Vitamin K Antagonists [VKA] are the most frequently used oral anticoagulants in clinical practice; however, many patients fail to achieve adequate anticoagulation control. We conducted a randomized, placebo controlled, double blind study of Vitamin K1 (200mcg per day, Swanson Vitamins) in a population with predominantly venous thromboembolism aimed at evaluating its effectiveness in improving anticoagulation control in unstable patients. This study also aimed to evaluate the impact that clinical variables, patient anticoagulation knowledge, and genetic polymorphisms in genes known to impact warfarin and Vitamin K metabolism [VKORC1, CYP4F2, CYP2C9] had on anticoagulation control and intervention effectiveness. A total of N=54 patients were enrolled in the study over 15 months [January 2009 to June 2010]. Change score analysis and multivariate linear regression modelling of anticoagulation control measures were performed. No statistically significant reduction was observed in the Vitamin K1 arm for percent time in therapeutic range; however, reduction was observed in standard deviation of INRs [Change Score Vitamin K = -0.259, p=0.0261; Regression Model 95% C.I Beta Vitamin K = 0.38 to -0.08] during the intervention period. Adjusting for treatment group allocation, independent predictors of increased INR standard deviation included: >5 alcoholic drinks per week [95% C.I Beta = 0.04 to 0.41], self-reported dosing errors [95% C.I Beta = 0.13 to 0.47], and missed INR appointments [95% C.I Beta = 0.002 to 0.05]

Background As a major cause of morbidity and mortality treatment of venous thromboembolism is important, with the correct use of anticoagulants it is possible to greatly reduce both mortality and morbidity. Warfarin is among the most widely used anticoagulants being effective in treatment and prevention of venous thromboembolism with few negative side effects other than bleeding complications. With a narrow therapeutic window warfarin treatment requires constant monitoring and adjustments to stay effective without an increased bleeding risk. The aim of this thesis was to study the efficacy and safety of warfarin treatment in venous thromboembolic disease. Methods Using AuriculA, the Swedish national quality register for atrial fibrillation and anticoagulation, a cohort was created of patients registered with warfarin treatment during the study time January 1st 2006 to December 31th 2011, including all different indications for anticoagulation. In all four studies the study design was retrospective with information added to the cohort from the Swedish national patient register about background data and endpoints in form of bleeding complications in all studies and thromboembolic events in study 1 and 2. In study 3 and 4 information was added from the cause of death register about occurrence of death and in study 3 cause of death. In study 3, information from the prescribed drugs register about retrieved prescriptions of acetylsalicylic acid was added. Results In study 1 the mean TTR was found to be high both among patients managed at primary healthcare centres and specialised anticoagulation clinics at 79.6% and 75.7%. There was no significant difference in rate of bleeding between the two types of managing centres being 2.22 and 2.26 per 100 treatment years. In study 2 no reduction in complication rate with increasing centre TTR was seen for patients with atrial fibrillation with few centres having centre TTR below 70% (2.9%), in contrast to previous findings by Wan et al(1). For those with warfarin due to VTE where a larger proportion of the centres had centre TTR below 70% (9.1%) there was a reduction in complication rate with increasing centre TTR. Among the 13859 patients with treatment for VTE in study 3 age (HR 1.02, CI 95% 1.01-1.03), hypertension (HR 1.29, CI 95%1.02-1.64), Cardiac failure (HR 1.55, CI 95% 1.13-2.11), chronic obstructive pulmonary disease (HR 1.43, CI 95% 1.04- 1.96), alcohol abuse (HR 3.35, CI 95% 1.97-5.71), anaemia (HR 1.77, CI 95% 1.29-2.44) and a history of major bleeding (HR 1.75, CI 95% 1.27-2.42) increased the risk of bleeding during warfarin treatment. In study 4 both those with high iTTR and those with low INR variability had a low rate of bleedings at 1.27 (1.14-1.41) or 1.20 (0.94-1.21) per 100 treatment years compared to those with low iTTR and high INR variability having a rate of bleeding at 2.91 (2.61-3.21) or 2.61 (2.36-2.86) respectively. Those with the combination of both low iTTR and high INR variability had an increased risk of bleeding, hazard ratio HR 3.47 (CI 95 % 2.89-4.17). The quartile with both the lowest iTTR and the highest INR variability had an increased risk of bleeding with a hazard ratio 4.03 (3.20-5.08) and 3.80 (CI 95%, 3.01-4.79) compared to the quartile with the highest iTTR and lowest INR variability. Conclusion It is possible to achieve a safe warfarin treatment both in specialised anticoagulation centres and in primary health care. At initiation of treatment some of the patients at high risk of bleeding can be identified using knowledge about their background. With the use of quality indicators as TTR and INR variability during treatment those at high risk of complications can be identified and analysing treatment quality on centre level gives an opportunity to identify improvement areas among managing centres. With the addition of new treatment options warfarin can still be the most suitable option for some patients, being safe and effective when well managed.

Warfarin is the most widely prescribed oral anticoagulant used for the long-term treatment and prevention of thromboembolic events. Its administration is challenging as it may result in bleeding-related deaths, inadequate anticoagulation and fetal teratogenesis, including fetal warfarin syndrome. A number of environmental and genetic factors contribute to interindividual warfarin dosage variability. The CYP2C9 and VKORC1 genes explain 40- 50% of this variability. The aim of this study was to determine the frequency of known and any new variants in these genes in the SA black population, and correlate these variants and a small subset of environmental factors to dosage variability and pregnancy outcomes. I sequenced the exons and intron/exon boundaries of the CYP2C9 and VKORC1 genes in 100 random black control and 113 patient samples that had at least one pregnancy on warfarin. I observed six previously described CYP2C9 variants, 27 novel CYP2C9 variants, and three previously described VKORC1 variants. 14 of these variants were observed at an allele frequency of 0.02. Of these 14, six appear to decrease (all of which are CYP2C9 variants) and four increase (2 CYP2C9 variants and two VKORC1 variants) warfarin dosage requirement. These 14 CYP2C9 and VKORC1 variants along with a small subset of environmental factors account for 45.3% of warfarin dosage variability in the SA population. I observed an increase in the number of poor pregnancy outcomes in patients on high doses of warfarin. These results allow us to predict the maintenance dose of warfarin in SA black patients better, thereby reducing the risk of adverse effects, and identify those at risk of having a poor pregnancy outcome.

Faculty of Health Sciences School of Patholgy 8601804k erine.gregersen@nhls.ac.za / The oral anticoagulant, warfarin, when administered in pregnancy, can cause warfarin embryopathy, fetal central nervous system abnormalities, spontaneous abortion and fetal intrauterine death. Women with prosthetic heart valves usually require warfarin in pregnancy because of their high risk for thromboembolic complications. Anticoagulation regimens in pregnancy in these women aim to balance the fetal effects of warfarin with maternal risks of thromboembolism. This study was conducted by structured interview of 124 black urban South African women of childbearing age, who had at least one warfarin-exposed pregnancy. The study aimed to determine the pregnancy outcomes in this cohort, their awareness of the effects of warfarin in pregnancy, and what management practices, as reported by them, had occurred with regard to their anticoagulation in pregnancy and what genetic counselling they had received. There was a significant difference in outcome between warfarin-exposed and non-exposed pregnancies; 55.2% (123/223) of warfarin-exposed pregnancies ended in the birth of an abnormal baby, spontaneous abortion or intrauterine death. The warfarin embryopathy rate was estimated at 4.5 – 5.4%. Most women reported having been given information about warfarin in pregnancy, though their awareness about the personal and fetal effects of warfarin was often inaccurate. Of warfarin-exposed pregnancies, 95% were reportedly exposed during critical weeks six to ten of pregnancy, and >50% after 36 weeks. Only 5/124 (4%) interviewees had genetic counselling. Poor pregnancy outcomes, lack of awareness about the effects of warfarin in pregnancy, and management practices at odds with international regimens are all areas highlighted by this study that require urgent attention in this high-risk group of women.

Dans ce travail de thèse, nous avons synthétisé des dérivés de poly(acide (R,S)-3,3-diméthylmalique) (PDMMLA). Les copolymères de PDMMLA sont composésprincipalement de deux monomères: un monomère hydrophobe contenant un groupementhexylique et un monomère hydrophile contenant un groupement acide. Grâce à la proportionde chaque monomère dans le copolymère final, la balance hydrophile/hydrophobe est ajustée.Donc six copolymères ont été obtenus: trois copolymères statistiques PDMMLAHn-co-Hex100-n et trois copolymères à blocs PDMMLAHn-b-Hex100-n. Ces copolymères sont àl’origine de nanoparticules sans et avec un principe actif. La Warfarine a été encapsulée à lafois avec des nanoparticules de PDMMLAHn-co-Hex100-n et de PDMMLAHn-b-Hex100-n.Les nanoparticules formées sont caractérisées afin d'en déterminer la forme, la taille et lacharge de surface. Donc des nanoparticules de forme sphérique, ayant une taille inférieure à100 nm et ayant une charge de surface inférieure à -30 mV ont été obtenues. Lesnanoparticules de PDMMLAH30-co-Hex70, ont été choisies pour étudier la libérationcontrôlée de la warfarine dans des conditions de température et de pH physiologiques. Lesrésultats obtenus montrent une libération lente et progressive de la warfarine à partir dessystèmes nanoparticulaires ainsi conçus et réalisés. De tels systèmes nanoparticulaires à basede dérivés amphiphiles du PDMMLA offriraient ainsi des outils d'intérêt pour l'encapsulationet la libération contrôlée de nombreux principes actifs hydrophobes tels que le dérivécoumarinique inhibiteur de la thrombine (DCBC) dont l'activité antithrombine en systèmepurifié est plus élevée que celle de l'argatroban. / In this work we synthesized derivatives of poly((R,S)-3,3-dimethylmalic acid) (PDMMLA).PDMMLA copolymers are mainly composed of two monomers: a hydrophobic monomercontaining a hydroxyl group and a hydrophilic monomer containing an acid group. Due to theproportion of each monomer in the final copolymer, the hydrophilic / hydrophobic balance ismodulated. Thus, six copolymers were obtained: three random copolymers PDMMLAHn-co-Hex100-n and three block copolymers: PDMMLAHn-b-Hex100-n.These copolymers are at the origin of nanoparticles without and with an active principle.Warfarin, which has been successfully encapsulated with both PDMMLAHn-co-Hex100-nand block, copolymer nanoparticles: PDMMLAHn-b-Hex100-n. The formed nanoparticlesshowed fairly high encapsulation efficiency for both types of copolymers.The PDMMLA nanoparticles are characterized in order to determine their shape, size andsurface charge. Thus nanoparticles of spherical shape, having less than 100 nm size andhaving a surface charge of less than -30 mV have been obtained. The PDMMLAH30-co-Hex70nanoparticles were chosen to study the controlled release of warfarin under physiologicaltemperature and pH conditions. Obtained results show a slow and progressive release ofwarfarin. Such nanoparticulate systems based on amphiphilic derivatives of PDMMLA wouldthus offer tools of interest for the encapsulation and controlled release of many hydrophobicactive principles such as the coumarin derivative thrombin inhibitor (DCBC) whoseantithrombin activity in purified system is higher than that of argatroban.

Wu Wai Ping. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 163-177). / Abstracts in English and Chinese. / Abstract --- p.i / 摘要 --- p.iv / Acknowledgement --- p.vi / Table of Contents --- p.vii / Abbreviations --- p.x / Chapter Chapter 1 --- General introduction --- p.11 / Chapter 1.1 --- Introduction --- p.11 / Chapter 1.1.1 --- "Origin, processing and delivery form of TCM" --- p.11 / Chapter 1.1.2 --- Problems about the uses of TCM --- p.13 / Chapter 1.1.2.1 --- Quality control --- p.13 / Chapter 1.1.2.2 --- Efficacy --- p.14 / Chapter 1.1.2.3 --- Herb-drug interactions --- p.14 / Chapter 1.1.2.4 --- Authentication --- p.15 / Chapter 1.1.3 --- Commonly used Traditional Chinese Medicine --- p.15 / Chapter 1.2 --- Interactions between TCM and warfarin --- p.17 / Chapter 1.2.1 --- Danshen-warfarin interactions --- p.19 / Chapter 1.3 --- Danshen --- p.20 / Chapter 1.3.1 --- Chemical constituents --- p.20 / Chapter 1.3.2 --- Pharmacological effects of danshen --- p.24 / Chapter 1.3.2.1 --- Anti-oxidant effects --- p.24 / Chapter 1.3.2.2 --- Effects on liver fibrosis --- p.25 / Chapter 1.3.2.3 --- Effects on tumours --- p.26 / Chapter 1.3.2.4 --- Effects on cardiovascular system --- p.26 / Chapter 1.3.2.5 --- Effect on platelet aggregation --- p.27 / Chapter 1.4 --- Warfarin --- p.27 / Chapter 1.4.1 --- Pharmacology --- p.28 / Chapter 1.4.2 --- Pharmacokinetics --- p.30 / Chapter 1.4.3 --- Metabolism --- p.30 / Chapter 1.4.4 --- Warfarin-drug interactions --- p.32 / Chapter 1.4.4.1 --- Pharmacokinetic Interactions --- p.32 / Chapter 1.4.4.2 --- Pharmacodynamic interactions --- p.34 / Chapter 1.5 --- Aim of study --- p.35 / Chapter Chapter 2 --- Effects of danshen extract and some of its active ingredients on warfarin metabolism in rat liver microsomes --- p.36 / Chapter 2.1 --- Introduction --- p.36 / Chapter 2.2 --- Materials and methods --- p.39 / Chapter 2.2.1 --- Chemicals and reagents --- p.39 / Chapter 2.2.2 --- Animals --- p.39 / Chapter 2.2.3 --- Preparation of rat hepatic microsomes --- p.40 / Chapter 2.2.4 --- Protein assay --- p.40 / Chapter 2.2.5 --- Preparation of aqueous fraction and ethanolic fractions of danshen from danshen roots --- p.41 / Chapter 2.2.5.1 --- Aqueous extract of danshen --- p.41 / Chapter 2.2.5.2 --- Ethanolic extract of danshen --- p.42 / Chapter 2.2.6 --- Incubation condition for warfarin metabolism --- p.42 / Chapter 2.2.7 --- Effects of danshen extract and some of its active ingredients on warfarin metabolism in vitro --- p.43 / Chapter 2.2.8 --- Effects of danshen extract and some of its sctive ingredients on enzyme kinetics of warfarin metabolism in vitro --- p.44 / Chapter 2.2.9 --- High Pressure Liquid Chromatography (HPLC) analysis --- p.45 / Chapter 2.2.10 --- Calibration curves and validation of the HPLC systems --- p.48 / Chapter 2.2.11 --- Data analysis --- p.52 / Chapter 2.3 --- Results --- p.53 / Chapter 2.3.1 --- Effects of danshen extract on warfarin metabolism --- p.53 / Chapter 2.3.2 --- Effects of aqueous extract of danshen on warfarin metabolism --- p.60 / Chapter 2.3.3 --- Effects of ethanolic extract of danshen on warfarin metabolism --- p.62 / Chapter 2.3.4 --- Effects of tanshinone I on warfarin metabolism --- p.64 / Chapter 2.3.5 --- Effects of tanshinone IIA on warfarin metabolism --- p.70 / Chapter 2.3.6 --- Effects of cryptotanshinone on warfarin metabolism --- p.76 / Chapter 2.3.7 --- IC20 of danshen extract and its components on warfarin metabolism --- p.82 / Chapter 2.4 --- Discussion --- p.84 / Chapter Chapter 3 --- Effects of danshen extract and some of its active ingredients on warfarin metabolism in human pooled liver microsomes and the human CYP2C9 isoform --- p.89 / Chapter 3.1 --- Introduction --- p.89 / Chapter 3.2 --- Materials and methods --- p.92 / Chapter 3.2.1 --- Chemicals and reagents --- p.92 / Chapter 3.2.2 --- Incubation conditions for warfarin metabolism --- p.92 / Chapter 3.2.3 --- Effects of danshen extract and its components on warfarin metabolism in vitro --- p.93 / Chapter 3.2.4 --- High Pressure Liquid Chromatography (HPLC) analysis --- p.94 / Chapter 3.2.5 --- Calibration curves --- p.95 / Chapter 3.2.6 --- Data analysis --- p.95 / Chapter 3.3 --- Results --- p.96 / Chapter 3.3.1 --- Effects of danshen extract and its components on warfarin metabolism by using human pooled liver microsomes --- p.96 / Chapter 3.3.2 --- Effects of danshen extract and its components on S-warfarin metabolism by using human lymphoblast CYP2C9 isoform --- p.103 / Chapter 3.4 --- Discussion --- p.111 / Chapter Chapter 4 --- Effects of acute and subchonic pretreatment of danshen extract on the pharmacokinetics of warfarin in the rats in vivo --- p.115 / Chapter 4.1 --- Introduction --- p.115 / Chapter 4.2 --- Materials and methods --- p.118 / Chapter 4.2.1 --- Chemicals and reagents --- p.118 / Chapter 4.2.2 --- Animals Table of Contents --- p.118 / Chapter 4.2.3 --- Effects of acute danshen extract pretreatment on the pharmacokinetics of warfarin --- p.119 / Chapter 4.2.4 --- Effects of subchronic danshen extract pretreatment on the pharmacokinetics of warfarin --- p.119 / Chapter 4.2.5 --- Steady state warfarin study --- p.120 / Chapter 4.2.6 --- Sample extraction --- p.120 / Chapter 4.2.7 --- High Pressure Liquid Chromatography (HPLC) analysis --- p.121 / Chapter 4.2.8 --- Calibration curve --- p.121 / Chapter 4.4 --- Results --- p.123 / Chapter 4.3.1 --- Effects of acute danshen extract pretreatment on the pharmacokinetics of warfarin --- p.123 / Chapter 4.3.2 --- Effects of subchronic danshen extract pretreatment on the pharmacokinetics of warfarin --- p.128 / Chapter 4.3.3 --- Steady state warfarin study --- p.136 / Chapter 4.5 --- Discussion --- p.138 / Chapter Chapter 5 --- Effects of danshen extract on the absorption of warfarin by using Caco-2 cells model --- p.142 / Chapter 5.1 --- Introduction --- p.142 / Chapter 5.2 --- Materials and methods --- p.144 / Chapter 5.2.1 --- Materials for Caco-2 cells culture experiment --- p.144 / Chapter 5.2.2 --- Preparation of Caco-2 monolayer --- p.144 / Chapter 5.2.3 --- High Pressure Liquid Chromatography (HPLC) analysis for warfarin --- p.145 / Chapter 5.2.4 --- Calibration curve --- p.145 / Chapter 5.2.5 --- Stability test for warfarin and danshen extract --- p.145 / Chapter 5.2.6 --- Toxicity test of danshen extract on Caco-2 cells --- p.146 / Chapter 5.2.7 --- Transport study --- p.146 / Chapter 5.2.8 --- Data Analysis --- p.147 / Chapter 5.3 --- Results --- p.149 / Chapter 5.3.1 --- Stability of warfarin and danshen extract --- p.149 / Chapter 5.3.2 --- Toxicity test of danshen extract on Caco-2 cells --- p.149 / Chapter 5.3.3 --- Integrity of Caco-2 cells monolayer --- p.152 / Chapter 5.3.4 --- Transport study --- p.152 / Chapter 5.4 --- Discussion --- p.154 / Chapter Chapter 6 --- General discussion --- p.156 / References --- p.163

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No. of bitstreams: 2 Dissertacao Ely Rodrigues de Almeida - 2013.pdf: 1560361 bytes, checksum: 153a2514b81e70d5b31e01a1cc0d09b6 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-10-15 / INTRODUCTION: Anticoagulation with warfarin is used in the presence of hypercoagulability and as prophylaxis for thromboembolism. Prothrombin time and activity and the international normalized ratio (PTA/INR) are the standard tests for laboratory follow up of the anticoagulation rate. Hemorrhage is one complication of this therapy. Therefore, one speculates on the possibility of diagnosing cases in which there is excess anticoagulation, by means of the analysis of hematuria in urinalysis and the association with PTA/INR. OBJECTIVE: Analyze the existence of a correlation between hematuria in urinalysis and high PTA/INR, among users of warfarin. METHODOLOGY: This is a descriptive, analytical, primary, quantitative and cross-sectional investigation. The study included 128 patients, 63 of whom were being treated with warfarin, and formed the group of anticoagulated patients (ACG). The remaining 65 patients who were not using anticoagulants formed the non anticoagulated group (NACG). For this study, 152 blood and urine samples were collected; 24 patients of the ACG contributed twice for the PTA/INR and urinalysis, at two different times. All the participants of the NACG also had the PTA/INR and urinalysis tests done. Patients with a clinical suspicion of conditions that might cause hematuria were excluded. The social and demographic data of these individuals were analyzed and the numerical variables of hematuria and of other urinalysis and INR parameters were measured and analyzed. The prevalence and the correlation between hematuria and PTA/INR levels were calculated. Data from the tests, medical appointments and the records of patients recruited in the collection room of the Clinical Laboratory of the HC-UFG were evaluated statistically, and emphasis was placed on the Spearman's correlation for hematuria and PTA/INR (IC 95%; p< 0.05). The study was approved by the Committee on Ethics and Human Research of the HC-UFG, protocol No. 016/2012. RESULTS: The amount of warfarin given on a weekly basis ranged from 10 to 65 mg. If one considers the INR between 2 and 3.9 acceptable for adequate anticoagulation, 59.77% of the individuals were adequately anticoagulated, 35% were insufficiently anticoagulated and 5.75% were excessively anticoagulated. The prevalence of hematuria among the ACG members was 26.44 % (CI 95% 17.98 – 36.43) and among NACG members, 29.23 % (CI 95% 19.16 – 41.11). The correlation coefficient between hematuria and INR was 0.012 (p=0.887). CONCLUSIONS: The most of the patients (59.7%) were within the recommended therapeutic range for controlling patients. There was no correlation between hematuria as measured by urinalysis and anticoagulation levels measured by the INR. / INTRODUÇÃO: A anticoagulação com varfarina é usada na hipercoagubilidade e como profilaxia para o tromboembolismo. O tempo e atividade de protrombina e a relação normatizada internacional (TAP/RNI) são os exames padrões para acompanhamento laboratorial da taxa de anticoagulação. A hemorragia é uma complicação desta terapia. Dessa forma, especula-se a possibilidade de diagnosticar casos em que haja excesso de anticoagulação, por meio da análise da hematúria no exame dos elementos anormais e sedimentoscopia da urina (EAS) e a associação com TAP/RNI. OBJETIVO: Analisar a existência de correlação entre hematúria no EAS e TAP /RNI elevados, nos usuários do anticoagulante varfarina. METODOLOGIA: Estudo descritivo, analítico, primário, quantitativo e transversal. Incluíram-se 128 pacientes, sendo 63 tratados com varfarina, formando um grupo anticoagulado (GAC) e 65 que não faziam uso de anticoagulantes, grupo não anticoagulado (GNAC). Colheram-se 152 amostras de sangue e urina; das quais 24 pacientes do GAC contribuíram duas vezes para exames TAP/RNI e EAS, em dois momentos distintos. Todos os participantes do GNAC também se submeteram aos exames TAP/RNI e EAS. Excluíram-se pacientes com suspeita clínica de condições que causassem hematúria. Analisaram-se os dados sociodemográficos e fez-se a mensuração e a análise das variáveis numéricas hematúria e de outros parâmetros do EAS e RNI. Calculou-se a prevalência e a correlação entre hematúria e níveis de TAP/RNI. Os dados oriundos de exames, consultas médicas e dos prontuários dos pacientes recrutados na sala de coleta do Laboratório Clinico do HC-UFG, foram avaliados estatisticamente, com ênfase na correlação de Spearman para hematúria e TAP/RNI (IC 95%; p<0,05). O projeto foi aprovado pelo Comitê de Ética e Pesquisa Humana do HC-UFG sob o nº 016/2012. RESULTADOS: A quantidade de varfarina semanal variou de 10 a 65 mg. Considerando-se o valor de RNI entre 2 e 3,9, como valor aceitável para adequada anticoagulação, 59,77% estavam adequadamente anticoagulados, 35% insuficientemente e, com efeito anticoagulante excessivo, 5,75%. A prevalência de hematúria no GAC foi de 26,44 % (IC 95% 17,98 – 36,43) e no GNAC, foi de 29,23 % (IC 95% 19,16 – 41,11). O coeficiente de correlação entre hematúria e RNI foi de 0,012 (p=0,887). CONCLUSÕES: A maioria dos pacientes (59,7%) tinha a RNI na faixa terapêutica preconizada para anticoagulação. Não houve correlação entre hematúria ao exame EAS e os níveis de anticoagulação medidos pela RNI.

Introdução: A varfarina é um dos anticoagulantes orais (ACO) mais utilizados na atenção primária a saúde. Com janela terapêutica estreita, exibe grande variabilidade de resposta farmacológica, e maior suscetibilidade de eventos adversos, como sangramentos e tromboembolismo venoso. Entre os fatores que influenciam na variabilidade de dose destaca-se as interações tanto com medicamentos, como com a dieta e o polimorfismo genético. Objetivos: Estimar a incidência de eventos adversos relacionados ao uso de varfarina e descrever o itinerário do usuário pelo sistema público de saúde para resolução dos problemas. Métodos: trata-se de uma coorte prospectiva realizada por um período de 18 meses com usuários do serviço público de saúde, em uso de varfarina, do município de Ijuí/RS. Os dados foram coletados por entrevistas mensais nas residências e complementados com informações médicas obtidas na atenção primária e terciária. As interações medicamentosas foram checadas em bases de dados e os hábitos alimentares conforme metodologia validada. A estatística utilizada para associar sangramento e Time in Therapeutic Range (TTR) e os fatores de risco foi teste de Poison. O projeto foi aprovado no Comitê de Ética em Pesquisa da UFRGS, com parecer número 336.259/2013. Resultados: Foram entrevistados e acompanhados 69 pacientes, sendo que 64 concluíram o acompanhamento e 5 faleceram durante o estudo, 55,1% eram do sexo feminino, com idade média de 64,3 ±13,7 anos. O tempo médio de uso de varfarina foi de 5,5 anos, a dose média semanal foi de 30,69±15,19mg e o principal motivo para uso de varfarina foi prótese valvular (39,7%). A média de medicamentos utilizados por usuário foi de 9,6±4,5. Quanto aos eventos, os sangramentos tiveram incidência de 37,7/100 pacientes/ano, o tromboembolismo de 4,8/100 pacientes/ano e de óbitos de 4,8/100 pacientes/ano. Os sangramentos apresentaram associação com possuir mais que três interações medicamentosas com a varfarina (p=0,048) e com uso de medicamentos por automedicação (p=0,030). Já para o TTR houve associação com a idade inferior a 65 anos (p=0,032). E 67 usuários estavam suscetíveis a interações medicamentosasas com varfarina, com predomínio das moderadas, sendo a média de interações com este medicamento de 2,91±1,52. A maioria das interações agiam sobre o efeito anticoagulante da varfarina, aumentando a probabilidade de sangramento. Entre as interações que os usuários apresentavam, no momento do sangramento, as mais frequentes foram com: omeprazol, sinvastatina e paracetamol. A maioria dos entrevistados apresentou consumo baixo de vitamina K. Verificou-se que sangramentos e tromboembolismos venosos foram mais frequentes nos pacientes em início de tratamento. E todos os pacientes que foram a óbito durante o acompanhamento (5) eram pacientes com mais de um ano de uso de varfarina. Para a resolução de eventos adversos na maioria dos casos o paciente realizou cuidado domiciliar (53,4%), seguido por busca pela Unidades Básicas de Saúde, 7 pacientes buscaram o serviço de emergência e 5 realizaram internação hospitalar. Observou-se que aproximadamente metade dos pacientes não mostrou seus exames de INR (Razão Normalizada Internacional) ao médico. E na falta de varfarina na rede pública de saúde do município, que ocorreu entre os meses 13 e 16, entre 24,9 a 43,5%, deixaram de usar o medicamento. Os resultados do polimorfismo demonstram que 47 (71,2%) não apresentam polimorfismo ao genótipo CYP2C9, e 24 (36,4%) ao genótipo VKORC1. Avaliando os dois genótipos associados, verifica-se que 17 (25,8%) não apresentam polimorfismo a nenhum destes. Não foi observada associação estatística do polimorfismo com sexo e raça. Observou-se diferença significativa entre a dose utilizada para os diferentes polimorfismos (p=0,013). Da mesma forma, para o VKORC1, houve diferença significativa entre a dose e o genótipo (p=0,018). Conclusão: Estes resultados demonstram a necessidade de uma maior assistência a estes pacientes, buscando melhores resultados clínicos, com menos eventos adversos. / Introduction: Warfarin is an oral anticoagulant (OAC) most used in primary health care. With narrow therapeutic window, shows great variability in drug response, and greater susceptibility to adverse events such as bleeding and venous thromboembolism. Among the factors that influence the amount of variability highlights the interactions with both drugs, as with diet and genetic polymorphism. Objectives: To estimate the incidence of adverse events related to warfarin use and describe the user journey through the public health system to the problems. Methods: This is a prospective cohort study conducted over a period of 18 months with users of the public health service in the use of warfarin, the city of Ijuí/RS. The data were collected monthly interviews in homes and complemented with medical information obtained in primary and tertiary care. Drug interactions were checked in databases and eating habits as validated methodology. The statistics used to associate bleeding and Time in Therapeutic Range (TTR) and the risk factors was Poison test. The project was approved by the Research Ethics Committee of UFRGS, with opinion number 336259/2013. Results: We interviewed and followed 69 patients, 64 completed the follow-up and 5 died during the study, 55.1% were female, mean age 64.3 ± 13.7 years. The mean duration of warfarin use was 5.5 years, the average weekly dose was 30.69 ± 15,19mg and the main reason for warfarin use was valvular prosthesis (39.7%). The average per user used medications was 9.6 ± 4.5. As for events, the bleeding had incidence of 37.7 / 100 patients / year, thromboembolism of 4.8 / 100 patients / year and deaths of 4.8 / 100 patients / year. Bleeds were associated with having more than three drug interactions with warfarin (p = 0.048) and use of self-medication by drugs (p = 0.030). As for the TTR was no association with age less than 65 years (p = 0.032). And 67 users were susceptible to medicamentosasas interactions with warfarin, with a predominance of moderate, with an average of interactions with this drug of 2.91 ± 1.52. Most interactions acting on the anticoagulant effect of warfarin, increasing the probability of bleeding. Among the interactions that users had, at the time of bleeding, the most common were with: omeprazole, simvastatin and acetaminophen. Most respondents showed low consumption of vitamin K. It was found that bleeding and venous thromboembolism were more frequent in patients starting treatment. And all patients who died during follow-up (5) were patients with more than one year of warfarin use. For adverse event resolution in most cases the patient underwent home care (53.4%), followed by search for the Basic Health Units, 7 patients sought emergency services and 5 held hospitalization. It was observed that approximately half of the patients showed their INR test (International Normalized Ratio) to the doctor. And in the absence of warfarin in public municipal health, which occurred between the months 13:16, from 24.9 to 43.5% stopped using the drug. The polymorphism results demonstrate that 47 (71.2%) did not have the polymorphism CYP2C9 genotype, and 24 (36.4%) the VKORC1 genotype. Evaluating the two genotypes associated, it is found that 17 (25.8%) did not show any polymorphism thereof. There was no statistical association of the polymorphism with gender and race. A significant difference between the dose for different polymorphisms (p = 0.013). Likewise, for the VKORC1, a significant difference between the dose and genotype (p = 0.018). Conclusion: These results demonstrate the need for further assistance to these patients, looking for better clinical outcomes, with fewer adverse events.

Herbal medicines are widely used in our community. A survey of Australian consumers indicated that 60% had used complementary and/or alternative medicines in the past year with the majority not informing their doctor that they were using herbal medicines. Little is known about the potentially serious consequences of interactions between herbal and conventional medicines. Warfarin has an important role in treating people with heart disease, yet it has a narrow therapeutic range, is highly bound to plasma proteins, and is metabolised by cytochrome P450. This creates the potential for life-threatening interactions with other drugs and foods leading to excessive bleeding. Hence, warfarin is one of the most frequently investigated drugs for interaction studies. Early clinical reports suggest that there exists the potential for an interaction between warfarin and four herbal medicines: St John�s wort, ginseng, ginkgo and ginger. However, these herb-drug combinations have never been conclusively studied. The two clinical studies conducted as part of this research had an identical study design. Twenty-four healthy male subjects were recruited into the two separate studies. This was an open label, three-way crossover randomised study in twelve healthy male subjects, who received a single 25 mg dose of warfarin alone or after 14 days pre-treatment with St John�s wort, or 7 days pre-treatment with ginseng. Dosing with St John�s wort or ginseng was continued for 7 days after administration of the warfarin dose in study I or who received a single 25 mg dose of warfarin alone or after 7 days pre-treatment with recommended doses of ginkgo or ginger from single ingredient products of known quality. Dosing with ginkgo or ginger was continued for 7 days after administration of the warfarin dose in study II. Platelet aggregation, international normalised ratio (INR) of prothrombin time, warfarin enantiomer protein binding, warfarin enantiomer concentrations in plasma and S-7-hydroxywarfarin concentration in urine were measured in both studies. Statistical comparisons were made using ANOVA and 95% confidence interval (CI) for mean value and 90% CI for geometric mean ratio value are reported. n study I, the mean (95% CI) apparent clearance of S-warfarin after warfarin alone or with St John�s wort or ginseng were, respectively, 198 (174 � 223) ml/h, 269 (241 � 297) ml/h and 220 (201 � 238) ml/h. The respective apparent clearances of R-warfarin were 110 (94 � 126) ml/h, 142 (123 � 161) ml/h and 119 (106 � 131) ml/h. The mean ratio of apparent clearance for S-warfarin was 1.29 (1.16-1.46) and for R-warfarin was 1.23 (1.11-1.37) when St John�s wort was co-administered. The mean ratio of AUC0-168 of INR was 0.79 (0.70 - 0.95) when St John�s wort was co-administered. The urinary excretion ratio of S-7-hydroxywarfarin after administration of warfarin alone was 0.04 (0.03 � 0.06) mg/h and there was no significant difference following treatment with either St John�s wort 0.03 (0.02 � 0.04) mg/h or ginseng 0.03 (0.02 � 0.04) mg/h. The ratio of geometric means for S-7-hydroxywarfarin UER was 0.82 (0.61-1.12) for St John�s wort, and 0.68 (0.50-0.91) for ginseng. St John�s wort and ginseng did not affect the apparent volumes of distribution or protein binding of warfarin enantiomers. In study II, the mean (95% CI) apparent clearance of S-warfarin after warfarin alone, with ginkgo or ginger were 189 (167 � 210) ml/h, 200 (173 � 227) ml/h and 201 (171 � 231) ml/h, respectively. The respective apparent clearances of R-warfarin were 127 (106 � 149) ml/h, 126 (111 � 141) ml/h and 131 (106 � 156) ml/h. The mean ratio of apparent clearance for S-warfarin was 1.05 (0.98 -1.12) and for R-warfarin was 1.00 (0.93 -1.08) when co-administered with ginkgo. The mean ratio of AUC0-168 of INR was 0.93 (0.81 -1.05) when co-administered with ginkgo. The mean ratio of apparent clearance for S-warfarin was 1.05 (0.97 -1.13) and for R-warfarin was 1.02 (0.95 -1.10) when co-administered with ginger. The mean ratio of AUC0-168 of INR was 1.01 (0.93 -1.15) when co-administered with ginger. The urinary excretion ratio (UER) of S-7-hydroxywarfarin after administration of warfarin alone was 0.04 (0.03 � 0.05) mg/h and there was no significant difference following treatment with either ginkgo 0.04 (0.03 � 0.04) mg/h or ginger 0.03 (0.02 � 0.04) mg/h. The ratio of geometric means for S-7-hydroxywarfarin UER was 1.07 (0.69-1.67) for ginkgo, and 1.00 (0.64-1.56) for ginger. Ginkgo and ginger did not affect the apparent volumes of distribution or protein binding of either S-warfarin or R-warfarin. In conclusion, St John�s wort significantly induced the apparent clearance of both S-warfarin and R-warfarin, which in turn resulted in a significant reduction in the pharmacological effect of rac-warfarin. Ginseng, ginkgo and ginger at recommended doses affect neither clotting status, nor the pharmacokinetics or pharmacodynamics of either S-warfarin or R-warfarin in healthy subjects.

Warfarin is one of the most widely used anticoagulants in the world. Treatment is complicated by a large inter-individual variation in the dose needed to reach adequate levels of anticoagulation i.e. INR 2.0 – 3.0. The objective of this thesis was to evaluate which factors, mainly genetic but also non-genetic, that affect the response to warfarin in terms of required maintenance dose, efficacy and safety with special focus on warfarin dose prediction. Through candidate gene and genome-wide studies, we have shown that the genes CYP2C9 and VKORC1 are the major determinants of warfarin maintenance dose. By combining the SNPs CYP2C9 *2, CYP2C9 *3 and VKORC1 rs9923231 with the clinical factors age, height, weight, ethnicity, amiodarone and use of inducers (carbamazepine, phenytoin or rifampicin) into a prediction model (the IWPC model) we can explain 43 % to 51 % of the variation in warfarin maintenance dose. Patients requiring doses &lt; 29 mg/week and doses ≥ 49 mg/week benefitted the most from pharmacogenetic dosing. Further, we have shown that the difference across ethnicities in percent variance explained by VKORC1 was largely accounted for by the allele frequency of rs9923231. Other novel genes affecting maintenance dose (NEDD4 and DDHD1), as well as the replicated CYP4F2 gene, have small effects on dose predictions and are not likely to be cost-effective, unless inexpensive genotyping is available. Three types of prediction models for warfarin dosing exist: maintenance dose models, loading dose models and dose revision models. The combination of these three models is currently being used in the warfarin treatment arm of the European Pharmacogenetics of Anticoagulant Therapy (EU-PACT) study. Other clinical trials aiming to prove the clinical validity and utility of pharmacogenetic dosing are also underway. The future of pharmacogenetic warfarin dosing relies on results from these ongoing studies, the availability of inexpensive genotyping and the cost-effectiveness of pharmacogenetic driven warfarin dosing compared with new oral anticoagulant drugs.