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Influence of Vitamin D Status on the Maintenance Dose of Warfarin in Patients Receiving Chronic Warfarin Therapy. Cardiol Ther 2022; 11:421-432. [PMID: 35718837 PMCID: PMC9381664 DOI: 10.1007/s40119-022-00268-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 05/30/2022] [Indexed: 11/02/2022] Open
Abstract
INTRODUCTION Considering the anticoagulant actions of vitamin D, we hypothesize that vitamin D status might affect the required dose of warfarin for maintaining the therapeutic international normalized ratio (INR). METHODS In a retrospective single-center cohort study, serum levels of 25-hydroxyvitamin D were assessed for 89 subjects receiving a stable dose of warfarin for 3 months or longer and had a stable INR between 2 and 3.5 for at least three consecutive visits. A warfarin sensitivity index (WSI), defined as the steady-state INR divided by the mean daily warfarin dose, was used for measuring the warfarin dose response. The relation between the serum level of 25-hydroxyvitamin D and WSI value and the difference in the mean WSI value between the subjects with different vitamin D status categories (sufficient, insufficient, and deficient) were assessed. RESULTS Twenty-one subjects had vitamin D deficiency, 43 had vitamin D insufficiency, and only 25 had normal levels of 25-hydroxyvitamin D. Based on the multiple linear regression analysis, there was a significant but weakly positive correlation between WSI and 25-hydroxyvitamin D serum levels, as the value of WSI increases by almost 0.0027434 for every unit increase in 25-hydroxyvitamin D serum level (p value = 0.041). Using one-way ANOVA analysis, there was a trend in a significant difference between the groups with different vitamin D status categories regarding the mean WSI value (F = 2.95, p value = 0.057), as subjects with sufficient vitamin D state compared to those with vitamin D deficiency had a higher WSI value. CONCLUSIONS Although the study's limitations limit our ability to draw definite conclusions, the present data suggest that in addition to other traditional factors, vitamin D status might also affect warfarin sensitivity and maintenance dose requirement. However, to more clearly explain this link, further studies with high involvement subjects are required.
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Michaud V, Dow P, Turgeon J. Illustrative and historic cases of phenoconversion. Am J Transl Res 2021; 13:13328-13335. [PMID: 35035679 PMCID: PMC8748136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/11/2021] [Indexed: 06/14/2023]
Abstract
Intersubject variability in drug response, whether related to efficacy or toxicity, is well recognized clinically. Over the years, drug selection from our pharmacologic armamentarium has moved from providers' preferred choices to more personalized treatments as clinicians' decisions are guided by data from clinical trials. Since the advent of more accessible and affordable pharmacogenomic (PGx) testing, the promise of precise pharmacotherapy has been made. Results have accumulated in the literature with numerous examples demonstrating the value of PGx to improve drug response or prevent drug toxicity. Unfortunately, limited availability of reimbursement policies has dampened the enthusiasm of providers and organizations. The clinical application of PGx knowledge remains difficult for most clinicians under real-world conditions in patients with numerous chronic conditions and polypharmacy. This may be due to phenoconversion, a condition where there is a discrepancy between the genotype-predicted phenotype and the observed phenotype. This condition complicates the interpretation of PGx results and may lead to inappropriate recommendations and clinical decision making. For this reason, regulatory agencies have limited the transfer of information from PGx laboratories directly to consumers, especially recommendations about the use of certain drugs. This mini-review presents cases (mexiletine, propafenone, clopidogrel, warfarin, codeine, procainamide) from historical observations where drug response was modified by phenoconversion. The cases illustrate, from decades ago, that we are still in great need of advanced clinical decision systems that cope with conditions associated with phenoconversion, especially in patients with polypharmacy.
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Affiliation(s)
- Veronique Michaud
- TRHC Precision Pharmacotherapy Research and Development Institute13485 Veterans Way, Suite 410, Orlando, FL 32827, USA
- Université de Montréal, Faculty of PharmacyMontreal, Quebec, H3T 1J4, Canada
| | - Pamela Dow
- TRHC Precision Pharmacotherapy Research and Development Institute13485 Veterans Way, Suite 410, Orlando, FL 32827, USA
| | - Jacques Turgeon
- TRHC Precision Pharmacotherapy Research and Development Institute13485 Veterans Way, Suite 410, Orlando, FL 32827, USA
- Université de Montréal, Faculty of PharmacyMontreal, Quebec, H3T 1J4, Canada
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Ndadza A, Muyambo S, Mntla P, Wonkam A, Chimusa E, Kengne AP, Ntsekhe M, Dandara C. Profiling of warfarin pharmacokinetics-associated genetic variants: Black Africans portray unique genetic markers important for an African specific warfarin pharmacogenetics-dosing algorithm. J Thromb Haemost 2021; 19:2957-2973. [PMID: 34382722 PMCID: PMC9543705 DOI: 10.1111/jth.15494] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/28/2021] [Accepted: 08/09/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Warfarin dose variability observed in patients is attributed to variation in genes involved in the warfarin metabolic pathway. Genetic variation in CYP2C9 and VKORC1 has been the traditional focus in evaluating warfarin dose variability, with little focus on other genes. OBJECTIVE We set out to evaluate 27 single nucleotide polymorphisms (SNPs) in the CYP2C cluster loci and 8 genes (VKORC1, ABCB1, CYP2C9, CYP2C19, CYP2C8, CYP1A2, CYP3A4, and CYP3A5) involved in pharmacokinetics of warfarin. PATIENTS/METHODS 503 participants were recruited among black Africans and Mixed Ancestry population groups, from South Africa and Zimbabwe, and a blood sample taken for DNA. Clinical parameters were obtained from patient medical records, and these were correlated with genetic variation. RESULTS Among black Africans, the SNPs CYP2C rs12777823G>A, CYP2C9 c.449G>A (*8), CYP2C9 c.1003C>T (*11) and CYP2C8 c.805A>T (*2) were significantly associated with warfarin maintenance dose. Conversely, CYP2C9 c.430C>T (*2), CYP2C8 c.792C>G (*4) and VKORC1 g.-1639G>A were significantly associated with maintenance dose among the Mixed Ancestry. The presence of CYP2C8*2 and CYP3A5*6 alleles was associated with increased mean warfarin maintenance dose, whereas CYP2C9*8 allele was associated with reduced warfarin maintenance dose. CONCLUSION African populations present with a diversity of variants that are important in predicting pharmacogenetics-based warfarin dosing in addition to those reported in CYP2C9 and VKORC1. It is therefore important, to include African populations in pharmacogenomics studies to be able to identify all possible biomarkers that are potential predictors for drug response.
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Affiliation(s)
- Arinao Ndadza
- Pharmacogenomics and Drug Metabolism Research GroupDivision of Human GeneticsDepartment of Pathology & Institute of Infectious Disease and Molecular Medicine (IDM)Faculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Sarudzai Muyambo
- Department of Clinical PharmacologyCollege of Health ScienceUniversity of ZimbabweHarareZimbabwe
- Department of Biological SciencesFaculty of Science and EngineeringBindura University of Science and EducationBinduraZimbabwe
| | - Pindile Mntla
- Department of CardiologySefako Makgatho Health Sciences University and Dr. George Mukhari HospitalPretoriaSouth Africa
| | - Ambroise Wonkam
- Pharmacogenomics and Drug Metabolism Research GroupDivision of Human GeneticsDepartment of Pathology & Institute of Infectious Disease and Molecular Medicine (IDM)Faculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Emile Chimusa
- Pharmacogenomics and Drug Metabolism Research GroupDivision of Human GeneticsDepartment of Pathology & Institute of Infectious Disease and Molecular Medicine (IDM)Faculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Andre P. Kengne
- Non‐Communicable Diseases Research UnitSouth African Medical Research Council and University of Cape TownCape TownSouth Africa
| | - Mpiko Ntsekhe
- Division of CardiologyDepartment of MedicineFaculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Collet Dandara
- Pharmacogenomics and Drug Metabolism Research GroupDivision of Human GeneticsDepartment of Pathology & Institute of Infectious Disease and Molecular Medicine (IDM)Faculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
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GERDAN V. Akılcı ilaç kullanımı: Varfarin. EGE TIP DERGISI 2021. [DOI: 10.19161/etd.863730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Martín Enguix D, Aguirre Rodríguez JC, Hidalgo Rodríguez A. Mortality in a cohort of primary care patients treated with vitamin K antagonist anticoagulants. Med Clin (Barc) 2021; 157:427-433. [PMID: 33509604 DOI: 10.1016/j.medcli.2020.07.037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 01/22/2023]
Abstract
INTRODUCTION AND OBJECTIVES The use of anticoagulants to prevent embolic events in Spain is very high, tending to a progressive increase. For this reason, we intend to analyse the mortality of patients from a metropolitan area of Granada treated with vitamin K antagonist anticoagulants (VKA), over 2 non-consecutive years. PATIENTS AND METHODS Longitudinal, observational, retrospective study of 205 patients treated with VKA. Sociodemographic data, previous clinical conditions, pathology causing VKA treatment, degree of control and mortality were collected 2 years after the start of the study. RESULTS Average age, 76±11.8 years (57.56% women). Two-year mortality was 22.4%, with a significant increase depending on age (p<.001) and years of treatment (p<.001). Patients with dementia (p<.05), with chronic kidney disease (p<.01) or with chronic obstructive pulmonary disease (p<.01) also presented higher mortality. Multivariate analysis showed significant effect of chronic kidney disease (odds ratio=4.075), chronic obstructive pulmonary disease (odds ratio=3.694), and years of treatment (odds ratio=1.236). CONCLUSIONS At 2 years of follow-up, 1 in 5 patients treated with VKA died. The presence of chronic kidney disease, chronic obstructive pulmonary disease and a longer treatment time were independently associated with this increase of mortality. Most of the patients were anticoagulated by atrial fibrillation, they were elderly and had a high prevalence of comorbidities.
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Affiliation(s)
- David Martín Enguix
- Medicina Familiar y Comunitaria, Centro de Salud Fortuny Velutti, Distrito Sanitario Granada Metropolitano, Granada, España.
| | - Juan Carlos Aguirre Rodríguez
- Medicina Familiar y Comunitaria, Centro de Salud Fortuny Velutti, Distrito Sanitario Granada Metropolitano, Granada, España
| | - Abraham Hidalgo Rodríguez
- Medicina Familiar y Comunitaria, Centro de Salud Casería de Montijo, Distrito Sanitario Granada Metropolitano, Granada, España
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Ndadza A, Thomford NE, Mukanganyama S, Wonkam A, Ntsekhe M, Dandara C. The Genetics of Warfarin Dose-Response Variability in Africans: An Expert Perspective on Past, Present, and Future. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2020; 23:152-166. [PMID: 30883300 DOI: 10.1089/omi.2019.0018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Coumarins such as warfarin are prescribed for prevention and treatment of thromboembolic disorders. Warfarin remains the most widely prescribed and an anticoagulant of choice in Africa. Warfarin use is, however, limited by interindividual variability in pharmacokinetics and a narrow therapeutic index. The difference in patients' pharmacodynamic responses to warfarin has been attributed to genetic variation in warfarin metabolism and molecular targets (e.g., CYP2C9 and VKORC1) and host-environment interactions. This expert review offers a synthesis of human genetics studies in Africans with respect to pharmacogenetics-informed warfarin dosing. We identify areas that need future research attention or could benefit from harnessing existing pharmacogenetics knowledge toward rational and optimal therapeutics with warfarin in African patients. A literature search was conducted until January 2019. A total of 343 articles were retrieved from nine African countries: Botswana, Ethiopia, Egypt, Ghana, Kenya, South Africa, Sudan, Tanzania, and Mozambique. We found 19 studies on genetics of warfarin treatment specifically among Africans. Genes examined included CYP2C9, VKORC1, CYP4F2, APOE, CALU, GGCX, and EPHX1. CYP2C9*2 and *3 alleles were highly frequent among Egyptians, while rare in other African populations. CYP2C9*5, *8, *9, and *11, and VKORC1 Asp36Tyr genetic variants explained warfarin variability in Africans better, compared to CYP2C9*2 and *3. In Africa, there is limited pharmacogenetics data on warfarin. Therefore, future research and funding commitments should be prioritized to ensure safe and effective use of warfarin in Africa. Lessons learned in Africa from the science of pharmacogenetics would inform rational therapeutics in hematology, cardiology, and surgical specialties worldwide.
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Affiliation(s)
- Arinao Ndadza
- 1 Pharmacogenomics and Drug Metabolism Research Group, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Nicholas Ekow Thomford
- 1 Pharmacogenomics and Drug Metabolism Research Group, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | | | - Ambroise Wonkam
- 1 Pharmacogenomics and Drug Metabolism Research Group, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Mpiko Ntsekhe
- 3 Division of Cardiology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Collet Dandara
- 1 Pharmacogenomics and Drug Metabolism Research Group, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
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Wang Y, Bromberg Y. Identifying mutation-driven changes in gene functionality that lead to venous thromboembolism. Hum Mutat 2019; 40:1321-1329. [PMID: 31144782 PMCID: PMC6745089 DOI: 10.1002/humu.23824] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 04/26/2019] [Accepted: 05/27/2019] [Indexed: 12/14/2022]
Abstract
Venous thromboembolism (VTE) is a common hematological disorder. VTE affects millions of people around the world each year and can be fatal. Earlier studies have revealed the possible VTE genetic risk factors in Europeans. The 2018 Critical Assessment of Genome Interpretation (CAGI) challenge had asked participants to distinguish between 66 VTE and 37 non-VTE African American (AA) individuals based on their exome sequencing data. We used variants from AA VTE association studies and VTE genes from DisGeNET database to evaluate VTE risk via four different approaches; two of these methods were most successful at the task. Our best performing method represented each exome as a vector of predicted functional effect scores of variants within the known genes. These exome vectors were then clustered with k-means. This approach achieved 70.8% precision and 69.7% recall in identifying VTE patients. Our second-best ranked method had collapsed the variant effect scores into gene-level function changes, using the same vector clustering approach for patient/control identification. These results show predictability of VTE risk in AA population and highlight the importance of variant-driven gene functional changes in judging disease status. Of course, more in-depth understanding of AA VTE pathogenicity is still needed for more precise predictions.
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Affiliation(s)
- Yanran Wang
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey
| | - Yana Bromberg
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, New Jersey
- Department of Genetics, Rutgers University, New Brunswick, New Jersey
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Johnson D, Hughes D, Pirmohamed M, Jorgensen A. Evidence to Support Inclusion of Pharmacogenetic Biomarkers in Randomised Controlled Trials. J Pers Med 2019; 9:jpm9030042. [PMID: 31480618 PMCID: PMC6789450 DOI: 10.3390/jpm9030042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 08/15/2019] [Accepted: 08/19/2019] [Indexed: 01/01/2023] Open
Abstract
Pharmacogenetics and biomarkers are becoming normalised as important technologies to improve drug efficacy rates, reduce the incidence of adverse drug reactions, and make informed choices for targeted therapies. However, their wider clinical implementation has been limited by a lack of robust evidence. Suitable evidence is required before a biomarker’s clinical use, and also before its use in a clinical trial. We have undertaken a review of five pharmacogenetic biomarker-guided randomised controlled trials (RCTs) and evaluated the evidence used by these trials to justify biomarker inclusion. We assessed and quantified the evidence cited in published rationale papers, or where these were not available, obtained protocols from trial authors. Very different levels of evidence were provided by the trials. We used these observations to write recommendations for future justifications of biomarker use in RCTs and encourage regulatory authorities to write clear guidelines.
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Affiliation(s)
- Danielle Johnson
- Institute of Translational Medicine, Department of Biostatistics, University of Liverpool, Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, UK.
| | - Dyfrig Hughes
- Centre for Health Economics and Medicines Evaluation, Bangor University, Ardudwy, Normal Site, Bangor LL57 2PZ, UK
| | - Munir Pirmohamed
- MRC Centre for Drug Safety Science and Wolfson Centre for Personalised Medicine, Institute of Translational Medicine, Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, UK
| | - Andrea Jorgensen
- Institute of Translational Medicine, Department of Biostatistics, University of Liverpool, Waterhouse Building, 1-5 Brownlow Street, Liverpool L69 3GL, UK
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Helin TA, Joutsi-Korhonen L, Asmundela H, Niemi M, Orpana A, Lassila R. Warfarin dose requirement in patients having severe thrombosis or thrombophilia. Br J Clin Pharmacol 2019; 85:1684-1691. [PMID: 30933373 DOI: 10.1111/bcp.13948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 03/12/2019] [Accepted: 03/23/2019] [Indexed: 12/17/2022] Open
Abstract
AIMS Warfarin dose requirement varies significantly. We compared the clinically established doses based on international normalized ratio (INR) among patients with severe thrombosis and/or thrombophilia with estimates from genetic dosing algorithms. METHODS Fifty patients with severe thrombosis and/or thrombophilia requiring permanent anticoagulation, referred to the Helsinki University Hospital Coagulation Center, were screened for thrombophilias and genotyped for CYP2C9*2 (c.430C>T, rs1799853), CYP2C9*3 (c.1075A>C, rs1057910) and VKORC1 c.-1639G>A (rs9923231) variants. The warfarin maintenance doses (target INR 2.0-3.0 in 94%, 2.5-3.5 in 6%) were estimated by the Gage and the International Warfarin Pharmacogenetics Consortium (IWPC) algorithms. The individual warfarin maintenance dose was tailored, supplementing estimates with comprehensive clinical evaluation and INR data. RESULTS Mean patient age was 47 years (range 20-76), and BMI 27 (SD 6), 68% being women. Forty-six (92%) had previous venous or arterial thrombosis, and 26 (52%) had a thrombophilia, with 22% having concurrent aspirin. A total of 40% carried the CYP2C9*2 or *3 allele and 54% carried the VKORC1-1639A allele. The daily mean maintenance dose of warfarin estimated by the Gage algorithm was 5.4 mg (95% CI 4.9-5.9 mg), and by the IWPC algorithm was 5.2 mg (95% CI 4.7-5.7 mg). The daily warfarin maintenance dose after clinical visits and follow-up was higher than the estimates, mean 6.9 mg (95% CI 5.6-8.2 mg, P < 0.006), with highest dose in patients having multiple thrombophilic factors (P < 0.03). CONCLUSIONS In severe thrombosis and/or thrombophilia, variation in thrombin generation and pharmacodynamics influences warfarin response. Pharmacogenetic dosing algorithms seem to underestimate dose requirement.
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Affiliation(s)
- Tuukka A Helin
- Coagulation Disorders Unit, Clinical Chemistry, University of Helsinki and HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Lotta Joutsi-Korhonen
- Coagulation Disorders Unit, Clinical Chemistry, University of Helsinki and HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Heidi Asmundela
- Coagulation Disorders Unit, Hematology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
| | - Mikko Niemi
- Department of Clinical Pharmacology, Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki and HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Arto Orpana
- Genetics and Clinical Chemistry, University of Helsinki and HUSLAB, Helsinki University Hospital, Helsinki, Finland
| | - Riitta Lassila
- Coagulation Disorders Unit, Clinical Chemistry, University of Helsinki and HUSLAB, Helsinki University Hospital, Helsinki, Finland.,Coagulation Disorders Unit, Hematology, University of Helsinki, Helsinki University Hospital, Helsinki, Finland
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Maintenance dose of warfarin beyond time in therapeutic range for preventing vascular events. J Neurol Sci 2019; 398:69-74. [PMID: 30684767 DOI: 10.1016/j.jns.2019.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/29/2018] [Accepted: 01/17/2019] [Indexed: 11/21/2022]
Abstract
BACKGROUND The quality of anticoagulation is closely associated with efficacy and safety in warfarin users. Although genetic polymorphisms have been related to warfarin dosages and vascular events(VE), genetic evaluations have not been recommended for all warfarin users. The aim is to evaluate the significance of the maintenance dose of warfarin (MDW) on VE, considering the time in therapeutic range (TTR). METHODS This retrospective study analyzed the data of patients who received warfarin for any reasons. A total of 11,835 patients with warfarin were divided into quartiles by MDW. We assessed TTR using the Rosendaal method and VE. RESULTS VE occurred in 9.1% of the warfarin users. The mean TTR level was 34.0 ± 25.7%, and the MDW was 3.38 ± 1.06 mg per day. Patients with VE were more likely to have a lower MDW and lower TTR levels. In moderate- or well-controlled TTR status, a lower MDW was significantly related to under-controlled anticoagulation and associated with higher risks of VE. Lower MDW had a higher risk of stroke or arterial/venous thromboembolism (Q1: OR, 1.57; 95% CI 1.25 to 1.96; Q2: OR, 1.40; 95% CI 1.12 to 1.75; Q3: OR, 1.35; 95% CI 1.08 to 1.68). CONCLUSIONS We suggest that patients with very low MDW might be at risk when using warfarin. Therefore, we propose that patients with a very low MDW might be alternatively considered for novel oral anticoagulants rather than warfarin.
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Formea CM, Nicholson WT, Vitek CR, Wix KK, McCullough KB, Cunningham JL, Zeuli JD, Matey ET, Merten JA, Richardson DM, Billings AL, Schramm GE. Implementation of a pharmacogenomics education program for pharmacists. Am J Health Syst Pharm 2018; 75:1939-1946. [PMID: 30301720 DOI: 10.2146/ajhp170771] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The development, implementation, and evaluation of a pharmacogenomics education program for pharmacists in a large, integrated multicampus health system are described. SUMMARY Pharmacogenomics has been described as tailoring medications to each patient's unique genetic sequence with the goals of minimizing harmful effects and optimizing therapeutic effects. Pharmacists are uniquely trained to lead the implementation of pharmacogenomics in clinical care. After assessment of pharmacists' comfort with pharmacogenomics, different approaches were explored to develop, pilot test, and disseminate pharmacogenomics education across a multicampus academic medical center. Limited success with large-audience, single-lecture didactic education led to development and delivery of targeted, competency-based online modules using the institution's academic virtual learning environment and course management system. Implementation steps included (1) collaboration with the Mayo Clinic Center for Individualized Medicine to create an interprofessional development team and project charter, (2) galvanizing pharmacy leadership support across multiple campuses, (3) development of competency-based interactive modules, and (4) assessment of the quality of and learner satisfaction with the modules. Significant improvements in competency scores were observed with each module and across the multiple campuses. Satisfaction with the education program was assessed at the end of a 4-module series. CONCLUSION A pharmacogenomics educational program targeting pharmacists was developed through interprofessional collaboration and provided a novel opportunity to construct an educational infrastructure to support enterprise health-system campuses with limited educational resources.
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Affiliation(s)
- Christine M Formea
- Department of Pharmacy, Mayo Clinic College of Medicine, Rochester, MN, and Mayo Clinic Hospital-Rochester, Rochester, MN
| | - Wayne T Nicholson
- Department of Anesthesiology, Mayo Clinic Hospital-Rochester, Rochester, MN
| | | | - Kelly K Wix
- Department of Pharmacy, Mayo Clinic, Rochester, MN
| | | | | | - John D Zeuli
- Department of Pharmacy, Mayo Clinic, Rochester, MN
| | - Eric T Matey
- Department of Pharmacy, Mayo Clinic, Rochester, MN
| | | | | | - Andrea L Billings
- Department of Pharmacy, Mayo Clinic Hospital-Rochester, Rochester, MN
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Tarantino G, Capone D, Contaldi P, Gianno A, Teresa M, Tufano A. Phenotyping of CYP 4501A2 Activity by Total Overnight Salivary Caffeine Assessment (TOSCA) in Patients on Warfarin Treatment: A Cross-Sectional Study. Clin Appl Thromb Hemost 2018; 24:928-935. [PMID: 28992765 PMCID: PMC6714717 DOI: 10.1177/1076029617733040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Warfarin is an oral anticoagulant, commonly used for primary and secondary prevention of venous and arterial thromboembolic events. The drug is characterized by narrow therapeutic index, widespread individual variability in clinical response, and high rates of adverse events, particularly bleeding complications. For these reasons, a close monitoring of the dosage, using the frequent assessment of coagulation status by means of International Normalized Ratio value, is mandatory. Warfarin is metabolized by hepatic cytochrome P-450. High CYP 450 activity may lead to low drug concentration and requires high warfarin doses to reach efficacy; conversely, low CYP 450 activity is responsible for high drug concentration and needs for low doses to avoid potential toxicity risks. The major isoforms of CYP involved in the metabolism of warfarin sodium are CYP1A2 (for the R-warfarin) and CYP2C9 (for the S-warfarin). The probes for testing CYP1A2 are phenacetin and caffeine while for CYP2C9 tolbutamide. Although S-warfarin has major activity, it was decided to exclude its phenotyping for ethical issues, being mandatory to use a drug (tolbutamide). Instead, it was chosen to test the 1A2 isoform, as the activity of the latter isoform could be investigated by using caffeine contained in the caffeinated beverages. Specifically, a single-point concentration of salivary caffeine (total overnight salivary caffeine assessment [TOSCA]) after an overnight period of the caffeinated beverages abstinence was utilized. In the present study, 75 nonsmoker patients regularly receiving warfarin sodium were enrolled. The results have showed a significant association of the warfarin dose with TOSCA values (coefficient = -0.15, standard error = 0.04, 95% confidence interval = -0.24 to -0.06, t = -3.23, P = .002). In conclusion, the phenotyping of CYP1A2 by TOSCA could be useful, if further proven, to help manage patients on warfarin in order to lessen severe adverse events.
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Affiliation(s)
- Giovanni Tarantino
- Department of Clinical Medicine and Surgery, “Federico II” University, Naples, Italy
| | - Domenico Capone
- Integrated Care Department of Clinical Neurosciences, Anesthesiology and Drug-Use, Section of Clinical Pharmacology, “Federico II” University, Naples, Italy
| | - Paola Contaldi
- Department of Clinical Medicine and Surgery, “Federico II” University, Naples, Italy
| | - Adriana Gianno
- Department of Clinical Medicine and Surgery, “Federico II” University, Naples, Italy
| | - Mosca Teresa
- Integrated Care Department of Clinical Neurosciences, Anesthesiology and Drug-Use, Section of Clinical Pharmacology, “Federico II” University, Naples, Italy
| | - Antonella Tufano
- Department of Clinical Medicine and Surgery, “Federico II” University, Naples, Italy
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Bi YA, Lin J, Mathialagan S, Tylaska L, Callegari E, Rodrigues AD, Varma MVS. Role of Hepatic Organic Anion Transporter 2 in the Pharmacokinetics of R- and S-Warfarin: In Vitro Studies and Mechanistic Evaluation. Mol Pharm 2018; 15:1284-1295. [DOI: 10.1021/acs.molpharmaceut.7b01108] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Yi-an Bi
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - Jian Lin
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - Sumathy Mathialagan
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - Laurie Tylaska
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - Ernesto Callegari
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - A. David Rodrigues
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
| | - Manthena V. S. Varma
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research and Development, MS 8220-2451, Groton, Connecticut 06340, United States
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Chumnumwat S, Yi K, Lucksiri A, Nosoongnoen W, Chindavijak B, Chulavatnatol S, Sarapakdi A, Nathisuwan S. Comparative performance of pharmacogenetics-based warfarin dosing algorithms derived from Caucasian, Asian, and mixed races in Thai population. Cardiovasc Ther 2018; 36. [DOI: 10.1111/1755-5922.12315] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 11/17/2017] [Accepted: 12/07/2017] [Indexed: 01/16/2023] Open
Affiliation(s)
- Supatat Chumnumwat
- Department of Pharmacy; Faculty of Pharmacy; Mahidol University; Bangkok Thailand
| | - Kong Yi
- Department of Pharmacy; Faculty of Pharmacy; Mahidol University; Bangkok Thailand
| | - Aroonrut Lucksiri
- Department of Pharmaceutical Care; Faculty of Pharmacy; Chiangmai University; Chiangmai Thailand
| | - Wichit Nosoongnoen
- Department of Pharmacy; Faculty of Pharmacy; Mahidol University; Bangkok Thailand
| | - Busba Chindavijak
- Department of Pharmacy; Faculty of Pharmacy; Mahidol University; Bangkok Thailand
| | | | - Ajjima Sarapakdi
- Department of Pharmacy; Faculty of Medicine Siriraj Hospital; Mahidol University; Bangkok Thailand
| | - Surakit Nathisuwan
- Department of Pharmacy; Faculty of Pharmacy; Mahidol University; Bangkok Thailand
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Ragia G, Karantza IM, Kelli-Kota E, Kolovou V, Kolovou G, Konstantinides S, Maltezos E, Tavridou A, Tziakas D, Maitland-van der Zee AH, Manolopoulos VG. Role of CYP4F2, CYP2C19, and CYP1A2 polymorphisms on acenocoumarol pharmacogenomic algorithm accuracy improvement in the Greek population: need for sub-phenotype analysis. Drug Metab Pers Ther 2017; 32:183-190. [PMID: 29252193 DOI: 10.1515/dmpt-2017-0034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/15/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND We have earlier developed a pharmacogenomic algorithm for acenocoumarol dose prediction in Greek patients that included CYP2C9/VKORC1 genetic information. This study aims at analyzing the potential effect of CYP4F2, CYP2C19, and CYP1A2 gene polymorphisms on acenocoumarol dose requirements and at further improving the Greek-specific pharmacogenomic algorithm. METHODS A total of 205 Greek patients taking acenocoumarol (140 who reached and 65 who did not reach stable dose), participants of acenocoumarol EU-PACT trial, were included in the study. CYP4F2, CYP2C19, and CYP1A2 polymorphisms were genotyped by use of the PCR-RFLP method. All patients were previously genotyped for CYP2C9/VKORC1 polymorphisms. RESULTS In the pooled sample, CYP4F2, CYP2C19, and CYP1A2 polymorphisms do not affect independently acenocoumarol dose requirements. For CYP4F2, significant effects were found on patients' ability to reach stable dose and on acenocoumarol dose requirements when CYP2C9/VKORC1 sub-phenotypes were analyzed. Specifically, when the patients were stratified according to their CYP2C9/VKORC1 functional bins, in sensitive responders, CYP4F2*3 allele carriers (CYP4F2 *1/*3 and *3/*3 genotypes) were more frequent in the patient group who reached stable dose (p=0.049). Additionally, in CYP2C9 intermediate metabolizers (IMs), after adjusting for age, weight, and VKORC1 genotypes, CYP4F2 genotypes were significantly associated with acenocoumarol stable dose (β: 0.07; 95% CI: 0.006-0.134; p=0.033). CONCLUSIONS CYP4F2 gene shows a prominent weak association with acenocoumarol dose requirements. Sub-phenotype analysis is potentially important in determining additional gene polymorphisms that are associated with acenocoumarol dose requirements.
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Affiliation(s)
- Georgia Ragia
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Dragana Campus, 68100 Alexandroupolis, Greece, Phone: +30 2551 030523, Fax: +30 2551 030523; and DNALEX S.A., Alexandroupolis, Greece
| | - Ioanna-Maria Karantza
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Eleni Kelli-Kota
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Vana Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Genovefa Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Stavros Konstantinides
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Efstratios Maltezos
- Second Department of Internal Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anna Tavridou
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Dimitrios Tziakas
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anke H Maitland-van der Zee
- Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands
| | - Vangelis G Manolopoulos
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
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16
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Ragia G, Kolovou V, Kolovou G, Konstantinides S, Maltezos E, Tavridou A, Tziakas D, Maitland-van der Zee AH, Manolopoulos VG. A novel acenocoumarol pharmacogenomic dosing algorithm for the Greek population of EU-PACT trial. Pharmacogenomics 2017; 18:23-34. [DOI: 10.2217/pgs-2016-0126] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: To generate and validate a pharmacogenomic-guided (PG) dosing algorithm for acenocoumarol in the Greek population. To compare its performance with other PG algorithms developed for the Greek population. Patients & methods: A total of 140 Greek patients participants of the EU-PACT trial for acenocoumarol, a randomized clinical trial that prospectively compared the effect of a PG dosing algorithm with a clinical dosing algorithm on the percentage of time within INR therapeutic range, who reached acenocoumarol stable dose were included in the study. Results: CYP2C9 and VKORC1 genotypes, age and weight affected acenocoumarol dose and predicted 53.9% of its variability. EU-PACT PG algorithm overestimated acenocoumarol dose across all different CYP2C9/VKORC1 functional phenotype bins (predicted dose vs stable dose in normal responders 2.31 vs 2.00 mg/day, p = 0.028, in sensitive responders 1.72 vs 1.50 mg/day, p = 0.003, in highly sensitive responders 1.39 vs 1.00 mg/day, p = 0.029). The PG algorithm previously developed for the Greek population overestimated the dose in normal responders (2.51 vs 2.00 mg/day, p < 0.001). Conclusion: Ethnic-specific dosing algorithm is suggested for better prediction of acenocoumarol dosage requirements in patients of Greek origin.
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Affiliation(s)
| | - Vana Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Genovefa Kolovou
- Cardiology Department, Onassis Cardiac Surgery Center, Athens, Greece
| | - Stavros Konstantinides
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Efstratios Maltezos
- Second Department of Internal Medicine, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anna Tavridou
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
- Clinical Pharmacology Unit, Academic General Hospital of Evros, Alexandroupolis, Greece
| | - Dimitrios Tziakas
- University Cardiology Department, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
| | - Anke H Maitland-van der Zee
- Division of Pharmacoepidemiology & Clinical Pharmacology, Department of Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Vangelis G Manolopoulos
- Laboratory of Pharmacology, Medical School, Democritus University of Thrace, Alexandroupolis, Greece
- Clinical Pharmacology Unit, Academic General Hospital of Evros, Alexandroupolis, Greece
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17
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Roberts G, Razooqi R, Quinn S. Comparing Usual Care With a Warfarin Initiation Protocol After Mechanical Heart Valve Replacement. Ann Pharmacother 2016; 51:219-225. [PMID: 27798318 DOI: 10.1177/1060028016676830] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND The immediate postoperative warfarin sensitivity for patients receiving heart valve prostheses is increased. Established warfarin initiation protocols may lack clinical applicability, resulting in dosing based on clinical judgment. OBJECTIVE To compare current practice for warfarin initiation with a known warfarin initiation protocol, with doses proportionally reduced to account for the increased postoperative sensitivity. METHODS We compared the Mechanical Heart Valve Warfarin Initiation Protocol (Protocol group) with current practice (clinical judgment-Empirical group) for patients receiving mechanical heart valves in an observational before-and-after format. End points were the time to achieve a stable therapeutic international normalized ratio (INR), doses held in the first 6 days, and overanticoagulation in the first 6 days. RESULTS The Protocol group (n = 37) achieved a stable INR more rapidly than the Empirical group (n = 77; median times 5.1 and 8.7 days, respectively; P = 0.002). Multivariable analysis indicated that the Protocol group (hazard ratio [HR] = 2.22; P = 0.005) and men (HR = 1.76; P = 0.043) more rapidly achieved a stable therapeutic INR. Age, serum albumin, amiodarone, presence of severe heart failure, and surgery type had no impact. Protocol patients had fewer doses held (1.1% vs 10.1%, P < 0.001) and no difference in overanticoagulation (2.7% vs 9.1%, P = 0.27). CONCLUSION The Mechanical Heart Valve Warfarin Initiation Protocol provided a reliable approach to initiating warfarin in patients receiving mechanical aortic or mitral valves.
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Affiliation(s)
- Gregory Roberts
- 1 Flinders Medical Centre, Bedford Park, South Australia, Australia.,2 Flinders University, Bedford Park, South Australia, Australia
| | - Rasha Razooqi
- 3 University of South Australia, Adelaide, South Australia, Australia
| | - Stephen Quinn
- 2 Flinders University, Bedford Park, South Australia, Australia
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18
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Pengo V, Zasso A, Barbero F, Biasiolo A, Rampazzo P, Brocco T. Initiation of Warfarin Treatment in Outpatients with Nonrheumatic Atrial Fibrillation: A Scheme for Early Indication of Maintenance Dose. Clin Appl Thromb Hemost 2016. [DOI: 10.1177/107602969800400411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Eighty-four outpatients with nonrheumatic atrial fibrillation starting oral anticoagulant treatment were adminis tered warfarin (10 mg/day) for the first 2 days of treatment. Prothrombin time, expressed as International Normalized Ratio (INR), was measured on day 3 and plotted against the weekly warfarin maintenance dose, defined as the dose able to maintain INR between 2.0 and 3.0 (therapeutic range) on three consecu tive occasions, 1 week apart. The data fit a regression line (r = 0.74, p < .0001) that we use to estimate the weekly maintenance dose of other patients.
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Affiliation(s)
- Vittorio Pengo
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
| | - Antonella Zasso
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
| | - Fabio Barbero
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
| | - Allesandre Biasiolo
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
| | - Patrizia Rampazzo
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
| | - Tania Brocco
- Department of Cardiology, Thrombosis Center, University of Padova School of Medicine, Padova, Italy
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19
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Sehgal T, Hira JK, Ahluwalia J, Das R, Vijayvergiya R, Rana SS, Varma N. High prevalence of VKORC1*3 (G9041A) genetic polymorphism in north Indians: A study on patients with cardiac disorders on acenocoumarol. Drug Discov Ther 2016; 9:404-10. [PMID: 26781925 DOI: 10.5582/ddt.2015.01066] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Coumarin derivatives such as warfarin and acenocoumarol are used in various disorders such as deep venous thrombosis, pulmonary embolism, atrial fibrillation and artificial heart valves. They have improved prognosis of patients with thromboembolic disease. An individual's response to coumarins depends on several factors. The non-genetic factors include age, gender, body mass index, diet and interacting drugs. Among the genetic factors, the cytochrome P450 system and vitamin K epoxide reductase complex subunit 1 play a key role in drug metabolism. This was a prospective hospital based study in which allele and genotypic frequencies of CYP2C9 gene polymorphisms; 430C>T and 1075A>C and VKORC1 gene polymorphisms; 1639G>A, 9041G>A and 6009C>T in 106 alleles of north Indian patients with valve replacement on acenocoumarol were determined and their effect on acenocoumarol dosing was studied. To the best of our knowledge, this is first report of VKORC1 9041G>A and 6009C>T gene polymorphisms and their effect on acenocoumarol dosing from north India. In 53 patients with valve replacement on acenocoumarol with stable INR, the allele frequency of CYP2C9*2 and CYP2C9*3 gene polymorphisms was 0.05 and 0.17 respectively and that of VKORC1 *2,*3 and *4 gene polymorphisms was 0.15, 0.72 and 0.11 respectively. The presence of CYP2C9*3 or VKORC1*2 gene polymorphism were associated with decrease in acenocoumarol dose requirements (p values 0.03 and 0.02 respectively).This study confirmed the association of lower mean weekly dosages of acenocoumarol in patients with CYP2C9*3 and VKORC1*2 gene polymorphisms. An unusually high frequency of 9041A polymorphism in VKORC1 was found in study population.
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Affiliation(s)
- Tushar Sehgal
- Department of Hematology, Postgraduate Institute of Medical Education and Research
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20
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Mannheimer B, Andersson ML, Järnbert-Pettersson H, Lindh JD. The effect of carbamazepine on warfarin anticoagulation: a register-based nationwide cohort study involving the Swedish population. J Thromb Haemost 2016; 14:765-71. [PMID: 26792124 DOI: 10.1111/jth.13268] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/07/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND There are data indicating that the interaction between warfarin and carbamazepine results in decreased warfarin efficacy. However, the evidence on the magnitude of and interindividual differences in susceptibility to this interaction has remained scarce. OBJECTIVES To investigate the effect of carbamazepine on warfarin anticoagulation and warfarin maintenance doses by the use of data from three nationwide registries. PATIENTS/METHODS In a retrospective cohort study including 166 patients, warfarin doses were compared 2-4 weeks before and 10-13 weeks after initiation of cotreatment with carbamazepine. In addition, warfarin doses and International Normalized Ratio (INR) values were calculated week-by-week during cotreatment. Data on prescribed warfarin doses and INR measurements were obtained from two large Swedish warfarin registers. Data on carbamazepine use were retrieved from the Swedish Prescribed Drug Register. RESULTS The average warfarin doses were 49% (95% confidence interval 43-56) higher during carbamazepine treatment. The INR decreased upon carbamazepine initiation, and subtherapeutic INR levels were observed in 79% of all patients during the fifth week of cotreatment. Warfarin maintenance dose increases exceeding 50% and 100% were observed in 59% and 17% of patients, respectively. CONCLUSIONS Four of five warfarin-treated patients in whom cotreatment with carbamazepine was initiated experienced subtherapeutic anticoagulative effect within 3-5 weeks. The warfarin dose was subsequently increased by 49%, a change that differed widely between patients. In order to avoid thrombosis and ischemic stroke, carbamazepine initiation should be accompanied by close INR monitoring to better meet the anticipated increase in dose demand.
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Affiliation(s)
- B Mannheimer
- Department of Clinical Science and Education at Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - M L Andersson
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - H Järnbert-Pettersson
- Department of Clinical Science and Education at Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
| | - J D Lindh
- Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
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21
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Dimitrova-Karamfilova A, Tzveova R, Chilingirova N, Goranova T, Nachev G, Mitev V, Kaneva R. Acenocoumarol Pharmacogenetic Dosing Algorithms and Their Application in Two Bulgarian Patients with Low Anticoagulant Requirements. Biochem Genet 2015; 53:334-50. [PMID: 26377995 DOI: 10.1007/s10528-015-9695-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 09/05/2015] [Indexed: 11/28/2022]
Abstract
BACKGROUND The anticoagulant therapy with acenocoumarol is generally associated with a high risk of bleeding and thromboembolic events. PURPOSE We applied eight already existing acenocoumarol dosing algorithms to Bulgarian patients with low acenocoumarol dose requirements and investigated which of these algorithms would predict most precisely the dose anticoagulant. MATERIALS AND METHODS Two patients with Bulgarian origin were referred to the outpatient clinical laboratory of "St. Ekaterina" University Hospital for Cardiovascular Surgery and Cardiology, Sofia, Bulgaria. After obtaining written informed consent, both patients were genotyped for polymorphisms in genes for Cytochrome P450 2C9 (CYP2C9), Vitamin K epoxide reductase (VKORC1), Apolipoprotein E (APOE), and Cytochrome P450 4F2 (CYP4F2). RESULTS All applied acenocoumarol dosing algorithms predicted relatively similar doses of coumarin anticoagulant in both patients. However, van Schie et al.'s algorithm allowed more accurate calculation of the optimal dose in our patients with extremely low acenocoumarol requirements. Genotyping of selected polymorphic variants in CYP2C9 and VKORC1 showed that both patients were compound heterozygotes for CYP2C9 (CYP2C9*2/*3) and homozygotes for both variants in VKORC1 (VKORC1 1173 T/T, and VKORC1-1639 A/A). This combination of genotypes suggested high sensitivity to acenocoumarol leading to the low anticoagulant dose requirements (0.25 and 1 mg/day, respectively) needed to reach the target International Normalized Ratio of 2.5-3.5. CONCLUSIONS The genotyping of polymorphic variants in VKORC1 and CYP2C9, together with clinical and demographic parameters, can serve for more precise definition of the individual starting and maintenance doses of coumarin derivatives in each patient.
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Affiliation(s)
- Antoaneta Dimitrova-Karamfilova
- Department of Clinical Laboratory, University Hospital of Cardiovascular Surgery and Cardiology "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., 1431, Sofia, Bulgaria
| | - Reni Tzveova
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, 1431, Sofia, Bulgaria.
| | - Nezabravka Chilingirova
- Department of Clinical Laboratory, University Hospital of Cardiovascular Surgery and Cardiology "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., 1431, Sofia, Bulgaria
| | - Teodora Goranova
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, 1431, Sofia, Bulgaria
| | - Gencho Nachev
- Department of Cardiovascular Surgery, University Hospital of Cardiovascular Surgery and Cardiology "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., 1431, Sofia, Bulgaria
| | - Vanio Mitev
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, 1431, Sofia, Bulgaria
| | - Radka Kaneva
- Molecular Medicine Center, Department of Medical Chemistry and Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, 1431, Sofia, Bulgaria
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22
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Murphy R, Stehli A, Nguyen H, Leu SY, Nguyen DV, Schwarzkopf R. Assessment of Dosing and Patient Factors on the Efficacy of Warfarin Following Total Joint Replacement. Open Orthop J 2015; 9:129-38. [PMID: 26157529 PMCID: PMC4483539 DOI: 10.2174/1874325001509010129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 02/19/2015] [Accepted: 02/28/2015] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine the percentage of patients discharged with a subtherapeutic INR <1.8 using our institutions inpatient warfarin dosing nomogram following total joint arthroplasty (TJA). We examined predisposing risk factors for a subtherapeutic discharge (INR <1.8), including increased body weight, age, gender, end stage renal disease (ESRD), smoking, and peri-operative transfusion. Chart review identified 249 patients for study inclusion. Logistic regression (LR) was used to identify associated risk factors for a subtherapeutic INR (<1.8) on day of discharge. The majority of patients (58.6%, 146 of 249) following TJA surgery were found to have a subtherapeutic INR level (INR<1.8) at discharge (mean length of stay 2.6 days). Multivariate LR analysis found that weight greater than 180 lbs. (OR 2.08, CI 1.09, 3.98, P=0.027) was found to increase the odds of a subtherapeutic INR on day of discharge. Our results were not significant for weight 20% beyond ideal body weight, age (>65y), gender, peri-operative transfusion, smoking, ESRD or autoimmune disease. A patient’s body weight influences response to warfarin following TJA. An inpatient warfarin dosing nomogram that takes into account a patient’s weight should be used to reduce the risk of subtherapeutic INR levels in obese TJA patients.
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Affiliation(s)
- Ryan Murphy
- Department of Orthopaedic Surgery, University of California, Irvine School of Medicine, USA
| | - Annamarie Stehli
- Institute for Clinical and Translational Science, University of California, Irvine, CA 92687, USA
| | - Hiep Nguyen
- Inpatient Pharmacy, University of California, Irvine Medical Center, USA
| | - Szu-Yun Leu
- Institute for Clinical and Translational Science, University of California, Irvine, CA 92687, USA ; Department of Pediatrics, University of California, Irvine School of Medicine, USA
| | - Danh V Nguyen
- Institute for Clinical and Translational Science, University of California, Irvine, CA 92687, USA ; Department of Medicine, University of California Irvine, Orange, CA 92868, USA
| | - Ran Schwarzkopf
- Department of Orthopaedic Surgery, University of California, Irvine School of Medicine, USA
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23
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Tzveova R, Dimitrova-Karamfilova A, Saraeva R, Solarova T, Naydenova G, Petrova I, Hristova N, Popov I, Nachev G, Mitev V, Kaneva R. Estimation and validation of acenocoumarol dosing algorithms in Bulgarian patients with cardiovascular diseases. Per Med 2015; 12:209-220. [PMID: 29771648 DOI: 10.2217/pme.14.80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aim & Methods: A total of 169 Bulgarian patients were genotyped for CYP2C9*2,*3, VKORC1-1639G>A and VKORC11173C>T. The effect of genetic and nongenetic factors on acenocoumarol dose variability was tested in a derivation cohort of patients and the obtained algorithm was validated in a test cohort. RESULTS & DISCUSSION It was found that VKORC-1639G>A (25.5%), CYP2C9*2 (7.8%), CYP2C9*3 (6.1%), age (13.6%) and diagnosis (6.0%) significantly affected acenocoumarol dose variability in the derivation cohort. These factors with additional factors, such as sex (0.1%, p = 0.76), weight (2.6%, p = 0.14) and amiodarone use (3.0%, p = 0.059) accounted for 46.5% and 23.0% of the dose variability for genetic and clinical models, respectively. CONCLUSION Based on the results of this investigation, validated clinical and pharmacogenetic algorithms for the prediction of a stable anticoagulant dose were developed, specifically designed for the Bulgarian population.
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Affiliation(s)
- Reni Tzveova
- Molecular Medicine Center, Department of Medical Chemistry & Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, Sofia 1431, Bulgaria
| | - Antoaneta Dimitrova-Karamfilova
- Department of Clinical Laboratory, University National Multi-profile Active Treatment Hospital "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., Sofia 1431, Bulgaria
| | - Radoslava Saraeva
- Molecular Medicine Center, Department of Medical Chemistry & Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, Sofia 1431, Bulgaria
| | - Tanya Solarova
- Department of Clinical Laboratory, University National Multi-profile Active Treatment Hospital "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., Sofia 1431, Bulgaria
| | - Galya Naydenova
- Second Department of Cardiology, University NationalMulti-profile Active Treatment Hospital "Dr. G. Stansky"- Pleven, 8A Georgi Kochev str., Pleven 5800, Bulgaria
| | - Irina Petrova
- Department of Clinical Laboratory, University National Multi-profile Active Treatment Hospital "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., Sofia 1431, Bulgaria
| | - Nataliya Hristova
- Department of Clinical Laboratory, University National Multi-profile Active Treatment Hospital "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., Sofia 1431, Bulgaria
| | - Ivan Popov
- Molecular Medicine Center, Department of Medical Chemistry & Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, Sofia 1431, Bulgaria
| | - Gencho Nachev
- Department of Cardiac Surgery, University National Multi-profile Active Treatment Hospital "St. Ekaterina"- Sofia, 52A Pencho Slaveykov bul., Sofia 1431, Bulgaria
| | - Vanio Mitev
- Molecular Medicine Center, Department of Medical Chemistry & Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, Sofia 1431, Bulgaria
| | - Radka Kaneva
- Molecular Medicine Center, Department of Medical Chemistry & Biochemistry, Medical Faculty, Medical University - Sofia, 2 Zdrave str, Sofia 1431, Bulgaria
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Barajas MR, Formea CM, McCormick JB, Abdalrhim AD, Han LC, McBane RD, Fiksdal AS, Kullo IJ. A patient-centered approach to the development and pilot of a warfarin pharmacogenomics patient education tool for health professionals. CURRENTS IN PHARMACY TEACHING & LEARNING 2015; 7:249-255. [PMID: 25729462 PMCID: PMC4339072 DOI: 10.1016/j.cptl.2014.11.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
OBJECTIVE To describe an exploratory project to develop and pilot a novel patient educational tool that explains the concept of pharmacogenomics and its impact on warfarin dosing that can be utilized by health professionals providing patient counseling. METHODS A pharmacogenomics educational tool prototype was developed by an interdisciplinary team. During the pilot of the tool, focus group methodology was used to elicit input from patients based upon their perspectives and experiences with warfarin. Focus group sessions were audio-recorded and transcribed, and the data was analyzed through consensus coding in NVivo. RESULTS The focus group participants were generally unfamiliar with the concept of pharmacogenomics but were receptive to the information. They thought the patient education tool was informative and would provide the most benefit to patients newly initiated on warfarin therapy. CONCLUSIONS Preliminary results from this exploratory project suggest that implementation and further feasibility testing of this pharmacogenomics patient education tool should be performed in a population of newly initiated patients taking warfarin.
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Affiliation(s)
- Megan R Barajas
- Hospital Pharmacy Services, Mayo Clinic Hospital-St. Marys Campus, 200 First Street SW, Rochester, MN 55905,
| | - Christine M Formea
- Hospital Pharmacy Services, Mayo Clinic Hospital-St. Marys Campus, 200 First Street SW, Rochester, MN 55905, 1-507-255-7552,
| | - Jennifer B McCormick
- Biomedical Ethics Program, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
| | - Ahmed D Abdalrhim
- Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
| | - Leona C Han
- Biomedical Ethics Program, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
| | - Robert D McBane
- Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
| | - Alexander S Fiksdal
- Biomedical Ethics Program, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
| | - Iftikhar J Kullo
- Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905,
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Pharmacogenetics of Coumarin Anticoagulant Therapy. ADVANCES IN PREDICTIVE, PREVENTIVE AND PERSONALISED MEDICINE 2015. [DOI: 10.1007/978-3-319-15344-5_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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An acenocoumarol dosing algorithm exploiting clinical and genetic factors in South Indian (Dravidian) population. Eur J Clin Pharmacol 2014; 71:173-81. [PMID: 25519826 DOI: 10.1007/s00228-014-1791-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/03/2014] [Indexed: 02/03/2023]
Abstract
OBJECTIVE The objective of this study was to determine the influence of CYP2C9, VKORC1, CYP4F2, and GGCX genetic polymorphisms on mean daily dose of acenocoumarol in South Indian patients and to develop a new pharmacogenetic algorithm based on clinical and genetic factors. METHODS Patients receiving acenocoumarol maintenance therapy (n = 230) were included in the study. Single nucleotide polymorphisms (SNP) of CYP2C9, VKORC1, CYP4F2, and GGCX were genotyped by real-time polymerase chain reaction (RT-PCR) method. RESULTS The mean daily acenocoumarol maintenance dose was found to be 3.7 ± 2.3 (SD) mg/day. The CYP2C9 *1*2, CYP2C9 *1*3, and CYP2C9 *2*3 variant genotypes significantly reduced the dose by 56.7 % (2.0 mg), 67.6 % (1.6 mg), and 70.3 % (1.5 mg) than wild-type carriers 4.1 mg, p < 0.0001. The genetic variants of CYP2C9 and GGCX (rs11676382) were found to be associated with lower acenocoumarol dose, whereas CYP4F2 (rs2108622) was associated with higher doses. Age, body mass index (BMI), variation of CYP2C9, VKORC1, CYP4F2, and GGCX were the major determinants of acenocoumarol maintenance dose, accounting for 61.8 % of its variability (adjusted r (2) = 0.615, p < 0.0001). Among the VKORC1 variants, rs9923231 alone contributed up to 28.6 % of the acenocoumarol dose variation. CONCLUSION VKORC1 rs9923231 polymorphism had the highest impact on acenocoumarol daily dose. A new pharmacogenetic algorithm was established to determine the acenocoumarol dose in South Indian population.
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Brunner-Ziegler S, Jilma B, Magirr D, Sunder-Plassmann R, Giurgea GA, Hammer A, Margeta C, Brunner M, Koppensteiner R, Mannhalter C. Influence of proton pump inhibitors and VKORC1 mutations on CYP2C9-mediated dose requirements of vitamin K antagonist therapy: a pilot study. Br J Haematol 2014; 167:547-53. [PMID: 25142093 DOI: 10.1111/bjh.13082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/09/2014] [Indexed: 12/30/2022]
Abstract
Interindividual variations in dose requirements of oral vitamin K antagonists (VKA) are attributed to several factors, including genetic variant alleles of vitamin K epoxide reductase complex subunit 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9), but also interaction with co-medications. In this context, proton pump inhibitor (PPI)-related alterations of VKA maintenance dose requirements have been published. The present investigation aimed to test for an interaction profile of oral VKA-therapy and PPIs in relation to the CYP2C9 genotype. Median weekly stable VKA dose requirements over 1 year were recorded in 69 patients. Patients were genotyped for CYP2C9*2, CYP2C9*3, VKORC1c.-1639G>A and VKORC1c.174-136C>T and assessed for an association with PPI use and total VKA maintenance dose requirements. PPI users with CYP2C9 genetic variations required significantly lower weekly VKA maintenance doses than those with the wild-type genotype (t-test: P = 0·02). In contrast, in subjects without PPI use, the CYP2C9 genotype had no significant influence on oral VKA dose requirements. Further, the combined CYP2C9/VKORC1 genotype was a significant predictor for VKA dose requirements [linear regression: estimate: -1·47, standard error: 0·58 (P = 0·01)]. In conclusion, in carriers of CYP2C9 gene variations, the interference with the VKA metabolism is modified by PPI co-medication and the VCKORC1 genotype. Preceding knowledge of the genetic profile and the awareness for potentially occurring severe over-anticoagulation problems under PPI co-medication could contribute to a safer and personalized VKA pharmacotherapy.
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Affiliation(s)
- Sophie Brunner-Ziegler
- Division of Angiology, Department of Internal Medicine II, Medical University of Vienna, Vienna, Austria
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Abstract
Objective We examined the potential effect of sex and age on warfarin dosing in ambulatory adult patients. Methods We conducted a retrospective chart review of patients attending an anticoagulation clinic. We included patients anticoagulated with warfarin for atrial fibrillation or venous thromboembolism who had a therapeutic international normalized ratio of 2–3 for 2 consecutive months. We excluded patients who had been on any drug that is known to have a major interaction with warfarin, smokers, and heavy alcohol consumers. Out of 340 screened medical records, 96 met the predetermined inclusion criteria. The primary outcome assessed was warfarin total weekly dose (TWD). Results There was a statistically significant difference in the TWD among the ages (P<0.01); older patients required lower doses. However there was no statistically significant difference in the TWD between sexes (P=0.281). Conclusion Age was found to have a significant effect on warfarin dosing. Even though women did require a lower TWD than men, this observation was not statistically significant.
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Affiliation(s)
- Ghada Khoury
- School of Pharmacy, Lebanese American University, Byblos, Lebanon
| | - Marwan Sheikh-Taha
- Department of Pharmacy Practice, Lebanese American University, Byblos, Lebanon
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Bank PC, Swen JJ, Guchelaar HJ. Pharmacogenetic biomarkers for predicting drug response. Expert Rev Mol Diagn 2014; 14:723-35. [PMID: 24857685 DOI: 10.1586/14737159.2014.923759] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Drug response shows significant interpatient variability and evidence that genetics influences outcome of drug therapy has been known for more than five decades. However, the translation of this knowledge to clinical practice remains slow. Using examples from clinical practice six considerations about the implementation of pharmacogenetics (PGx) into routine care are discussed: the need for PGx biomarkers; the sources of genetic variability in drug response; the amount of variability explained by PGx; whether PGx test results are actionable; the level of evidence needed for implementation of PGx and the sources of information regarding interpretation of PGx data.
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Affiliation(s)
- Paul Christiaan Bank
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands
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30
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Wu AHB, Superko HR. The pharmacogenomics of warfarin from the COAG and EU-PACT: where do we go from here? Per Med 2014; 11:247-249. [DOI: 10.2217/pme.14.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- Alan HB Wu
- Department of Laboratory Medicine, University of California, San Francisco, CA, USA
- San Francisco General Hospital, 1001 Potrero Avenue, Room 2M27, San Francisco, CA 94110, USA
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Andersson ML, Lindh JD, Mannheimer B. The impact of interacting drugs on dispensed doses of warfarin in the Swedish population: A novel use of population based drug registers. J Clin Pharmacol 2013; 53:1322-7. [PMID: 24038065 DOI: 10.1002/jcph.174] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/24/2013] [Indexed: 11/06/2022]
Abstract
To investigate the impact of interacting drugs on the dispensed doses of warfarin in the Swedish population. This was a retrospective, cross-sectional population based register study of patients being dispensed warfarin. Warfarin doses were estimated in different age groups, in men and women, and in patients using interacting drugs. The influence of interacting drugs on the dispensed warfarin dose was analyzed using multiple regression. All 143,729 patients dispensed warfarin were analyzed. The dispensed dose of warfarin was highest in patients 30-39 years old and decreased with age. Co-medication with carbamazepine, simvastatin, paracetamol, amiodarone, fluconazole, lactulose, or bezafibrate was associated with significant changes in dispensed warfarin doses, by +40%, -3.4%, -7.3%, -8.2%, -8.8%, -9.0%, and -9.7%, respectively. After adjustment for age and gender, sulfamethoxazole was also found to significantly alter the dispensed warfarin dose (-6.1%). We provide new support for the previous scarce evidence of interactions between warfarin and carbamazepine, bezafibrate, and lactulose. Initiation or discontinuation of bezafibrate or lactulose in a patient on warfarin should warrant close clinical monitoring. The marked increased warfarin requirement associated with carbamazepine use supports moving from a more conservative reactive towards a proactive strategy including preventive warfarin dose adjustments to avoid potential adverse effects.
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Affiliation(s)
- M L Andersson
- Department of Laboratory Medicine, Division of Clinical Pharmacology, Karolinska University Hospital, Huddinge, Karolinska Institutet, Stockholm, Sweden
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32
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Bazan NS, Sabry NA, Rizk A, Mokhtar S, Badary OA. Factors affecting warfarin dose requirements and quality of anticoagulation in adult Egyptian patients: role of gene polymorphism. Ir J Med Sci 2013; 183:161-72. [DOI: 10.1007/s11845-013-0978-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 06/11/2013] [Indexed: 12/22/2022]
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Verhoef TI, Redekop WK, van Schie RM, Bayat S, Daly AK, Geitona M, Haschke-Becher E, Hughes DA, Kamali F, Levin LÅ, Manolopoulos VG, Pirmohamed M, Siebert U, Stingl JC, Wadelius M, de Boer A, Maitland-van der Zee AH. Cost-effectiveness of pharmacogenetics in anticoagulation: international differences in healthcare systems and costs. Pharmacogenomics 2013; 13:1405-17. [PMID: 22966889 DOI: 10.2217/pgs.12.124] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Genotyping patients for CYP2C9 and VKORC1 polymorphisms can improve the accuracy of dosing during the initiation of anticoagulation with vitamin K antagonists (coumarin derivatives). The anticipated degree of improvement in the safety of anticoagulation with coumarins through genotyping may vary depending on the quality of patient care, which varies both with and among countries. The management and the cost of anticoagulant care can therefore influence the cost-effectiveness of genotyping within any given country. In this article, we provide an overview of the cost-effectiveness of pharmacogenetics-guided dosing of coumarin derivatives. We describe the organization of anticoagulant care in the UK, Sweden, The Netherlands, Greece, Germany and Austria, where a genotype-guided dosing algorithm is currently being investigated as part of the EU-PACT trial. We also explore the costs of anticoagulant care for the treatment of atrial fibrillation in these countries.
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Affiliation(s)
- Talitha I Verhoef
- Department of Pharmaceutical Sciences, Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht University, Utrecht, The Netherlands
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van Schie RMF, Wessels JAM, Verhoef TI, Schalekamp T, le Cessie S, van der Meer FJM, Rosendaal FR, Visser LE, Teichert M, Hofman A, Buhre PNM, de Boer A, Maitland-van der Zee AH. Evaluation of the effect of genetic variations in GATA-4 on the phenprocoumon and acenocoumarol maintenance dose. Pharmacogenomics 2012; 13:1917-23. [DOI: 10.2217/pgs.12.174] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: To investigate whether the phenprocoumon and acenocoumarol maintenance doses are influenced by genetic variations in GATA-4, a transcription factor of CYP2C9. Patients & methods: The influence of seven GATA-4 SNPs on the coumarin maintenance dose was investigated by performing an analysis of variance trend analysis, stratified for CYP2C9 genotypes. Results of the best-explaining SNP were validated in the Rotterdam Study cohort. Results: The largest dose differences were found for rs3735814 in patients using acenocoumarol and having the common allele for CYP2C9. The mean dosages decreased from 2.92 mg/day for the patients having the GATA-4 common alleles to 2.65 mg/day for the patients carrying one GATA-4 variant allele and to 2.37 mg/day for patients carrying two GATA-4 variant alleles (p = 0.004). Results could not be replicated in the validation cohort. For phenprocoumon, no significant effects were observed. Conclusion: Genetic variation in GATA-4 does not seem relevant for clinical implementation. Original submitted 31 August 2012; Revision submitted 12 October 2012
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Affiliation(s)
- Rianne MF van Schie
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands
| | - Judith AM Wessels
- Department of Clinical Pharmacy & Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Talitha I Verhoef
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands
| | - Tom Schalekamp
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, 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
| | - 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
| | - 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
| | - Albert Hofman
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Peter NM Buhre
- Star Medical Diagnostic Center, Rotterdam, The Netherlands
| | - Anthonius de Boer
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands
| | - Anke-Hilse Maitland-van der Zee
- Division of Pharmacoepidemiology & Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, PO Box 80 082, Utrecht University, 3508 TB Utrecht, The Netherlands
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Effect of different genetics variants: CYP2C9*2, CYP2C9*3 of cytochrome P-450 CYP2C9 and 1639G>A of the VKORC1 gene; On acenocoumarol requirement in Moroccan patients. ACTA ACUST UNITED AC 2012. [PMID: 23201087 DOI: 10.1016/j.patbio.2012.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Coumarin derivatives such as acenocoumarol represent the therapy of choice for the long-term treatment and prevention of thromboembolic diseases. Many genetics determinants involved in the metabolism of acenocoumarol have been shown to influence the anticoagulant dosage. The aim of this work was to evaluate, for the first time in Maghreb, the allelic frequencies of CYP2C9*2, CYP2C9*3 and VKORC1 -1639G>A mutations, and to establish the role of this polymorphisms in modulating the acenocoumarol requirement in Moroccan patients receiving anticoagulation treatment. Three groups of patients, with low, medium, or high acenocoumarol dose requirements were studied. Genetic analyses of VKORC1 -1639G>A, CYP2C9*2, and CYP2C9*3, were performed in 114 Moroccan patients with stable acenocoumarol dose. The results showed that the allelic frequencies of the three mutations studied was varies, most of patients having CYP2C9*2 and CYP2C9*3 mutations belong to a group with low dose of acenocoumarol, with P-value of 0.0082 and the single patient with CYP2C9*3 on homozygous form belongs to the same group and carried the A allele for VKORC1 gene. In conclusion, the present study confirmed the large interindividual variability in acenocoumarol maintenance dose due to CYP2C9*2, CYP2C9*3 and VKORC1 -1639G>A polymorphisms, and demonstrated that these alleles modulates sensitivity to acenocoumarol, a finding indicating that a reduced initial loading dose of acenocoumarol should be used in carriers of this allele, also, she indicates the usefulness of predictive testing concerning these mutations when an hypocoagulability is installed and not explained by the dose of VKA.
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Xu XS, Moore K, Burton P, Stuyckens K, Mueck W, Rossenu S, Plotnikov A, Gibson M, Vermeulen A. Population pharmacokinetics and pharmacodynamics of rivaroxaban in patients with acute coronary syndromes. Br J Clin Pharmacol 2012; 74:86-97. [PMID: 22242932 DOI: 10.1111/j.1365-2125.2012.04181.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Population pharmacokinetics and pharmacodynamics of rivaroxaban have been characterized in healthy subjects and in patients with total venous thromboembolism, deep vein thrombosis or atrial fibrillation. WHAT THIS STUDY ADDS • This article is the first description of the population pharmacokinetics (PK) and pharmacodynamics (PD) of rivaroxaban in patients with acute coronary syndrome (ACS). It is the largest population pharmacokinetic and pharmacodynamic study on rivaroxaban conducted to date (n= 2290). The PK and PK-PD relationship of rivaroxaban in patients with ACS were similar to those in other patient populations. In addition, model-based simulations showed that the influence of renal function and age on the exposure to rivaroxaban in the ACS population were similar to the findings from Phase 1 special population studies. These findings suggest that rivaroxaban has highly predictable PK-PD and may provide a consistent anticoagulant effect across the studied patient populations, which allows an accurate prediction of the dose to control anticoagulation optimally. AIMS The aim of this analysis was to use a population approach to facilitate the understanding of the pharmacokinetics and pharmacodynamics of rivaroxaban in patients with acute coronary syndrome (ACS) and to evaluate the influence of patient covariates on the exposure of rivaroxaban in patients with ACS. METHODS A population pharmacokinetic model was developed using pharmacokinetic samples from 2290 patients in Anti-Xa Therapy to Lower Cardiovascular Events in Addition to Standard Therapy in Subjects with Acute Coronary Syndrome Thrombolysis in Myocardial Infarction 46. The relationship between pharmacokinetics and the primary pharmacodynamic end point, prothrombin time, was evaluated. RESULTS The pharmacokinetics of rivaroxaban in patients with ACS was adequately described by an oral one-compartment model. The estimated absorption rate, apparent clearance and volume of distribution were 1.24 h(-1) (interindividual variability, 139%), 6.48 l h(-1) (31%) and 57.9 l (10%), respectively. Simulations indicate that the influences of renal function, age and bodyweight on exposure in ACS patients are consistent with the findings in previous Phase 1 studies. Rivaroxaban plasma concentrations exhibit a close-to-linear relationship with prothrombin time in the ACS population, with little interindividual variability. The estimated pharmacokinetic and pharmacodynamic parameters for the ACS patients were comparable to those for venous thromboembolism prevention, deep vein thrombosis and atrial fibrillation patients. CONCLUSIONS The similarity in pharmacokinetics/pharmacodynamics of rivaroxaban among different patient populations and the low interindividual variability in the exposure-prothrombin time relationship indicate that the anticoagulant effect of rivaroxaban is highly predictable and consistent across all the patient populations studied.
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Affiliation(s)
- Xu Steven Xu
- Clinical Pharmacology, Advanced PK-PD Modeling and Simulation, Janssen Research & Development, Titusville, NJ 08560, USA.
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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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Bazan NS, Sabry NA, Rizk A, Mokhtar S, Badary O. Validation of pharmacogenetic algorithms and warfarin dosing table in Egyptian patients. Int J Clin Pharm 2012; 34:837-44. [PMID: 22851439 DOI: 10.1007/s11096-012-9678-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 07/16/2012] [Indexed: 01/10/2023]
Abstract
BACKGROUND Warfarin remains a difficult drug to use due to the large variability in dose response. Clear understanding of the accuracy of warfarin pharmacogenetic dosing methods might lead to appropriate control of anticoagulation. OBJECTIVE This study aims to evaluate the accuracy of warfarin dosing table and two pharmacogenetic algorithms, namely the algorithms of Gage et al. (Clin Pharmacol Ther 84:326-331, 2008), and the International Warfarin Pharmacogenetics Consortium algorithm (IWPC) in a real Egyptian clinical setting. Additionally, three non-pharmacogenetic dosing methods (the Gage, IWPC clinical algorithms and the empiric 5 mg/day dosing) were evaluated. SETTING Sixty-three Egyptian patients on a stable therapeutic warfarin dose were included. Patients were recruited from the outpatient clinic of the critical care medicine department. METHODS CYP2C9 and VKORC1 polymorphisms were genotyped by real time PCR system. Predicted doses by all dosing methods were calculated and compared with the actual therapeutic warfarin doses. RESULTS The Gage algorithm (adjusted R(2) = 0.421, and mean absolute error (MAE) = 3.3), and IWPC algorithm (adjusted R(2) = 0.419, MAE = 3.2) produced better accuracy than did the warfarin dosing table (adjusted R(2) = 0.246, MAE = 3.5), the two clinical algorithms (R(2) = 0.24, MAE = 3.7) and the fixed dose approach (MAE = 3.9). However, all dosing models produced comparable clinical accuracy with respect to proportion of patients within 1 mg/day of actual dose (ideal dose). Non-pharmacogenetic methods severely over-predicted dose (defined as ≥2 mg/day more than actual dose) compared to the three pharmacogenetic models. In comparison to non-pharmacogenetic methods, the three pharmacogenetic models performed better regarding the low dose group in terms of percentage of patients within ideal dose. In the high dose group, none of the dosing models predicted warfarin doses within ideal dose. CONCLUSION Our study showed that genotype-based dosing improved prediction of warfarin therapeutic dose beyond that available with the fixed-dose approach or the clinical algorithms, especially in the low-dose group. However, the two pharmacogenetic algorithms were the most accurate.
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Affiliation(s)
- Naglaa Samir Bazan
- Critical Care Medicine Department, Cairo University Hospitals, Cairo, Egypt.
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van Schie RMF, Babajeff AMV, Schalekamp T, Wessels JAM, le Cessie S, de Boer A, van der Meer FJM, van Meegen E, Verhoef TI, Rosendaal FR, Maitland-van der Zee AH. An evaluation of gene-gene interaction between the CYP2C9 and VKORC1 genotypes affecting the anticoagulant effect of phenprocoumon and acenocoumarol. J Thromb Haemost 2012; 10:767-72. [PMID: 22409277 DOI: 10.1111/j.1538-7836.2012.04694.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Previous studies have provided contradictory results regarding the interaction between the CYP2C9 and VKORC1 genotypes affecting various outcome measures. OBJECTIVES We aimed to provide a definite answer regarding the question whether there exists a gene-gene interaction between the CYP2C9 and VKORC1 genotypes affecting the anticoagulant effect of phenprocoumon and acenocoumarol. PATIENTS/METHODS The EU-PACT cohort dataset, which contains data on 624 phenprocoumon and 471 acenocoumarol patients, was used. Patient characteristics, pharmacogenetic data, International Normalized Ratios (INRs) and dosages were available. We investigated whether there was an interaction between the CYP2C9 and VKORC1 genotypes affecting the maintenance dose, time to severe over-anticoagulation and time to achieve stability during the first 180 days of phenprocoumon and acenocoumarol therapy, in addition to the effect of the separate genotypes. The interaction effect was investigated by adding the product term of the CYP2C9 and VKORC1 genotype classes for four different commonly used CYP2C9 classifications to the linear regression model - for the outcome measure maintenance dose - or to the Cox regression models - for the outcome measures time to severe over-anticoagulation and time to achieve stability. RESULTS No significant interactions - all P-values above 0.23 for phenprocoumon and 0.30 for acenocoumarol - were observed for all outcome measures. CONCLUSIONS There are no interactions between the CYP2C9 and VKORC1 genotypes affecting the maintenance dose, time to severe over-anticoagulation and time to achieve stability for phenprocoumon and acenocoumarol.
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Affiliation(s)
- R M F van Schie
- Division of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands
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Ageno W, Gallus AS, Wittkowsky A, Crowther M, Hylek EM, Palareti G. Oral anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest 2012; 141:e44S-e88S. [PMID: 22315269 PMCID: PMC3278051 DOI: 10.1378/chest.11-2292] [Citation(s) in RCA: 1016] [Impact Index Per Article: 84.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND The objective of this article is to summarize the published literature concerning the pharmacokinetics and pharmacodynamics of oral anticoagulant drugs that are currently available for clinical use and other aspects related to their management. METHODS We carried out a standard review of published articles focusing on the laboratory and clinical characteristics of the vitamin K antagonists; the direct thrombin inhibitor, dabigatran etexilate; and the direct factor Xa inhibitor, rivaroxaban RESULTS The antithrombotic effect of each oral anticoagulant drug, the interactions, and the monitoring of anticoagulation intensity are described in detail and discussed without providing specific recommendations. Moreover, we describe and discuss the clinical applications and optimal dosages of oral anticoagulant therapies, practical issues related to their initiation and monitoring, adverse events such as bleeding and other potential side effects, and available strategies for reversal. CONCLUSIONS There is a large amount of evidence on laboratory and clinical characteristics of vitamin K antagonists. A growing body of evidence is becoming available on the first new oral anticoagulant drugs available for clinical use, dabigatran and rivaroxaban.
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Affiliation(s)
| | | | | | - Mark Crowther
- McMaster University, St. Joseph's Hospital, Hamilton, ON, Canada
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Martin J, Somogyi A. Pharmacogenomics and Warfarin Therapy. Ther Drug Monit 2012. [DOI: 10.1016/b978-0-12-385467-4.00008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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van Schie RM, Wessels JA, le Cessie S, de Boer A, Schalekamp T, van der Meer FJ, Verhoef TI, van Meegen E, Rosendaal FR, Maitland-van der Zee AH. Loading and maintenance dose algorithms for phenprocoumon and acenocoumarol using patient characteristics and pharmacogenetic data. Eur Heart J 2011; 32:1909-17. [DOI: 10.1093/eurheartj/ehr116] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Rianne M.F. van Schie
- Study coordinating Centre, Department of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
| | - Judith A.M. Wessels
- Department of Clinical Pharmacy and Toxicology, Leiden University Medical Center, Leiden, The Netherlands
| | - Saskia le Cessie
- Department of Medical Statistics and Bioinformatics, Leiden University Medical Center, Leiden, The Netherlands
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Anthonius de Boer
- Study coordinating Centre, Department of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
| | - Tom Schalekamp
- Study coordinating Centre, Department of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
| | - Felix J.M. van der Meer
- Department of Thrombosis and Haemostasis, Leiden University Medical Center, Leiden, The Netherlands
| | - Talitha I. Verhoef
- Study coordinating Centre, Department of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
| | - Erik van Meegen
- Medial, medical-diagnostic laboratories, Hoofddorp, The Netherlands
| | - Frits R. Rosendaal
- Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Thrombosis and Haemostasis, Leiden University Medical Center, Leiden, The Netherlands
| | - Anke-Hilse Maitland-van der Zee
- Study coordinating Centre, Department of Pharmacoepidemiology and Clinical Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
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Finkelman BS, Gage BF, Johnson JA, Brensinger CM, Kimmel SE. Genetic warfarin dosing: tables versus algorithms. J Am Coll Cardiol 2011; 57:612-8. [PMID: 21272753 DOI: 10.1016/j.jacc.2010.08.643] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/16/2010] [Accepted: 08/24/2010] [Indexed: 01/21/2023]
Abstract
OBJECTIVES The aim of this study was to compare the accuracy of genetic tables and formal pharmacogenetic algorithms for warfarin dosing. BACKGROUND Pharmacogenetic algorithms based on regression equations can predict warfarin dose, but they require detailed mathematical calculations. A simpler alternative, recently added to the warfarin label by the U.S. Food and Drug Administration, is to use genotype-stratified tables to estimate warfarin dose. This table may potentially increase the use of pharmacogenetic warfarin dosing in clinical practice; however, its accuracy has not been quantified. METHODS A retrospective cohort study of 1,378 patients from 3 anticoagulation centers was conducted. Inclusion criteria were stable therapeutic warfarin dose and complete genetic and clinical data. Five dose prediction methods were compared: 2 methods using only clinical information (empiric 5 mg/day dosing and a formal clinical algorithm), 2 genetic tables (the new warfarin label table and a table based on mean dose stratified by genotype), and 1 formal pharmacogenetic algorithm, using both clinical and genetic information. For each method, the proportion of patients whose predicted doses were within 20% of their actual therapeutic doses was determined. Dosing methods were compared using McNemar's chi-square test. RESULTS Warfarin dose prediction was significantly more accurate (all p < 0.001) with the pharmacogenetic algorithm (52%) than with all other methods: empiric dosing (37%; odds ratio [OR]: 2.2), clinical algorithm (39%; OR: 2.2), warfarin label (43%; OR: 1.8), and genotype mean dose table (44%; OR: 1.9). CONCLUSIONS Although genetic tables predicted warfarin dose better than empiric dosing, formal pharmacogenetic algorithms were the most accurate.
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Affiliation(s)
- Brian S Finkelman
- Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, University of Pennsylvania School of Medicine, Philadelphia, USA
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Grady BJ, Ritchie MD. Statistical Optimization of Pharmacogenomics Association Studies: Key Considerations from Study Design to Analysis. CURRENT PHARMACOGENOMICS AND PERSONALIZED MEDICINE 2011; 9:41-66. [PMID: 21887206 PMCID: PMC3163263 DOI: 10.2174/187569211794728805] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Research in human genetics and genetic epidemiology has grown significantly over the previous decade, particularly in the field of pharmacogenomics. Pharmacogenomics presents an opportunity for rapid translation of associated genetic polymorphisms into diagnostic measures or tests to guide therapy as part of a move towards personalized medicine. Expansion in genotyping technology has cleared the way for widespread use of whole-genome genotyping in the effort to identify novel biology and new genetic markers associated with pharmacokinetic and pharmacodynamic endpoints. With new technology and methodology regularly becoming available for use in genetic studies, a discussion on the application of such tools becomes necessary. In particular, quality control criteria have evolved with the use of GWAS as we have come to understand potential systematic errors which can be introduced into the data during genotyping. There have been several replicated pharmacogenomic associations, some of which have moved to the clinic to enact change in treatment decisions. These examples of translation illustrate the strength of evidence necessary to successfully and effectively translate a genetic discovery. In this review, the design of pharmacogenomic association studies is examined with the goal of optimizing the impact and utility of this research. Issues of ascertainment, genotyping, quality control, analysis and interpretation are considered.
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Affiliation(s)
- Benjamin J. Grady
- Department of Molecular Physiology & Biophysics, Center for Human Genetics Research, Vanderbilt University, Nashville, TN, USA
| | - Marylyn D. Ritchie
- Department of Molecular Physiology & Biophysics, Center for Human Genetics Research, Vanderbilt University, Nashville, TN, USA
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Verhoef TI, Redekop WK, Darba J, Geitona M, Hughes DA, Siebert U, de Boer A, Maitland-van der Zee AH, Barallon R, Briz M, Daly A, Haschke-Becher E, Kamali F, Kirchheiner J, Manolopoulos VG, Pirmohamed M, Rosendaal FR, van Schie RMF, Wadelius M. A systematic review of cost-effectiveness analyses of pharmacogenetic-guided dosing in treatment with coumarin derivatives. Pharmacogenomics 2011; 11:989-1002. [PMID: 20602617 DOI: 10.2217/pgs.10.74] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Anticoagulant therapy with coumarin derivatives is often sub- or supra-therapeutic, resulting in an increased risk of thromboembolic events or hemorrhage, respectively. Pharmacogenetic-guided dosing has been proposed as an effective way of reducing bleeding rates. Clinical trials to confirm the safety, efficacy and effectiveness of this strategy are ongoing, but in addition, it is also necessary to consider the cost-effectiveness of this strategy. This article describes the findings of a systematic review of published cost-effectiveness analyses of pharmacogenetic-guided dosing of coumarin derivatives. Similarities and differences in the approaches used were examined and the quality of the analyses was assessed. The results of the analyses are not sufficient to determine whether or not pharmacogenetic-guided dosing of coumarins is cost effective. More reliable cost-effectiveness estimates need to become available before it is possible to recommend whether or not this strategy should be applied in clinical practice.
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Affiliation(s)
- Talitha I Verhoef
- Division of Pharmacoepidemiology & Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80 082, 3508 TB Utrecht, The Netherlands
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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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Abstract
Rivaroxaban is a small-molecule, direct factor Xa inhibitor that is under investigation for the prevention and treatment of venous and arterial thrombosis. To date, oral anticoagulants have been limited largely to vitamin K antagonists. Despite their remarkable benefits, vitamin K antagonists are limited by their narrow therapeutic window, the existence of multiple food and drug interactions, and the need for frequent monitoring and dose-adjustment. Rivaroxaban represents a potentially attractive alternative to warfarin, as it could enable simplified once-daily dosing, requires no therapeutic monitoring, and has a lower potential for drug interactions. At present, the safety and efficacy of rivaroxaban for the prophylaxis and treatment of venous thromboembolism has been evaluated in phase-II and phase-III trials involving over 24,000 patients. Rivaroxaban is also being evaluated for the treatment of pulmonary embolism, secondary prevention after acute coronary syndromes, and the prevention of stroke and non-central nervous system embolism in patients with non-valvular atrial fibrillation. The need for new oral anticoagulants, the development and pharmacology of rivaroxaban, results of completed studies of rivaroxaban, and details of ongoing phase-II and phase-III trials with rivaroxaban are the subjects of this chapter.
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Squassina A, Manchia M, Manolopoulos VG, Artac M, Lappa-Manakou C, Karkabouna S, Mitropoulos K, Zompo MD, Patrinos GP. Realities and expectations of pharmacogenomics and personalized medicine: impact of translating genetic knowledge into clinical practice. Pharmacogenomics 2010; 11:1149-67. [DOI: 10.2217/pgs.10.97] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The implementation of genetic data for a better prediction of response to medications and adverse drug reactions is becoming a reality in some clinical fields. However, to be successful, personalized medicine should take advantage of an informational structured framework of genetic, phenotypic and environmental factors in order to provide the healthcare system with useful tools that can optimize the effectiveness of specific treatment. The impact of personalized medicine is potentially enormous, but the results that have so far been gathered are often difficult to translate into clinical practice. In this article we have summarized the most relevant applications of pharmacogenomics on diseases to which they have already been applied and fields in which they are currently emerging. The article provides an overview of the opportunities and shortcomings of the implementation of genetic information into personalized medicine and its full adoption in the clinic. In the second instance, it provides readers from different fields of expertise with an accessible interpretation to the barriers and opportunities in the use/adoption of pharmacogenomic testing between the different clinical areas.
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Affiliation(s)
| | - Mirko Manchia
- University of Cagliari, Cagliari, Italy
- Dalhousie University, Halifax, Nova Scotia, Canada
| | | | | | | | | | | | | | - George P Patrinos
- University of Patras, Department of Pharmacy, School of Health Sciences, University Campus, Rion, GR-265 04, Patras, Greece
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Manolopoulos VG, Ragia G, Tavridou A. Pharmacogenetics of coumarinic oral anticoagulants. Pharmacogenomics 2010; 11:493-6. [PMID: 20350128 DOI: 10.2217/pgs.10.31] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Coumarinic oral anticoagulants are life-saving drugs, but are also one of the leading causes of drug-induced major bleeding events. Moreover, there is substantial individual variation in response to coumarinic oral anticoagulants caused by several factors including variations in the CYP2C9 and VKORC1 genes. Several retrospective and a few small prospective clinical studies have shown that polymorphisms in CYP2C9 and VKORC1 genes together account for 35-50% of the variability in warfarin initiation and maintenance dose requirements. Large randomized clinical trials are currently underway to further solidify the safety, clinical utility and cost-effectiveness of pharmacogenetic-guided dosing algorithms for warfarin, acenocoumarol and phenprocoumon. By 2020, coumarinic oral anticoagulant pharmacogenetic testing will be part of routine clinical practice in anticoagulant therapy.
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Affiliation(s)
- Vangelis G Manolopoulos
- Laboratory of Pharmacology & Clinical Pharmacology, Medical School, Democritus University of Thrace, Dragana Campus, 68100 Alexandroupolis, Greece.
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Garwood, CL, Clemente JL, Ibe GN, Kandula VA, Curtis KD, Whittaker P. Warfarin maintenance dose in older patients: Higher average dose and wider dose frequency distribution in patients of African ancestry than those of European ancestry. Blood Cells Mol Dis 2010; 45:93-7. [DOI: 10.1016/j.bcmd.2010.03.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 03/18/2010] [Accepted: 03/18/2010] [Indexed: 11/29/2022]
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