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Mohamed S, Mei Fong C, Jie Ming Y, Naila Kori A, Abdul Wahab S, Mohd Ali Z. Evaluation of an Initiation Regimen of Warfarin for International Normalized Ratio Target 2.0 to 3.0. J Pharm Technol 2021; 37:286-292. [PMID: 34790965 DOI: 10.1177/87551225211034175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
Abstract
Background: he number of patients on warfarin therapy is rising steadily. Although warfarin is beneficial, it carries a high risk of bleeding, especially if the international normalized ratio (INR) values exceed 3.0. Currently, no warfarin initiation regimens have been developed for the Asian population, especially for Malaysians. Objective: This article describes the efficacy and safety of a new initiation regimen for warfarin among warfarin-naive patients. Method: Data were retrospectively collected from the ambulatory and inpatient settings. Results: A total of 165 patients who each had a target INR of 2.0 to 3.0 were included in the study. The mean age was 57.2 years and 94 patients were male. A total of 108 patients used Regimen 1 (5 mg/5 mg/3mg) and the rest of the patients used Regimen 2 (5 mg/3 mg/3 mg). Most patients used warfarin either for atrial fibrillation (52.1%) or for venous thromboembolism (29.7%). Overall, 88 of the patients had INR values above 50% from the baseline on Day 4. Additionally, 13 patients had INR values of >3.2, which required withholding and lower dose of warfarin. The predicted weekly maintenance warfarin dose (23 ± 0.5 mg/week) was found to have correlated closely with the actual maintenance dose (22.8 ± 0.5 mg/week; r 2 = 0.75). Nearly two thirds (70.3%) of the patients achieved the target INR on Day 11. Conclusion: The warfarin initiation regimens in this study was simple, safe, and suitable to be used in both ambulatory and inpatient settings for managing warfarin therapy.
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Affiliation(s)
| | - Chan Mei Fong
- Hospital Tengku Ampuan Afzan, Kuantan, Pahang, Malaysia
| | - Yew Jie Ming
- Hospital Tengku Ampuan Afzan, Kuantan, Pahang, Malaysia
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Bertoletti L, Sanchez O. [What are the special features of treatment in "fragile" patients (elderly, renal failure)]. Rev Mal Respir 2021; 38 Suppl 1:e157-e160. [PMID: 33744077 DOI: 10.1016/j.rmr.2019.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- L Bertoletti
- F-CRIN INNOVTE, 42055 Saint-Étienne cedex 2, France; Équipe dysfonction vasculaire et hémostase, Inserm UMR1059, Inserm, CIC-1408, service de médecine vasculaire et thérapeutique, CHU de Saint-Étienne, université Jean-Monnet, 42000 Saint-Étienne, France
| | - O Sanchez
- F-CRIN INNOVTE, 42055 Saint-Étienne cedex 2, France; Inserm UMRS 1140, service de pneumologie et de soins intensifs, université Paris Descartes, Sorbonne Paris cité, hôpital européen Georges-Pompidou, Assistance publique-hôpitaux de Paris, 20, rue Leblanc, 75015 Paris, France.
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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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Shoji M, Suzuki S, Otsuka T, Arita T, Yagi N, Semba H, Kano H, Matsuno S, Kato Y, Uejima T, Oikawa Y, Matsuhama M, Yajima J, Yamashita T. A Simple Formula for Predicting the Maintenance Dose of Warfarin with Reference to the Initial Response to Low Dosing at an Outpatient Clinic. Intern Med 2020; 59:29-35. [PMID: 31511484 PMCID: PMC6995699 DOI: 10.2169/internalmedicine.3415-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Objective The pharmacodynamic effect of warfarin varies among individuals, and its maintenance dose is widely distributed. Although many formulae for predicting the maintenance dose of warfarin have been developed, most of them are complex and not in practical use. Methods and Materials Among 12,738 new patients visiting the Cardiovascular Institute between 2004 and 2009, we identified 127 patients (66.6±8.8 years, 89 men) with atrial fibrillation for whom warfarin was newly started with an initial dose of 2 mg/day and the international normalized ratio (INR) at 1 year after warfarin was started was within the therapeutic range. The prediction models for the maintenance dose were developed by an exponential equation and a first-order equation. Results The initial response of the INR to the dose of 2 mg/day (initial INR) ranged from 1.00-3.24 (mean 1.43), while the maintenance dose of warfarin ranged from 0.5-14 mg (mean 3.8 mg). The maintenance dose showed an exponential correlation to the initial INR: (predicted maintenance dose) =5.522× (initial INR) -1.556 (R2=0.795, p<0.001). Excluding the patients with a poor response to the initial dose (initial INR <1.1, n=32) permitted a simple correlation with a first-order approximation: (predicted maintenance dose) =-2.009× (initial INR) +6.172 (R2=0.706, p<0.001). Conclusion We developed a simple formula for predicting the maintenance dose of warfarin using the initial response of the INR to low-dose warfarin.
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Affiliation(s)
- Masaaki Shoji
- Department of Cardiovascular Medicine, National Cancer Center Hospital, Japan
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Shinya Suzuki
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Takayuki Otsuka
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Takuto Arita
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Naoharu Yagi
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Hiroaki Semba
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Hiroto Kano
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Shunsuke Matsuno
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Yuko Kato
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Tokuhisa Uejima
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Yuji Oikawa
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Minoru Matsuhama
- Department of Cardiovascular Surgery, The Cardiovascular Institute, Japan
| | - Junji Yajima
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
| | - Takeshi Yamashita
- Department of Cardiovascular Medicine, The Cardiovascular Institute, Japan
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Smadja DM, Gendron N, Sanchez O. [Who should supervise anticoagulant treatment and how?]. Rev Mal Respir 2019; 38 Suppl 1:e113-e119. [PMID: 31611030 DOI: 10.1016/j.rmr.2019.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- D-M Smadja
- F-CRIN INNOVTE, 42055 St-Étienne cedex 2, France; Inserm UMR-S1140, service d'hématologie, laboratoire de recherche biochirurgicale, Fondation Carpentier, hôpital européen Georges-Pompidou, université Paris Descartes, Sorbonne Paris Cité, hôpital européen Georges-Pompidou, AP-HP, 75015 Paris, France
| | - N Gendron
- Inserm UMR 1148, laboratoire d'hématologie, hôpital Bichat-Claude Bernard, université Paris Diderot, Sorbonne Paris Cité, AP-HP, 75018 Paris, France
| | - O Sanchez
- F-CRIN INNOVTE, 42055 St-Étienne cedex 2, France; Service de pneumologie et de soins intensifs, hôpital européen Georges-Pompidou, université de Paris, Sorbonne Paris Cité, Assistance publique des Hôpitaux de Paris, 20, rue Leblanc, 75015 Paris, France; Innovations thérapeutiques en hémostase, Inserm UMRS 1140, 75006 Paris, France.
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Lafuente-Lafuente C, Oasi C, Belmin J. [Treatment with oral anticoagulants in older patients: Should warfarin still be prescribed?]. Presse Med 2018; 48:154-164. [PMID: 30528147 DOI: 10.1016/j.lpm.2018.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/07/2018] [Indexed: 11/17/2022] Open
Abstract
Vitamin-K antagonists (VKA) have been the standard for oral anticoagulation. However, they carry several problems in older patients: frequent bleeding complications, complex management, risk of interactions with multiple drugs. Two classes of direct oral anticoagulants (DOA) are currently available in France: (a) direct thrombin inhibitors: dabigatran; and (b) direct factor Xa inhibitors: rivaroxaban, apixaban and others. Their management is easier: quickly effective after administration, they are given at fixed doses and do not need regular laboratory monitoring. Several randomized trials have shown that DOA are non-inferior to VKA for treating venous thromboembolic disease (prophylactic or curative treatment) and atrial fibrillation (prevention of associated embolisms). DOA might be also effective for long-term treatment of coronary disease, in some cases. No trial has specifically studied older patients. In the context of atrial fibrillation, subgroup analysis show similar results between patients above and below 75-years-old. Lower doses of dabigatran and apixaban should be used in many older people. All DOA are eliminated at least partly by kidneys. Their dose must be reduced in moderate renal failure (filtration glomerular rate (FGR) 30 to 50mL/min) and they are contraindicated in older patients with severe renal failure (FGR<30mL/min). DOA also have other problems: (a) important drug interactions are still possible, (b) the clinical application of specific coagulation tests need to be defined, (c) their safety in some subgroups of elderly patients, very different from patients included in clinical trials, is not known.
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Affiliation(s)
- Carmelo Lafuente-Lafuente
- AP-HP, hôpitaux universitaires Pitié-Salpêtrière-Charles Foix, site Charles Foix, service de gériatrie à orientation cardiologique et neurologique, 94205 Ivry-sur-Seine, France; Sorbonne université, faculté de médecine, 75013 Paris, France.
| | - Christel Oasi
- AP-HP, hôpitaux universitaires Pitié-Salpêtrière-Charles Foix, site Charles Foix, service de gériatrie à orientation cardiologique et neurologique, 94205 Ivry-sur-Seine, France
| | - Joël Belmin
- AP-HP, hôpitaux universitaires Pitié-Salpêtrière-Charles Foix, site Charles Foix, service de gériatrie à orientation cardiologique et neurologique, 94205 Ivry-sur-Seine, France; Sorbonne université, faculté de médecine, 75013 Paris, France
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Hasan SS, Kow CS, Curley LE, Baines DL, Babar ZUD. Economic evaluation of prescribing conventional and newer oral anticoagulants in older adults. Expert Rev Pharmacoecon Outcomes Res 2018; 18:371-377. [PMID: 29741099 DOI: 10.1080/14737167.2018.1474101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
INTRODUCTION Anticoagulants refer to a variety of agents that inhibit one or more steps in the coagulation cascade. Generally, clinical conditions that require the prescribing of an oral anticoagulant increase in frequency with age. However, a major challenge of anticoagulation use among older patients is that this group of patients also experience the highest bleeding risk. To date, economic evaluation of prescribing of anticoagulants that includes the novel or newer oral anticoagulants (NOACs) in older adults has not been conducted and is warranted. AREAS COVERED A review of articles that evaluated the cost of prescribing conventional (e.g. vitamin K antagonists) and NOACs (e.g. direct thrombin inhibitors and direct factor Xa inhibitors) in older adults. EXPERT COMMENTARY While the use of NOACs significantly increases the cost of the initial treatment for thromboembolic disorders, they are still considered cost-effective relative to warfarin since they offer reduced risk of intracranial haemorrhagic events. The optimum anticoagulation with warfarin can be achieved by providing specialised care; clinics managed by pharmacists have been shown to be cost-effective relative to usual care. There are suggestions that genotyping the CYP2C9 and VKORC1 genes is useful for determining a more appropriate initial dose and thereby increasing the effectiveness and safety of warfarin.
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Affiliation(s)
- Syed Shahzad Hasan
- a Department of Pharmacy , University of Huddersfield , Huddersfield , United Kingdom.,e School of Biomedical Sciences and Pharmacy, The University of Newcastle , Newcastle , Australia
| | - Chia Siang Kow
- b Department of Pharmacy , Health Clinic Bukit Kuda , Klang , Malaysia
| | - Louise E Curley
- c School of Pharmacy, The University of Auckland , Auckland , New Zealand
| | - Darrin L Baines
- d Department of Accounting , Finance & Economics, Bournemouth University , Bournemouth , United Kingdom
| | - Zaheer-Ud-Din Babar
- a Department of Pharmacy , University of Huddersfield , Huddersfield , United Kingdom.,c School of Pharmacy, The University of Auckland , Auckland , New Zealand
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Kim SW, Yoon SJ, Choi JY, Kang MG, Cho Y, Oh IY, Kim CH, Kim KI. Clinical implication of frailty assessment in older patients with atrial fibrillation. Arch Gerontol Geriatr 2016; 70:1-7. [PMID: 28006693 DOI: 10.1016/j.archger.2016.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 11/02/2016] [Accepted: 12/03/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND We aimed to show the frailty status in older AF patients, and to find the association between frailty and the scores of CHA2DS2-VASc and HAS-BLED. Ultimately, we sought to investigate the impact of frailty on cardiovascular and all-cause mortality in older AF patients. METHODS We retrospectively evaluated 365 patients (≥65years old) with AF, who underwent comprehensive geriatric assessment (CGA) between 2007 and 2014 in a single tertiary hospital. The CHA2DS2-VASc and HAS-BLED scores were calculated based on the electronic medical records and the frailty index was computed from the CGA data. The primary outcomes were cardiovascular and all-cause mortality. RESULTS Frailty status was positively associated with the CHA2DS2-VASc score (P<0.001) and the HAS-BLED score (P=0.01). Patients with high CHA2DS2-VASc and HAS-BLED scores were more likely to be treated with anticoagulants rather than antiplatelet agents. However, frailty status was not associated with antithrombotic therapy. During the follow-up period (median [interquartile range], 22.9 [8.4-42.2] months), 141 patients (38.6%) died, of which 48 were due to cardiovascular events. CHA2DS2-VASc score could predict cardiovascular mortality, but not all-cause mortality. In contrast, frailty status was the independent predictor for both cardiovascular and all-cause mortality after adjusting for possible confounders (hazard ratio for all-cause mortality, 4.549; 95% CI, 2.756-7.509; P<0.001). CONCLUSION Frailty assessment can be used to predict mortality in older AF patients, and provides additional prognostic value, along with the CHA2DS2-VASc and HAS-BLED scores.
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Affiliation(s)
- Sun-Wook Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Sol-Ji Yoon
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Jung-Yeon Choi
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Min-Gu Kang
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Youngjin Cho
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Il-Young Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Cheol-Ho Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
| | - Kwang-Il Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Republic of Korea.
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Hyun G, Li J, Bass AR, Mohapatra A, Woller SC, Lin H, Eby C, McMillin GA, Gage BF. Use of signals and systems engineering to improve the safety of warfarin initiation. J Thromb Thrombolysis 2016; 42:529-33. [PMID: 27443162 DOI: 10.1007/s11239-016-1402-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Warfarin-dosing algorithms combine clinical factors and dosing history with the current international normalized ratio (INR) to estimate the therapeutic warfarin dose. Unfortunately, these approaches can result in an overdose if the INR is spuriously low. Our goal was to develop an alert mechanism based on prior INRs in addition to the current INR. Using data from the Genetics InFormatics Trial (GIFT) of Warfarin to Prevent DVT, we analyzed warfarin dose estimates for days 3 through 11 that were ≥10 % higher than an average of the previous two dose estimates. We fit a stepwise mixed model to current and prior dose estimates, and subsequently compared the root-mean-square-error (RMSE) in predicting the final therapeutic dose using the GIFT algorithm versus the mixed model. From 861 dosing records (obtain from 556 patients), 646 dosing records (75 %) were randomly selected for the derivation cohort and 215 dosing records (25 %) for the validation cohort. Using one prior dose estimate improved the accuracy of the warfarin dose estimate. Compared to a dose estimate based on current INR (GIFT algorithm), the mixed model reduced the RMSE in the derivation cohort by 0.0015 mg/day (RMSE 0.2079 vs. 0.2094; p = 0.039). In the validation cohort, the RMSE reduction was not significant. A mixed model of dose estimates based on the current and most recent INRs shows potential to improve the safety of warfarin dosing. Clinicians should be cautious about aggressively escalating the warfarin dose after an INR that is lower than expected.
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Affiliation(s)
- G Hyun
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA
| | - J Li
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA
| | - A R Bass
- Hospital for Special Surgery, Weill Cornell Medical College, 535 E 70th Street, New York, NY, 10021, USA
| | - A Mohapatra
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA
| | - S C Woller
- Intermountain Medical Center, 5121 Cottonwood St, Murray, UT, 84157, USA
| | - H Lin
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA
| | - C Eby
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA
| | - G A McMillin
- Department of Pathology and ARUP Laboratories, University of Utah, 500 Chipeta Way, Salt Lake City, UT, 84108, USA
| | - B F Gage
- Washington University School of Medicine, 660 S. Euclid Ave, Campus Box 8005, St. Louis, MO, 63110, USA.
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Kasner SE, Wang L, French B, Messe SR, Horenstein R, Mohler ER, Muldowney JAS, Ellenberg J, Kimmel SE. The Impact of Inpatient Versus Outpatient Initiation on Early Warfarin Dosing. Am J Cardiovasc Drugs 2015; 15:267-74. [PMID: 26037731 PMCID: PMC4508217 DOI: 10.1007/s40256-015-0126-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND AND OBJECTIVES Dosing algorithms for warfarin incorporate clinical and genetic factors but may not account for the numerous comorbidities affecting patients who start warfarin while hospitalized. We aimed to determine whether these algorithms perform differently when warfarin is initiated for inpatients compared with outpatients. PATIENTS AND METHODS We analyzed a prospective cohort of 1015 participants from the Clarification of Optimal Anticoagulation through Genetics (COAG) trial who were randomized to either pharmacogenetically or clinically guided warfarin dosing algorithms. Clinicians and participants were blinded to dose during the first 28 days. We compared groups, based on location at the time of the first warfarin dose request, in relation to the following outcomes: percentage of time in the therapeutic international normalized ratio (INR) range (PTTR) during the first 4 weeks, time to first therapeutic INR, time to maintenance dose, and the difference between predicted and observed maintenance doses. RESULTS A total of 527 participants started warfarin as inpatients and 488 as outpatients. There was no difference in PTTR based on location: 43.2 % for inpatient versus 47.4 % for outpatient initiation [mean adjusted difference -2.2 %; 95 % confidence interval (CI) -5.9 to 1.6]. Similarly, there were no differences in time to first therapeutic INR [hazard ratio (HR) 1.06; 95 % CI 0.91-1.24] or to maintenance dose (HR 0.96; 95 % CI 0.81-1.14). There was no evidence of interaction between study intervention (pharmacogenetically vs. clinically guided therapy) and location of initiation for these main outcomes. The difference between predicted and observed maintenance doses was similar for both locations. CONCLUSION The warfarin dosing algorithms performed similarly for subjects who initiated warfarin as inpatients and outpatients, regardless of whether dosing was pharmacogenetically or clinically guided.
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Affiliation(s)
- Scott E Kasner
- Department of Neurology, University of Pennsylvania Medical Center, 3W Gates Bldg, 3400 Spruce Street, Philadelphia, PA, 19104, USA,
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Bereznicki LR, Jackson SL, Morgan SM, Boland C, Marsden KA, Jupe DM, Vial JH, Peterson GM. Improving Clinical Outcomes for Hospital Patients Initiated on Warfarin. JOURNAL OF PHARMACY PRACTICE AND RESEARCH 2015. [DOI: 10.1002/j.2055-2335.2007.tb00769.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Robert-Ebadi H, Righini M. Diagnosis and management of pulmonary embolism in the elderly. Eur J Intern Med 2014; 25:343-9. [PMID: 24703814 DOI: 10.1016/j.ejim.2014.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 03/11/2014] [Accepted: 03/12/2014] [Indexed: 12/15/2022]
Abstract
Elderly patients are a population not only at particularly high risk of venous thromboembolism including pulmonary embolism (PE), but also at high risk of adverse clinical outcomes and treatment-related complications. Major progresses have been achieved in the diagnosis and treatment of PE over the last two decades. Nevertheless, some of elderly patients' specificities still represent important challenges in the management of PE in this population, from its suspicion to its diagnosis and treatment, and are discussed in this review. Perspectives for the future are from a diagnostic point of view the potential implementation of age-adjusted d-dimer cut-offs that will allow ruling out PE in a greater proportion of elderly patients without the need for thoracic imaging. From a therapeutic point of view, acquisition of post-marketing clinical experience with the use of new oral anticoagulants is still necessary, and in the meantime, these drugs should be prescribed with great caution in thoroughly selected elderly patients.
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Affiliation(s)
- Helia Robert-Ebadi
- Angiology and Haemostasis Unit, University Hospitals of Geneva, Switzerland.
| | - Marc Righini
- Angiology and Haemostasis Unit, University Hospitals of Geneva, Switzerland
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Sex differences in the effective warfarin dosage in Han and aboriginal Taiwanese patients with the VKORC1-1639AA genotype. Tzu Chi Med J 2013. [DOI: 10.1016/j.tcmj.2013.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Use of Vitamin K Antagonist Therapy in Geriatrics: A French National Survey from the French Society of Geriatrics and Gerontology (SFGG). Drugs Aging 2013; 30:1019-28. [DOI: 10.1007/s40266-013-0127-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Siguret V, Gouin-Thibault I, Gaussem P, Pautas E. Optimizing the Use of Anticoagulants (Heparins and Oral Anticoagulants) in the Elderly. Drugs Aging 2013; 30:687-99. [DOI: 10.1007/s40266-013-0101-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Expert consensus of the French Society of Geriatrics and Gerontology and the French Society of Cardiology on the management of atrial fibrillation in elderly people. Arch Cardiovasc Dis 2013; 106:303-23. [DOI: 10.1016/j.acvd.2013.04.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 04/04/2013] [Indexed: 11/19/2022]
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Lafuente-Lafuente C, Pautas É, Belmin J. Anticoagulation du sujet âgé : nouveautés thérapeutiques. Presse Med 2013; 42:187-96. [DOI: 10.1016/j.lpm.2012.05.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Revised: 04/27/2012] [Accepted: 05/03/2012] [Indexed: 10/27/2022] Open
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Abstract
INTRODUCTION This study aimed to investigate potential drug-drug interactions (pDDIs) with warfarin to minimize them, assess the acceptability of pharmaceutical interventions by the medical team and the impact on the international normalized ratio (INR) results. METHODS This pertains to a prospective study involving inpatients who started warfarin therapy in a university hospital located in southern Brazil. The pDDIs with warfarin were identified using the interaction screening program Drug-Reax, Micromedex Healthcare Series 1.0. RESULTS Two hundred and two inpatients were monitored. The mean of 10 different drugs was prescribed for each patient (SD = 3.6). At least 1 major or moderate pDDIs with warfarin per patient was observed, the mean was 3.6 (SD = 1.6). The most common pDDIs with warfarin involved in the increase of anticoagulation effect were enoxaparin (32.2%), simvastatin (27.6%), omeprazole (22.5%), and tramadol (21.5%). For 32 patients (15.8%), interventions were rejected, and they had a higher risk (relative risk= 2.17; 95% confidence interval 1.10-4.27) for abnormal test results (INR > 5). Multivariate analysis showed that age, length of hospital stay, exposure to ≥4 major or moderate pDDIs, and refusal of pharmacist recommendations contribute significantly to the patient's INR result >5. Consequently, the risk of bleeding is increased. CONCLUSIONS Major and moderate pDDIs with warfarin are very common in inpatients and are associated with INR results outside the therapeutic range. Pharmaceutical interventions concerning the management of interactions by providing information to physicians can improve the patient safety.
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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: 1026] [Impact Index Per Article: 85.5] [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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Reversal of overanticoagulation in very elderly hospitalized patients with an INR above 5.0: 24-hour INR response after vitamin K administration. Am J Med 2011; 124:527-33. [PMID: 21605730 DOI: 10.1016/j.amjmed.2011.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 01/12/2011] [Accepted: 01/14/2011] [Indexed: 11/23/2022]
Abstract
BACKGROUND Reversal of overanticoagulation to minimize the bleeding risk is important in elderly inpatients receiving vitamin K antagonist therapy. However, no study has specifically focused on this population. The objective of this study is to evaluate whether guidelines based on American College of Chest Physicians recommendations for the management of overanticoagulation (international normalized ratio [INR] ≥5.0) can apply to elderly inpatients, and notably allow 24-hour INRs to return to the 1.8-3.2 range in this population. The influence of different factors on the vitamin K response also was evaluated. METHODS Inpatients aged ≥75 years with INR ≥5.0 were included in this observational study. INRs were assessed on the day of the overdosage (Day 0) and on the following day (Day 1). RESULTS Of 385 Day 0 INRs ≥5.0 (239 patients; 86±6 years), 217 were managed according to recommendations, with a mean INR decreasing from 6.8±2.4 (range: 5.0-20.0) on Day 0 to 2.7±1.3 (range: 1.1-10.1) on Day 1 (P<.0001); 55% of INRs were within the 1.8-3.2 range, 20% <1.8, and 25% >3.2. In the subset of Day 0 INRs between 5.0 and 6.0, mean INR decreased from 5.5±0.3 to 2.7±1.0 (P<.0001) on Day 1 after oral administration of 1 mg vitamin K1 (n=121) and from 5.3±0.3 to 5.0±1.6 (P=.149) without vitamin K1 administration (n=48). Among covariates entered in the multivariate analysis, including co-medications, only the vitamin K1 dose influenced Day 1 INRs, with higher doses of vitamin K1 associated with Day 1 INRs <1.8 (P<.0001). CONCLUSION In elderly inpatients with INR ≥5.0, both vitamin K antagonist dose omission and vitamin K1 administration according to recommendations were effective in reversing overanticoagulation, allowing most INRs to return to the 1.8-3.2 range without excessive overcorrection. Therefore, American College of Chest Physicians recommendations may be applied to elderly inpatients.
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Pruthi RK. ASH 2010 meeting report-Top 10 clinically oriented abstracts in coagulation medicine and platelet disorders. Am J Hematol 2011. [DOI: 10.1002/ajh.22003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Moreau C, Pautas E, Gouin-Thibault I, Golmard JL, Mahé I, Mulot C, Loriot MA, Siguret V. Predicting the warfarin maintenance dose in elderly inpatients at treatment initiation: accuracy of dosing algorithms incorporating or not VKORC1/CYP2C9 genotypes. J Thromb Haemost 2011; 9:711-8. [PMID: 21255252 DOI: 10.1111/j.1538-7836.2011.04213.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND Initiating warfarin is challenging in frail elderly patients because of low-dose requirements and interindividual variability. OBJECTIVES We investigated whether incorporating VKORC1 and CYP2C9 genotype information in different models helped to predict the warfarin maintenance dose when added to clinical data and INR values at baseline (Day 0), and during warfarin induction. PATIENTS We prospectively enrolled 187 elderly inpatients (mean age, 85.6 years), all starting on warfarin using the same 'geriatric dosing-algorithm' based on the INR value measured on the day after three 4-mg warfarin doses (INR(3)) and on INR(6 ± 1). RESULTS On Day 0, the clinical model failed to accurately predict the maintenance dose (R(2) < 0.10). Adding the VKORC1 and CYP2C9 genotypes to the model increased R(2) to 0.31. On Day 3, the INR(3) value was the strongest predictor, completely embedding the VKORC1 genotype, whereas the CYP2C9 genotype remained a significant predictor (model- R(2) 0.55). On Day 6 ± 1, none of the genotypes predicted the maintenance dose. Finally, the simple 'geriatric dosing-algorithm' was the most accurate algorithm on Day 3 (R(2) 0.77) and Day 6 (R(2) 0.81), under-estimating (≥ 1 mg) and over-estimating the dose (≥ 1 mg) in fewer than 10% and 2% of patients, respectively. Clinical models and the 'geriatric dosing-algorithm' were validated on an independent sample. CONCLUSIONS Before starting warfarin therapy, the VKORC1 genotype is the best predictor of the maintenance dose. Once treatment is started using induction doses tailored for elderly patients, the contribution of VKORC1 and CYP2C9 genotypes in dose refinement is negligible compared with two INR values measured during the first week of treatment.
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Affiliation(s)
- C Moreau
- Université Paris Descartes, Paris, France
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[Initial antithrombotic therapy for pulmonary embolism]. Rev Mal Respir 2011; 28:216-26. [PMID: 21402235 DOI: 10.1016/j.rmr.2010.09.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 09/09/2010] [Indexed: 11/22/2022]
Abstract
The initial therapy for patients with pulmonary embolism who are haemodynamically stable relies on antithrombotic treatment. The aim of anticoagulant treatment is to prevent any thrombus extension or recurrence, with revascularization dependent on the fibrinolytic system. Current treatment is biphasic, with parenteral heparin or derivatives (low molecular weight heparins and fondaparinux) followed by oral vitamin K antagonists. Although these treatments are efficient, they suffer from some limitations including parenteral administration and the need for surveillance and monitoring. Use of low molecular weight heparins or fondaparinux is recommended in French guidelines, but unfractionated heparin still has an important role in some specific situations such as severe renal insufficiency, around the time of surgery and where there is a high risk of bleeding. The next generation of anticoagulants will soon be licensed for treatment in pulmonary embolism and may well replace heparin and/or vitamin K antagonists for the majority of patients, although "older" treatments will always be requested in some specific situations.
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Wittkowsky AK, Spinler SA, Dager W, Gulseth MP, Nutescu EA. Dosing guidelines, not protocols, for managing warfarin therapy. Am J Health Syst Pharm 2010; 67:1554-6. [PMID: 20811035 DOI: 10.2146/ajhp100064] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Affiliation(s)
- Ann K Wittkowsky
- School of Pharmacy, University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA.
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25
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Abstract
Management of anticoagulation in elderly patients represents a particularly challenging issue. Indeed, this patient population is at high thromboembolic risk, but also at high hemorrhagic risk. Assessment of the benefit-risk balance of anticoagulation is the key point when decisions are made about introducing and/or continuing such treatments in the individual elderly patient. In order to maximise the safety of anticoagulation in the elderly, some specific considerations need to be taken into account, including renal insufficiency, modified pharmacodynamics of anticoagulants, especially vitamin K antagonists, and the presence of multiple comorbidities and concomitant medications. New anticoagulants could greatly simplify and possibly increase the safety of anticoagulation in the elderly in the near future.
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Ho WK. Treatment of Venous Thromboembolism in Older People. JOURNAL OF PHARMACY PRACTICE AND RESEARCH 2010. [DOI: 10.1002/j.2055-2335.2010.tb00566.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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King CR, Deych E, Milligan P, Eby C, Lenzini P, Grice G, Porche-Sorbet RM, Ridker PM, Gage BF. Gamma-glutamyl carboxylase and its influence on warfarin dose. Thromb Haemost 2010; 104:750-4. [PMID: 20694283 DOI: 10.1160/th09-11-0763] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 06/08/2010] [Indexed: 11/05/2022]
Abstract
Via generation of vitamin K-dependent proteins, gamma-glutamyl carboxylase (GGCX) plays a critical role in the vitamin K cycle. Single nucleotide polymorphisms (SNPs) in GGCX, therefore, may affect dosing of the vitamin K antagonist, warfarin. In a multi-centered, cross-sectional study of 985 patients prescribed warfarin therapy, we genotyped for two GGCX SNPs (rs11676382 and rs12714145) and quantified their relationship to therapeutic dose. GGCX rs11676382 was a significant (p=0.03) predictor of residual dosing error and was associated with a 6.1% reduction in warfarin dose (95% CI: 0.6%-11.4%) per G allele. The prevalence was 14.1% in our predominantly (78%) Caucasian cohort, but the overall contribution to dosing accuracy was modest (partial R2 = 0.2%). GGCX rs12714145 was not a significant predictor of therapeutic dose (p = 0.26). GGCX rs11676382 is a statistically significant predictor of warfarin dose, but the clinical relevance is modest. Given the potentially low marginal cost of adding this SNP to existing genotyping platforms, we have modified our non-profit website (www.WarfarinDosing.org) to accommodate knowledge of this variant.
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Affiliation(s)
- Cristi R King
- Department of Internal Medicine, Washington University School of Medicine, Saint Louis, Missouri 63110, USA
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Abstract
Although warfarin has been the mainstay of oral anticoagulation therapy for decades, evidence-based methods for improving the quality of warfarin therapy remain underused. The arrival of new anticoagulants that do not require routine laboratory monitoring and lack the significant dietary and drug interaction potential that are seen with warfarin is an important evolutionary step in the management of thromboembolic disease. However, it will be years before the efficacy and long-term safety of these new agents are defined. Newer oral anticoagulants will be more expensive than generic warfarin. This article examines various approaches to optimize the clinical use of warfarin. For patients able to achieve stable anticoagulation control, warfarin remains an important therapeutic option, delivering similar clinical outcomes at a fraction of the cost to the health care system.
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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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Siguret V, Pautas E, Gouin-Thibault I. Vitamin K antagonist use in the elderly: special considerations. Future Cardiol 2010; 3:321-30. [PMID: 19804223 DOI: 10.2217/14796678.3.3.321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
As the population ages, the number of patients aged 75 years and over treated with vitamin K antagonists (VKAs) is steadily increasing. In this age group, the two main indications for oral anticoagulant therapy are the treatment of venous thromboembolic disease and the prevention of systemic embolism in patients with nonvalvular atrial fibrillation. In both indications, a target international normalized ratio of 2.5 (range: 2.0-3.0) is recommended. Although VKAs are beneficial in thromboembolic disorders, they are still underused. In this review, we will focus on two crucial topics in elderly patients, the specific management of VKAs in these patients and the hemorrhagic risk. Current recommendations concerning the management at the start of treatment, education and adequate monitoring may help to minimize the hemorrhagic risk in these frail patients.
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Affiliation(s)
- Virginie Siguret
- Hôpital Charles Foix (AP-HP), Laboratoire d'Hématologie, 7 Avenue de la République, 94205 Ivry-sur-Seine cedex, France.
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Abstract
Warfarin has long been the mainstay of oral anticoagulation therapy for the treatment and prevention of venous and arterial thrombosis. The narrow therapeutic index of warfarin, and the complex number of factors that influence international normalized ratio (INR) response, makes optimization of warfarin therapy challenging. Determination of the appropriate warfarin dose during initiation and maintenance therapy requires an understanding of patient factors that influence dose response: age, body weight, nutritional status, acute and chronic disease states, and changes in concomitant drug therapy and diet. This review will examine specific clinical factors that can affect the pharmacokinetics and pharmacodynamics of warfarin, as well as the role of pharmacogenetics in optimizing warfarin therapy.
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Affiliation(s)
- Pamela J. White
- Pharmacy Clinical Specialist, Legacy Health Anticoagulation Clinics, Portland, OR, USA
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Pharmacogénétique et antivitamine K aujourd’hui : un débat ouvert. Rev Med Interne 2010; 31:361-8. [DOI: 10.1016/j.revmed.2009.07.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 06/03/2009] [Accepted: 07/08/2009] [Indexed: 11/22/2022]
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Lenzini P, Wadelius M, Kimmel S, Anderson JL, Jorgensen AL, Pirmohamed M, Caldwell MD, Limdi N, Burmester JK, Dowd MB, Angchaisuksiri P, Bass AR, Chen J, Eriksson N, Rane A, Lindh JD, Carlquist JF, Horne BD, Grice G, Milligan PE, Eby C, Shin J, Kim H, Kurnik D, Stein CM, McMillin G, Pendleton RC, Berg RL, Deloukas P, Gage BF. Integration of genetic, clinical, and INR data to refine warfarin dosing. Clin Pharmacol Ther 2010; 87:572-8. [PMID: 20375999 PMCID: PMC2858245 DOI: 10.1038/clpt.2010.13] [Citation(s) in RCA: 182] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Well-characterized genes that affect warfarin metabolism (cytochrome P450 (CYP) 2C9) and sensitivity (vitamin K epoxide reductase complex 1 (VKORC1)) explain one-third of the variability in therapeutic dose before the international normalized ratio (INR) is measured. To determine genotypic relevance after INR becomes available, we derived clinical and pharmacogenetic refinement algorithms on the basis of INR values (on day 4 or 5 of therapy), clinical factors, and genotype. After adjusting for INR, CYP2C9 and VKORC1 genotypes remained significant predictors (P < 0.001) of warfarin dose. The clinical algorithm had an R(2) of 48% (median absolute error (MAE): 7.0 mg/week) and the pharmacogenetic algorithm had an R(2) of 63% (MAE: 5.5 mg/week) in the derivation set (N = 969). In independent validation sets, the R(2) was 26-43% with the clinical algorithm and 42-58% when genotype was added (P = 0.002). After several days of therapy, a pharmacogenetic algorithm estimates the therapeutic warfarin dose more accurately than one using clinical factors and INR response alone.
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Affiliation(s)
- P Lenzini
- Department of Internal Medicine, Washington University, St Louis, Missouri, USA
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Heneghan C, Tyndel S, Bankhead C, Wan Y, Keeling D, Perera R, Ward A. Optimal loading dose for the initiation of warfarin: a systematic review. BMC Cardiovasc Disord 2010; 10:18. [PMID: 20403189 PMCID: PMC2873399 DOI: 10.1186/1471-2261-10-18] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Accepted: 04/19/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Selection of the right warfarin dose at the outset of treatment is not straightforward, and current evidence is lacking to determine the optimal strategy for initiation of therapy. METHODS We included randomized controlled trials in patients commencing anticoagulation with warfarin, comparing different loading dose or different regimens.We searched Medline, EMBASE, the Cochrane Library and the NHS Health Economics Database up to June 2009. Primary outcomes were time to stable INR and adverse events. We summarised results as proportion of INRs in range from date of initiation and compared dichotomous outcomes using relative risks (RR) and calculated 95% confidence intervals (CIs). RESULTS We included 11 studies of 1,340 patients newly initiated on warfarin. In two studies that used single INR measures, a loading dose of 10 mg compared to 5 mg led to more patients in range on day five. However, in two studies which measured two consecutive INRs, a loading dose of 10 mg compared to 5 mg did not lead to more patients in range on day five (RR = 0.86, 95% CI, 0.62 to 1.19, p = 0.37). Patients receiving a 2.5 mg initiation does took longer to achieve the therapeutic range, whilst those receiving a calculated initiation dose achieved target range 0.8 days quicker (4.2 days vs. 5 days, p = 0.007). More elderly patients receiving an age adjusted dose achieved a stable INR compared to the Fennerty protocol (48% vs. 22% p = 0.02) and significantly fewer patients on the age adjusted regimens had high out-of-range INRs. Two studies report no significant differences between genotype guided and 5 mg or 10 mg initiation doses and in the one significant genotype study the control group INRs were significantly lower than expected. CONCLUSION Our review findings suggest there is still considerable uncertainty between a 10 mg and a 5 mg loading dose for initiation of warfarin. In the elderly, lower initiation doses or age adjusted doses are more appropriate, leading to less higher INRs. Currently there is insufficient evidence to warrant genotype guided initiation, and adequately powered trials to detect effects on adverse events are currently warranted.
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Affiliation(s)
- Carl Heneghan
- Department of Primary Health Care, University of Oxford, Oxford, UK.
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Pendleton RC, Wheeler M, Wanner N, Strong MB, Vinik R, Peters CL. A safe, effective, and easy to use warfarin initiation dosing nomogram for post-joint arthroplasty patients. J Arthroplasty 2010; 25:121-7. [PMID: 19062248 DOI: 10.1016/j.arth.2008.09.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Accepted: 09/21/2008] [Indexed: 02/01/2023] Open
Abstract
Venous thromboembolism (VTE) is a complication after joint arthroplasty, and pharmacologic prophylaxis is recommended to reduce this risk. Warfarin is often used, but initial dosing and management can be difficult. We studied a single-center prospective cohort of consecutive (n = 351) post-joint arthroplasty/revision patients who were initiated on warfarin using a new initiation nomogram and then discharged to home with home health services. The mean time to an international normalized ratio (INR) of 2.0 or higher was 5 days, with a mean INR of 2.1 on the fifth postoperative day. Two patients (0.6%) had an INR higher than 5 in the first 10 days of therapy. Adverse events were uncommon: 4 patients (1.14%) had VTE, 1 had major bleeding episode, and 6 patients (1.7%) had minor bleeding. A specific warfarin dosing nomogram managed by an anticoagulation service and used in joint arthroplasty/revision patients who are discharged to home with home health services leads to effective anticoagulation with few associated adverse events.
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Affiliation(s)
- Robert C Pendleton
- Department of Medicine, General Internal Medicine, University Healthcare Thrombosis Service, University of Utah, Salt Lake City, Utah 84132, USA
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Ferder NS, Eby CS, Deych E, Harris JK, Ridker PM, Milligan PE, Goldhaber SZ, King CR, Giri T, McLeod HL, Glynn RJ, Gage BF. Ability of VKORC1 and CYP2C9 to predict therapeutic warfarin dose during the initial weeks of therapy. J Thromb Haemost 2010; 8:95-100. [PMID: 19874474 PMCID: PMC3718044 DOI: 10.1111/j.1538-7836.2009.03677.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
BACKGROUND CYP2C9 and VKORC1 genotypes predict therapeutic warfarin dose at initiation of therapy; however, the predictive ability of genetic information after a week or longer is unknown. Experts have hypothesized that genotype becomes irrelevant once international normalized ratio (INR) values are available because INR response reflects warfarin sensitivity. METHODS We genotyped the participants in the Prevention of Recurrent Venous Thromboembolism (PREVENT) trial, who had idiopathic venous thromboemboli and began low-intensity warfarin (therapeutic INR 1.5-2.0) using a standard dosing protocol. To develop pharmacogenetic models, we quantified the effect of genotypes, clinical factors, previous doses and INR on therapeutic warfarin dose in the 223 PREVENT participants who were randomized to warfarin and achieved stable therapeutic INRs. RESULTS A pharmacogenetic model using data from day 0 (before therapy initiation) explained 54% of the variability in therapeutic dose (R(2)). The R(2) increased to 68% at day 7, 75% at day 14, and 77% at day 21, because of increasing contributions from prior doses and INR response. Although CYP2C9 and VKORC1 genotypes were significant independent predictors of therapeutic dose at each weekly interval, the magnitude of their predictive ability diminished over time: partial R(2) of genotype was 43% at day 0, 12% at day 7, 4% at day 14, and 1% at day 21. CONCLUSION Over the first weeks of warfarin therapy, INR and prior dose become increasingly predictive of therapeutic dose, and genotype becomes less relevant. However, at day 7, genotype remains clinically relevant, accounting for 12% of therapeutic dose variability.
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Affiliation(s)
- N S Ferder
- Saint Louis College of Pharmacy, St Louis, MO, USA
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Le Gal G, Carrier M, Tierney S, Majeed H, Rodger M, Wells PS. Prediction of the warfarin maintenance dose after completion of the 10 mg initiation nomogram: do we really need genotyping? J Thromb Haemost 2010; 8:90-4. [PMID: 19874475 DOI: 10.1111/j.1538-7836.2009.03676.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Initiation of warfarin therapy is complicated by its narrow therapeutic index and inter-patient dose-effect variability. A '10-mg nomogram' warfarin initiation protocol permits safe therapeutic anticoagulation in outpatients started on warfarin. We aimed to develop a safe and effective warfarin maintenance dose prediction tool in these patients. METHODS Baseline potential predictor variables were collected on a retrospective cohort of outpatients initiated on warfarin for venous thromboembolism treatment. The primary outcome was the warfarin maintenance dose, defined as mean warfarin dose over the last 10 days of the first month of warfarin treatment. Univariate and multivariate analyses were performed to determine which baseline variables were warfarin maintenance dose predictors. An independent cohort of patients validated the derived warfarin maintenance dose prediction rule. RESULTS Patient's age and weight, cumulative dose of warfarin over the first week of induction and international normalized ratio (INR) on days 3, 5 and 8 were statistically significant predictors of the warfarin maintenance dose. Our final prediction rule reads: maintenance dose (in mg) = 2.5 + 10% of the first week cumulative dose - INR value at day 8 + 1.5 if INR was below 2.0 at day 5. In the validation cohort, the predicted dose was strongly correlated with the actual maintenance dose (r = 0.88, P < 0.0001). The mean difference between observed and predicted dose was not clinically significant: -0.1 +/- 1.1 mg. CONCLUSION In outpatients initiated on warfarin using a '10-mg nomogram', a simple prediction rule can accurately predict warfarin maintenance dose. Prospective studies employing the rule are indicated.
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Affiliation(s)
- G Le Gal
- Thrombosis Program, Division of Hematology, Department of Medicine, University of Ottawa, Ottawa, ON, Canada
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Abstract
Initiation of warfarin therapy is a clinical challenge. A 10-mg warfarin initiation nomogram was recently validated in a randomized controlled trial. We sought to determine the efficacy and safety of this 10-mg warfarin initiation nomogram in 'real-life' daily practice. A retrospective cohort including all outpatients beginning concurrent treatment with warfarin and low-molecular-weight heparin over a 24-month period in our Thrombosis Unit was reviewed. Eight hundred and forty-one patients were included; of them, 640 (76.1%) were started on the nomogram. The nomogram was entirely followed in 324 patients (38.5%). The efficacy and safety profile was similar to that observed in the original clinical trial; 86% of patients managed according to the nomogram reached the international normalized ratio target of 2.0-3.0 within 5 days. Mean duration of low-molecular-weight heparin treatment was 6.0 +/- 1.9 days, and 3.7% of patients had an international normalized ratio of at least 5.0 in the first 4 weeks of treatment. The 10-mg nomogram effectively results in an early therapeutic international normalized ratio with a good safety profile in 'real-life' daily practice.
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Office management of deep venous thrombosis in the elderly. Am J Med 2009; 122:904-6. [PMID: 19786156 DOI: 10.1016/j.amjmed.2009.05.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 05/11/2009] [Accepted: 05/13/2009] [Indexed: 11/22/2022]
Abstract
Deep venous thrombosis is common in the elderly. Diagnosis and management are now a part of office practice. As signs and symptoms are inconsistent and nonspecific, diagnostic testing is necessary. For patients with a low clinical probability, a normal D-dimer result can rule out disease. For patients with a high clinical suspicion or an elevated D-dimer, duplex ultrasonography may confirm the diagnosis. Anticoagulation, usually with low-molecular-weight heparin, should begin on suspicion and continue, along with warfarin, until the international normalized ratio is therapeutic. Arrangements for the initial daily injections can be made with a visiting nurse. Treatment should continue for at least 3 months, when a risk-versus-benefit analysis for continuing anticoagulation should be undertaken. Therapy may be discontinued for thromboses associated with a reversible risk factor or for patients in whom anticoagulant management was unstable or complicated by bleeding. A persistently high D-dimer result or evidence of residual clot on repeat duplex ultrasonography may support continuation. For all patients, the use of compression stockings to prevent the post-thrombotic syndrome is recommended.
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Pautas E, Moreau C, Gouin-Thibault I, Golmard JL, Mahé I, Legendre C, Taillandier-Hériche E, Durand-Gasselin B, Houllier AM, Verrier P, Beaune P, Loriot MA, Siguret V. Genetic Factors (VKORC1, CYP2C9, EPHX1, and CYP4F2) Are Predictor Variables for Warfarin Response in Very Elderly, Frail Inpatients. Clin Pharmacol Ther 2009; 87:57-64. [DOI: 10.1038/clpt.2009.178] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Lazo-Langner A, Monkman K, Kovacs MJ. Predicting warfarin maintenance dose in patients with venous thromboembolism based on the response to a standardized warfarin initiation nomogram. J Thromb Haemost 2009; 7:1276-83. [PMID: 19453939 DOI: 10.1111/j.1538-7836.2009.03483.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Polymorphisms in the VKORC1 and CYP2C9 genes influence warfarin requirements. It has been suggested that dosing algorithms incorporating them might outperform usual care. Standardized warfarin initiation nomograms are safe and effective and patients' responses to them could be used to predict warfarin requirements without the need for genetic testing. OBJECTIVES To develop a model to predict warfarin dose requirements based on the response to a standard nomogram without using genetic testing. PATIENTS/METHODS We included 363 outpatients with acute venous thromboembolism who were started on treatment using a standardized warfarin nomogram and achieved a stable maintenance warfarin dose defined as a dose prescribed twice consecutively after two consecutive INR measurements between 2.0 and 3.0. Linear regression was used to derive equations predicting the maintenance dose and models were validated using non-parametric bootstrapping and tested in an independent cohort. RESULTS Three models were constructed for patients completing the nomogram until day 3 (warfarin dose (mg week(-1)) = Exp [2.737 + 1.896(INR(3)(-1))-0.008(Age)]; R2adj = 0.462), day 5 (warfarin dose (mg week(-1)) = Exp[2.261 + 2.412(INR(3)(-1)) -0.285(DeltaINR(5-3))]; R2adj = 0.603) and day 8 (warfarin dose (mg week(-1)) = Exp[1.574 + 1.788(INR(8)(-1)) + 0.024(cumulated warfarin dose until nomogram day 7)]; R2adj = 0.643), where Exp is the exponential function; INR3 and INR8 are the INR on days 3 or 8 of the nomogram, and DeltaINR(5-3) is the difference in the INR on days 5 and 3. All models were internally and externally validated and were accurate to within 25% of the actual dose in >60% of patients. CONCLUSION Maintenance warfarin dose can be accurately predicted using individual response to a standard warfarin initiation nomogram without the need for costly genetic testing.
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Affiliation(s)
- A Lazo-Langner
- Division of Hematology, Department of Medicine, University of Western Ontario, London, ON, Canada
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Robert-Ebadi H, Le Gal G, Righini M. Use of anticoagulants in elderly patients: practical recommendations. Clin Interv Aging 2009; 4:165-77. [PMID: 19503778 PMCID: PMC2685237 DOI: 10.2147/cia.s4308] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Elderly people represent a patient population at high thromboembolic risk, but also at high hemorrhagic risk. There is a general tendency among physicians to underuse anticoagulants in the elderly, probably both because of underestimation of thromboembolic risk and overestimation of bleeding risk. The main indications for anticoagulation are venous thromboembolism (VTE) prophylaxis in medical and surgical settings, VTE treatment, atrial fibrillation (AF) and valvular heart disease. Available anticoagulants for VTE prophylaxis and initial treatment of VTE are low molecular weight heparins (LMWH), unfractionated heparin (UFH) or synthetic anti-factor Xa pentasaccharide fondaparinux. For long-term anticoagulation vitamin K antagonists (VKA) are the first choice and only available oral anticoagulants nowadays. Assessing the benefit-risk ratio of anticoagulation is one of the most challenging issues in the individual elderly patient, patients at highest hemorrhagic risk often being those who would have the greatest benefit from anticoagulants. Some specific considerations are of utmost importance when using anticoagulants in the elderly to maximize safety of these treatments, including decreased renal function, co-morbidities and risk of falls, altered pharmacodynamics of anticoagulants especially VKAs, association with antiplatelet agents, patient education. Newer anticoagulants that are currently under study could simplify the management and increase the safety of anticoagulation in the future.
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Affiliation(s)
- Helia Robert-Ebadi
- Division of Angiology and Hemostasis, Department of Internal Medicine, Geneva University Hospital and Faculty of Medicine, Geneva, Switzerland.
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Monkman K, Lazo-Langner A, Kovacs MJ. A 10 mg warfarin initiation nomogram is safe and effective in outpatients starting oral anticoagulant therapy for venous thromboembolism. Thromb Res 2009; 124:275-80. [PMID: 19155056 DOI: 10.1016/j.thromres.2008.12.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 12/03/2008] [Accepted: 12/03/2008] [Indexed: 01/21/2023]
Abstract
The optimal means of initiating warfarin therapy for acute venous thromboembolism in the outpatient setting remains controversial. We have previously demonstrated the efficacy of a 10 mg initiation nomogram in a randomized controlled trial; however, some clinicians remain reluctant to use this nomogram due to a fear of potential increased bleeding. To review the safety and efficacy of a 10 mg warfarin nomogram we conducted a retrospective cohort study of patients prospectively treated for venous thromboembolism according to a 10 mg nomogram in an outpatient thrombosis clinic. All patients received standard treatment with low molecular weight heparin for 5 to 7 days and warfarin for at least 3 months. Four-hundred and fourteen patients were included in the analysis, of whom 295 (71%) fully adhered to the nomogram. In the whole cohort, 8 patients (1.9%) experienced recurrent thrombosis, 4 (0.97%) suffered a major bleeding event, and 3 (0.72%) suffered a minor bleeding event. There were no deaths related to thrombosis or bleeding. Four patients (0.97%) died from unrelated causes. Twenty-two (5.3%) patients experienced an INR > or =5.0 in the first 8 days of therapy, and none of these patients experienced a bleeding event. Eighty-four percent of patients achieved a therapeutic INR by day 5. In outpatients, a 10 mg nomogram results in timely achievement of a therapeutic INR with an acceptable incidence of bleeding and recurrent thromboembolism.
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Affiliation(s)
- Katherine Monkman
- Department of Medicine, Division of Hematology, University of Western Ontario, London, Ontario, Canada
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Gulseth MP, Grice GR, Dager WE. Pharmacogenomics of warfarin: Uncovering a piece of the warfarin mystery. Am J Health Syst Pharm 2009; 66:123-33. [DOI: 10.2146/ajhp080127] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Michael P. Gulseth
- Anticoagulation Services, Sanford–University of South Dakota Medical Center, Sioux Falls
| | - Gloria R. Grice
- St. Louis College of Pharmacy, and Manager, Barnes-Jewish Hospital Anticoagulation Service, Washington University, St. Louis, MO
| | - William E. Dager
- University of California Davis Medical Center, Davis, and Clinical Professor of Pharmacy, School of Pharmacy, University of California San Francisco, San Francisco
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Homme MB, Reynolds KK, Valdes R, Linder MW. Dynamic Pharmacogenetic Models in Anticoagulation Therapy. Clin Lab Med 2008; 28:539-52. [DOI: 10.1016/j.cll.2008.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Vogel T, Coriol V, Kaltenbach G, Kiesmann M, Berthel M. Difficultés pour équilibrer les antivitamines K chez des personnes très âgées hospitalisées : étude prospective chez 110 patients avec recherche de facteurs de risque de déséquilibre. Presse Med 2008; 37:1723-30. [DOI: 10.1016/j.lpm.2008.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 03/31/2008] [Accepted: 04/04/2008] [Indexed: 11/16/2022] Open
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Lenzini PA, Grice GR, Milligan PE, Dowd MB, Subherwal S, Deych E, Eby CS, King CR, Porche-Sorbet RM, Murphy CV, Marchand R, Millican EA, Barrack RL, Clohisy JC, Kronquist K, Gatchel SK, Gage BF. Laboratory and clinical outcomes of pharmacogenetic vs. clinical protocols for warfarin initiation in orthopedic patients. J Thromb Haemost 2008; 6:1655-62. [PMID: 18662264 PMCID: PMC2920450 DOI: 10.1111/j.1538-7836.2008.03095.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Warfarin is commonly prescribed for prophylaxis and treatment of thromboembolism after orthopedic surgery. During warfarin initiation, out-of-range International Normalized Ratio (INR) values and adverse events are common. METHODS In orthopedic patients beginning warfarin therapy, we developed and prospectively validated pharmacogenetic and clinical dose refinement algorithms to revise the estimated therapeutic dose after 4 days of therapy. RESULTS The pharmacogenetic algorithm used the cytochrome P450 (CYP) 2C9 genotype, smoking status, peri-operative blood loss, liver disease, INR values and dose history to predict the therapeutic dose. The R(2) was 82% in a derivation cohort (n = 86) and 70% when used prospectively (n = 146). The R(2) of the clinical algorithm that used INR values and dose history to predict the therapeutic dose was 57% in a derivation cohort (n = 178) and 48% in a prospective validation cohort (n = 146). In 1 month of prospective follow-up, the percent time spent in the therapeutic range was 7% higher (95% CI: 2.7-11.7) in the pharmacogenetic cohort. The risk of a laboratory or clinical adverse event was also significantly reduced in the pharmacogenetic cohort (Hazard Ratio 0.54; 95% CI: 0.30-0.97). CONCLUSIONS Warfarin dose adjustments that incorporate genotype and clinical variables available after four warfarin doses are accurate. In this non-randomized, prospective study, pharmacogenetic dose refinements were associated with more time spent in the therapeutic range and fewer laboratory or clinical adverse events. To facilitate gene-guided warfarin dosing we created a non-profit website, http://www.WarfarinDosing.org.
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Affiliation(s)
- Petra A. Lenzini
- Washington University School of Medicine, Department of Internal Medicine
| | - Gloria R. Grice
- Washington University School of Medicine, Department of Internal Medicine
- St. Louis College of Pharmacy
| | - Paul E. Milligan
- Washington University School of Medicine, Department of Internal Medicine
- St. Louis College of Pharmacy
| | | | - Sumeet Subherwal
- Washington University School of Medicine, Department of Internal Medicine
| | - Elena Deych
- Washington University School of Medicine, Department of Internal Medicine
| | - Charles S. Eby
- Washington University School of Medicine, Department of Pathology
| | - Cristi R. King
- Washington University School of Medicine, Department of Internal Medicine
| | | | | | | | - Eric A. Millican
- Washington University School of Medicine, Department of Internal Medicine
| | - Robert L. Barrack
- Washington University School of Medicine, Department of Orthopedic Surgery
| | - John C. Clohisy
- Washington University School of Medicine, Department of Orthopedic Surgery
| | | | - Susan K. Gatchel
- Washington University School of Medicine, Department of Internal Medicine
| | - Brian F. Gage
- Washington University School of Medicine, Department of Internal Medicine
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Ansell J, Hirsh J, Hylek E, Jacobson A, Crowther M, Palareti G. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest 2008; 133:160S-198S. [PMID: 18574265 DOI: 10.1378/chest.08-0670] [Citation(s) in RCA: 1448] [Impact Index Per Article: 90.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
This article concerning the pharmacokinetics and pharmacodynamics of vitamin K antagonists (VKAs) is part of the American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). It describes the antithrombotic effect of the VKAs, the monitoring of anticoagulation intensity, and the clinical applications of VKA therapy and provides specific management recommendations. Grade 1 recommendations are strong and indicate that the benefits do or do not outweigh the risks, burdens, and costs. Grade 2 recommendations suggest that the individual patient's values may lead to different choices. (For a full understanding of the grading, see the "Grades of Recommendation" chapter by Guyatt et al, CHEST 2008; 133:123S-131S.) Among the key recommendations in this article are the following: for dosing of VKAs, we recommend the initiation of oral anticoagulation therapy, with doses between 5 mg and 10 mg for the first 1 or 2 days for most individuals, with subsequent dosing based on the international normalized ratio (INR) response (Grade 1B); we suggest against pharmacogenetic-based dosing until randomized data indicate that it is beneficial (Grade 2C); and in elderly and other patient subgroups who are debilitated or malnourished, we recommend a starting dose of < or = 5 mg (Grade 1C). The article also includes several specific recommendations for the management of patients with nontherapeutic INRs, with INRs above the therapeutic range, and with bleeding whether the INR is therapeutic or elevated. For the use of vitamin K to reverse a mildly elevated INR, we recommend oral rather than subcutaneous administration (Grade 1A). For patients with life-threatening bleeding or intracranial hemorrhage, we recommend the use of prothrombin complex concentrates or recombinant factor VIIa to immediately reverse the INR (Grade 1C). For most patients who have a lupus inhibitor, we recommend a therapeutic target INR of 2.5 (range, 2.0 to 3.0) [Grade 1A]. We recommend that physicians who manage oral anticoagulation therapy do so in a systematic and coordinated fashion, incorporating patient education, systematic INR testing, tracking, follow-up, and good patient communication of results and dose adjustments [Grade 1B]. In patients who are suitably selected and trained, patient self-testing or patient self-management of dosing are effective alternative treatment models that result in improved quality of anticoagulation management, with greater time in the therapeutic range and fewer adverse events. Patient self-monitoring or self-management, however, is a choice made by patients and physicians that depends on many factors. We suggest that such therapeutic management be implemented where suitable (Grade 2B).
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Affiliation(s)
- Jack Ansell
- From Boston University School of Medicine, Boston, MA.
| | - Jack Hirsh
- Hamilton Civic Hospitals, Henderson Research Centre, Hamilton, ON, Canada
| | - Elaine Hylek
- Boston University School of Medicine, Boston, MA
| | | | - Mark Crowther
- McMaster University, St. Joseph's Hospital, Hamilton, ON, Canada
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