidence for previously identified loci.
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Affiliation(s)
- Michael H Kohn
- Department of Organismic Biology, Ecology, and Evolution (OBEE), University of California, Los Angeles, California 90095-1606, USA.
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