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Anticoagulation Control with Acenocoumarol or Warfarin in Non-Valvular Atrial Fibrillation in Primary Care (Fantas-TIC Study). INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18115700. [PMID: 34073370 PMCID: PMC8199061 DOI: 10.3390/ijerph18115700] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/06/2021] [Accepted: 05/18/2021] [Indexed: 12/15/2022]
Abstract
Introduction: The use of vitamin K antagonists (VKAs) in non-valvular atrial fibrillation (NVAF) is complicated due to the narrow therapeutic margin they present and their unpredictable dose–response relationship. Most studies are based on warfarin, with the results being extrapolated to acenocoumarol. However, studies comparing the two treatments in terms of the degree of anticoagulation control are scarce, justifying the present study. Main factors associated with poor control of time in therapeutic range (TTR) of anticoagulated patients are also studied. Methods: Cross-sectional study, with real-world data from patients treated in primary care (PC). Data were obtained from the System for the Improvement of Research in PC (SIDIAP) database, covering 60,978 NVAF-anticoagulated patients from 287 PC centres in 2018. Descriptive statistics were derived, and odds ratios were estimated by multivariate logistic regression. Results: 41,430 patients were considered: 93% were being treated with acenocoumarol and 7% with warfarin. There was no difference in poor control of TTR between the two types of VKA treatment, acenocoumarol and warfarin (38.9 vs. 38.4; p = 0.610). Poor anticoagulation control was mainly associated with advanced alcoholism (OR = 1.38), liver failure (OR = 1.37) and intracranial haemorrhage (OR = 1.35) as well as female sex, age < 60 years, cardiovascular history, diabetes mellitus and other variables. Conclusions: There is no association between poor anticoagulation control and the type of VKA treatment administered. Factors associated with poor control of TTR must be considered in clinical practice to improve control and decision-making.
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Genetic risk assessment towards warfarin application: Saudi Arabia study with a potential to predict and prevent side effects. Saudi J Biol Sci 2019; 27:456-459. [PMID: 31889870 PMCID: PMC6933267 DOI: 10.1016/j.sjbs.2019.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/06/2019] [Accepted: 11/11/2019] [Indexed: 12/31/2022] Open
Abstract
Warfarin doses are greatly affected by polymorphism altering cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) gene. This study evaluated the prevalence of alleles (either single or double) and carriers of single nucleotide polymorphisms (SNPs) in both genotypes CYP2C9 and VKORC1 in alkharj area, Saudi Arabia and its association with warfarin use risk. Total 112 samples were collected and genotyped using FlexiGene DNA Kit for isolation and StepOnePlus Real-Time PCR System by TaqMan allelic discrimination methods. The results indicated the frequency of 11%, 8% and 45% for CYP2C9 *2 *3 and VKORC1-1639 G > A polymorphism. And as a combination genotype it was 15.18% For both CYP2C9 and VKORC1 polymorphism, 27.67% for CYP2C9 and 42.86% for VKORC1. Non-carriers rate came to be at 30.3%. According to previously published dosing changes in warfarin for polymorphism carriers (single-double-triple). The predicted warfarin doses reduction in order of 1–1.6, 2–2.9, 2.9–3.7 mg/day. It was found that 72.3% of the study population was carrier of a type of polymorphism, 15.18% for two types of polymorphisms. These findings predict changes in warfarin metabolism and eventually dosing alteration among patients on warfarin. Both genotypes (CYP2C9 and VKORC1) require different dosing of warfarin than non-carriers in order to minimize the risk of warfarin overdosing and avoidance of the drug-related problems (DRPs).
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Cîmpan PL, Chira RI, Mocan M, Anton FP, Farcaş AD. Oral Anticoagulant Therapy-When Art Meets Science. J Clin Med 2019; 8:jcm8101747. [PMID: 31640208 PMCID: PMC6832236 DOI: 10.3390/jcm8101747] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 12/15/2022] Open
Abstract
Anticoagulant treatment is extremely important and frequently encountered in the therapy of various cardiovascular diseases. Vitamin K antagonists (VKA) are in use for the prevention and treatment of arterial and venous thromboembolism, despite the introduction of new direct-acting oral anticoagulants (NOAC). The VKA still have the clear recommendation in patients with a mechanical prosthetic heart valve replacement or moderate to severe mitral stenosis of the rheumatic origin, in deep vein thrombosis associated with congenital thrombophilia, and in cases where NOAC are prohibited by social condition (financial reason) or by comorbidities (extreme weight, severe renal or liver disease). VKA dosing required to reach the targeted therapeutic range varies largely between patients (inter-individual variability). This inter-individual variability depends on multiple environmental factors such as age, mass, diet, etc. but it is also influenced by genetic determinism. About 30 genes implicated in the metabolism coumarins derivatives were identified, the most important being CYP2C9 and VKORC, each with several polymorphisms. Herein, we review the data regarding genetic alterations in general and specific populations, highlight the diagnosis options in particular cases presenting with genetic alteration causing higher sensitivity and/or resistance to VKA therapy and underline the utility of NOAC in solving such rare and difficult problems.
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Affiliation(s)
| | - Romeo Ioan Chira
- Internal Medicine Department, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania.
- Emergency Clinical County Hospital, 40006 Cluj Napoca, Romania.
| | - Mihaela Mocan
- Internal Medicine Department, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania.
- Emergency Clinical County Hospital, 40006 Cluj Napoca, Romania.
| | - Florin Petru Anton
- Internal Medicine Department, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania.
- Emergency Clinical County Hospital, 40006 Cluj Napoca, Romania.
| | - Anca Daniela Farcaş
- Internal Medicine Department, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania.
- Emergency Clinical County Hospital, 40006 Cluj Napoca, Romania.
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Ham AC, Ziere G, Broer L, Swart KMA, Enneman AW, van Dijk SC, van Wijngaarden JP, van der Zwaluw NL, Brouwer-Brolsma EM, Dhonukshe-Rutten RAM, van Schoor NM, Zillikens MC, van Gelder T, de Vries OJ, Lips P, Deeg DJH, de Groot LCPGM, Hofman A, Witkamp RF, Uitterlinden AG, Stricker BH, van der Velde N. CYP2C9 Genotypes Modify Benzodiazepine-Related Fall Risk: Original Results From Three Studies With Meta-Analysis. J Am Med Dir Assoc 2016; 18:88.e1-88.e15. [PMID: 27889507 DOI: 10.1016/j.jamda.2016.09.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate whether the CYP2C9*2 and *3 variants modify benzodiazepine-related fall risk. DESIGN Three prospective studies; the Rotterdam Study, B-PROOF, and LASA. SETTING Community-dwelling individuals living in or near five Dutch cities. PARTICIPANTS There were 11,485 participants aged ≥55 years. MEASUREMENTS Fall incidents were recorded prospectively. Benzodiazepine use was determined using pharmacy dispensing records or interviews. Cox proportional hazard models adjusted for age and sex were applied to determine the association between benzodiazepine use and fall risk stratified for CYP2C9 genotype and comparing benzodiazepine users to nonusers. The results of the three studies were combined applying meta-analysis. Within benzodiazepine users, the association between genotypes and fall risk was also assessed. RESULTS Three thousand seven hundred five participants (32%) encountered a fall during 91,996 follow-up years, and 4% to 15% (depending on the study population) used benzodiazepines. CYP2C9 variants had frequencies of 13% for the *2 allele and 6% for the *3 allele. Compared to nonusers, current benzodiazepine use was associated with an 18% to 36% increased fall risk across studies with a combined hazard ratio (HR) = 1.26 (95% confidence interval [CI], 1.13; 1.40). CYP2C9*2 or *3 allele variants modified benzodiazepine-related fall risk. Compared to nonusers, those carrying a CYP2C9*2 or *3 allele and using benzodiazepines had a 45% increased fall risk (HR, 1.45 95% CI, 1.21; 1.73), whereas CYP2C9*1 homozygotes using benzodiazepines had no increased fall risk (HR, 1.14; 95% CI, 0.90; 1.45). Within benzodiazepine users, having a CYP2C9*2 or *3 allele was associated with an increased fall risk (HR, 1.35; 95% CI, 1.06; 1.72). Additionally, we observed an allele dose effect; heterozygous allele carriers had a fall risk of (HR = 1.30; 95% CI, 1.05; 1.61), and homozygous allele carriers of (HR = 1.91 95% CI, 1.23; 2.96). CONCLUSIONS CYP2C9*2 and *3 allele variants modify benzodiazepine-related fall risk. Those using benzodiazepines and having reduced CYP2C9 enzyme activity based on their genotype are at increased fall risk. In clinical practice, genotyping might be considered for elderly patients with an indication for benzodiazepine use. However, because the exact role of CYP2C9 in benzodiazepine metabolism is still unclear, additional research is warranted.
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Affiliation(s)
- Annelies C Ham
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Gijsbertus Ziere
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Linda Broer
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Karin M A Swart
- Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Anke W Enneman
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Suzanne C van Dijk
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | | | | | | | | | - Natasja M van Schoor
- Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - M Carola Zillikens
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Teun van Gelder
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Oscar J de Vries
- Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | - Paul Lips
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Endocrinology, VU University Medical Centre, Amsterdam, the Netherlands
| | - Dorly J H Deeg
- Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands
| | | | - Albert Hofman
- Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Epidemiology, Harvard H.T. Chan School of Public Health, Boston, MA
| | - Renger F Witkamp
- Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands
| | - André G Uitterlinden
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands
| | - Bruno H Stricker
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Inspectorate of Health Care, Utrecht, the Netherlands
| | - Nathalie van der Velde
- Department of Internal Medicine, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands; Department of Internal Medicine, Section of Geriatric Medicine, Academic Medical Centre, Amsterdam, the Netherlands.
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Brehm K, Krumnau O, Heilmann C, Beyersdorf F. Genetic variations of phenprocoumon metabolism in patients with ventricular assist devices. Eur J Cardiothorac Surg 2016; 50:275-80. [PMID: 26984978 DOI: 10.1093/ejcts/ezw060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 01/25/2016] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Anticoagulation in patients with ventricular assist device (VAD) support is crucial and to date, no alternative to vitamin K antagonists (VKAs) can be safely used. Genetic variances of cytochrome p450 2C9 (CYP2C9) and vitamin K epoxide reductase (VKORC) have been recently connected with variation of VKA maintenance as well as loading doses. In this retrospective study, we assessed the incidence of genetic variations and the influence of different genotypes of CYP2C9 and VKORC1 in VAD patients. METHODS A total of 161 patients received a VAD implant in our institution between January 2006 and July 2014. Of these, 63 consented to genetic analysis and completed an interview with standardized questions on phenprocoumon (PC) dosage, international normalized ratio and anticoagulation-related complications. Determination of VKORC (-1639 G > A; -1173 C > T) and of CYP2C9 (*2, 430 C > T; *3, 1075 A > C) polymorphisms was performed by polymerase chain reaction and restriction analysis. RESULTS The most common VKORC-1639 allele combination was wild-type GG (41%) followed by GA (32%) and AA (27%). Patients with VKORC1 polymorphisms AA and GA needed less PC in the maintenance phase of anticoagulation (P < 0.001) compared with wild-type GG patients. In contrast, CYP2C9 polymorphisms showed no effect on PC doses. Similar findings were observed in the initiation phase of PC therapy. High complications rates under PC therapy were observed particularly at the beginning. CONCLUSIONS VKORC polymorphism affects PC dosage in the initiation as well as the maintenance phase. High rates of bleeding complications and thromboembolic events were found at the beginning of PC therapy in VAD patients. Therefore, a genotype-guided dosage algorithm might be useful in VAD patients.
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Affiliation(s)
- Kerstin Brehm
- Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany
| | - Oliver Krumnau
- Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany
| | - Claudia Heilmann
- Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany
| | - Friedhelm Beyersdorf
- Department of Cardiovascular Surgery, University Heart Center Freiburg - Bad Krozingen, Freiburg, Germany
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Verhoef TI, Redekop WK, Daly AK, van Schie RMF, de Boer A, Maitland-van der Zee AH. Pharmacogenetic-guided dosing of coumarin anticoagulants: algorithms for warfarin, acenocoumarol and phenprocoumon. Br J Clin Pharmacol 2014; 77:626-41. [PMID: 23919835 DOI: 10.1111/bcp.12220] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 07/17/2013] [Indexed: 12/13/2022] Open
Abstract
Coumarin derivatives, such as warfarin, acenocoumarol and phenprocoumon are frequently prescribed oral anticoagulants to treat and prevent thromboembolism. Because there is a large inter-individual and intra-individual variability in dose-response and a small therapeutic window, treatment with coumarin derivatives is challenging. Certain polymorphisms in CYP2C9 and VKORC1 are associated with lower dose requirements and a higher risk of bleeding. In this review we describe the use of different coumarin derivatives, pharmacokinetic characteristics of these drugs and differences amongst the coumarins. We also describe the current clinical challenges and the role of pharmacogenetic factors. These genetic factors are used to develop dosing algorithms and can be used to predict the right coumarin dose. The effectiveness of this new dosing strategy is currently being investigated in clinical trials.
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Affiliation(s)
- Talitha I Verhoef
- Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht
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Lee HJ, You MR, Moon WR, Sul H, Chung CH, Park CY, Park SG. Evaluation of risk factors in patients with vitamin K-dependent coagulopathy presumed to be caused by exposure to brodifacoum. Korean J Intern Med 2014; 29:498-508. [PMID: 25045298 PMCID: PMC4101597 DOI: 10.3904/kjim.2014.29.4.498] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 07/22/2013] [Accepted: 10/04/2013] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND/AIMS Recently, many cases of vitamin K-dependent coagulopathy of unknown origin have been reported. Such patients lack any relevant family history and have no systemic disease, raising suspicion of superwarfarin intoxication. We evaluated individual risk factors causing coagulopathy and hemorrhagic symptoms in patients with suspected superwarfarin intoxication. In addition, we determined how to effectively treat vitamin K-dependent coagulopathy caused by suspected superwarfarin intoxication. METHODS Seven patients with suspected superwarfarin intoxication who lacked any definitive history of rodenticide ingestion were included. Thirty-one patients initially diagnosed with rodenticide poisoning were also included. We performed a retrospective chart review of all subjects and examined clinical data including patient demographics and medical histories. RESULTS Patients initially diagnosed with rodenticide poisoning were divided into two groups, one of which had a laboratory abnormality (prothrombin time [PT] > 13 seconds) and another group with PTs in the normal range. There was no significant difference between the two groups in any of age, gender, the extent of chronic alcohol consumption, the causative rodenticide, psychiatric problems, ingestion of drugs interacting with warfarin, the extent of intoxication, or the type of ingestion attempt. The albumin level of the former group was significantly lower than that of the latter group (p = 0.014). Furthermore, a significant difference between the two groups was evident in terms of simultaneous ingestion of rodenticide and alcohol (p = 0.023). CONCLUSIONS Most patients with superwarfarin poisoning did not exhibit any complication. When such complications were evident, they were associated with serum albumin level and coingestion of rodenticide and alcohol.
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Affiliation(s)
- Hee-Jeong Lee
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Mi-Ra You
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Woo-Ram Moon
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Hyoung Sul
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Choon-Hae Chung
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Chi-Young Park
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
| | - Sang-Gon Park
- Division of Hematology and Oncology, Department of Internal Medicine, Chosun University Hospital, Gwangju, Korea
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Gschwind L, Rollason V, Boehlen F, Rebsamen M, Combescure C, Grünenwald M, Matthey A, Bonnabry P, Dayer P, Desmeules JA. Impact of CYP2C9 polymorphisms on the vulnerability to pharmacokinetic drug-drug interactions during acenocoumarol treatment. Pharmacogenomics 2014; 14:745-53. [PMID: 23651023 DOI: 10.2217/pgs.13.55] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
AIM The objective of this study was to investigate the impact of CYP2C9 polymorphisms and drug-drug interactions on the risk of overanticoagulation in patients treated with acenocoumarol, a vitamin K antagonist. MATERIALS & METHODS A prospective observational study was performed on patients starting acenocoumarol (n = 115). CYP2C9 genotypes were assessed. Data on International Normalized Ratio, comedications and doses of acenocoumarol were collected during the first 35 days of therapy. Overanticoagulation was defined as the occurrence of at least one International Normalized Ratio ≥4. RESULTS The presence of a CYP2C9 inhibitor or a CYP2C9 polymorphisms statistically increased the risk of overanticoagulation (hazard ratio [HR]: 2.8, p < 0.001 and HR: 1.7, p = 0.04, respectively). The presence of CYP2C9 polymorphisms almost tripled the risk of overanticoagulation (HR: 2.91, p = 0.01) in the presence of a clinically significant drug-drug interaction. CONCLUSION These findings support the fact that CYP2C9 genotyping could be useful to identify patients requiring closer monitoring, especially when a drug-drug interaction is expected.
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Affiliation(s)
- Liliane Gschwind
- Division of Clinical Pharmacology & Toxicology, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14, Switzerland
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Botton MR, Viola PP, Bandinelli E, Leiria TLL, Rohde LEP, Hutz MH. A New Algorithm for Weekly Phenprocoumon Dose Variation in a Southern Brazilian Population: Role for CYP2C9, CYP3A4/5 and VKORC1 Genes Polymorphisms. Basic Clin Pharmacol Toxicol 2013; 114:323-9. [DOI: 10.1111/bcpt.12172] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 10/28/2013] [Indexed: 12/13/2022]
Affiliation(s)
- Mariana R. Botton
- Genetics Department; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Patrícia P. Viola
- Genetics Department; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Eliane Bandinelli
- Genetics Department; Federal University of Rio Grande do Sul; Porto Alegre Brazil
| | - Tiago L. L. Leiria
- Rio Grande do Sul Cardiology Institute - Cardiology University Foundation; Porto Alegre Brazil
| | - Luis E. P. Rohde
- Cardiology Division; Porto Alegre Clinics Hospital; Porto Alegre Brazil
| | - Mara H. Hutz
- Genetics Department; Federal University of Rio Grande do Sul; Porto Alegre Brazil
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Rakicevic LB, Kusic-Tisma JS, Kovac MK, Backovic DT, Radojkovic DP. Rationalized DNA sequencing-based protocol for genotyping patients receiving coumarin therapy. Scandinavian Journal of Clinical and Laboratory Investigation 2013; 73:523-7. [PMID: 23806093 DOI: 10.3109/00365513.2013.809142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
During the last decade genetic factors affecting coumarin therapy have been extensively investigated. The most important genes appear to be CYP2C9 and VKORC1, and different studies have shown that DNA testing can dramatically improve the safety and effectiveness of the therapy. However, the implementation of pharmacogenetic testing in everyday practice is still not a reality. Facilities and ability to get results before the start of therapy are very important. The implementation of specific methodology and equipment for particular type of diagnostics can represent a serious, even impossible, financial hurdle to overcome (especially in developing countries). For this reason, the use of every tool that contributes to rationalization of the existing methods can be a considerable asset. Therefore, we set the goal to rationalize our current DNA sequencing based protocol for analysis of the VKORC1 c.-1639G> A, CYP2C9*2 and CYP2C9*3 variant alleles, in order to obtain shorter and easier procedure. Simplification of the protocol was achieved by setting up multiplex PCR and omitting DNA extraction. This rationalization of the existing DNA sequencing based procedure allows getting results in 12 hours. The new protocol was tested on 118 samples. Obtained results have shown full accordance to those obtained with previous, non-modified protocol. Therefore, given the circumstances, we consider that protocol for pharmocogenetic testing should be made more accessible - both to doctors and patients. It is one of the prerequisites in order to make genotyping prior to the therapy common practice.
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Affiliation(s)
- Ljiljana B Rakicevic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade , Serbia
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Pop TR, Vesa ŞC, Trifa AP, Crişan S, Buzoianu AD. An acenocoumarol dose algorithm based on a South-Eastern European population. Eur J Clin Pharmacol 2013; 69:1901-7. [PMID: 23774941 DOI: 10.1007/s00228-013-1551-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Accepted: 06/04/2013] [Indexed: 01/11/2023]
Abstract
AIM To develop and validate an algorithm for the prediction of therapeutic dose of acenocoumarol in Romanian patients. METHODS The inclusion criteria for entry to the study was age ≥ 18 years and starting acenocoumarol treatment for at least one of the following clinical indications: acute deep vein thrombosis of the lower limbs, persistent or permanent atrial fibrillation, and/or the presence of valvular prostheses requiring prolonged oral anticoagulant therapy. The patients were followed up for 3 months. Patients admitted to the internal medicine, cardiology, and geriatrics wards of the Municipal Clinical Hospital, Cluj-Napoca and "Niculae Stăncioiu" Heart Institute between October 2009 and June 2011 who fulfilled the inclusion criteria were included in the study. Clinical and demographic data that could influence the acenocoumarol stable dose were recorded for each patient. Genetic analysis included the genotyping the CYP2C9*2 and *3, and the VKORC1 -1693 G > A polymorphisms. The patients were randomly divided into two groups: (1) the main group on which the development of the clinical and genetic algorithms for acenocoumarol dose prediction was based; (2) the validation group. RESULTS The study included 301 patients, of whom 155 were women (51.5 %) and 146 were men (48.5 %). The median age of the patient cohort was 66 (women, 57; men, 73) years. After randomization the main group comprised 200 patients (66.4 %) and the validation group 101 patients (33.6 %). Age and body mass index explained 18.8 % (R (2)) of the variability in acenocoumarol weekly dose in patients in the main group. When the genetic data were added to the algorithm, the CYP2C9*2 and *3 polymorphisms and the VKORC1 -1693 G > A polymorphism accounted for 4.7 and 19. 6 % of acenocoumarol dose variability, respectively. For the main group, we calculated a mean absolute error of 5 mg/week (0.71 mg/day). In the validation group, clinical parameters explained 22.2 % of the weekly acenocoumarol dose variability. Genetic polymorphisms increased the R(2) coefficient to 32.8 %. CONCLUSION We have developed and validated an accurate algorithm for prediction of the stable therapeutic dose of acenocoumarol in a Romania population.
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Affiliation(s)
- Tudor Radu Pop
- 5th Department of Surgery, Municipal Hospital of Cluj-Napoca, "Iuliu Haţieganu" University of Medicine and Pharmacy Cluj-Napoca, 11th Tăbăcarilor Street, 400139, Cluj-Napoca, Cluj, Romania
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Brehm K, Schack J, Heilmann C, Blanke P, Geissler HJ, Beyersdorf F. Mechanical heart valve recipients: anticoagulation in patients with genetic variations of phenprocoumon metabolism†. Eur J Cardiothorac Surg 2013; 44:309-14; discussion 314-5. [DOI: 10.1093/ejcts/ezt002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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van Schie RMF, el Khedr N, Verhoef TI, Teichert M, Stricker BH, Hofman A, Buhre PN, Wessels JAM, Schalekamp T, le Cessie S, van der Meer FJM, Rosendaal FR, de Boer A, Maitland-van der Zee AH, Visser LE. Validation of the acenocoumarol EU-PACT algorithms: similar performance in the Rotterdam Study cohort as in the original study. Pharmacogenomics 2012; 13:1239-45. [DOI: 10.2217/pgs.12.101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Aim: To evaluate the performance of the European Pharmacogenetics of Anticoagulant Therapy (EU-PACT) acenocoumarol dose algorithms in an independent data set. The EU-PACT trial investigates the added value of pretreatment genotyping for use of warfarin, phenprocoumon and acenocoumarol. Patients & methods: External validation was performed in the Rotterdam Study cohort using information about 707 acenocoumarol users. R2, which measures the strength of correlation between the predicted and observed acenocoumarol dose, mean absolute error and mean squared error were calculated to evaluate the performance of the original algorithm. Results: Validation resulted in a R2 of 52.7 and 12.9% compared with an R2 of 52.6 and 17.8% in the original study for the genotype-guided and nongenotype-guided dose algorithm, respectively. For the genotype-guided dose algorithm, the mean absolute error was 0.48 mg/day and the mean squared error was 0.38 (mg/day)2. For the nongenotype-guided dose algorithm, the mean absolute error was 0.62 mg/day and the mean squared error was 0.63 (mg/day)2. Conclusion: The EU-PACT acenocoumarol algorithm performs just as accurately in this study as in the original study, which implies applicability in various populations. Original submitted 4 April 2012; Revision submitted 31 May 2012
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Affiliation(s)
- Rianne MF van Schie
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Nadia el Khedr
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Talitha I Verhoef
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Martina Teichert
- R&D Department, Royal Dutch Pharmacists Association, The Hague, The Netherlands and Scientific Institute for Quality of Healthcare (IQ healthcare), Radboud University Nijmegen, The Netherlands
| | - Bruno H Stricker
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands and Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands and Department of Medical Informatics, Erasmus Medical Center, Rotterdam, The Netherlands and Inspectorate of Health Care, The Hague, The Netherlands
| | - Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Peter N Buhre
- Star Medical Diagnostic Center, Rotterdam, The Netherlands
| | - Judith AM Wessels
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tom Schalekamp
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Saskia le Cessie
- Department of Medical Statistics & Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands and Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Felix JM van der Meer
- Department of Thrombosis & Hemostasis, Leiden University Medical Center, Leiden, The Netherlands and Medial, Medical-Diagnostic Laboratories, Hoofddorp, The Netherlands
| | - Frits R Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands and Department of Thrombosis & Hemostasis, Leiden University Medical Center, Leiden, The Netherlands
| | - Anthonius de Boer
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Anke-Hilse Maitland-van der Zee
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, PO Box 80 082, 3508 TB, Utrecht, The Netherlands
| | - Loes E Visser
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands and Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands and Department of Hospital Pharmacy, Erasmus Medical Center, Rotterdam, The Netherlands
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15
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Della-Morte D, Guadagni F, Palmirotta R, Testa G, Caso V, Paciaroni M, Abete P, Rengo F, Ferroni P, Sacco RL, Rundek T. Genetics of ischemic stroke, stroke-related risk factors, stroke precursors and treatments. Pharmacogenomics 2012; 13:595-613. [DOI: 10.2217/pgs.12.14] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Stroke remains a leading cause of death worldwide and the first cause of disability in the western world. Ischemic stroke (IS) accounts for almost 80% of the total cases of strokes and is a complex and multifactorial disease caused by the combination of vascular risk factors, environment and genetic factors. Investigations of the genetics of atherosclerosis and IS has greatly enhanced our knowledge of this complex multifactorial disease. In this article we sought to review common single-gene disorders relevant to IS, summarize candidate gene and genome-wide studies aimed at discovering genetic stroke risk factors and subclinical phenotypes, and to briefly discuss pharmacogenetics related to stroke treatments. Genetics of IS is, in fact, one of the most promising research frontiers and genetic testing may be helpful for novel drug discoveries as well as for appropriate drug and dose selection for treatment of patients with cerebrovascular disease.
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Affiliation(s)
- David Della-Morte
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
- Department of Laboratory Medicine & Advanced Biotechnologies, IRCCS San Raffaele Pisana, 00163 Rome, Italy
| | - Fiorella Guadagni
- Department of Laboratory Medicine & Advanced Biotechnologies, IRCCS San Raffaele Pisana, 00163 Rome, Italy
| | - Raffaele Palmirotta
- Department of Laboratory Medicine & Advanced Biotechnologies, IRCCS San Raffaele Pisana, 00163 Rome, Italy
| | - Gianluca Testa
- Department of Clinical Medicine, Cardiovascular Science & Immunology, Cattedra di Geriatria, University of Naples Federico II, Naples, Italy
- Department of Health Sciences, University of Molise, Campobasso, Italy
| | - Valeria Caso
- Stroke Unit & Division of Cardiovascular Medicine, University of Perugia, 06126 Perugia, Italy
| | - Maurizio Paciaroni
- Stroke Unit & Division of Cardiovascular Medicine, University of Perugia, 06126 Perugia, Italy
| | - Pasquale Abete
- Department of Clinical Medicine, Cardiovascular Science & Immunology, Cattedra di Geriatria, University of Naples Federico II, Naples, Italy
| | - Franco Rengo
- Department of Clinical Medicine, Cardiovascular Science & Immunology, Cattedra di Geriatria, University of Naples Federico II, Naples, Italy
| | - Patrizia Ferroni
- Department of Laboratory Medicine & Advanced Biotechnologies, IRCCS San Raffaele Pisana, 00163 Rome, Italy
| | - Ralph L Sacco
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Tatjana Rundek
- Department of Neurology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
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16
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Hofman A, van Duijn CM, Franco OH, Ikram MA, Janssen HLA, Klaver CCW, Kuipers EJ, Nijsten TEC, Stricker BHC, Tiemeier H, Uitterlinden AG, Vernooij MW, Witteman JCM. The Rotterdam Study: 2012 objectives and design update. Eur J Epidemiol 2011; 26:657-86. [PMID: 21877163 PMCID: PMC3168750 DOI: 10.1007/s10654-011-9610-5] [Citation(s) in RCA: 263] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 08/08/2011] [Indexed: 01/09/2023]
Abstract
The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in over a 1,000 research articles and reports (see www.erasmus-epidemiology.nl/rotterdamstudy ). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.
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Affiliation(s)
- Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands.
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17
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Mahajan P, Meyer KS, Wall GC, Price HJ. Clinical applications of pharmacogenomics guided warfarin dosing. Int J Clin Pharm 2011; 33:10-9. [PMID: 21365388 DOI: 10.1007/s11096-011-9486-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 10/11/2010] [Indexed: 12/26/2022]
Abstract
AIM OF THE REVIEW To assess the state of the literature concerning pharmacogenomic testing in patients requiring vitamin K antagonists, specifically warfarin. METHOD We conducted a literature search of MEDLINE and International Pharmaceutical Abstracts using the following words: warfarin, pharmacogenetic, and pharmacogenomic. The search results were reviewed by the authors and papers concerning pharmacogenomic testing in warfarin dosing were procured and reviewed. Additionally bibliographies of papers procured were also examined for other studies. The authors focused on clinical trials concerning the use of pharmacogenomic testing in warfarin dosing. RESULTS Although numerous studies have demonstrated that a significant portion of warfarin dosing variability can be explained by genetic polymorphisms, few prospective studies have been conducted that examine the integration of this information in practical dosing situations. Those that have, have shown that using pharmacogenomic information improves initial dosing estimates and decreases the need for frequent clinic visits and laboratory testing. Data showing a reduction in serious bleeding events is sparse. Cost-effectiveness analyses have generally shown a small but positive effect with pharmacogenomic testing in patients receiving warfarin. CONCLUSION Several studies have shown that pharmacogenomic testing for warfarin dosing is more accurate that other dosing schemes. Pharmacogenomic testing improves time to a therapeutic international normalized ratio while requiring fewer dosing adjustments. Patients who require higher or lower than usual doses seem to benefit the most. The cost-effectiveness of pharmacogenomic testing as well as preventing of outcomes such as bleeding or thrombosis are not yet elucidated. Pharmacists, especially those in a community setting can play a role in this new technology by educating prescribers and patients concerning pharmacogenomic testing, and by developing and using dosing protocols that incorporate its use.
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Affiliation(s)
- Pramod Mahajan
- College of Pharmacy and Health Sciences, Drake University, 2507 University Ave, Des Moines, IA 50310, USA
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18
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López-Cuenca A, Marín F, Roldán V, González-Conejero R, Hernández-Romero D, Valdés M, Lip GYH. Genetic polymorphisms and atrial fibrillation: Insights into the prothrombotic state and thromboembolic risk. Ann Med 2010; 42:562-75. [PMID: 20681943 DOI: 10.3109/07853890.2010.507601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The pathophysiology of thromboembolism in atrial fibrillation (AF) is a multifactorial and complex process. Abnormalities of haemostasis, fibrinolysis, endothelium, and platelets have all been described in AF. This prothrombotic state observed in AF appears to be additive to the presence of clinical and echocardiography risk factors for thromboembolism. Nonetheless, the precise mechanistic pathway(s) leading to the prothrombotic state in AF remain to be elucidated. Of note, there are limited data on the influence of genetic polymorphisms in thromboembolic risk associated with AF. On the other hand, the response to coumarin derivatives depends on several factors, such as sex, age, diet, or interacting drugs. Optimal anticoagulation control is usually hampered by significant interindividual variability in dose requirements for a given target level of anticoagulation. There is increasing evidence that interindividual sensitivity and side-effects to coumarinics may be largely determined genetically. Thus, genetic polymorphisms could explain the individual risk of developing an adverse drug reaction (bleeding) or drug inefficacy (thrombosis) with oral anticoagulation. In this article, we provide an overview of the limited data about the possible influence of genetic polymorphisms on thromboembolic risk in AF, as well as the genetic influences on anticoagulant drug responsiveness.
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Affiliation(s)
- Angel López-Cuenca
- Department of Cardiology, Hospital Universitario Virgen Arrixaca, Murcia, Spain
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19
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Geisen C, Luxembourg B, Watzka M, Toennes SW, Sittinger K, Marinova M, von Ahsen N, Lindhoff-Last E, Seifried E, Oldenburg J. Prediction of phenprocoumon maintenance dose and phenprocoumon plasma concentration by genetic and non-genetic parameters. Eur J Clin Pharmacol 2010; 67:371-381. [PMID: 21110013 PMCID: PMC3291838 DOI: 10.1007/s00228-010-0950-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 10/31/2010] [Indexed: 11/25/2022]
Abstract
Purpose The anticoagulation response to vitamin K antagonists is characterised by high inter-individual variability. The impact of single nucleotide polymorphisms (SNPs) in several genes of enzymes involved in the vitamin K cycle on phenprocoumon dose variability and phenprocoumon plasma concentrations is still under investigation. Methods We assessed the influence of VKORC1 c.-1639G>A, CYP2C9*2, CYP2C9*3, CYP4F2 c.1297G>A, CALU c.*4A>G, EPHX1 c.337T>C, GGCX c.214+597G>A, F7 c.-402G>A, F7 c.-401G>T, PROC c.-228C>T and PROC c.-215G>A along with clinical and demographic parameters on steady-state phenprocoumon therapy in 75 patients. A prediction model was developed for total phenprocoumon plasma concentrations and daily phenprocoumon doses required for therapeutic anticoagulation. Results The VKORC1 c.-1639 genotype was the main predictor of the phenprocoumon daily dose (adjusted R2 = 37.6%) and the total phenprocoumon concentration (adjusted R2 = 38.3%). CYP2C9 affected the phenprocoumon concentration, but not the dose requirements. SNPs in the other genes of the vitamin K cycle, concomitant medication, nicotine use and alcohol consumption did not predict phenprocoumon concentrations and phenprocoumon dose requirements in a multiple linear regression model. Phenprocoumon concentrations were predicted by VKORC1 c.-1639, CYP2C9 genotype, age and BMI. The final prediction model for the daily phenprocoumon dose requirements comprised VKORC1 c.-1639 genotype, age and height accounting for 48.6% of the inter-individual variability. Conclusions A rough prediction of phenprocoumon maintenance doses can be achieved by a limited set of parameters (VKORC1, age, height). The investigated SNPs in CYP4F2, CALU, EPHX1, GGCX, F7, and PROC did not improve the predictive value of a pharmacogenetic-based dosing equation for phenprocoumon.
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Affiliation(s)
- Christof Geisen
- German Red Cross, Institute of Transfusion Medicine and Immunohaematology, University Hospital Frankfurt, Frankfurt, Germany
| | - Beate Luxembourg
- German Red Cross, Institute of Transfusion Medicine and Immunohaematology, University Hospital Frankfurt, Frankfurt, Germany
- Department of Internal Medicine, Division of Vascular Medicine and Haemostaseology, University Hospital Frankfurt, Frankfurt, Germany
| | - Matthias Watzka
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Stefan W Toennes
- Institute of Legal Medicine, University Hospital Frankfurt, Frankfurt, Germany
| | - Katja Sittinger
- German Red Cross, Institute of Transfusion Medicine and Immunohaematology, University Hospital Frankfurt, Frankfurt, Germany
| | - Milka Marinova
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany
| | - Nicolas von Ahsen
- Department of Clinical Chemistry, University of Göttingen, Göttingen, Germany
| | - Edelgard Lindhoff-Last
- Department of Internal Medicine, Division of Vascular Medicine and Haemostaseology, University Hospital Frankfurt, Frankfurt, Germany
| | - Erhard Seifried
- German Red Cross, Institute of Transfusion Medicine and Immunohaematology, University Hospital Frankfurt, Frankfurt, Germany
| | - Johannes Oldenburg
- German Red Cross, Institute of Transfusion Medicine and Immunohaematology, University Hospital Frankfurt, Frankfurt, Germany.
- Institute of Experimental Haematology and Transfusion Medicine, University Hospital Bonn, Bonn, Germany.
- Institute of Experimental Haematology and Transfusion Medicine, University Clinic Bonn, Sigmund-Freud-Strasse 25, Bonn, Germany.
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20
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Mahajan P, Meyer KS, Wall GC, Price HJ. Clinical applications of pharmacogenomics guided warfarin dosing. Int J Clin Pharm 2010; 35:359-68. [DOI: 10.1007/s11096-010-9448-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 10/11/2010] [Indexed: 12/28/2022]
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21
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Piatkov I, Rochester C, Jones T, Boyages S. Warfarin toxicity and individual variability-clinical case. Toxins (Basel) 2010; 2:2584-92. [PMID: 22069565 PMCID: PMC3153177 DOI: 10.3390/toxins2112584] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Revised: 10/21/2010] [Accepted: 10/27/2010] [Indexed: 11/16/2022] Open
Abstract
Warfarin is a widely used anticoagulant in the treatment and prevention of thrombosis, in the treatment for chronic atrial fibrillation, mechanical valves, pulmonary embolism, and dilated cardiomyopathy. It is tasteless and colorless, was used as a poison, and is still marketed as a pesticide against rats and mice. Several long-acting warfarin derivatives-superwarfarin anticoagulants-such as brodifacoum, diphenadione, chlorophacinone, bromadiolone, are used as pesticides and can produce profound and prolonged anticoagulation. Several factors increase the risk of warfarin toxicity. However, polymorphisms in cytochrome P450 genes and drug interactions account for most of the risk for toxicity complications. Each person is unique in their degree of susceptibility to toxic agents. The toxicity interpretation and the health risk of most toxic substances are a subject of uncertainty. Genetically determined low metabolic capacity in an individual can dramatically alter the toxin and metabolite levels from those normally expected, which is crucial for drugs with a narrow therapeutic index, like warfarin. Personalized approaches in interpretation have the potential to remove some of the scientific uncertainties in toxicity cases.
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Affiliation(s)
- Irina Piatkov
- Diversity Health Institute, DHI Laboratory, ICPMR level 2, Sydney-West Area Health Service, Westmead Hospital, Westmead, NSW 2145, Australia.
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22
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Gervasini G, Benítez J, Carrillo JA. Pharmacogenetic testing and therapeutic drug monitoring are complementary tools for optimal individualization of drug therapy. Eur J Clin Pharmacol 2010; 66:755-74. [PMID: 20582584 DOI: 10.1007/s00228-010-0857-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 06/02/2010] [Indexed: 01/08/2023]
Abstract
Genetic factors contribute to the phenotype of drug response, but the translation of pharmacogenetic outcomes into drug discovery, drug development or clinical practice has proved to be surprisingly disappointing. Despite significant progress in pharmacogenetic research, only a few drugs, such as cetuximab, dasatinib, maraviroc and trastuzumab, require a pharmacogenetic test before being prescribed. There are several gaps that limit the application of pharmacogenetics based upon the complex nature of the drug response itself. First, pharmacogenetic tests could be more clinically applicable if they included a comprehensive survey of variation in the human genome and took into account the multigenic nature of many phenotypes of drug disposition and response. Unfortunately, much of the existing research in this area has been hampered by limitations in study designs and the nonoptimal selection of gene variants. Secondly, although responses to drugs can be influenced by the environment, only fragmentary information is currently available on how the interplay between genetics and environment affects drug response. Third, the use of a pharmacogenetic test as a standard of care for drug therapy has to overcome significant scientific, economic, commercial, political and educational barriers, among others, in order for clinically useful information to be effectively communicated to practitioners and patients. Meanwhile, the lack of efficacy is in this process is quite as costly as drug toxicity, especially for very expensive drugs, and there is a widespread need for clinically and commercially robust pharmacogenetic testing to be applied. In this complex scenario, therapeutic drug monitoring of parent drugs and/or metabolites, alone or combined with available pharmacogenetic tests, may be an alternative or complementary approach when attempts are made to individualize dosing regimen, maximize drug efficacy and enhance drug safety with certain drugs and populations (e.g. antidepressants in older people).
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Affiliation(s)
- Guillermo Gervasini
- Department of Medical and Surgical Therapeutics, Division of Clinical Pharmacology, Medical School, University of Extremadura, 06071 Badajoz, Spain
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23
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Stamer UM, Zhang L, Stüber F. Personalized therapy in pain management: where do we stand? Pharmacogenomics 2010; 11:843-64. [DOI: 10.2217/pgs.10.47] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Genomic variations influencing response to pharmacotherapy of pain are currently under investigation. Drug-metabolizing enzymes represent a major target of ongoing research in order to identify associations between an individual’s drug response and genetic profile. Polymorphisms of the cytochrome P450 enzymes (CYP2D6) influence metabolism of codeine, tramadol, hydrocodone, oxycodone and tricyclic antidepressants. Blood concentrations of some NSAIDs depend on CYP2C9 and/or CYP2C8 activity. Genomic variants of these genes associate well with NSAIDs’ side effect profile. Other candidate genes, such as those encoding (opioid) receptors, transporters and other molecules important for pharmacotherapy in pain management, are discussed; however, study results are often equivocal. Besides genetic variants, further variables, for example, age, disease, comorbidity, concomitant medication, organ function as well as patients’ compliance, may have an impact on pharmacotherapy and need to be addressed when pain therapists prescribe medication. Although pharmacogenetics as a diagnostic tool has the potential to improve patient therapy, well-designed studies are needed to demonstrate superiority to conventional dosing regimes.
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Affiliation(s)
| | - Lan Zhang
- Department of Anaesthesiology & Intensive Care Medicine, Rheinische Friedrich-Wilhelms-Universität Bonn, Sigmund-Freud-Str. 25, 53105 Bonn, Germany
- Department of Anaesthesiology and Pain Therapy, Inselspital, University of Bern, Freiburgstr., CH-3010 Bern, Switzerland
| | - Frank Stüber
- Department of Anaesthesiology and Pain Therapy, Inselspital, University of Bern, Freiburgstr., CH-3010 Bern, Switzerland
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24
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Puehringer H, Loreth RM, Klose G, Schreyer B, Krugluger W, Schneider B, Oberkanins C. VKORC1 -1639G>A and CYP2C9*3 are the major genetic predictors of phenprocoumon dose requirement. Eur J Clin Pharmacol 2010; 66:591-8. [PMID: 20376629 DOI: 10.1007/s00228-010-0809-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
Abstract
PURPOSE Phenprocoumon, similar to other coumarin-derived anticoagulants, is associated with a large variation in the individual dose requirement to achieve stable anticoagulation. Polymorphisms in the vitamin K epoxide reductase complex subunit 1 (VKORC1) and the liver enzyme cytochrome P450 2C9 (CYP2C9) effectively account for the variability in warfarin and acenocoumarol response but are less well-defined pharmacogenetic predictors in phenprocoumon therapy. METHODS A retrospective study was performed on 185 outpatients attending anticoagulation clinics in Austria and Germany. These patients were genotyped for the VKORC1 -1639G>A and 3730G>A polymorphisms as well as for the CYP2C9 *2 and *3 polymorphisms using a reverse hybridisation-based teststrip assay. RESULTS The VKORC1 -1639A allele, which was present at a frequency of 41.4% in the study cohort, significantly reduced the mean weekly phenprocoumon dose by 3 mg (19%) in the heterozygous and by 6.7 mg (43%) in the homozygous state compared to wild-type carriers (15.5 +/- 6.8 mg, p < 0.0001). A stepwise multiple regression analysis revealed that VKORC1 -1639G>A, age and CYP2C9*3 were the major independent determinants of phenprocoumon dose, accounting for 14.2, 9.1 and 4.7% of its variability, respectively (p </= 0.0007). The CYP2C9*2 polymorphism had a marginal influence (1.4%) and failed to reach statistical significance (p = 0.062). The VKORC1 3730G>A genotype had no additional predictive power for individual dose variability. CONCLUSION Similar to warfarin and acenocoumarol, the VKORC1 -1639G>A polymorphism had the highest impact on the maintenance dose of phenprocoumon. The factor age was the second most important predictor and explained a greater percentage of the variability than CYP2C9 genotype.
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Affiliation(s)
- Helene Puehringer
- ViennaLab Diagnostics GmbH, Gaudenzdorfer Guertel 43-45, 1120, Vienna, Austria.
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25
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Marín F, González-Conejero R, Capranzano P, Bass TA, Roldán V, Angiolillo DJ. Pharmacogenetics in cardiovascular antithrombotic therapy. J Am Coll Cardiol 2009; 54:1041-57. [PMID: 19744613 DOI: 10.1016/j.jacc.2009.04.084] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Revised: 03/25/2009] [Accepted: 04/14/2009] [Indexed: 01/09/2023]
Abstract
Thrombosis is the most important underlying mechanism of coronary artery disease and embolic stroke. Hence, antithrombotic therapy is widely used in these scenarios. However, not all patients achieve the same degree of benefit from antithrombotic agents, and a considerable number of treated patients will continue to experience a new thrombotic event. Such lack of clinical benefit may be related to a wide variability of responses to antithrombotic treatment among individuals (i.e., interindividual heterogeneity). Several factors have been identified in this interindividual heterogeneity in response to antithrombotic treatment. Pharmacogenetics has emerged as a field that identifies specific gene variants able to explain the variability in patient response to a given drug. Polymorphisms affecting the disposition, metabolism, transporters, or targets of a drug all can be implicated in the modification of an individual's antithrombotic drug response and therefore the safety and efficacy of the aforementioned drug. The present paper reviews the modulating role of different polymorphisms on individuals' responses to antithrombotic drugs commonly used in clinical practice.
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Affiliation(s)
- Francisco Marín
- Department of Cardiology, Hospital Universitario Virgen de Arrixaca, Murcia, Spain
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26
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Teichert M, Eijgelsheim M, Rivadeneira F, Uitterlinden AG, van Schaik RHN, Hofman A, De Smet PAGM, van Gelder T, Visser LE, Stricker BHC. A genome-wide association study of acenocoumarol maintenance dosage. Hum Mol Genet 2009; 18:3758-68. [PMID: 19578179 DOI: 10.1093/hmg/ddp309] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Several genome-wide association studies have been performed on warfarin. For acenocoumarol, the most frequently used coumarin in many countries worldwide, pharmacodynamic influences are expected to be comparable. Pharmacokinetics however might differ. We aimed to confirm known or identify new genetic variants contributing to interindividual variation on stabilized acenocoumarol dosage by a GWAS. The index population consisted of 1451 Caucasian subjects from the Rotterdam study and results were replicated in 287 subjects from the Rotterdam study extended cohort. Both cohorts were genotyped on the Illumina 550K Human Map SNP array. From polymorphisms tested for association with acenocoumarol dosage, 35 single nucleotide polymorphisms (SNPs) on chromosome 16 and 18 SNPs on chromosome 10 reached genome-wide significance. The SNP with the lowest P-value was rs10871454 on chromosome 16 linked to SNPs within the vitamin K epoxide reductase complex subunit 1 (VKORC1) (P = 2.0 x 10(-123)). The lowest P-value on chromosome 10 was obtained by rs4086116 within cytochrome P450 2C9 (CYP2C9) (P = 3.3 x 10(-24)). After adjustment for these SNPs, the rs2108622 polymorphism within cytochrome P450 4F2 (CYP4F2) gene on chromosome 19 reached genome-wide significance (P = 2.0 x 10(-8)). On chromosome 10, we further identified genetic variation in the cytochrome P450 2C18 (CYP2C18) gene contributing to variance of acenocoumarol dosage. Thus we confirmed earlier findings that acenocoumarol dosage mainly depends on polymorphisms in the VKORC1 and CYP2C9 genes. Besides age, gender, body mass index and target INR, one polymorphism within each of the VKORC1, CYP2C9, CYP4F2 and CYP2C18 genes could explain 48.8% of acenocoumarol dosage variation.
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Affiliation(s)
- Martina Teichert
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
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Branco CC, Pereirinha T, Cabral R, Pacheco PR, Mota-Vieira L. Thrombotic genetic risk factors and warfarin pharmacogenetic variants in São Miguel's healthy population (Azores). Thromb J 2009; 7:9. [PMID: 19538716 PMCID: PMC2706804 DOI: 10.1186/1477-9560-7-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 06/18/2009] [Indexed: 11/26/2022] Open
Abstract
SUMMARY BACKGROUND The Azorean population presents the highest standardized mortality rate for cardiovascular diseases (CVD) when compared to mainland Portugal and other populations. Since thrombosis is a common cause of CVD, we assessed four polymorphisms in three thrombotic risk genes - F5 (G1691A), F2 (G20210A) and MTHFR (C677T, A1298C), in 469 healthy blood donors from São Miguel Island (Azores). We also analysed the CYP2C9 (C430T, A1075C) and VKORC1 (G1639A) variants in fifty-eight individuals with predisposition to thrombosis (possessing at least one variation in F5 or F2 genes and one in MTHFR) to evaluate their warfarin drug response genetic profiles. RESULTS Among the 469 individuals, the data showed that thrombotic risk allele frequencies - 1691A (4.9%), 20210A (1.8%), 677T (41.7%) and 1298C (24.8%) - were similar to other Caucasians, but significantly different from mainland Portuguese (chi2, p < 0.001). The combined analysis of these variants identified twenty-two different genetic profiles (genotype order: F5, F2, MTHFR C677T and A1298C). Complete homozygosity for all wild-type alleles (GG GG CC AA) was present in 11.7%, being GG GG CT AA (22.4%) the most frequent profile. The results also demonstrated that 12.4% (58 out of 469) of São Miguel islanders have increased genetic predisposition to thrombosis. Subsequently, we evaluated these individuals for their warfarin response genetic profiles. The data showed that seven out of fifty-eight individuals are poor metabolizers (two with CYP2C9*2/*2 and five with CYP2C9*2/*3 genotypes). VKORC1 polymorphism analysis identified twelve individuals (20.7%) with AA genotype, who probably will require lower doses of warfarin. The joint analysis of CYP2C9 and VKORC1 revealed that 79.3% (46 out of 58) of the individuals carry at least one polymorphism in these genes. Within these, twenty-five individuals (43.1%) need intermediate and/or low doses of warfarin, if treatment is started. CONCLUSION The present study demonstrated, for the first time, that São Miguel, and possibly the Azores population, shows significant differences on allele frequencies of thrombotic risk factors when compared to mainland Portugal. This research constitutes a primary approach for future studies on CVD, as well as for the implementation of warfarin dosing protocols using the patient's genotypic information.
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Affiliation(s)
- Claudia C Branco
- Molecular Genetics and Pathology Unit, Hospital of Divino Espirito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Tânia Pereirinha
- Molecular Genetics and Pathology Unit, Hospital of Divino Espirito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal
| | - Rita Cabral
- Molecular Genetics and Pathology Unit, Hospital of Divino Espirito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Paula R Pacheco
- Molecular Genetics and Pathology Unit, Hospital of Divino Espirito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Luisa Mota-Vieira
- Molecular Genetics and Pathology Unit, Hospital of Divino Espirito Santo of Ponta Delgada, EPE, São Miguel Island, Azores, Portugal
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
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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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Genotypes Associated With Reduced Activity of VKORC1 and CYP2C9 and Their Modification of Acenocoumarol Anticoagulation During the Initial Treatment Period. Clin Pharmacol Ther 2009; 85:379-86. [DOI: 10.1038/clpt.2008.294] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hofman A, Breteler MMB, van Duijn CM, Janssen HLA, Krestin GP, Kuipers EJ, Stricker BHC, Tiemeier H, Uitterlinden AG, Vingerling JR, Witteman JCM. The Rotterdam Study: 2010 objectives and design update. Eur J Epidemiol 2009; 24:553-72. [PMID: 19728115 PMCID: PMC2744826 DOI: 10.1007/s10654-009-9386-z] [Citation(s) in RCA: 201] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 08/19/2009] [Indexed: 12/19/2022]
Abstract
The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric and respiratory diseases. As of 2008, 14,926 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in close to a 1,000 research articles and reports (see www.epib.nl/rotterdamstudy). This article gives the rationale of the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.
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Affiliation(s)
- Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, PO Box 2040, 3000 CA Rotterdam. The Netherlands.
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Markatos CN, Grouzi E, Politou M, Gialeraki A, Merkouri E, Panagou I, Spiliotopoulou I, Travlou A. VKORC1 and CYP2C9 allelic variants influence acenocoumarol dose requirements in Greek patients. Pharmacogenomics 2008; 9:1631-8. [DOI: 10.2217/14622416.9.11.1631] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Aim: To identify the frequencies of the polymorphisms CYP2C9*2, CYP2C9*3 and VKORC1-1639 G>A in the Greek population and investigate whether these polymorphisms and patient demographics (age, sex and comedication) could explain the interindividual variability of acenocoumarol dose requirements for efficient anticoagulation. Materials & methods: CYP2C9*2 (Arg144Cys), CYP2C9*3 (Ile359Leu) and VKORC1–1639G>A allelic variants were analyzed in 98 patients treated with acenocoumarol. Results: Allelic frequencies of CYP2C9*2, CYP2C9*3 and VKORC1A were found to be 0.155, 0.075 and 0.485, respectively. Carriership of at least one CYP2C9*3 allele led to the most pronounced reduction in the required mean dose (p < 0.0001). In contrast, the CYP2C9*2 allele played a minor role (p = 0.3). VKORC1 A/A patients needed approximately a third of the dose required by wild-type patients to achieve the target INR (p < 0.0001). Age was the only demographical factor significantly affecting acenocoumarol dose (p < 0.0001). In a multivariable regression model, CYP2C9, VKORC1 genotypes and age explained 55% of acenocoumarol dosing variability. Conclusion: VKORC1-1639G>A, CYP2C9*2 and CYP2C9*3 polymorphisms were found to predispose to acenocoumarol sensitivity in Greeks. Other hereditary and nongenetic parameters must be incorporated in an individualized dosing algorithm to achieve a safer anticoagulant effect.
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Affiliation(s)
- Christos N Markatos
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
| | - Elissavet Grouzi
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
| | - Marianna Politou
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
| | - Argyri Gialeraki
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
| | - Efrosyni Merkouri
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
| | | | | | - Anthi Travlou
- ATTIKON University General Hospital, 23–27 Makrigianni Street, 11742 Athens, Greece
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Ufer M, Kammerer B, Kahlich R, Kirchheiner J, Yasar U, Brockmöller J, Rane A. Genetic polymorphisms of cytochrome P450 2C9 causing reduced phenprocoumon (S)-7-hydroxylationin vitroandin vivo. Xenobiotica 2008; 34:847-59. [PMID: 15742978 DOI: 10.1080/00498250400009197] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The effect of cytochrome P450 (CYP) 2C9 polymorphisms on the stereoselective biotransformation of the oral anticoagulant phenprocoumon (PPC) to inactive, monohydroxylated metabolites was studied in vitro and in vivo. In human liver microsomes, the (S)-7-hydroxylation--being the major metabolic pathway--was significantly compromised in a gene-dose-dependent manner in samples expressing the CYP2C9*2 or CYP2C9*3 allele. The CYP2C9*3/*3 genotype corresponded to an almost fourfold lower (S)-7-hydroxylation rate than CYP2C9*1/*1 (wild-type). The intrinsic clearance of human recombinant CYP2C9*2 and CYP2C9*3 for the (S)-7-hydroxylation was 28.9 and 50.9% lower than of CYP2C9*1, respectively. The area under the plasma concentration-time curve (AUC) of PPC metabolites after oral intake of 12 mg racemic PPC was significantly lower in volunteers expressing the CYP2C9*2 or CYP2C9*3 allele. Increasing plasma AUC metabolic ratios (parent compound/metabolite) in CYP2C9*2 and CYP2C9*3 variant allele carriers were found for each hydroxylation reaction and the CYP2C9*3/*3 genotype corresponded to an about 10-fold higher metabolic ratio of PPC (S)-7-hydroxylation relative to CYP2C9*1/*1. CYP2C9 polymorphisms cause a markedly compromised PPC (S)-7-hydroxylation. However, PPC metabolism appears overall less influenced by CYP2C9 genotype compared with other oral anticoagulants and it may thus be a valuable alternative for therapeutic anticoagulation of patients expressing CYP2C9 variant alleles.
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Affiliation(s)
- M Ufer
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Spreafico M, Lodigiani C, van Leeuwen Y, Pizzotti D, Rota LL, Rosendaal FR, Mannucci PM, Peyvandi F. Effects of CYP2C9 and VKORC1 on INR variations and dose requirements during initial phase of anticoagulant therapy. Pharmacogenomics 2008; 9:1237-50. [DOI: 10.2217/14622416.9.9.1237] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Introduction: Anticoagulants of the coumarin type are effective drugs for the treatment and prevention of thromboembolic diseases. However, they have a narrow therapeutic range and show inter- and intra-individual variability in dose requirement, largely conditioned by both environmental and genetic factors. Methods: This prospective study investigated, during the initial phase of acenocoumarol therapy, the effect of CYP2C9 variant alleles and VKORC1 haplotypes, single and in combination, in 220 Italians. Results: CYP2C9*3 was associated with a 25% dose reduction and an increased risk of over-anticoagulation (International Normalized Ratio [INR] > 6) on day 4. Two copies of the VKORC1*2 haplotype were associated with a 45% dose reduction and an increased risk of over-anticoagulation. Homozygosity for VKORC1*3 and VKORC1*4 was associated with an increased dose requirement and a reduced risk of over-anticoagulation. The VKORC1*3 or *4 plus CYP2C9*1 genotype combination was associated with the highest dose requirement and the lowest INR on day 4; VKORC1*2 plus CYP2C9*3 was associated with the lowest dose requirement, the highest INR and an increased risk of over-anticoagulation. Even though they spent approximately 50% of the time within the target therapeutic range, VKORC1*3 or *4 plus CYP2C9*1 carriers spent a large percentage of the remaining time below and carriers of VKORC1*2 plus CYP2C9*3 above the target range. Discussion: The determination of VKORC1*3 and VKORC1*4 haplotypes may be an important addition to CYP2C9 and VKORC1*2 genotyping to identify patients at risk of being outside the target range during initial anticoagulation with acenocoumarol.
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Affiliation(s)
- Marta Spreafico
- A Bianchi Bonomi Hemophilia and Thrombosis Center, University of Milan and Department of Medicine and Medical Specialties, IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, via Pace 9, 20122 Milan, Italy
| | - Corrado Lodigiani
- Thrombosis Center, IRCCS Istituto Clinico Humanitas, Italy, via Manzoni, 56, 20089 Rozzano, Milan, Italy
| | - Y van Leeuwen
- Department of Clinical Epidemiology, Leiden University Medical Center, and Einthoven Laboratory for Experimental Vascular Medicine, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Denise Pizzotti
- Department of Transfusional Medicine Hematology, SIMT, S.Paolo Hospital, Via Di Rudini’ Antonio, 20142 Milan, Italy
| | - Lidia L Rota
- Thrombosis Center, IRCCS Istituto Clinico Humanitas, Italy, via Manzoni, 56, 20089 Rozzano, Milan, Italy
| | - FR Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, and Einthoven Laboratory for Experimental Vascular Medicine, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Pier M Mannucci
- A Bianchi Bonomi Hemophilia and Thrombosis Center, University of Milan and Department of Medicine and Medical Specialties, IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, via Pace 9, 20122 Milan, Italy
| | - Flora Peyvandi
- A Bianchi Bonomi Hemophilia and Thrombosis Center, University of Milan and Department of Medicine and Medical Specialties, IRCCS Maggiore Hospital, Mangiagalli and Regina Elena Foundation, via Pace 9, 20122 Milan, Italy
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Evidence for a pharmacogenetic adapted dose of oral anticoagulant in routine medical practice. Eur J Clin Pharmacol 2008; 64:953-60. [DOI: 10.1007/s00228-008-0542-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Accepted: 07/08/2008] [Indexed: 01/31/2023]
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Dependency of phenprocoumon dosage on polymorphisms in the VKORC1 and CYP2C9 genes. J Thromb Thrombolysis 2008; 28:211-4. [DOI: 10.1007/s11239-008-0252-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2008] [Accepted: 07/01/2008] [Indexed: 11/25/2022]
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Ruaño G, Thompson PD, Villagra D, Bower B, Kocherla M, Yazdanpanah G, Seip RL, Windemuth A, White CM, Duconge J, Holford TR, Wu AH. High carrier prevalence of combinatorial CYP2C9 and VKORC1 genotypes affecting warfarin dosing. Per Med 2008; 5:225-232. [PMID: 29783498 DOI: 10.2217/17410541.5.3.225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BACKGROUND Polymorphisms in the cytochrome P450 2C9 (CYP2C9) and vitamin K epoxide reductase complex subunit 1 (VKORC1) genes significantly alter the effective warfarin dose. The CYP2C9*2 (430C>T), CYP2C9*3 (1075A>C) and VKORC1 -1639 G>A polymorphisms affect warfarin dose through altered metabolism (CYP2C9) and sensitivity (VKORC1). OBJECTIVE We determined the frequencies of SNPs in the CYP2C9 and VKORC1 genes in a clinical outpatient population and the carrier prevalences for a variety of genotype combinations to gauge the impact of these polymorphisms on warfarin dosage using published algorithms. METHOD A total of 127 patients from an outpatient clinic at Hartford Hospital (Hartford, CT, USA) were genotyped for five SNPs in the CYP2C9 gene and seven SNPs in the VKORC1 gene using Luminex® technology. RESULTS The polymorphism frequencies were 10.2, 7.9 and 37.4% for the functionally deficient CYP2C9*2, CYP2C9*3 and VKORC1 -1639 G>A polymorphisms, respectively. Combining prevalence of combinatorial genotypes, 18% were carriers of both CYP2C9 and VKORC1 polymorphisms, 13% were CYP2C9 polymorphism carriers only, 42.5% were VKORC1 carriers only, and the remaining 27% were noncarriers for either gene. Based on published warfarin dosing algorithms, carriers of 1, 2, 3 and 4 functionally deficient polymorphisms predict reductions of 1.0 to 1.6, 2.0 to 2.9, 2.9 to 3.7, and 3.6 to 4.4 mg/day, respectively, in warfarin dose. CONCLUSION Overall, 73% of the population carried at least one polymorphism predicting deficient warfarin metabolism or responsiveness and 18% were carriers for polymorphisms in both genes studied. Combinatorial genotyping of CYP2C9 and VKORC1 can allow for individualized dosing of warfarin amongst patients with gene polymorphisms potentially reducing the risk of accentuated responses and bleeding.
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Affiliation(s)
| | - Paul D Thompson
- Department of Cardiology, Hartford Hospital, Hartford, CT 06102-5037 USA
| | - David Villagra
- Genomas, Inc., 67 Jefferson St., Hartford CT 06106, USA.
| | - Bruce Bower
- Genomas, Inc., 67 Jefferson St., Hartford CT 06106, USA.
| | - Mohan Kocherla
- Genomas, Inc., 67 Jefferson St., Hartford CT 06106, USA.
| | | | - Richard L Seip
- Genomas, Inc., 67 Jefferson St., Hartford CT 06106, USA. .,Department of Cardiology, Hartford Hospital, Hartford, CT 06102-5037 USA
| | | | - C Michael White
- Department of Cardiology, Hartford Hospital, Hartford, CT 06102-5037 USA
| | - Jorge Duconge
- School of Pharmacy, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
| | - Theodore R Holford
- Department of Biostatistics, Yale University School of Medicine, New Haven, CT, USA
| | - Alan Hb Wu
- University of California, San Francisco, Department of Laboratory Medicine, Clinical Chemistry Laboratory, San Francisco General Hospital; 1001 Portero Avenue, San Francisco, CA 94110, USA
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The relationship between maintenance dosages of three vitamin K antagonists: acenocoumarol, warfarin and phenprocoumon. Thromb Res 2008; 123:225-30. [PMID: 18407321 DOI: 10.1016/j.thromres.2008.01.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Revised: 01/09/2008] [Accepted: 01/27/2008] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Vitamin K antagonists of the coumarin type are widely used oral anticoagulants. OBJECTIVE We developed a transition algorithm for the maintenance dosages of three frequently used coumarins: warfarin, phenprocoumon and acenocoumarol. METHODS The study was conducted at the Leiden Anticoagulation Clinic. Patients were participants in a trial of which the main objective was to compare the quality of an oral anticoagulant therapy with phenprocoumon to warfarin. We included patients who initiated oral anticoagulant therapy and patients who were already using acenocoumarol. Patients were randomized to a treatment with warfarin or phenprocoumon. Patients who were randomized to warfarin switched to phenprocoumon at the end of follow-up. We analysed the switch from acenocoumarol to warfarin or phenprocoumon at the start of follow-up and the switch of warfarin to phenprocoumon at the end of follow-up and calculated the transition factors for stable anticoagulation between these three vitamin K antagonists. RESULTS Fifty-eight patients switched from warfarin to phenprocoumon, 39 from acenocoumarol to phenprocoumon and 44 from acenocoumarol to warfarin. The maintenance dose of warfarin was 0.41 (95%CI 0.39-0.43) times the maintenance dose of phenprocoumon. The transition factor between acenocoumarol and phenprocoumon was 0.84 (95%CI 0.79-0.89) and between acenocoumarol and warfarin 1.85 (95%CI 1.78-1.92). CONCLUSIONS We determined the transition factors between warfarin, phenprocoumon and acenocoumarol. With these transition factors physicians are able to estimate the maintenance dose when it is necessary for a patient to switch from one coumarin to the other.
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Saraeva RB, Paskaleva ID, Doncheva E, Eap CB, Ganev V. Pharmacogenetics of acenocoumarol: CYP2C9, CYP2C19, CYP1A2, CYP3A4, CYP3A5 and ABCB1 gene polymorphisms and dose requirements. J Clin Pharm Ther 2007; 32:641-9. [DOI: 10.1111/j.1365-2710.2007.00870.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Hofman A, Breteler MMB, van Duijn CM, Krestin GP, Pols HA, Stricker BHC, Tiemeier H, Uitterlinden AG, Vingerling JR, Witteman JCM. The Rotterdam Study: objectives and design update. Eur J Epidemiol 2007; 22:819-29. [PMID: 17955331 PMCID: PMC2071967 DOI: 10.1007/s10654-007-9199-x] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Accepted: 10/05/2007] [Indexed: 01/01/2023]
Abstract
The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in the Netherlands. The study targets cardiovascular, neurological, ophthalmological and endocrine diseases. As of 2008 about 15,000 subjects aged 45 years or over comprise the Rotterdam Study cohort. The findings of the Rotterdam Study have been presented in some 600 research articles and reports (see http://www.epib.nl/rotterdamstudy). This article gives the reasons for the study and its design. It also presents a summary of the major findings and an update of the objectives and methods.
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Affiliation(s)
- Albert Hofman
- Department of Epidemiology & Biostatistics, Erasmus Medical Center, Rotterdam, The Netherlands.
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Gage BF, Lesko LJ. Pharmacogenetics of warfarin: regulatory, scientific, and clinical issues. J Thromb Thrombolysis 2007; 25:45-51. [PMID: 17906972 DOI: 10.1007/s11239-007-0104-y] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Accepted: 08/30/2007] [Indexed: 12/14/2022]
Abstract
Using pharmacogenetics-based therapy, clinicians can estimate the therapeutic warfarin dose by genotyping patients for single nucleotide polymorphisms (SNPs) that affect warfarin metabolism or sensitivity. SNPs in the cytochrome P450 complex (CYP2C9) affect warfarin metabolism: patients who have the CYP2C9*2 and/or CYP2C9*3 variants metabolize warfarin slowly and are more likely to have an elevated International Normalized Ratio INR or to hemorrhage during warfarin initiation than patients without these variants. SNPs in vitamin K epoxide reductase (VKORC1) correlate with warfarin sensitivity. Patients who are homozygous for a common VKORC1 promoter polymorphism, -1639 G>A (also designated as VKOR 3673, haplotype A, or haplotype*2), are warfarin sensitive and typically require lower warfarin doses. By providing an estimate of the therapeutic warfarin dose, pharmacogenetics-based therapy may improve the safety of anticoagulant therapy. To improve drug safety, the FDA updates labels of previously approved drugs as new clinical and genetic evidence accrues. The labels of medical products serve to inform prescribers and patients about potential ways to improve the benefit/risk ratio and/or optimize doses of medical products. On August 16, 2007, the FDA updated the label of warfarin to include information on pharmacogenetic testing and to encourage, but not require, the use of this information in dosing individual patients initiating warfarin therapy. The FDA completed the label update in August 2007.
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Affiliation(s)
- Brian F Gage
- Washington University Medical Center, St Louis, MO 63110, USA.
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Swen JJ, Huizinga TW, Gelderblom H, de Vries EGE, Assendelft WJJ, Kirchheiner J, Guchelaar HJ. Translating pharmacogenomics: challenges on the road to the clinic. PLoS Med 2007; 4:e209. [PMID: 17696640 PMCID: PMC1945038 DOI: 10.1371/journal.pmed.0040209] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Pharmacogenomics is one of the first clinical applications of the postgenomic era. It promises personalized medicine rather than the established "one size fits all" approach to drugs and dosages. The expected reduction in trial and error should ultimately lead to more efficient and safer drug therapy. In recent years, commercially available pharmacogenomic tests have been approved by the Food and Drug Administration (FDA), but their application in patient care remains very limited. More generally, the implementation of pharmacogenomics in routine clinical practice presents significant challenges. This article presents specific clinical examples of such challenges and discusses how obstacles to implementation of pharmacogenomic testing can be addressed.
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Siguret V. Antivitamines K et pharmacogénétique: vers une meilleure compréhension de la variabilité individuelle de l'effet dose–réponse. ACTA ACUST UNITED AC 2007; 55:295-8. [PMID: 17611042 DOI: 10.1016/j.patbio.2007.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Vitamin K antagonists (VKA) are difficult to use because of a narrow therapeutic index and of a marked inter- and intra individual variability among patients in the required dosage. Beside well known demographic or environmental factors (advanced age, co-morbid conditions, acute illnesses, concomitant drugs, vitamin K intake), genetic single nucleotide polymorphisms (SNPs) have been identified as strongly affecting the maintenance dosage and its variability. First, SNPs of vitamin K epoxide reductase complex subunit-1 (VKORC1) gene have been identified, affecting the enzyme shown as one of the target of VKA. Secondly, SNPs of cytochrome P450 2C9 (CYP2C9) gene have been shown to decrease the catabolism of coumarin derivatives (acenocoumarol, warfarin). Several recent studies have shown that being carrier of at least one mutated allele of either VKORC1 or CYP2C9 (CYP2C9*2, CYP2C9*3) allele is associated with a hypersensitivity to VKA therapy, i.e. a lower maintenance dose. Moreover, it has been associated with an increased risk of over-anticoagulation, a longer time to achieve the maintenance dose and an increased risk of bleeding. Finally, the combined analysis of VKORC1 and CYP2C9 SNPs with age may account for more than 50% of the individual variability of the warfarin maintenance dosage. Predicting models of warfarin maintenance dosage taking into account these individual parameters are currently developed.
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Affiliation(s)
- V Siguret
- Service d'hématologie-hémostase, Inserm U765, faculté des sciences pharmaceutiques et biologiques, université Paris-Descartes (Paris-V), France.
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Tomalik-Scharte D, Lazar A, Fuhr U, Kirchheiner J. The clinical role of genetic polymorphisms in drug-metabolizing enzymes. THE PHARMACOGENOMICS JOURNAL 2007; 8:4-15. [PMID: 17549068 DOI: 10.1038/sj.tpj.6500462] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
For most drug-metabolizing enzymes (DMEs), the functional consequences of genetic polymorphisms have been examined. Variants leading to reduced or increased enzymatic activity as compared to the wild-type alleles have been identified. This review tries to define potential fields in the therapy of major medical conditions where genotyping (or phenotyping) of genetically polymorphic DMEs might be beneficial for drug safety or therapeutic outcome. The possible application of genotyping is discussed for depression, cardiovascular diseases and thromboembolic disorders, gastric ulcer, malignant diseases and tuberculosis. Some drugs used for relief of these ailments are metabolized with participation of genetically polymorphic DMEs including CYP2D6, CYP2C9, CYP2C19, thiopurine-S-methyltransferase, dihydropyrimidine dehydrogenase, uridine diphosphate glucuronosyltransferase and N-acetyltransferase type 2. Current evidence suggests that taking genetically determined metabolic capacities of DMEs into account has the potential to improve individual risk/benefit relationship. However, more prospective studies with clinical endpoints are needed before the paradigm of 'personalized medicine' based on DME variants can be established.
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Affiliation(s)
- D Tomalik-Scharte
- Department of Pharmacology, Clinical Pharmacology, University of Cologne, Köln, Germany.
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Parra D, Beckey NP, Stevens GR. The Effect of Acetaminophen on the International Normalized Ratio in Patients Stabilized on Warfarin Therapy. Pharmacotherapy 2007; 27:675-83. [PMID: 17461702 DOI: 10.1592/phco.27.5.675] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
STUDY OBJECTIVE To determine whether an interaction exists between acetaminophen and warfarin that alters the international normalized ratio (INR). DESIGN Prospective, randomized, double-blind, placebo-controlled trial. SETTING Anticoagulation clinic at a Veterans Affairs Medical Center. PATIENTS Thirty-six adult patients receiving warfarin with stable INRs, defined as two consecutive INRs at least 3 weeks apart that were within the therapeutic range. INTERVENTION Patients were randomly assigned to receive acetaminophen 1 g twice/day along with matching placebo twice/day (12 patients), acetaminophen 1 g 4 times/day (12 patients), or matching placebo 4 times/day (12 patients) for 4 weeks. MEASUREMENTS AND MAIN RESULTS The primary end point was the difference in mean INR between groups at weekly intervals. Secondary end points were the percentages of patients in each group with supratherapeutic (INR > or = 0.3 above the upper limit of their therapeutic range) or subtherapeutic (INR > or = 0.2 or 0.3 below the lower limit of their respective therapeutic range of 2.0-3.0 or 2.5-3.5) INRs, and the difference in mean serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels between groups at biweekly intervals. Slow enrollment and a preliminary observation that 15 patients experienced an elevated INR prompted early termination of the study. At week 2, the group receiving acetaminophen 2 g/day had a significantly higher mean INR versus the placebo group (p=0.01). At weeks 1, 2, and 3, the acetaminophen 4-g/day group had significantly higher mean INRs compared with those in the placebo group (p=0.04, p=0.01, p=0.01, respectively). In addition, 13 (54%) of 24 patients in the acetaminophen groups combined exceeded the upper limit of their therapeutic range by 0.3 or greater compared with only 2 (17%) of 12 patients in the placebo group. No statistically significant differences in serum ALT or AST levels between either acetaminophen group versus the placebo group were found at week 4; however, there was a statistically significant increase in mean ALT level at week 2 in the acetaminophen 4-g/day group versus the placebo group. CONCLUSION These findings support the existence of a clinically significant interaction between warfarin and daily use of acetaminophen 2-4 g, necessitating close monitoring of patients who receive this drug combination. Whether this interaction occurs when acetaminophen is taken in lower doses or is used sporadically requires further study.
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Affiliation(s)
- David Parra
- Section of Clinical Pharmacy, Patient Support Service, Department of Veterans Affairs Medical Center, West Palm Beach, Florida 33410-6400, USA.
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Schalekamp T, van Geest-Daalderop JHH, Kramer MHH, van Holten-Verzantvoort ATM, de Boer A. Coumarin anticoagulants and co-trimoxazole: avoid the combination rather than manage the interaction. Eur J Clin Pharmacol 2007; 63:335-43. [PMID: 17318526 PMCID: PMC1914266 DOI: 10.1007/s00228-007-0268-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Accepted: 01/18/2007] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The objective of our study was to examine the management of the interaction between acenocoumarol or phenprocoumon and several antibiotics by anticoagulation clinics and to compare the consequences of this interaction on users of co-trimoxazole with those for users of other antibiotics. METHODS A follow-up study was conducted at four anticoagulation clinics in The Netherlands. Data on measurements of the International Normalised Ratio (INR), application of a preventive dose reduction (PDR) of the coumarin anticoagulant, fever and time within or outside the therapeutic INR range were collected. RESULTS The study cohort consisted of 326 subjects. A PDR was given more often to users of co-trimoxazole PDR than to users of other antibiotics. The PDR in co-trimoxazole users resulted in a significantly reduced risk of both moderate overanticoagulation (INR >4.5) and severe overanticoagulation (INR >6.0) compared with no PDR, with odds ratios (ORs) of 0.06 [95% confidence interval (CI): 0.01-0.51] and 0.09 (95% CI: 0.01-0.92), respectively. In co-trimoxazole users without PDR, the risk of overanticoagulation was significantly increased compared with users of other antibiotics. All co-trimoxazole users spent significantly more time under the therapeutic INR range during the first 6 weeks after the course than users of other antibiotics. CONCLUSION PDR is effective in preventing overanticoagulation in co-trimoxazole users, but results in a significantly prolonged period of underanticoagulation after the course. Avoidance of concomitant use of co-trimoxazole with acenocoumarol or phenprocoumon seems to be a safer approach than management of the interaction between these drugs.
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Affiliation(s)
- Tom Schalekamp
- Division of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute of Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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Schalekamp T, Brassé BP, Roijers JFM, van Meegen E, van der Meer FJM, van Wijk EM, Egberts ACG, de Boer A. VKORC1 and CYP2C9 genotypes and phenprocoumon anticoagulation status: interaction between both genotypes affects dose requirement. Clin Pharmacol Ther 2006; 81:185-93. [PMID: 17192772 DOI: 10.1038/sj.clpt.6100036] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In a prospective follow-up study of the effects of VKORC1 and CYP2C9 genotypes on the anticoagulation status of patients, we assessed the CYP2C9 and the VKORC1 C1173T genotypes of patients during the initial 6 months of phenprocoumon treatment. We used linear regression models and Cox proportional hazard models to determine the effects of the VKORC1 and CYP2C9 genotypes on phenprocoumon dose requirements, overanticoagulation, and time to achieve stability. Allele frequencies of interest within the cohort (N=281) were 40.8% VKORC1 T-1173, 12.8% CYP2C9*2, and 6.9% CYP2C9*3. In patients with the VKORC1 CC genotype, carriers of a CYP2C9 polymorphism needed dosages that were nearly 30% lower than those for CYP2C9*1/*1 patients (P<0.001). In patients with a VKORC1 polymorphism, differences between carriers of a CYP2C9 polymorphism and CYP2C9*1/*1 were far smaller and largely not statistically significant. A larger part of the variability in dose requirement was explained by the VKORC1 genotype than by the CYP2C9 genotype (28.7% and 7.2%, respectively). Carriers of a combination of a CYP2C9 polymorphism and a VKORC1 polymorphism had a strongly increased risk of severe overanticoagulation (hazard ratio (HR) 7.20, P=0.002). Only carriers of a CYP2C9*2 allele had a decreased chance to achieve stability compared to CYP2C9*1/*1 patients (HR 0.61, P=0.004). In conclusion, the VKORC1 genotype modifies the effect of the CYP2C9 genotype on phenprocoumon dose requirements. A combination of polymorphisms of both genotypes is associated with a strongly increased risk of overanticoagulation, whereas delayed stabilization is mainly associated with the CYP2C9 genotype.
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Affiliation(s)
- T Schalekamp
- Division of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, The Netherlands.
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Gardiner SJ, Begg EJ. Pharmacogenetics, drug-metabolizing enzymes, and clinical practice. Pharmacol Rev 2006; 58:521-90. [PMID: 16968950 DOI: 10.1124/pr.58.3.6] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The application of pharmacogenetics holds great promise for individualized therapy. However, it has little clinical reality at present, despite many claims. The main problem is that the evidence base supporting genetic testing before therapy is weak. The pharmacology of the drugs subject to inherited variability in metabolism is often complex. Few have simple or single pathways of elimination. Some have active metabolites or enantiomers with different activities and pathways of elimination. Drug dosing is likely to be influenced only if the aggregate molar activity of all active moieties at the site of action is predictably affected by genotype or phenotype. Variation in drug concentration must be significant enough to provide "signal" over and above normal variation, and there must be a genuine concentration-effect relationship. The therapeutic index of the drug will also influence test utility. After considering all of these factors, the benefits of prospective testing need to be weighed against the costs and against other endpoints of effect. It is not surprising that few drugs satisfy these requirements. Drugs (and enzymes) for which there is a reasonable evidence base supporting genotyping or phenotyping include suxamethonium/mivacurium (butyrylcholinesterase), and azathioprine/6-mercaptopurine (thiopurine methyltransferase). Drugs for which there is a potential case for prospective testing include warfarin (CYP2C9), perhexiline (CYP2D6), and perhaps the proton pump inhibitors (CYP2C19). No other drugs have an evidence base that is sufficient to justify prospective testing at present, although some warrant further evaluation. In this review we summarize the current evidence base for pharmacogenetics in relation to drug-metabolizing enzymes.
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Affiliation(s)
- Sharon J Gardiner
- Department of Medicine, Christchurch School of Medicine, Private Bag 4345, Christchurch, New Zealand.
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Kirchheiner J, Seeringer A. Clinical implications of pharmacogenetics of cytochrome P450 drug metabolizing enzymes. Biochim Biophys Acta Gen Subj 2006; 1770:489-94. [PMID: 17113714 DOI: 10.1016/j.bbagen.2006.09.019] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2006] [Revised: 09/29/2006] [Accepted: 09/29/2006] [Indexed: 01/23/2023]
Abstract
For many drugs, pharmacogenetic polymorphisms are known affecting biotransformation and clinical outcome. The clinical importance of these variants depends on allele-frequency and the effect size of the clinical outcome parameters. Further, it depends on the therapeutic range of the drug which is affected, on predictability of drug response as well as on duration until onset of therapeutic efficacy. Consequences which arise from genotyping might be: adjustment of dose according to genotype, choice of therapeutic strategy or even choice of drug. In antidepressant drug treatment, most drugs are metabolized via the polymorphic cytochrome P450 enzyme CYP2D6. Huge differences in pharmacokinetic parameters have been consistently shown for many tricyclics, some SSRIs, and other antidepressant drugs whereas the effects on therapeutic efficacy and adverse events have been described controversially. In cardiovascular disease, oral anticoagulants, nonsteroidal anti-inflammatory drugs, oral hypoglycemic drugs and other drugs are affected by genetic polymorphisms of the cytochrome P450 drug metabolizing enzyme CYP2C9. Studies in patients or healthy volunteers revealed up to 10-fold differences in pharmacokinetic parameters due to genetic polymorphisms of CYP2C9. Pharmacogenetics based dose adjustments are one tool to individualize drug treatment according to genetic factors. They can be derived from pharmacokinetic data with the aim to obtain equal drug concentrations in each individual. Prospective validation of dose adjustments based on pharmacogenetics should be performed before routine application of such strategies. A controlled prospective clinical trial with one arm receiving genotype-based dose adjustments and the other arm receiving therapy as usual will elucidate the benefit of pharmacogenomics-based individualization of certain drug therapies.
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Affiliation(s)
- Julia Kirchheiner
- Department of Pharmacology of Natural Products and Clinical Pharmacology, University of Ulm, Helmholtzstr. 20, 89081 Ulm, Germany.
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Meyer zu Schwabedissen C, Mevissen V, Schmitz F, Woodruff S, Langebartels G, Rau T, Zerres K, Hoffmann R, Ortlepp JR. Obesity is associated with a slower response to initial phenprocoumon therapy whereas CYP2C9 genotypes are not. Eur J Clin Pharmacol 2006; 62:713-20. [PMID: 16847664 DOI: 10.1007/s00228-006-0158-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 05/10/2006] [Indexed: 10/24/2022]
Abstract
BACKGROUND Initiation of phenprocoumon therapy is associated with a variable individual response. The CYP2C9 genotype has been shown to influence the response to warfarin therapy, but such an effect on phenprocoumon therapy remains uncertain. METHOD Two hundred sixty hospital patients started on phenprocoumon were recruited for this study. Body mass index (BMI), waist and hip circumference, dietary habits, comorbidity, and comedication were initially assessed. A 5' exonuclease assay (TaqManR) was used to analyze the presence of five polymorphisms of the CYP2C9 gene in each of the study patients. Study endpoints included the time necessary to achieve the international normalized ratio (INR) target (INR >2) and the total drug amount required to attain target INR. For 250 of 260 patients, the subsequent required daily maintenance dose of phenprocoumon was also recorded. RESULTS Both the necessary time and total dose required to attain target INR correlated significantly with BMI. The leaner the patient, the shorter the required time interval [BMI <22 (n=31), 5.48+/-2.49 days; BMI 22-25 (n=70), 6.09+/-2.40; BMI 25-30 (n=113), 6.76+/-3.61; BMI >30 (n=46), 8.50+/-5.75; p=0.001] and the lower the required dosage until the therapeutic range was achieved [BMI <22 (n=31), 23.8+/-12.1 mg; BMI 22-25 (n=70), 25.9+/-11.4 mg; BMI 25-30 (n=113), 29.6+/-25.2; BMI >30 (n=46), 35.8+/-19.7; p=0.027]. Overweight and waist circumference as a surrogate marker for abdominal fat were also associated significantly with these two parameters. Moreover, obesity was associated with a lower body-weight-adjusted maintenance dosage. All CYP2C9 genotypes that were tested failed to reveal an association with individual response variability. CONCLUSION Patient obesity appears to directly correspond to the amount of phenprocoumon required during initiation of therapy. The CYP2C9 genotype was not shown to influence the necessary therapeutic dosage.
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