Dissertations / Theses on the topic 'Anticoagulant drugs'

Thesis (M.S.M.) PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
BACKGROUND: Although novel anticoagulant drugs have proven safety and efficacy profiles from Phase III clinical trials, those patients with significant kidney disease were excluded. The lack of knowledge about incidence, severity and risk factors for severe renal dysfunction in patients requiring oral anticoagulation impedes development of strategies to mitigate risks of hemorrhage associated with renally-eliminated novel oral anticoagulants. METHODS: Patients taking warfarin for atrial fibrillation (AF) or venous thromboembolism (VTE) were consecutively enrolled from January 2007 to December 2010. Baseline kidney function was assessed and patients were followed to their first decline in Glomerular Filtration Rate (GFR) to < 30 ml/min estimated by the Cockcroft-Gault calculation. Independent risk factors for development of severe kidney dysfunction were assessed by multivariate analysis. RESULTS: Of 787 patients identified, 34 were excluded for baseline eGFR < 30 ml/min. The mean age of the cohort was 71 years. At baseline, 23% (n=174) had moderate renal impairment, or Stage 3 CKD (eGFR 30-59 ml/min), while 31% had mild disease. Overall, those with hypertension, congestive heart failure (CHF), diabetes mellitus (DM), and coronary artery disease (CAD) were 74%, 33%, 31%, 24%, and 9% of the cohort, respectively. A decline in eGFR to < 30 ml/min (the primary outcome) occurred in 91 patients, 25% of which happened within 5.3 months. Of those with baseline Stage 3 CKD, 37% experienced the primary outcome. In multiple logistic regression analysis, a baseline eGFR 30–59 ml/min conferred a greater than 14-fold increased risk in the development of eGFR < 30 ml/min (OR 14.5, 99% CI: 5.3 to 39.8, P<0.001) during the warfarin exposure period. CAD was associated with a greater than two-fold increased risk (OR 2.2, 95% CI 1.1 to 4.4, P=0.004). After adjusting for baseline kidney function, age was not an independent risk factor for a decline in eGFR to < 30 ml/min. CONCLUSIONS: Acute and chronic renal dysfunction is common among individuals on chronic warfarin therapy. Better understanding of the fluctuations in renal function would inform patient selection and monitoring strategies for optimal use of novel anticoagulants.
2031-01-01

The occurrence of thrombosis in several pathophysiological conditions creates a huge need for anticoagulation therapy. Thrombin and factor Xa have been prime targets for regulation of clotting through the direct and indirect mechanism of inhibition. This work investigates chemo-enzymatically prepared oligomers of 4-hydroxycinnamic acids (DHPs) as potential anticoagulants. Oligomers were prepared through peroxidase-catalyzed oxidative coupling of 4-hydroxycinnamic acids. The products resulting from this reaction are called CDs, FDs and SDs. Structurally, these sulfated DHPs are unique and do not resemble any of the anticoagulants known in the literature.DHP oligomers were found to increase clotting times at concentrations comparable to heparin. Studies in blood and plasma show that DHPs possess an anticoagulation profile similar to enoxaparin. To understand the mechanism of action of DHPs, we studied the inhibition of thrombin, FXa, FIXa, and FVIIa in the presence and absence of antithrombin. CDs and FDs display a preference for direct inhibition of thrombin and FXa, and exhibit a high level of specificity over FIXa and FVIIa. In the presence of AT, CDs and FDs displayed weaker inhibition of FXa and thrombin suggesting that binding to AT is a competitive side reaction. SDs exhibited potent inhibition of FXa and thrombin in the absence of antithrombin, but was inactive against FIXa and FVIIa representing the best selectivity among the DHPs. For SDs, inhibition of all the pro-coagulant enzymes favored the antithrombin dependent pathway. Binding studies were performed to determine how CDs directly inhibits thrombin. Competitive binding studies suggest that CDs interacts with exosite II and disrupts the catalytic triad of thrombin. These results indicate that the preferred mechanism of CDs action is exosite II mediated allosteric disruption of thrombin. CDs appears to be the first exosite II mediated DTI and this represents a novel mechanism of inhibitor function. The inhibition characteristics of DHPs are unique and radically different in structure from all the current clinically used anticoagulants. To the best of our knowledge this dual mechanism of anticoagulation and unique binding mode has not been described as yet in literature and represents a novel strategy that our laboratory has discovered.

Made available in DSpace on 2014-12-17T14:03:28Z (GMT). No. of bitstreams: 1 JulianaMCS.pdf: 573830 bytes, checksum: 9b4db031d8ca76bd1eed966ee42dfb5b (MD5) Previous issue date: 2008-11-25
Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Sulfated polysaccharides (PS) are biomolecules with a great biotechnological potential. There are few data about PS from high plants. In addition, pharmacological activities of PS from plants have not been carrying out. The aim of this work was extract PS from the angiosperm Halodule wrightii and study their anticoagulant and antioxidant activities. Histological analysis showed the presence of the PS manly in the roots. A polysaccharide-rich extract was obtained from H. wrightii by proteolysis followed by methanol and TCA precipitation. Chemical, infra-red analysis and agarose gel electrophoresis in 1.3 diaminopropane acetate buffer confirmed the presence of sulfated polysaccharides made by glucose, galactose, xylose and sulfate residues in the proportion 1: 0,9: 1: 1. In addition polyacrilamide electrophoresis have shown that extract is mainly compose by 11kDa sulfated polysaccharides. Pharmacological analysis have shown total antioxidant capacity (CAT) that resulted in 15,21 μg for equivalent of ascorbic acid, scavenging activity of the DPPH radical with 41,36 % of scavenging, activity of reducing power with the maximum of 0,290 nm (50 % of vitamin C activity) and scavenging activity superoxide radical (O2-) with a maximum of 32,23 %. Chelating activity of metal less than 4% and scavenging activity of the radical hydroxyl (OH-) less than 2%. Time of activated partial tromboplastin (aPTT) doubling the time of coagulation from 20μg of and protrombin time (PT) was not present. The data indicate that PS from Halodule wrightii could be considered for future applications in medicine, food production or cosmetic industry
Os polissacar?deos sulfatados (PS) s?o biomol?culas com um grande potencial biotecnol?gico por apresentarem uma diversidade estrutural e farmacol?gica muito grande. Poucos s?o os relatos da exist?ncia destes pol?meros em vegetais superiores, al?m disso, ainda n?o se tem relatos da identifica??o de atividades antioxidantes e anticoagulantes com PS extra?dos destes vegetais. Com o intuito de verificar a presen?a destes polissacar?deos em angiospermas marinhas conhecidas popularmente como capim do mar, foi coletada a esp?cie marinha Halodule wrightii. As por??es vegetativas (folha, caule e raiz) n?o foram separadas sendo preparado inicialmente um extrato denominado de extrato bruto (EB). Ap?s descontamina??o prot?ica o material obtido foi chamado de extrato de polissacar?deos totais (EPT). A presen?a destes polissacar?deos foi investigada e confirmada por an?lises qu?micas, espectroscopia de infravermelho e eletroforese em gel de agarose sendo denominados de extrato rico em polissacar?deos sulfatados (EPS). A an?lise histol?gica da localiza??o dos PS resultou na presen?a destes polissacar?deos principalmente na epiderme da por??o vegetativa raiz. As an?lises qu?micas mostraram que os polissacar?deos contem glicose, galactose, xilose e sulfato na propor??o de 1: 0,9: 1: 1 e massa molecular de aproximadamente 11 kDa. Os grupos sulfatos est?o provavelmente ligados principalmente em C2 de um monossacar?deo. Testes de atividade antioxidante demonstraram que os PS de H. wrightii n?o apresentaram resultado para o teste de capacidade antioxidante total pelo m?todo CAT. Desta forma foi utilizada a atividade de seq?estro do radical DPPH indicado na literatura por dosar a capacidade antioxidante total que resultou em 41,36%. O seq?estro do ?on super?xido tamb?m foi realizado e resultou em 32,23% assim como o poder redutor que equivaleu a 50% da atividade da Vit. C. N?o houve atividade de seq?estro do radical hidroxila assim como atividade quelante de metal. O teste de atividade anticoagulante (aPTT) mostrou que EPS dobra o tempo de coagula??o com 20 g, que ? apenas 2,5 vezes a quantidade da Clexane? (heparina de baixo peso molecular). Para o tempo de protrombina (PT) H.wrightii n?o apresentou atividade. Os dados indicam que EPS possuem um potencial biotecnol?gico anticoagulante e antioxidante e que futuras an?lises se fazem necess?rias para confirmarem esse potencial

Made available in DSpace on 2014-12-17T14:03:29Z (GMT). No. of bitstreams: 1 JulianaMCS.pdf: 573830 bytes, checksum: 9b4db031d8ca76bd1eed966ee42dfb5b (MD5) Previous issue date: 2008-11-25
Sulfated polysaccharides (PS) are biomolecules with a great biotechnological potential. There are few data about PS from high plants. In addition, pharmacological activities of PS from plants have not been carrying out. The aim of this work was extract PS from the angiosperm Halodule wrightii and study their anticoagulant and antioxidant activities. Histological analysis showed the presence of the PS manly in the roots. A polysaccharide-rich extract was obtained from H. wrightii by proteolysis followed by methanol and TCA precipitation. Chemical, infra-red analysis and agarose gel electrophoresis in 1.3 diaminopropane acetate buffer confirmed the presence of sulfated polysaccharides made by glucose, galactose, xylose and sulfate residues in the proportion 1: 0,9: 1: 1. In addition polyacrilamide electrophoresis have shown that extract is mainly compose by 11kDa sulfated polysaccharides. Pharmacological analysis have shown total antioxidant capacity (CAT) that resulted in 15,21 μg for equivalent of ascorbic acid, scavenging activity of the DPPH radical with 41,36 % of scavenging, activity of reducing power with the maximum of 0,290 nm (50 % of vitamin C activity) and scavenging activity superoxide radical (O2-) with a maximum of 32,23 %. Chelating activity of metal less than 4% and scavenging activity of the radical hydroxyl (OH-) less than 2%. Time of activated partial tromboplastin (aPTT) doubling the time of coagulation from 20μg of and protrombin time (PT) was not present. The data indicate that PS from Halodule wrightii could be considered for future applications in medicine, food production or cosmetic industry
Os polissacar?deos sulfatados (PS) s?o biomol?culas com um grande potencial biotecnol?gico por apresentarem uma diversidade estrutural e farmacol?gica muito grande. Poucos s?o os relatos da exist?ncia destes pol?meros em vegetais superiores, al?m disso, ainda n?o se tem relatos da identifica??o de atividades antioxidantes e anticoagulantes com PS extra?dos destes vegetais. Com o intuito de verificar a presen?a destes polissacar?deos em angiospermas marinhas conhecidas popularmente como capim do mar, foi coletada a esp?cie marinha Halodule wrightii. As por??es vegetativas (folha, caule e raiz) n?o foram separadas sendo preparado inicialmente um extrato denominado de extrato bruto (EB). Ap?s descontamina??o prot?ica o material obtido foi chamado de extrato de polissacar?deos totais (EPT). A presen?a destes polissacar?deos foi investigada e confirmada por an?lises qu?micas, espectroscopia de infravermelho e eletroforese em gel de agarose sendo denominados de extrato rico em polissacar?deos sulfatados (EPS). A an?lise histol?gica da localiza??o dos PS resultou na presen?a destes polissacar?deos principalmente na epiderme da por??o vegetativa raiz. As an?lises qu?micas mostraram que os polissacar?deos contem glicose, galactose, xilose e sulfato na propor??o de 1: 0,9: 1: 1 e massa molecular de aproximadamente 11 kDa. Os grupos sulfatos est?o provavelmente ligados principalmente em C2 de um monossacar?deo. Testes de atividade antioxidante demonstraram que os PS de H. wrightii n?o apresentaram resultado para o teste de capacidade antioxidante total pelo m?todo CAT. Desta forma foi utilizada a atividade de seq?estro do radical DPPH indicado na literatura por dosar a capacidade antioxidante total que resultou em 41,36%. O seq?estro do ?on super?xido tamb?m foi realizado e resultou em 32,23% assim como o poder redutor que equivaleu a 50% da atividade da Vit. C. N?o houve atividade de seq?estro do radical hidroxila assim como atividade quelante de metal. O teste de atividade anticoagulante (aPTT) mostrou que EPS dobra o tempo de coagula??o com 20 ug, que ? apenas 2,5 vezes a quantidade da Clexane? (heparina de baixo peso molecular). Para o tempo de protrombina (PT) H.wrightii n?o apresentou atividade. Os dados indicam que EPS possuem um potencial biotecnol?gico anticoagulante e antioxidante e que futuras an?lises se fazem necess?rias para confirmarem esse potencial

Estudo exploratório, de delineamento longitudinal, com 81 pacientes em uso de anticoagulante oral e que foram avaliados durante internação e dois meses após a alta. Os objetivos foram acompanhar a evolução quanto á terapia de anticoagulação oral e adesão ao tratamento; comparar o estado geral de saúde e a presença de sintomas de ansiedade e depressão. Foram utilizados instrumentos específicos para avaliar adesão ao tratamento medicamentoso (Medida de Adesão aos Tratamentos), estado geral de saúde (Escala Visual Analógica) e presença de sintomas de ansiedade (HADS-Ansiedade) e depressão (HADS- Depressão). As análises estatísticas realizadas foram: Teste t de Student pareado para comparar as médias do estado geral de saúde e da HADS; Modelo Linear de Efeitos Mistos para analisar a associação entre estado geral de saúde, ansiedade, depressão e tempo de avaliação no estudo. O nível de significância adotado foi 0,05. Entre os participantes, 54,3% eram mulheres, com idade média de 59,5 anos e nível médio de instrução de 5,1 anos. A principal indicação clínica para uso do medicamento foi formação de trombos (34,6%), sendo a varfarina o anticoagulante oral mais utilizado (97,5%). Dois meses após a alta, todos os pacientes foram classificados como aderentes ao tratamento e 42% mantiveram o INR na faixa terapêutica. As diferenças entre as médias do estado geral de saúde, HADS-Ansiedade e HADS-Depressão durante a internação e dois meses após a alta não foram estatisticamente significantes (p=0,78; p=0,27 e p=0,40, respectivamente). Em relação á presença de ansiedade, quando associamos as duas variáveis de forma categórica, com e sem sintomas, e o tempo de avaliação, 38 (46,9%) pacientes foram classificados como \"sem sintomas\" de ansiedade e 22 (27,1%) \"com sintomas\", sendo esta associação estatisticamente significante (p<0,001). Para depressão, a maioria (55; 67,9%) foi classificada como \"sem sintomas\" e 11 (13,6%) \"com sintomas\", sendo tal associação estatisticamente significante (p<0,001). Ao analisarmos as médias do estado geral de saúde segundo tempo e grupo de sintomas, resultados estatisticamente significantes foram obtidos apenas quando comparamos os valores entre os grupos sem sintomas de depressão (M=80,5; D.P.=23,46) e com sintomas (M=62,5; D.P.=26,07) (p=0,021), dois meses após a alta e quando comparamos as médias do grupo com sintomas de depressão, na internação (M= 75,37; D.P.=25,02) e dois meses após a alta (M=62,5; D.P.=26,07) (p=0,046). Identificar o perfil clínico de pacientes em uso de anticoagulante oral, desde a internação até dois meses de seguimento ambulatorial; conhecer sua percepção sobre estado de saúde, presença de sintomas de ansiedade e de depressão e a adesão ao tratamento são ações importantes a serem consideradas no atendimento desses pacientes. Tais resultados poderão ser utilizados para nortear mudanças na organização do ambulatório de anticoagulação oral e no planejamento da assistência de enfermagem a tais pacientes.
This exploratory and longitudinal research involved 81 patients under oral anticoagulation treatment, who were evaluated during hospitalization and two months after discharge. The objectives were to follow the patients\' clinical evolution, considering the oral anticoagulation therapy and treatment adherence; and to compare the general health condition and the presence of anxiety and depression symptoms. Specific instruments were used to assess adherence to medication treatment (Treatment Adherence Measure), general health condition (visual analogue scale) and the presence of anxiety (HADS-Anxiety) and depression symptoms (HADS-depression). For the sake of statistical analysis, the following were applied: Student\'s paired t-test to compare the mean scores for the general health condition and HADS scores; the Linear Fixed Effects Model to analyze the association between general health condition, anxiety, depression and research moment. Significance was set at 0.05. Among the participants, 54.3% were women, with a mean age of 59.5 years and a mean education time of 5.1 years. The main clinical indication for medication use was the formation of thrombi (34.6%), with warfarin as the most used oral anticoagulant drug (97.5%). AT two months after discharge, all patients were classified as adherent to the treatment and 42% maintained their INR within the therapeutic range. The differences between the mean general health, HADS-Anxiety and HADS-Depression scores during hospitalization and two months after discharge were not statistically significant (p=0.78; p=0.27 and p=0.40, respectively). As regards the presence of anxiety, when the two variables are associated categorically, with and without symptoms, and the research moment, 38 (46.9%) patients were classified as \"without symptoms\" of anxiety and 22 (27.1%) \"with symptoms\", with a statistically significant association (p<0.001). As for depression, the majority (55; 67.9%) was classified as \"without symptoms\" and 11 (13.6%) \"with symptoms\", a statistically significant association (p<0.001). The analysis of the mean general health condition scores according to the research moment and group of symptoms only revealed statistically significant results when comparing the groups without (M=80.5; S.D.=23.46) and with symptoms (M=62.5; S.D.=26.07) (p=0.021) two months after the discharge and when comparing the mean scores for the group with depression symptoms during hospitalization (M= 75.37; S.D.=25.02) and two months after the discharge (M=62.5; S.D.=26.07) (p=0.046). Identifying the clinical profile of patients under oral anticoagulant therapy since hospitalization and after two months of outpatient monitoring and getting to know their perceived health condition, presence of anxiety and depression symptoms and treatment adherence are important actions for consideration in care delivery to these patients. These results can be used to guide changes in the organization of the oral anticoagulation outpatient clinic and in nursing care planning for these patients.

Made available in DSpace on 2014-12-17T14:13:41Z (GMT). No. of bitstreams: 1 NednaldoDS_TESE.pdf: 2321205 bytes, checksum: c08caa8155a3fd7b840048363939c371 (MD5) Previous issue date: 2012-03-19
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Sulfated polysaccharides (SP) are widely distributed in animals and seaweeds tissues. These polymers have been studied in light of their important pharmacological activities, such as anticoagulant, antioxidant, antitumoral, anti-inflammatory, and antiviral properties. On other hand, SP potential to synthesize biomaterials like as nanoparticules has not yet been explored. In addition, to date, SP have only been found in six plants and all inhabit saline environments. However, the SP pharmacological plant activities have not been carrying out. Furthermore, there are no reports of SP in freshwater plants. Thus, do SP from marine plants show pharmacological activity? Do freshwater plants actually synthesize SP? Is it possible to synthesize nanoparticles using SP from seaweed? In order to understand this question, this Thesis was divided into tree chapters. In the first chapter a sulfated polysaccharide (SPSG) was successfully isolated from marine plant Halodule wrightii. The data presented here showed that the SPSG is a 11 kDa sulfated heterogalactan contains glucose and xylose. Several assays suggested that the SPSG possessed remarkable antioxidant properties in different in vitro assays and an outstanding anticoagulant activity 2.5-fold higher than that of heparin Clexane? in the aPTT test; in the next chapter using different tools such as chemical and histological analyses, energy-dispersive X-ray analysis (EDXA), gel electrophoresis and infra-red spectroscopy we confirm the presence of sulfated polysaccharides in freshwater plants for the first time. Moreover, we also demonstrate that SP extracted from E. crassipes root has potential as an anticoagulant compound; and in last chapter a fucan, a sulfated polysaccharide, extracted from the brown seaweed was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution for hydrophobic chains of 1H NMR was approximately 93%. SNFfuc-TBa125 in aqueous media had a mean diameter of 123 nm and zeta potential of -38.3 ? 0.74 mV, measured bydynamic light scattering. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0 43.7% at SNFuc concentrations of 0.05 0.5 mg/ mL and RAEC non-tumor cell line proliferation displayed inhibition of 8.0 22.0%. On the other hand, nanogel improved CHO and RAW non-tumor cell line proliferation in the same concentration range. Flow cytometric analysis revealed that this fucan nanogel inhibited 786 cell proliferation through caspase and caspaseindependent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle
Os polissacar?deos sulfatados (PS) s?o amplamente distribu?dos em animais e tecidos de algas. Estes pol?meros t?m sido estudados em fun??o da import?ncia de suas atividades farmacol?gicas, tais como: anticoagulante, antioxidante, antitumoral, anti-inflamat?ria e as propriedades antivirais. Contudo, o potencial dos PS para sintetizar biomateriais, tais como nanopart?culas, ainda ? pouco explorado. At? ent?o, os PS s? foram encontrados em seis plantas e todas habitam ambientes salino. N?o havendo relatos de PS em plantas de ?gua doce. O que nos levou aos seguintes questionamentos: Os PS extraidos de vegetais marinhos n?o apresentam atividades farmacol?gicas? Os vegetais de ?gua doce realmente sintetizam PS? ? poss?vel sintetizar nanopart?culas utilizando PS a partir de algas marinhas? Para melhor entender as quest?es, esta tese foi dividida em tr?s cap?tulos. No primeiro cap?tulo, um polissacar?deo sulfatado (SPSG) foi isolado a partir de um vegetal marinho Halodule wrightii. Os dados aqui apresentados mostram que o SPSG ? uma heterogalactana sulfatada de 11 kDa constituida de glucose e xilose. Os ensaios realizados sugerem que o SPSG possue propriedades antioxidantes not?veis em diferentes ensaios in vitro e uma excelente actividade anticoagulante de 2,5 vezes mais elevadas do que a de heparina Clexane ? no teste APTT. No cap?tulo seguinte, utilizando ferramentas diferentes, tais como an?lises qu?micas e histol?gicas, an?lise de dispers?o de raios-X (EDXA), eletroforese em gel e espectroscopia de infra-vermelho,confirmamos, em primeira m?o, a presen?a de polissacar?deos sulfatados em vegetais de ?gua doce. Al?m de demonstrarmos que o PS extra?do a partir da raiz de E. crassipes tem potencial como um composto anticoagulante.No ?ltimo cap?tulo uma fucana, um polissac?rido sulfatado, extra?do a partir de uma alga marrom, foi quimicamente modificada por adi??o de hexadecilamina ? cadeia principal do pol?mero hidrof?lico. O material resultante (SNFuc) forneceu part?culas nanom?tricas. O grau de substitui??o para as cadeias hidrof?bicas de 1H RMN foi de aproximadamente 93%. SNFuc em meios aquosos tinha um di?metro m?dio de 123 nm e potencial zeta de -38,3 ? 0,74 mV. Os ensaios com c?lulas tumorais (HepG2, 786, H-S5) demonstrou a ocorr?ncia de uma inibi??o que variou de 2,0-43,7% em concentra??es diferentes de SNFuc (0,05-0,5 mg / mL) resultado semelhante foi obtido com a RAEC monstrando uma inibi??o entre 8,0-22,0%. Por outro lado, o nanogel estimulou a prolifera??o de linhagens celulares n?o tumorais como CHO e RAW nas mesmas concentra??es. An?lise por citometria de fluxo revelou que este nanogel de fucana inibiu a prolifera??o celular de 786 por mecanismos dependentes e independentes de caspases. Al?m disso, bloqueou a passagens da c?lula 786 na fase S e G2-M do ciclo celular
2020-01-01

In this thesis I use the most widely prescribed anticoagulant drug, warfarin, as a model to investigate the effect of genetic determinants on drug efficacy and safety. Following a literature review of all the genes involved in warfarin pharmacokinetics and pharmacodynamics, 35 candidate genes were selected for investigation. Two independent Swedish cohorts of warfarin-treated patients were analysed. First linkage disequilibrium maps were constructed for each gene. Selected SNPs integrated with putative functional variants were genotyped in 201 patients recruited at the Uppsala University. A panel of 216 haplotype tag SNPs were then derived to analyse an independent cohort of 1496 patients from the prospective Warfarin Genetic Study in Sweden. The two studies were analysed separately for genetic association to warfarin dose requirement (single marker and haplotypic tests).  Common SNPs in the vitamin K epoxide reductase gene (VKORC1) are significantly associated with dose in the Uppsala and WARG studies (p=1.9 x 10^-15 and 6.5 x 10^-100, respectively). Cytochrome P450 2C9 (CYP2C9) has been known to affect dose requirement and was confirmed in both Swedish cohorts (p= 2.3 x 10^-5 and 4.9 x 10^-32). The two genes together explain ~40% of warfarin dose variation. SNPs in microsomal epoxides hydrolase (EPHX1) and orosomucoid 1 (ORM1) genes do not show a broad effect but are associated with dose in both studies. Genes encoding PROC, APOE, CALU, PDIA2 and GGCX showed nominal association with dose in the Uppsala study. Likewise, PROS1, CYP1A1, CYP3A4, PDIA5, PDIA3 and F10 showed nominal association to dose in the WARG study. Most of these minor effects if real are most likely to be population/treatment specific. A model taking in to account genetic factors (VKORC1 and CYP2C9*2/*3) and non genetic factors (age, gender, and drug interaction) together explained more than 50% inter-individual dose variance. We analysed 64 patients from the Uppsala and WARG studies with recorded severe bleeding episodes using the same 216 common SNPs. Case-control analysis found SNPs in PDIA4, P4HB, and NR1I3 to be associated (p≤0.01) with bleeding. Using a recessive model, patients with a gastrointestinal bleeding sub-phenotype in the WARG cohort showed association with common variants in PD1A6 (P=0.0014, odds ratio = 6.98). We sequenced the exons of 11 of the candidate genes in 36 bleeders and 12 non-bleeders (Uppsala study). However, no high prevalence mutation was discovered.

L'objectiu principal d'aquesta Tesi doctoral ha estat l’obtenció d’una via alternativa a les existents per a l'obtenció d'un intermedi clau, 1, en la síntesi d'un fàrmac anticoagulant. La nova via havia de ser novedosa i patentable per tal de poder obtenir el producte industrialment. Així doncs inicialment es va fer una cerca bibliogràfica per tal de conèixer els precedents sintètics existents i a partir d'aquests es van proposar una sèrie d’objectius més concrets: una primera aproximació per tal de sintetitzar el ciclohexà central de 1, una altra basada en una reacció de iodolactamització per tal de tenir un dels nitrògens del sistema cis-diamino ja introduït i una tercera basada en una aziridina com a intermedi clau tenint en aquest cas tambè ja un dels nitrògens presents en la molècula. La primera aproximació es basava en una reacció Diels-Alder com a etapa clau per a formar el ciclohexà central de la molècula objectiu. Tot i arribar a un intermedi força avançat, no es va poder arribar a producte final i es va haver de descartar aquesta aproximació. La segona via que es va provar consistia en una reacció de iodolactamització com a etapa clau seguida de la formació del derivat de Boc. A partir d’aquest intermedi es van proposar vàries alternatives per a substituir l’àtom de iode i introduir el segon nitrogen a la molècula, ja fos directament amb amoníac per exemple, o a travès d’un equivalent sintètic del grup amina com podia ser l’azida o bè el grup ftalimida. Tambè es va provar de formar intermedis tipus urea amb isocianats i introduïr així el segon nitrogen de l’anell de sis baules intramolecularment. Malauradament cap d’elles va permetre arribar a obtenir el producte objectiu 1 així que es va passar a estudiar la darrera aproximació. La tercera via proposada passava per un intermedi clau aziridínic que es formava per reacció d’una olefina amb una sulfamida amb catàlisi de rodi. Desprès de provar la reacció principal a partir de diferents substrats, es va trobar un intermedi de tipus lactona inesperat però que va ser clau en aquesta aproximació. Seguint una sèrie de reaccions senzilles partint de la lactona es va arribar a obtenir 1. Així doncs es va assolir l’objectiu d’obtenir una via per tal d’obtenir 1. Malaurdament degut a una reivindicació d’una patent que protegeix l’últim intermedi de la síntesi i la transformació d’aquest a 1, no serà possible sintetitzar industrialment 1 seguint aquest nou procès obtingut. Tot i això, es va decidir seguir les reaccions de l’aproximació que havia permès obtenir 1, però variant el grup dimetilamida per altres grups alternatius. Es va pensar en formar èsters activats amb el 2,2,2-trifluoroetanol, el fenol i la N,N- dietilhidroxilamina. Aquesta estratègia permetria arribar a obtenir la molècula objectiu però sense infringir la patent ja que, en la darrera etapa, seria on s’introduiria el grup dimetilamida de manera que no es passaria per l’intermedi reivindicat. Malauradament, amb cap dels grups alternatius utilitzats es va aconseguir arribar a l’objectiu degut a la formació d’ intermedis tipus aziridina, els quals no es van poder transformar a la sulfamida bicíclica desitjada de cinc baules.
The main objective of this Thesis was to obtain a novel and alternative route to the existing key intermediate 1 in the synthesis of an anticoagulant drug. The new approach had to be innovative and patentable in order to produce the product industrially. First of all, we searched in the literature the existing synthetic precedents and from these we proposed a series of more specific objectives: a first approach to synthesize the central cyclohexane, another based on a iodolactamization reaction, having one of the nitrogens in the cis-diamino system already introduced, and a third approach based on aziridine as a key intermediate, in this case it has also already one of the nitrogens present in the molecule. The first approach was based on a Diels-Alder reaction as a key step to form the central cyclohexane target molecule. Despite reaching an advanced intermediate, this approach failed to reach the final product and had to discard it. The second route that was tested had a iodolactamization reaction as a key step and followed the synthesis of the Boc derivative of this product . From this intermediate we proposed several alternatives to replace the iodine atom and introduce the second nitrogen in the molecule, either directly with ammonia for example, or through a synthetic equivalent of the amino group for example with an azide or a phthalimide group. We also tried to form an urea intermediate with isocyanate and thus insert the second nitrogen in the six member ring intramolecularly. Unfortunately none of the methods allowed us to arrive at the desired product so we kept on studying the latest approach. The third proposed route passes through a key aziridine intermediate that was formed by the reaction of an olefin with a sulfamide using rhodium catalysts. After testing the main reaction from different substrates, we found a lactone intermediate which was key in this approach. Following a series of simple reactions starting from the lactone we get the objective molecule 1. The main objective was achieved, unfortunately, due to a claim of a patent that protects the last intermediate synthesis and transformation of this to 1, it will not be possible to synthesize 1 industrially following this new process. However, we decided to follow the reactions of the approach that had yielded 1, but varying the dimethylamide group to other alternative groups. We thought about forming activated esters with 2,2,2-trifluoroethanol, phenol and N,N- diethylhydroxylamine. This strategy would reach the target molecule obtained without infringing the patent because it was in the last stage, where it would introduce the dimethylamide group so the route would not pass through the intermediate claimed.

Cette thèse est consacrée à la modélisation mathématique de la coagulation sanguine et de la formation de thrombus dans des conditions normales et pathologiques. La coagulation sanguine est un mécanisme défensif qui empêche la perte de sang suite à la rupture des tissus endothéliaux. C'est un processus complexe qui est règlementé par différents mécanismes mécaniques et biochimiques. La formation du caillot sanguin a lieu dans l'écoulement sanguin. Dans ce contexte, l'écoulement à faible taux de cisaillement stimule la croissance du caillot tandis que la circulation sanguine à fort taux de cisaillement la limite. Les désordres qui affectent le système de coagulation du sang peuvent provoquer différentes anomalies telles que la thrombose (coagulation exagérée) ou les saignements (insuffisance de coagulation). Dans la première partie de la thèse, nous présentons un modèle mathématique de coagulation sanguine. Le modèle capture la dynamique essentielle de la croissance du caillot dans le plasma et le flux sanguin quiescent. Ce modèle peut être réduit à un modèle qui consiste en une équation de génération de thrombine et qui donne approximativement les mêmes résultats. Nous avons utilisé des simulations numériques en plus de l'analyse mathématique pour montrer l'existence de différents régimes de coagulation sanguine. Nous spécifions les conditions pour ces régimes sur différents paramètres pathophysiologiques du modèle. Ensuite, nous quantifions les effets de divers mécanismes sur la croissance du caillot comme le flux sanguin et l'agrégation plaquettaire. La partie suivante de la thèse étudie certaines des anomalies du système de coagulation sanguine. Nous commençons par étudier le développement de la thrombose chez les patients présentant une carence en antihrombine ou l'une des maladies inflammatoires. Nous déterminons le seuil de l'antithrombine qui provoque la thrombose et nous quantifions l'effet des cytokines inflammatoires sur le processus de coagulation. Puis, nous étudions la compensation de la perte du sang après un saignement en utilisant un modèle multi-échelles qui décrit en particulier l'érythropoïèse et la production de l'hémoglobine. Ensuite, nous évaluons le risque de thrombose chez les patients atteints de cancer (le myélome multiple en particulier) et le VIH en combinant les résultats du modèle de coagulation sanguine avec les produits des modèles hybrides (discret-continues) multi-échelles des systèmes physiologiques correspondants. Finalement, quelques applications cliniques possibles de la modélisation de la coagulation sanguine sont présentées. En combinant le modèle de formation du caillot avec les modèles pharmacocinétiques pharmacodynamiques (PK-PD) des médicaments anticoagulants, nous quantifions l'action de ces traitements et nous prédisons leur effet sur des patients individuels
This thesis is devoted to the mathematical modelling of blood coagulation and clot formation under flow in normal and pathological conditions. Blood coagulation is a defensive mechanism that prevents the loss of blood upon the rupture of endothelial tissues. It is a complex process that is regulated by different mechanical and biochemical mechanisms. The formation of the blood clot takes place in blood flow. In this context, low-shear flow stimulates clot growth while high-shear blood circulation limits it. The disorders that affect the blood clotting system can provoke different abnormalities such thrombosis (exaggerated clotting) or bleeding (insufficient clotting). In the first part of the thesis, we introduce a mathematical model of blood coagulation. The model captures the essential dynamics of clot growth in quiescent plasma and blood flow. The model can be reduced to a one equation model of thrombin generation that gives approximately the same results. We used both numerical simulations and mathematical investigation to show the existence of different regimes of blood coagulation. We specify the conditions of these regimes on various pathophysiological parameters of the model. Then, we quantify the effects of various mechanisms on clot growth such as blood flow and platelet aggregation. The next part of the thesis studies some of the abnormalities of the blood clotting system. We begin by investigating the development of thrombosis in patients with antihrombin deficiency and inflammatory diseases. We determine the thrombosis threshold on antithrombin and quantify the effect of inflammatory cytokines on the coagulation process. Next, we study the recovery from blood loss following bleeding using a multiscale model which focuses on erythropoiesis and hemoglobin production. Then, we evaluate the risk of thrombosis in patients with cancer (multiple myeloma in particular) and HIV by combining the blood coagulation model results with the output of hybrid multiscale models of the corresponding physiological system. Finally, possible clinical applications of the blood coagulation modelling are provided. By combining clot formation model with pharmacokinetics-pharmacodynamics (PK-PD) models of anticoagulant drugs, we quantify the action of these treatments and predict their effect on individual patients

O estudo farmacognóstico comparativo das folhas de duas espécies de capuchinha, T. majus e de T. pentaphyllum, constituiu o escopo deste trabalho Artigos científicos sobre a espécie T. majus reportam a atividade antibacteriana, antifúngica, antiviral e antitumoral, devidas ao benzilisotiocianato, presente nos órgãos aéreos da espécie. Na medicina popular, também é utilizada para \"afinar\" o sangue. O efeito anticoagulante é de grande importância para indivíduos predispostos a distúrbios hemostáticos. No âmbito farmacológico, foram avaliadas, in vitro, as atividades anticoagulante sobre o plasma humano e antileishmania dos extratos e das frações. O benzilisotiocianato não apresentou atividade anticoagulante nem anti-leishmania. Foi observada atividade anticoagulante nos ensaios com os extratos e as frações hidrofílicas de T.majus e de T. pentaphyllum e a ausência de efeito destes sobre a viabilidade da forma promastigota de Leishmania chagasi. Os resultados apontam os flavonóides como os responsáveis pelo prolongamento do tempo de trombina provocado pelos extratos de T.majus e T. pentaphyllum.
The aim of this work was the pharmacognostic comparative study of leaves and flowers of nasturtium: Tropaeolum majus e Tropaeolum pentaphyllum. Scientific articles report the antibacterial, antiviral and antitumoral activity due to benzyl-isothiocianate, wich is present in the aerial organs of both species. Folk medicine uses leaves extract of T. majus to \"thin\" the blood. Anticoagulant effect is of great importance for predisposed individuals to haemostatic disturbances. Hidroalcoholic extracts of leaves and flowers of T. majus and T. pentaphyllum were appraised for the anticoagulant and anti-leishmania activities. The benzyl-isothiocianate neither presented anticoagulant activity nor anti-leishmania. Anticoagulant activity was observed in the essays with the extracts and the hidrofilic fractions of both species. The extracts and benzyl-isothiocianate showed no activity against Leishmania chagasi. The results allowed conclude that flavonoids are responsible for the prolongation of thrombin time (TT), provoked by the extracts of T. majus e T. pentaphyllum.

Rotas sintéticas foram empregadas no grupo funcional ligado ao carbono 4 da trans-hidroxi-L-prolina para a obtenção de quatro análogos de prolina com amino e guanido grupos nesta posição e isomeria espacial cis e trans. Adicionalmente, o aminoácido guanidino fenilalanina foi comparado com os análogos de prolina em todos os ensaios realizados. Entre os análogos de prolina sintetizados, o peptídeo contendo o aminoácido não natural com o grupo funcional guanido e isomeria trans apresentou a melhor atividade inibitória contra trombina. Entretanto, o peptídeo sintetizado com o aminoácido guanidino fenilalanina ainda demonstra ter uma melhor atividade inibitória em comparação com os análogos de prolina.
Synthetic routes were employed in the functional group attached to the carbon 4 of trans-4-hydroxy-L-proline to obtain four proline analogues with amino and guanido groups in this position and cis and trans spatial isomerism. Additionally, the amino acid guanidino phenylalanine was compared with the analogues of proline in all tests. Among the proline analogues synthesized, the peptide containing the unnatural amino acid functional group with guanido and trans isomerism showed the best inhibitory activity against thrombin. However, the peptide synthesized with the amino acid guanidino phenylalanine exhibits an even better inhibitory activity in comparison to proline analogues.

Thrombin is the key protease that regulates hemostasis; the delicate balance between procoagulation and anticoagulation of blood. In clotting disorders, like deep vein thrombosis or pulmonary embolism, procoagulation is up-regulated, but propagation of clotting can be inhibited with drugs targeting the proteases involved, like thrombin. Such drugs however, have serious side effects (e.g., excessive bleeding) and some require monitoring during the course of treatment. The reason for these side effects is the mechanism by which the drugs’ act. The two major mechanisms are direct orthosteric and indirect allosteric inhibition, which will completely abolish the protease’s activity. Herein we sought an alternative mechanism called allosteric, partial inhibition, that has shown promise to truly regulate coagulation. Partial inhibition through allosteric mechanisms are well described for membrane-bound and oligomeric proteins. However proteases, specifically monomeric proteases (i.e., thrombin), have not shown this phenomenon until now. A small library of coumarin-based sulfated allosteric modulators (CSAMs) was synthesized to target a surface region called exosite 2; mainly composed of highly positively charged residues surrounded by hydrophobic patches. Studies revealed a non-competitive mechanism of binding with a range of IC50s between 0.2-58 µM combined with inhibitory efficacies (ΔY) between 22-73%; indicative of allosteric, partial inhibition. The KD was determined for the most potent compound (3g; IC50 = 0.2 µM, ΔY = 47%) at 0.15 µM. 3g was observed to bind at exosite 2 through unfractionated heparin competition and thrombin mutant studies. Additional computational studies were in agreement with the mutant and competition studies, showing the sulfate of 3g binding within a pocket containing R126 and R233. Fluorescence quenching and antithrombin inactivation rate studies described a conformational change to thrombin’s active site in the presence of 3g, supporting reduction of thrombin’s catalytic efficiency, without complete inhibition of thrombin’s proteolytic activities. Coupled enzyme assays and gel electrophoresis showed that in the presence of 3g, hydrolysis of fibrinogen (IC50 = 0.51 µM, ΔY = 94%) and protein C activation (IC50 = 1.7 µM, ΔY = 91%) is fully inhibited. Alternatively, FXIII activation was shown to be only partially inhibited by the presence of 3g, and FXI activation did not show any significant activation or inhibition. 3g was also shown to be active in human plasma and whole blood, but requiring much higher concentrations to induce an anticoagulant effect. Mice studies looking at the effects of 3g in vivo showed that even at high concentrations, showed no abnormal bleeding or any other irregularities. This work highlights a novel occurrence regarding thrombin’s allosteric functionality against multiple endogenous substrates. This library of compounds may be useful in the future development of allosteric inhibitors and probes that pose little to no risk of bleeding events by inducing partial inhibition.

Class of 2016 Abstract
Objectives: To identify common and serious drug-drug interactions involving novel anticoagulant drugs in cancer patients. Subjects: 60 patients who were treated at the Banner University of Arizona Cancer Center between November 1, 2013 and April 1, 2015 with rivaroxaban, dabigatran, or apixaban. Methods: A retrospective chart review was performed for patients who received a NOAC (novel oral anticoagulant) to determine if a medication regimen contained a drug-drug interaction involving the NOAC. Results: When analyzing the DDIs involving rivaroxaban, dabigatran, and apixaban, Micromedex® detected a total of 123 interactions, compared to Lexicomp®, which detected 111 interactions. When using Lexicomp®, there were 59 (32%) instances of no detected interactions, 19 (10%) moderate interactions, 27 (15%) major interactions, and 65 (36%) contraindicated DDIs with rivaroxaban. When using Micromedex®, there were 47 (26%) instances where no interaction was detected, 4 (2%) moderate interactions, and 119 (65%) major interactions, and no interactions were classified as contraindicated with rivaroxaban. Lexicomp® detected 3 (50%) interactions as major, and found no DDIs in 3 (50%) instances for dabigatran, and detected 1 (7%) moderate, 2 (14%) major and 6 (43%) contraindicated interactions for apixaban. Micromedex® detected 3 (50%) interactions as major, and found no DDIs in 3 (50%) instances for dabigatran, and detected 12 (86%) of interactions as major and found no DDIs in 2 (14%) instances for apixaban. Conclusions: There was significant variation in DDI detection between current literature4,5 and the drug information databases, Lexicomp® and Micromedex®, however most interactions detected were major or contraindicated.

Introduction :Les anticoagulants oraux soulèvent des problématiques majeures en termes de risque hémorragique et de bon usage. L’informatisation du dossier médical offre la possibilité d’accéder à de grandes bases de données que l’on peut exploiter de manière automatisée. L’objectif de ce travail est de montrer comment la réutilisation de données peut permettre d’étudier des problématiques liées aux anticoagulants et accompagner une démarche d’assurance de la qualité des soins. MéthodesCe travail a été réalisé sur les données informatisées (97 355 séjours) d’un centre hospitalier général. Pour chaque séjour nous disposons des données diagnostiques, biologiques, médicamenteuses, administratives et des courriers de sortie. Ce travail est organisé autour de 3 axes :Axe I. L’objectif est d’évaluer la qualité de la détection des facteurs pouvant majorer l’effet anticoagulant des antivitamines K (AVK), à l’aide de règles développées au cours de du projet européen PSIP (convention de subvention n° 216130). Une revue des cas sur une année a permis de calculer la valeur prédictive positive et la sensibilité des règles. Axe II. Nous avons réalisé une étude de cohorte historique sur les données de 2007 à 2012 pour déterminer les éléments majeurs impliqués dans l’élévation du risque hémorragique sous AVK dans la réalité clinique. Les cas étaient les séjours présentant une élévation de l’INR au-delà de 5, les témoins n’en présentaient pas. Axe III. Nous avons mis la réutilisation de données au service de l’étude de la qualité des prescriptions. D’une part nous avons évalué le suivi des recommandations de traitement du risque thromboembolique dans la fibrillation atriale (FA) chez la personne âgée, d’autre part nous avons étudié les modalités de prescription des anticoagulants oraux directs (AOD).Résultats : Axe I : La valeur prédictive positive des règles de détection des facteurs favorisant l’élévation de l’INR sous AVK est de 22,4%, leur sensibilité est de 84,6%. Les règles les plus contributives sont les règles de détection d’un syndrome infectieux et de l’administration d’amiodarone. Axe II : Les facteurs majeurs d’élévation du risque hémorragique sous AVK mis en évidence par l’étude de cohorte sont le syndrome infectieux, le cancer, l’hyprotidémie et l’insuffisance hépatique. Axe III : Le taux de suivi des recommandations dans la fibrillation atriale chez le sujet âgé est de 47.8%. Seuls 45% des patients reçoivent des anticoagulants oraux, 22,9% ne reçoivent aucun traitement antithrombotique et 32,1% reçoivent des antiagrégants plaquettaires. Les AOD sont quant à eux prescrits à des posologies inadaptées chez 15 à 31,4% des patients, respectivement pour le dabigatran et le rivaroxaban. Ces erreurs sont principalement des sous-dosages en AOD dans la FA de la personne âgée (82.6%). Discussion : L’informatisation des dossiers médicaux a permis la constitution de grandes bases de données médico-administratives, qui peuvent être utilisées à des fins variées comme nous le montrons dans ce travail. Dans le premier axe nous avons montré que des systèmes d’aide à la décision à base de règles permettent de caractériser les facteurs impliqués dans les surdosages en AVK avec une bonne sensibilité mais avec une faible valeur prédictive positive. Le second axe a montré que l’on pouvait utiliser ces données à des fins exploratoires pour identifier les facteurs liés à l’élévation de l’INR chez les patients recevant des AVK en pratique réelle. Le troisième axe montre que les systèmes à base de règles peuvent aussi être utilisés pour identifier des prescriptions inappropriées à des fins d’amélioration de la qualité des soins. Dans le domaine de l’anticoagulation ce travail ouvre des perspectives innovantes en vue de l’amélioration de la qualité des soins
Introduction :Oral anticoagulants raise major issues in terms of bleeding risk and appropriate use. The computerization of medical records offers the ability to access large databases that can be explored automatically. The objective of this work is to show how routinely collected data can be reused to study issues related to anticoagulants in a supportive approach to quality of care.MethodsThis work was carried out on the electronic data (97,355 records) of a community hospital. For each inpatient stay we have diagnostic, biological, drug and administrative data, and the discharge letters. This work is organized around three axes:Axis I. The objective is to evaluate the accuracy of the detection of factors that may increase the anticoagulant effect of vitamin K antagonists (VKA), using rules developed in the PSIP european project (grant agreement N° 216130). A case review on one year enabled the calculation of the positive predictive value and sensitivity of the rules. Axis II. We conducted a cohort study on data from 2007 to 2012 to determine the major elements involved in raising the risk of bleeding related to VKA in clinical reality. Cases were the stays with an elevation of the INR beyond 5, the controls did not have.Axis III. We made data reuse serve a study of the quality of the prescriptions. On the one hand we assessed treatment of the thromboembolic risk recommendations in atrial fibrillation (AF) in the elderly, on the other hand we investigated the prescription of direct oral anticoagulants.Results : Axis I : The positive predictive value of the rules intended to detect the factors favoring the elevation of INR in case of treatment with VKA is 22.4%, the sensitivity is 84.6%. The main contributive rules are the ones intended to detect an infectious syndrome and amiodarone.Axis II : The major factor increasing the INR with VKA treatment highlighted by the cohort study are infectious syndrome, cancer, hepatic insufficiency and hypoprotidemia. The recommendations compliance rate in atrial fibrillation in the elderly is 47.8%. Only 45% of patients receive oral anticoagulants, 22.9% do not receive antithrombotic treatment at all and 32.1% received platelet aggregation inhibitors. Direct oral anticoagulants are prescribed at inadequate dosages in 15 to 31.4% of patients, respectively for dabigatran and rivaroxaban. These errors are mainly underdosages in the elderly with atrial fibrillation (82.6%).Discussion : The computerization of medical records has led to the creation of large medical databases, which can be used for various purposes as we show in this work. In the first work axis we have shown that rule-based decision support systems detect the contributing factors for VKA overdose with a good sensitivity but a low positive predictive value. The second line shows that we could use the data for exploratory purposes to identify factors associated with increased INR in patients receiving VKA in “real life practice”. The third line shows that the rule-based systems can also be used to identify inappropriate prescribing for the purpose of improving the quality of care. In the field of anticoagulation this work opens up innovative perspectives for improving the quality of care

A anticoagulação inadequada pode ocasionar eventos tromboembólicos e hemorrágicos, representando um desafio para a medicina. A varfarina, anticoagulante oral de amplo uso, está associada a reações adversas graves, frequentes nos pacientes em tratamento com múltiplos fármacos. Objetivo: Este estudo pretende avaliar as potenciais interações medicamentosas com a varfarina, descrever e quantificar as intervenções farmacêuticas para minimizá-las, verificar o grau de aceitação da equipe médica em relação às intervenções e a repercussão no resultado do RNI. Método: Estudo de coorte, realizado entre os meses de agosto de 2009 a janeiro de 2010, envolvendo pacientes internados que iniciaram o tratamento com varfarina em duas unidades de clínica médica em um hospital universitário localizado no sul do Brasil. As potenciais interações medicamentosas com a varfarina (graves e moderadas) foram identificadas no sistema Drug-Reax, Micromedex Healthcare. Outras informações foram obtidas diretamente no prontuário. As intervenções com a equipe médica ocorreram por meio de registro em prontuário ou por informação verbal. O valor do RNI (Relação Normatizada Internacional) foi constantemente monitorado e serviu como medida do resultado da intervenção. Resultados: Foram acompanhados 202 pacientes. O total de medicamentos prescritos foi de 2071, com média de 10 (DP=3,6) por paciente. Todos pacientes apresentaram pelo menos uma interação medicamentosa potencial grave ou moderada com a varfarina, sendo a média de 3,6 (DP=1,6) por paciente. Pacientes com mais de 4 interações medicamentosas potenciais apresentaram maior risco para eventos hemorrágicos (RNI > 5 - RR = 2,57; IC95% 1,37–4,80). Foram identificadas 737 potenciais interações; 675 (91,5%) com possibilidade de potencializar o efeito anticoagulante e 29 (3,9%) de reduzir este efeito. Os medicamentos mais envolvidos em interações de potencialização foram enoxaparina (32,2%), sinvastatina (27,6%), omeprazol (22,5%) e tramadol (21,5%). Das intervenções realizadas com a equipe médica, 116 (57,4%) se deram através de registros em prontuário e 86 (42,6%) de forma verbal. Para 32 pacientes (15,8%) as intervenções não foram aceitas e estes apresentaram maior risco (RR = 2,17; IC95% 1,10 –4,27) para exame alterado (RNI > 5). Análise multivariada mostrou que idade, tempo de internação, apresentar 4 ou mais interações potenciais graves ou moderadas e não aceitar a intervenção farmacêutica contribuem significativamente para o paciente apresentar resultado de RNI > 5, o que implica em risco para eventos hemorrágicos. Conclusão: Interações medicamentosas graves e moderadas envolvendo a varfarina são muito comuns nos pacientes internados e estão associadas à maior risco do paciente apresentar RNI fora da faixa terapêutica desejada. A participação do farmacêutico no manejo das interações através de informações e orientações aos prescritores mostrou ter boa aceitação em nosso meio e parece contribuir para a segurança do paciente.
Introduction: Inadequate anticoagulation may cause bleeding and thromboembolic events, representing a challenge for medicine. Warfarin, an oral anticoagulant in wide use, has severe adverse reactions, common in patients taking multiple drugs. Objectives: This study aims to evaluate potential drug interactions with warfarin; to describe and quantify pharmaceutical interventions in order to minimize them; to assess the degree of acceptability by the medical team in relation to interventions as well as the impact on the outcome of the INR. Method: A Cohort study, done between August 2009 and January 2010 involving hospitalized patients who started warfarin therapy in two internal medicine units in a university hospital located in southern Brazil. Potential pDDIs with warfarin with warfarin (major and moderate) were identified in the online system Drug-Reax, Micromedex Healthcare. Additional information was obtained directly from medical records. Interventions with medical team were through medical record notes or verbal information. The value of the INR (international normalized ratio) was continuously monitored and served as a measure of the outcome of the intervention. Results: Two hundred and two inpatients were followed. The total number of prescribed drugs was 2071, with mean of 10 (SD = 3.6) per patient. All inpatients had at least one potential moderate or severe pDDIs with warfarin, the mean was 3.6 (SD = 1.6) per patient. Patients with more than four potential drug interactions showed a higher risk for hemorrhagic problems (INR> 5 - RR = 3.00, 95% CI 1.59-5.70). For 737 pDDIs identified, 675 (91.5%) may result in increased anticoagulation activity and 29 (3.9%) may reduce this effect. The drugs most commonly involved in these pDDIs were enoxaparin (32.2%), simvastatin (27.6%), omeprazole (22.5%) and tramadol (21.5%). The medical team’s intervention were 116 (57.4%) through medical records and 86 (42.6%) were orally. For 32 patients (15.8%), interventions were not accepted and they had higher risk (RR = 2.17; 95% CI 1.10 – 4.27) for amended exam (INR > 5). Multivariate analysis showed that age, length of hospital stay, having four or more major or moderate potential interactions and unwillingness to accept pharmaceutical intervention contribute significantly to the patient current values of INR> 5, which implies a risk of bleeding. Conclusion: Major and moderate drug interactions involving warfarin are very common in hospitalized patients and are associated with patient’s high risk of having an INR outside the target range. The collaboration of pharmacists in the management of interactions with information and guidance to physicians showed a good acceptance and seems to contribute to patient safety.

Anticoagulants are used as the first line therapy for management and prevention of thrombotic disorders. Thrombin and factor Xa have been the prime targets for regulation of the coagulation cascade. In this work, a small library of 17 benzofuran derivatives were synthesized and screened against thrombin and factor Xa. The derivatives that displayed inhibitory potential were docked on the exosite-II of factor Xa using a docking protocol that was developed in our research group. These compounds were based on the β-5 structural unit found in the oligomer -'CDSO3‘, which was prepared in our lab and was found to inhibit both thrombin and factor Xa by an exosite-II mediated allosteric disruption of the catalytic triad.The results revealed that these β-5 like derivatives are inhibitory against thrombin and factor Xa, although their potency is weak. Thrombin and factor Xa appear to recognize different structural features suggesting a significant selectivity in recognition. Furthermore, a slight preference for the benzofuran scaffold was observed with factor Xa. Probing the mechanism of inhibition using Michaelis-Menten kinetics reveal that these compounds display uncompetitive inhibition of these proteases and the mechanism of inhibition is allosteric. Docking of these compounds on factor Xa were done using GOLD (Genetic algorithm for ligand docking) and the results, explain the observed inhibition profile. The computed docked poses also give an idea of the residues on the exosite-II of factor Xa critical for inhibition. The molecules studied here are radically different in terms of structure and mechanism of inhibition from any other ligand described in literature. This represents an opportunity to discover novel molecules with a possibly different pharmacological and toxicological profile.

Au cours de son cycle de vie, le principe actif se retrouve en solution dans différentes situations : dans desformes pharmaceutiques liquides, dans l’organisme et dans les eaux usées. Or, par rapport à l’état solide, lamise en solution du principe actif l’expose davantage à des facteurs susceptibles de conduire à sa dégradation.Les transformations modifient sa structure chimique et donc potentiellement ses activités pharmacologiques ettoxicologiques.L’objectif de ce travail de thèse est de présenter une méthodologie et des études visant à prédire le devenir ensolution de principes actifs et les impacts potentiels consécutifs à leur dégradation.Trois principes actifs ont été sélectionnés pour la réalisation de ce travail. Ils ont en commun de présenter,d’une part, une activité pharmacologique élevée corrélée à une toxicité potentielle de leurs produits dedégradation et, d’autre part, l'absence de données sur leurs comportements en solution. Dans tous les cas,bien que le contexte soit singulier pour chaque molécule, l’approche méthodologique suivie intègre aussi biendes travaux expérimentaux que des études ab initio et in silico.La première étude porte sur le devenir de l’apixaban, principe actif actuellement commercialisé sous formeorale solide, en solution aqueuse. Les données expérimentales ont mis en évidence des groupementschimiques du principe actif pouvant contribuer à son instabilité. L’approche ab initio a permis d’expliquer larégio-spécificité de la réaction d’hydrolyse dépendamment du pH. À partir de la structure des produits dedégradation caractérisés, l’étude de leur potentiel toxique a été réalisée par approche in silico. Ces donnéesconcourent à la démarche d'analyse et évaluation des risques déployée lors de développements de formespharmaceutiques liquides ou des situations particulières impliquant la mise en solution de l'apixaban aumoment de l'administration.De telles approches ont également été employées pour caractériser les mécanismes de photodégradation del’argatroban et évaluer le potentiel toxique des produits de dégradation. Les processus initiant laphotodégradation ont fait l’objet d’études complémentaires reposant sur des calculs d’énergies. Cesconnaissances pourront apporter le rationnel nécessaire au choix de procédés capables de réduire laphotodégradation de l’argatroban et son impact sur les patients. Elles pourront également servir à anticiper lessituations d’écarts pouvant mettre en jeu le rapport bénéfice risque du médicament telles que le mésusage oula modification de la forme pharmaceutique administrée.Enfin, dans un contexte autre que le contexte pharmaceutique, une étude de dégradation du pémétrexed parphotocatalyse via un procédé d'oxydation avancée a été réalisée. Il s'agit d'un procédé particulièrement étudiépour sa capacité à réduire l’empreinte environnementale de composés organiques en accélérant leurdégradation. Le choix de ce principe actif utilisé comme anticancéreux a été justifié par son caractère toxiqueet rémanent dans les eaux de surface, ce qui en fait un produit à haut risque environnemental. Ce travail amontré que des produits de plus faible masse résultant de la transformation photocatalytique du pémétrexedsont malheureusement plus toxiques et encore plus rémanents que la molécule mère elle-même. Ces résultatscontribuent donc à souligner que les procédés d'oxydation avancée, bien qu'efficaces pour l'élimination despolluants médicamenteux, sont à évaluer au regard de l'existence d'un risque accru pour l'environnementavant toute perspective d'utilisation à grande échelle.Les approches et les résultats présentés dans cette thèse pourront être employés pour d’autres études visant àprédire, prévenir et réduire l’impact de la dégradation du principe actif sur le patient et l’environnement
During its life cycle, an active substance is in solution for various reasons: in a liquid pharmaceutical form, in the body and in wastewater. However, compared to the solid state, the active substance in solution exposes it more to factors likely to cause its degradation. The transformations modify its chemical structure and thus potentially its pharmacological and toxicological activities.The objective of this thesis is to present a methodology and studies aiming to predict the fate in solution of active substances and the potential impacts following their degradation.Three active ingredients have been selected for this work. They have in common, on the one hand, a high pharmacological activity correlated to a potential toxicity of their degradation products and, on the other hand, the fact that there is little information on their behaviour in solution. In all cases, although the context is specific to each molecule, the methodological approach followed integrates both experimental work and ab initio and in silico studies.The first study concerns the fate of apixaban, an active substance currently marketed in solid oral form, in aqueous solutions. The experimental data made it possible to highlight chemical groups of the active ingredient that could contribute to its own instability. The ab initio approach explained the regio-specificity of the hydrolysis reaction as a function of pH. Based on the structure of the characterized degradation products, their toxic potential was studied using an in silico approach. These data contribute to the risk analysis and evaluation process deployed at different stages of development of liquid pharmaceutical forms or in particular situations involving the solution of apixaban at the time of administration.Such approaches have also been used to characterize the photodegradation mechanisms of argatroban and assess the toxic potential of degradation products. The processes that initiate photodegradation were also addressed by calculating the energies potentially involved. This knowledge provides a rational basis for the choice of processes and formulations to limit photodegradation of argatroban and its impact on patients. They also make it possible to anticipate situations where the benefit/risk ratio of the medicinal product may be modified, such as incorrect handling or modification of the pharmaceutical form administered.Finally, in a context other than the pharmaceutical context, a study of degradation of pemetrexed by photocatalysis via an advanced oxidation process was carried out. This process is particularly studied for its ability to reduce the environmental footprint of organic compounds by accelerating their degradation. The choice of this active substance as an anti-cancer agent was justified by its toxic and persistent nature in surface waters, making it a product with a high environmental risk. This work has shown that products of lower mass produced by photocatalytic transformation of pemetrexed are unfortunately more toxic and even more persistent than the parent molecule itself. These results underline the fact that advanced oxidation processes, although effective in removing drug pollutants, must be evaluated because of an increased risk to the environment before any prospect of large-scale use.The approaches and results presented in this thesis can be used for other studies to predict, prevent and reduce the impact of active ingredient degradation on the patient and the environment

La maladie rénale chronique (MRC) touche entre 8 et 15 % de la population adulte mondiale et jusqu’à un tiers des personnes âgées. Par rapport à la population ayant une fonction rénale normale, les patients avec une MRC présentent un risque majoré d’hospitalisation, d’effets indésirables médicamenteux (EIM) et de mortalité. Les données des résumés des caractéristiques des produits relatifs aux médicaments sont limitées chez les patients ayant une fonction rénale altérée, car cette population est exclue de la grande majorité des essais thérapeutiques. La MRC entraine une modification de la pharmacocinétique et de la pharmacodynamique d’un grand nombre de médicaments nécessitant des contre-indications et des adaptations de posologie à la fonction rénale.À partir des données de la cohorte CKD-REIN, ce travail de thèse a permis d’apporter de nouvelles informations concernant l’utilisation des médicaments dans la population de patients atteints de maladie rénale chronique modérée à avancée, suivie en néphrologie.CKD-REIN est une étude de cohorte prospective représentative réalisée dans 40 consultations de néphrologie en France. L’étude a inclus 3033 patients atteints de MRC modérée à avancée , dont 65% d’hommes, avec une médiane d’âge de 69 ans [écart interquartile (EI), 60-76]. A l’inclusion, 45% avait un débit de filtration glomérulaire estimé (DFGe) à moins de 30 mL/min/1,73m2.La plupart des patients étaient polymédiqués à l’entrée dans CKD-REIN. Le nombre médian de médicaments prescrits par patient était de 8 [EI, 5-10]. De plus, nous avons mis en évidence que plus de la moitié des patients inclus (52%) recevaient au moins une prescription qui était contre-indiquée ou dont la posologie était surdosée par rapport à leur fonction rénale. L’équation permettant d’estimer la fonction rénale du patient au moment de la prescription avait une grande importance dans l’évaluation du caractère approprié ou non des prescriptions. La baisse du DFGe et le nombre de médicaments étaient les principaux facteurs de risque d’exposition aux prescriptions inappropriées.L’étude des EIM ont montré qu’ils étaient fréquents chez les patients atteints de MRC, qu’ils soient graves ou non (taux d’incidence : 14,4 % personnes-années (PA) [intervalle de confiance (IC)95%, 12,6–16,5] pour les EIM (toute gravité confondue) et de 2,7 %PA [IC95%, 1,7–4,3] pour les EIM graves). Des médicaments tels que les inhibiteurs du système rénine-angiotensine, les antithrombotiques ou encore les diurétiques, fréquemment prescrits dans cette population, étaient les classes les plus pourvoyeuses d’EIM. Un DFGe diminué, un nombre de médicaments supérieur à 10 et une mauvaise observance thérapeutique étaient des facteurs de risque importants de survenue d’EIM.Enfin, nous nous sommes focalisés sur l’évaluation des risques associés à l’utilisation des antithrombotiques oraux dans cette population atteinte de MRC. Le risque d’hémorragie chez les patients recevant un anticoagulant oral était deux fois et demie supérieur à celui des patients ne recevant aucun antithrombotique oral (rapport de risque de 2,36 [IC95%, 1,44 ; 3,85]) et ce risque était majoré lorsque la prise d’anticoagulant oral s’accompagnait d’une prise d’antiagrégant plaquettaire (rapport de risque de 4,01[IC95%, 2,23 ; 7,20]). Un risque augmenté d’insuffisance rénale aiguë a également été mis en évidence avec la prise d’anticoagulant oral (rapport de risque de 1,89 [IC95%, 1,46; 2,44]). En revanche, nous n’avons pas retrouvé d’association significative entre la prise d’antithrombotique oral et la progression de la maladie rénale chronique vers l’insuffisance rénale terminale traitée (rapport de risque de 1,37 [IC95%, 0,92 ; 2,04]).Ce travail de thèse rend compte que la prise en charge thérapeutique des patients atteints de MRC est complexe. Il met en lumière de nombreuses pistes pour optimiser la prise en charge thérapeutique des patients atteints de MRC modérée à avancée
Chronic kidney disease (CKD) affects between 8% and 15% of the world's adult population and up to one third of the elderly. Compared to the population with normal kidney function, patients with CKD are at increased risk of hospitalization, adverse drug reactions (ADRs) and mortality. Data in summaries of product characteristics are limited in patients with impaired renal function as this population is excluded from the vast majority of clinical trials. CKD greatly alters the pharmacokinetics and pharmacodynamics of a large number of drugs that require contraindications and dosage adjustments with regard to kidney function.Based on data from the CKD-REIN cohort study, this thesis made it possible to provide new information about the use of drugs in the population of patients with moderate to advanced CKD under nephrology care.CKD-REIN is a representative prospective cohort study, based on 40 nationally public and private facilities. The CKD-REIN study included 3,033 patients with moderate to advanced CKD, 65% of whom were men, with a median age of 69 years [interquartile range (IQR), 60-76]. At baseline, 45% had an estimated glomerular filtration rate (eGFR) of less than 30 mL/min/1.73m2.Polypharmacy concerned most of the patients in CKD-REIN at baseline. The median number of drugs prescribed per patient was 8 [IQR, 5-10]. In addition, we have shown that more than half of the patients included (52%) received at least one prescription that was contraindicated or with an overdosed dosage according to their renal function. The equation used to estimate the patient's eGFR at the time of prescription was of great importance in assessing the appropriateness of prescriptions. A low eGFR and the number of drugs were the main risk factors for exposure to inappropriate prescriptions.The study on ADRs showed that they were common in patients with CKD, whether serious or not (incidence rate: 14.4% person-years (PA) [confidence interval (CI) 95%, 12.6–16.5] for ADRs (all severity) and 2.7% PA [95%CI, 1.7–4.3] for serious ADRs). Drugs such as inhibitors of the renin-angiotensin system, antithrombotics or diuretics, frequently prescribed in this population, were the pharmacological classes with the most ADRs. Decreased eGFR, receiving more than 10 drugs, and poor treatment adherence were significant risk factors for undergoing ADRs.Finally, we focused on assessing the risks associated with the use of oral antithrombotics in this population with CKD. The risk of hemorrhage in patients receiving an oral anticoagulant was two and a half times greater than that in patients not receiving any oral antithrombotic (hazard ratio (HR) of 2.36 [95%CI, 1.44; 3.85]) and this risk was increased when taking concomitantly an oral anticoagulant and an antiplatelet agent (HR of 4.01 [95%CI, 2.23; 7.20]). An increased risk of acute kidney injury has also been associated with the take of an oral anticoagulant (HR of 1.89 [95%CI, 1.46; 2.44]). On the other hand, we did not find a significant association between taking oral antithrombotic medication and end-stage renal disease (HR of 1.37 [95%CI, 0.92; 2.04]).This thesis shows that the therapeutic management of patients with CKD is complex. It highlights many opportunities for optimizing the therapeutic management of patients with moderate to advanced CKD

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-21T18:09:44Z No. of bitstreams: 0
Made available in DSpace on 2016-12-21T18:09:44Z (GMT). No. of bitstreams: 0
A Austrália é um país cuja fauna é um repositório de potenciais novos biofármacos, pois se encontram no continente os animais mais mortais do planeta, dentre eles, as serpentes. A serpente Pseudechis australis (Mulga snake) é a maior serpente venenosa da Austrália e tem ampla distribuição geográfica. Os venenos de serpentes são complexas misturas com proteínas e peptídeos que apresentam uma variedade de atividades biológicas. Devido à riqueza de seus componentes, várias moléculas encontradas no veneno vêm sendo utilizadas com fins terapêuticos, como agentes anticoagulantes ou analgésicos. Apesar dessas informações, existem poucos dados disponíveis sobre os componentes específicos deste veneno. O presente trabalho tem como objetivo isolar e caracterizar as proteases desse veneno, ainda não descritas, um primeiro passo para compreender o papel destas enzimas no processo de envenenamento, assim como seus inibidores endógenos. Estes desempenham uma função protetora da glândula de veneno, inibindo a ação das enzimas in loco, prevenindo assim a degradação do tecido glandular por estas toxinas. O interesse nestes inibidores está relacionado ao seu potencial uso na terapia de diversas doenças como distúrbios da coagulação, hipertensão e câncer.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

L’augmentation de la prévalence des hémorragies cérébrales (HC) sous traitement antithrombotique constitue un problème de Santé Publique à cause du mauvais pronostic vital et fonctionnel et du risque compétitif de récidive hémorragique ou ischémique chez les survivants, qui pose le problème d’une prévention secondaire adaptée._x000D_L’objectif de la thèse était d’étudier l’impact des traitements antithrombotiques sur le pronostic des HC. Le terme d’HC, entendu au sens large, regroupe les HC spontanées et les microhémorragies cérébrales.La première partie avait comme objectif de comparer les caractéristiques des HC survenant avec ou sans traitement par antagonistes de la vitamine K (AVK), stratifiant l’analyse selon la localisation de l’HC. L’analyse a porté sur 545 patients de la cohorte Lilloise (PITCH), parmi lesquels 83 (15%) étaient sous AVK. La prise d’un traitement par AVK n’influençait pas la localisation de l’HC, mais était prédictive d’HC plus volumineuses (25 ml vs 12 ; p=0.002) chez les victimes d’HC non lobaire, alors que aucune différence existait en cas d’HC lobaire (26 ml vs 30; p=0.507). Ces résultats suggèrent que l’impact des AVK diffère en fonction de la localisation de l’HC et de la vasculopathie sous-jacente.La deuxième partie avait comme objectif d’analyser l’impact du traitement antithrombotique sur l’apparition de nouvelles microhémorragies cérébrales stratifiant l’analyse selon la localisation de l’HC. L’étude a porté sur 168 survivants à 6 mois d’une HC (cohorte PITCH) ayant bénéficié d’une IRM cérébrale 1.5T lors de l’HC et durant le suivi. Lors de l’HC, 89 (53%) patients présentaient des microhémorragies, et 80 (48%) ont développé des microhémorragies durant le suivi. La présence sur la première IRM de microhémorragies (aOR 2,3; IC 95%1,2-4,3), leur position mixte, lobaire et profonde (aOR 3.7; IC95% 1,7-8,3), et la présence de séquelles de macrohémorragies (aOR 6,8; IC95% 2,8-16,7), étaient associées à l’apparition de microhémorragies. Chez les patients avec HC non lobaire, l’apparition de microhémorragies était associée à l’utilisation d’un traitement antithrombotique durant le suivi (aOR 2,9 ; IC95% 1,1-7,3) et avec l’apparition de lacunes (aOR: 2,9; 95%CI 1,0-7,8). Chez les patients avec HC lobaire, l’apparition de microhémorragies était associée à l’apparition de macrohémorragie (aOR 9.8 ; IC95% 1,1-88,8). Ces résultats suggèrent que l’impact des traitements antithrombotiques diffère en fonction de la vasculopathie sous-jacente.La troisième partie avait comme objectif de : (i) comparer les proportions de survivants d’une HC ayant une indication formelle au traitement antithrombotique chez lesquels ce traitement était repris à la sorite ; (ii) identifier les caractéristiques associées à la reprise du traitement antithrombotique, au sein de 5 cohortes européennes (Lille, n=542; Utrecht, n=389 ; Amsterdam, n= 403 ; Londres, n=667 ; Lothian, n=137). Un traitement antithrombotique était recommencé chez 96 (20%) des 469 survivants ayant une indication formelle, mais en proportions différentes dans les 5 cohortes (Lille 18%, Utrecht 45%, Amsterdam 30% ; Londres 11% ; Lothian 15%; p<0.001). Nous n’avons retrouvé aucun autre facteur prédictif de reprise du traitement antithrombotique en dehors de la cohorte d’origine. Ces résultats montrent que la décision de reprise du traitement antithrombotique ne repose pas sur des critères reproductibles, et soulignent la nécessité de réaliser des essais randomisés.La quatrième partie, actuellement en cours, prévoit d’évaluer chez ces mêmes patients (survivants d’une HC ayant une indication formelle au traitement antithrombotique) le risque de récidive hémorragique ou ischémique en fonction de la reprise ou de l’arrêt du traitement antithrombotique. Il s’agit d’une étude observationnelle portant sur 274 patients de 4 cohortes Européennes, avec un suivi d’environ 2.5 ans. L’analyse statistique est en cours
The proportion of patients who are taking antithrombotic drugs at the time they suffer a spontaneous intracerebral hemorrhage (ICH) is increasing over time, and this is a major issue in public health because of the poor prognosis of patients. Also, the decision to restart or not antithrombotic drugs in survivors is still a clinical dilemma. _x000D_The aim of this work was to evaluate the impact of antithrombotic drugs on ICH prognosis. The term ICH regroups (i) spontaneous ICH and (ii) cerebral microbleeds (CMBs).As a first step, we compared baseline characteristics of 545 consecutive patients with ICH included in the PITCH cohort (Lille, France), receiving or not Vitamin K Antagonists (VKAs) at the time of ICH, stratifying the analysis according to the ICH location (lobar vs non lobar). VKAs-ICH accounted for 83 patients (15%). The use of VKAs did not influence ICH location, but influenced ICH volume: in non lobar ICH, VKAs use was associated with larger ICH volumes (25 ml versus 12 ml, p=0.002). In lobar ICH, no difference was observed (26ml versus 30ml; p=0.507). The different impact of VKAs on ICH volumes according to location suggests a different susceptibility of the underlying vasculopathies to VKAs.As a second step, we aimed to evaluate the impact of antithrombotic drugs on the incidence of CMBs in 168 ICH survivors from the PITCH cohort who underwent 1.5T Magnetic resonance imaging (MRI) at ICH onset and during follow-up, stratifying the analysis according to the index ICH location. At the time of ICH, 89 (53%) patients had CMBs at ICH onset, and 80 (48%) showed new CMBs during follow-up. Predictors of incident CMBs were the presence on the first MRI of: at least 1 CMB (aOR 2.3; 95% CI: 1.2-4.3), old macro-hemorrhage (aOR 6.8; 95%CI 2.8-16.7), and CMBs in mixed location (aOR 3.7; 95%CI 1.7-8.3). In non lobar ICH, incident CMBs were associated with incident lacunes (aOR: 2.9; 95%CI 1.0-7.8) and with the use of antiplatelet agents (aOR 2.9; 95%CI 1.1-7.3). In lobar ICH, incident CMBs were associated with incident macro-hemorrhage (aOR 9.8; 95%CI 1.1-88.8). These results suggest that the impact of antithrombotic drugs differs according to the index ICH location, and therefore according to the underlying vasculpathy.The third step consisted in comparing the characteristics and proportions of patients taking antithrombotic drugs at ICH discharge in five European cohorts (Lille, France, n=542; Utrecht, The Netherlands, n=389; Amsterdam, The Netherlands, n=403; multicenter UK cohort, n=667; Lothian, Scotland, n=137). We then identified characteristics associated with restarting. Antithrombotic drugs were restarted in 96 (20%) of the 469 survivors who had an indication for antithrombotic drugs (secondary prevention or atrial fibrillation), but in different proportions according to the cohort of origin (Lille 18%, Utrecht 45%, Amsterdam 30%, CROMIS-2 ICH 11%, Lothian 15%; p<0.001). We did not find other consistent associations with restarting antithrombotic drugs. The variation in clinical practice in restarting antithrombotic drugs after ICH supports the need for randomized controlled trials.In the fourth step, we aim to analyse the risk of ICH recurrences or ischemic events in the same population of patients (ICH survivors who suffered from ICH while on antithrombotic drugs because of secondary prevention or atrial fibrillation) according to the antithrombotic drug status during follow-up. We included 274 patients from 4 European cohorts, with a median follow-up of 2.5 years. Statistical analysis is ongoing

Relatório de Estágio do Mestrado Integrado em Ciências Farmacêuticas apresentado à Faculdade de Farmácia
Os Anticoagulantes orais diretos (DOACs) são os medicamentos de primeira linha usados no tratamento do tromboembolismo venoso e na prevenção de acidentes vasculares cerebrais em doentes com fibrilação auricular, sobretudo porque os DOACs não requerem a monitorização bioquímica tipicamente obrigatória para a varfarina e porque apresentam tempos de meia-vida mais curtos e início de ação mais rápido. Uma vez que estudos recentes na população real evidenciaram uma maior prevalência de efeitos secundários comparativamente aos que estavam previstos nos Ensaios clínicos iniciais, a monitorização plasmática dos DOACs está a começar a ser cada vez mais utilizada de modo a permitir uma personalização da farmacoterapia de acordo com as características individuais do doente e de modo a avaliar a adesão à terapêutica. Para satisfazer as necessidades clínicas mencionadas previamente, estão disponíveis ensaios de coagulação específicos que determinam indiretamente a concentração de DOACs, no entanto estes não são suficientemente precisos e sensíveis. Na verdade, as técnicas de cromatografia líquida, sobretudo associadas à deteção de espetrometria massa, são atualmente consideradas os métodos mais adequados para determinar as concentrações plasmáticas dos DOACs com precisão adequada. Deste modo, esta monografia tem como objetivo fornecer pela primeira vez uma revisão dos métodos analíticos desenvolvidos e validados até à presente data, para a determinação quantitativa do apixabano, dabigatrano, edoxabano, rivaroxabano bem como os seus metabolitos principais em amostras biológicas. Será dado um maior enfase aos métodos cromatográficos e às principais dificuldades sentidas durante a otimização e validação das várias etapas. Para além disso, as caraterísticas físico-químicas, a farmacocinética e a farmacodinâmica dos vários fármacos serão relacionadas com as condições cromatográficas aplicadas, assim como a sua influência nos procedimentos de pré-tratamento da amostra e nas condições de armazenamento dos DOACs, sugerindo estratégias de otimização dos métodos de quantificação dos DOACs.
Direct oral anticoagulant drugs (DOACs) are the first-line drugs used on the treatment of venous thromboembolism and prevention of stroke in patients with atrial fibrillation particularly because DOACs do not require the regular biochemical monitoring that is mandatory for warfarin, and they exhibit shorter half-lives and a faster onset of action. Since recent real-world studies evidence higher prevalence of adverse side effects than it was anticipated in clinical trials, monitoring plasma concentrations of DOACs is starting to be used for personalizing their pharmacotherapy in accordance to individual characteristics and to assess therapy adherence. To attain the aforementioned clinical unmet need, there are specific coagulation assays available that indirectly assess the plasma concentrations of DOACs, however they are not sufficiently accurate or sensitive. Indeed, liquid chromatography techniques, mainly coupled with mass spectrometry detection, are considered the gold standard methods to accurately assess DOACs plasma concentrations. Therefore, the present paper aims at providing, for the first time, a comprehensive review of the current analytical methods that were developed and validated for the quantitative determination of apixaban, dabigatran, rivaroxaban and/or edoxaban and their main metabolites in biological samples. The chromatographic methods will be particularly highlighted and an emphasis will be placed on the major difficulties faced during optimization and development steps. In addition, physicochemical characteristics, pharmacokinetics and pharmacodynamics of each drug will be herein critically related with the employed chromatographic conditions as well as their influence on pre-treatment procedures and storage conditions of DOACs, suggesting strategies that should be employed to accurately quantify DOACs in biological samples.

Relatório de Estágio do Mestrado Integrado em Ciências Farmacêuticas apresentado à Faculdade de Farmácia
No âmbito da unidade curricular de Estágio Curricular do Mestrado Integrado em Ciências Farmacêuticas da Faculdade de Farmácia da Universidade de Coimbra, o presente documento apresenta, sob a forma de uma análise SWOT, o relatório de estágio em Farmácia Comunitária, realizado na Farmácia do Fórum, e o relatório de estágio na Direção de Avaliação de Medicamentos do INFARMED - Autoridade Nacional do Medicamento e Produtos de Saúde, I. P. Este documento inclui ainda a monografia intitulada “Influence of ABC-efflux transporters on the toxic effects of the direct oral anticoagulant drugs”. Os anticoagulantes orais diretos têm demonstrado importantes vantagens clínicas relativamente aos antagonistas da vitamina K, apesar de permanecem com o grave problema do seu efeito tóxico: as hemorragias. Há diversas características individuais que parecem aumentar a ocorrência destes eventos como por exemplo insuficiência renal, interações medicamentosas e apresentação de concentrações plasmáticas diferentes mesmo após a administração da mesma dose de fármaco. Sendo os anticoagulantes orais diretos substratos da Breast Cancer Resistance Protein (BCRP) e da P-glycoprotein (P-gp), poderão estes transportadores de efluxo estar relacionados com os efeitos tóxicos destes fármacos?No presente trabalho foi feita uma revisão da literatura internacional no que diz respeito às evidências, não clínicas e clínicas, da influência dos transportadores de efluxo na biodisponibilidade dos anticoagulantes orais diretos e consequentemente no seu efeito terapêutico e tóxico. Apesar de estarem disponíveis no mercado há menos de uma década, há atualmente diversos estudos que provam que a BCRP e a P-gp determinam a farmacocinética destes fármacos, e que a escolha clínica do anticoagulante deve ter em conta as interações relacionadas com os transportadores de efluxo e o polimorfismo a eles associado.
Within the scope of the curricular unit of the Integrated Master in Pharmaceutical Sciences of the Faculty of Pharmacy of the University of Coimbra, this document presents, in the form of a SWOT analysis, the internship report in Community Pharmacy, held at the Forum Pharmacy, and the internship report from the Medicines Evaluation Direction of INFARMED - National Authority of Medicines and Health Products, I.P.. This document also includes the monograph entitled "Influence of ABC-efflux transporters on the toxic effects of the direct oral anticoagulant drugs".In spite of their clinical advantages comparing to vitamin K antagonists, direct oral anticoagulant drugs (DOACs) keep the main toxic effect: the hemorrhages. There are several individual characteristics that seem to increase the occurrence of these events, as renal failure, drug-drug interactions (DDI) and different plasmatic concentrations after administration of the same dose. As DOACs are substrates of Breast Cancer Resistance Protein (BCRP) and P-glycoprotein (P-gp), can these efflux transporters be related with the toxic effects of those drugs?The present work reviews the international literature regarding the non-clinical and clinical evidence of the impact of efflux transporters on the bioavailability of DOACs and on their therapeutic and toxic effect. Although they have been marketed for less than a decade, there are currently several studies proving that BCRP and P-gp influence the pharmacokinetics of DOACs and that the interactions related to the efflux transporters and their associated polymorphism should be considered in clinical practice.

碩士
高雄醫學大學
藥學系碩士在職專班
106
Background Atrial fibrillation (AF) patients have a higher risk of ischemic stroke (IS), and anticoagulants are generally used for the stroke prevention. Non-vitamin K antagonist oral anticoagulants (NOACs) had been shown to have similar efficacy and fewer bleeding events as compared to warfarin by clinical trials. However, since some studies indicated that Asian people tended to have higher incidence of bleeding, it is crucial to evaluate the real world evidence for the effectiveness and safety of NOACs in Taiwan setting. Aims This study aims to construct a cohort study with the National Health Insurance (NHI) Database to compare the effectiveness of IS prevention and the safety of intracranial hemorrhage (ICH) between the NOACs and warfarin in AF patients. Methods We used the 2-million random sample 2010 cohort of the NHI database between January 1st, 2010, and December 31, 2015. The patients with AF and with any anticoagulants were extracted during this follow-up period. We conducted subgroup analyses of low dose (dabigatran 110 mg, rivaroxaban 10mg and 15mg and apixaban 2.5mg) and standard dose (dabigatran 150mg, rivaroxaban 20 mg and apixaban 5mg). The primary outcomes were IS and intracranial hemorrhage. Regarding the outcome measurements, we used survival analysis and calculate hazard ratio (HR) with 95% confidence intervals (CIs) for each event. Result In NOAC group, the proportion of using low dose was 85% (194/228) in dabigatran and 90.52% (191/211) in rivaroxaban, but in apixaban group 100% using standard dose. In general, dabigatran had no significant difference in IS prevention (HR 0.78, 95% CI 0.36 - 1.66, p=0.51), ICH (HR 0.56, 95% CI 0.12 - 2.57, p=0.45) and all-cause mortality (HR 0.86, 95% CI 0.48 - 1.54, p=0.61) comparing with warfarin. In subgroup analysis, there was no significant difference between low dose dabigatran and warfarin in IS (HR 0.70, 95% CI 0.30 - 1.62, p=0.41), ICH (HR 0.63, 95% CI 0.14 - 2.91, p=0.56) and all-cause mortality (HR 0.84, 95% CI 0.47 - 1.52, p=0.57). In standard dose dabigatran group, we did not find any significant difference in IS prevention (HR 1.31, 95% CI 0.31 - 5.54, p=0.71) and all-cause mortality (HR 1.86, 95% CI 0.23 - 15.17, p=0.56). In general, rivaroxaban and low dose rivaroxaban had no significant difference in IS prevention, ICH and all-cause mortality. In subgroup analysis, more ICH events had been noticed in standard dose rivaroxaban group (hazard ratio 8.07; 95% CI 1.51-43.20, p=0.01). Apixaban had no significant difference in IS prevention. Conclusion In Taiwan, most of patients were prescribed low dose of dabigatran and rivaroxaban, and standard dose of apixaban in clinical practice. Our study results showed that the use of standard dose rivaroxaban have higher risk of ICH comparing to warfarin group, but this trend did not reach statistical significance. Low dose rivaroxaban may be a better agent for Taiwanese rather than standard dose rivaroxaban. However, future research with larger sample size will be needed.

Orientação: Ana Mirco
Os novos anticoagulantes orais são opções emergentes para a prevenção e tratamento das doenças tromboembólicas. São cada vez mais usados na prática clínica pela facilidade do seu uso e pelos seus benefícios clínicos mas a sua utilização mais generalizada carece de demonstração de custo efetividade. O objectivo consistiu na realização de uma revisão sistemática dos estudos de custo-efetividade dos novos anticoagulantes orais, dabigatrano, rivaroxabano e apixabano, em todas as suas indicações clínicas e descrever os resultados principais. Foi realizada uma revisão sistemática da literatura nas bases de dados Pubmed, Embase, Scopus, Cochrane e Web of Knowledge, para identificar todos os estudos de custo-efetividade dos novos anticoagulantes orais em todas as suas indicações clínicas. A pesquisa selecionou 42 estudos, 15 relacionados com a tromboprofilaxia na artroplastia total da anca ou na artroplastia total do joelho e 27 na prevenção do acidente vascular cerebral na fibrilhação auricular. Não foram identificados estudos para as indicações de tratamento e prevenção secundária do tromboembolismo venoso ou para a prevenção secundária após síndromes coronários agudos. Os resultados principais incluíram os rácios custo-efetividade incremental por anos de vida ajustados pela qualidade, comparações com o limite pré-fixado à disponibilidade a pagar e análises de sensibilidade que revelaram custo-efetividade ou dominância dos novos anticoagulantes orais. A presente revisão sistemática demonstra que os novos anticoagulantes orais são custo-efetivos para a tromboprofilaxia em cirurgia ortopédica major e para a prevenção do acidente vascular cerebral na fibrilhação auricular.
Novel oral anticoagulants are emerging options for the prevention and treatment of thromboembolic diseases. They are increasingly used in clinical practice due to simplicity of use and clinical benefits but an important step is to evaluate their cost-effectiveness. We aimed to perform a systematic review of cost-effectiveness studies of novel oral anticoagulants, dabigatran, rivaroxaban and apixaban, in all their clinical indications and describe key findings. A systematic review of the literature was conducted searching Pubmed, Embase, Scopus, Cochrane and Web of Knowledge databases to identify all cost-effectiveness studies of novel oral anticoagulants in all their clinical indications. The research selected 42 studies, 15 related to thromboprophylaxis in total hip arthroplasty or total knee arthroplasty and 27 to stroke prevention in non-valvular atrial fibrillation. No studies were identified for the indications of treatment and secondary prevention of venous thromboembolism or for the secondary prevention after acute coronary syndromes. Key findings included incremental cost-effectiveness ratios per quality-adjusted life-years, comparisons with appropriate willingness-to-pay thresholds and sensitivity analysis that revealed cost-effectiveness or dominance for the novel oral anticoagulants. This present systematic review demonstrates that novel oral anticoagulants are cost-effective for the thromboprophylaxis in major orthopedic surgery and for stroke prevention in atrial fibrillation.

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2020
Introdução: Críticas têm sido apontadas à utilização isolada do valor P na interpretação de resultados de randomized controlled trials (RCT). Ferramentas adicionais têm sido propostas, como o índice de fragilidade (IF)- uma medida da robustez/fragilidade de um estudo- e outras que dele derivam. Define-se IF como o número mínimo de doentes que teriam que ser convertidos de não-eventos a eventos, no grupo com menos eventos, para os resultados perderem a sua significância estatística. Avaliamos aqui os RCT citados nas recomendações referentes a antitrombóticos das guidelines da Sociedade Europeia de Cardiologia (SEC), através do IF e medidas associadas. Métodos: Calculamos o IF, quociente de fragilidade (QF) e IF menos lost to follow-up (IF-LTF) para os RCT citados nas recomendações referentes a terapêutica antitrombótica das versões atualizadas das guidelines da SEC. Comparamos o lost to follow-up (LTF) ao IF. Estes parâmetros foram calculados para o conjunto global de estudos, por guideline e por tipo de recomendação. Resultados: Foram incluídos 57 estudos. A mediana do IF foi 24.0 (DIQ, 9.0-60.0) e a do QF foi 0.0035 (DIQ, 0.0018-0.0051). A mediana do IF-LTF foi 1.0 (DIQ, 0.0-41.0). Vinte (35.1%) dos estudos tiveram um outcome primário ou outcome principal de segurança com LTF superior ao IF. As guidelines de doença arterial periférica e de síndrome coronário crónico tiveram, respetivamente, os IF mais baixo (2.5, IIQ, 1.8-3.3) e mais alto (48.5; IIQ, 23.8-73.0). Conclusões: O IF mediano sugere robustez dos ensaios acerca de terapêutica antitrombótica citados nas guidelines, mas cerca de um terço destes tem LTF superior ao IF. Isto realça a necessidade de avaliar a robustez dos estudos quando se constroem guidelines.
Background: Criticisms have been raised against the sole use of P value in interpreting results from randomized controlled trials (RCT). Additional tools have been suggested, like the fragility index (FI)- a measure of a trial’s robustness/fragility – and derivative measures. FI is the minimum number of patients who would have to be converted from non-events to events, in the group with the least events, for a result to lose statistical significance. We evaluate RCT supporting European Society of Cardiology (ESC) guidelines regarding antithrombotics, using the FI and FI-related measures. Methods: FI, fragility quotient (FQ) and FI minus lost to follow-up (FI-LTF) were calculated for the RCT underpinning recommendations regarding antithrombotic therapy from the updated ESC guidelines. Lost to follow-up (LTF) was compared to FI. Results were calculated for the overall group of studies, per guideline and per recommendation type. Results: 57 studies were included. The median FI was 24.0 (IQR, 9.0-60.0) and median FQ was 0.0035 (IQR, 0.0018-0.0051). Median FI-LTF was 1.0 (IQR, 0.0-41.0). Twenty (35.1%) of the studies had one primary or main safety outcome with LTF exceeding FI. Peripheral arterial disease guideline and chronic coronary syndrome guideline had, respectively, the lowest (2.5, IQR, 1.8-3.3) and the highest (48.5; IQR, 23.8-73.0) FI. Conclusions: The median fragility index suggests robustness in the trials evaluating antithrombotic drugs cited in the guidelines, but about one third of them had LTF larger than FI. This emphasizes the need for assessing trials’ robustness when constructing guidelines.

Unfractionated heparin (UFH) therapy is frequently used in tertiary paediatric healthcare facilities despite a lack of paediatric-specific research informing the optimal therapeutic intensity, monitoring recommendations or side-effect-profile in infants and children. As a result, the majority of clinical recommendations regarding UFH management in children have been extrapolated from adult evidence. The process of developmental haemostasis, in association with the variable pathogenesis of thromboembolic disease (TED) in children compared to adults, suggests that extrapolation of adult guidelines for UFH management to children is not ideal.
This study hypothesised that the process of developmental haemostasis would influence both the action and effect of UFH in children of different ages. This hypothesis was tested by addressing the following aims: 1. To determine the pharmacokinetics (PK) of UFH in children of different ages; 2. To compare the different methods of monitoring UFH in children of different ages; 3. To identify the impact of competitive plasma binding of UFH in children of different ages; 4. To determine the impact of UFH upon tissue factor pathway inhibitor (TFPI) release in children.
A prospective cohort study of children receiving a single bolus dose of UFH for primary thromboprophylaxis in the setting of cardiac angiography was conducted. Venous blood samples were collected prior to the UFH, then at 15, 30, 45 and 120 minutes post-UFH bolus. Laboratory assays performed included activated partial thromboplastin time (APTT), anti-Xa assay, anti-IIa assay, thrombin clotting time (TCT), protamine titration and TFPI. Levels of two plasma proteins known to competitively bind UFH (vitronectin and platelet factor 4) were determined and the impact of competitive plasma binding upon UFH activity, as measured by the anti-Xa assay, was quantified. A population approach to pharmacokinetic analysis, based on protamine titration results, was performed using WinNonMix™ Professional 2.0.1 (®1998-2000 Pharsight Corporation, Mountain View, CA, USA). Results were analysed according to the following age-groups: less than one year; one to five years; six to ten years; 11-16 years.
Sixty-four children were recruited, ranging in age from six months to fifteen-and-ahalf years. The mean dose/Kg of UFH across the entire cohort was 90.9± 15.5 IU/Kg.
Pharmacokinetic model specifications were systematically assessed, investigating the impact of parameter covariates and different error models upon objective function value and/or curve fitting. A first-order kinetic model best fitted the data. This model used weight 0.75 as the covariate of clearance and total weight as the covariate for volume of distribution. Parameter estimates for clearance and volume of distribution both demonstrated variance from adult and small neonatal PK studies of UFH, however methodological differences in PK analysis techniques limited comparisons. The half-life of UFH reported in this study was consistently and significantly shorter than that previously reported for adults, but longer than that reported for neonates.
All measures of UFH-effect demonstrated a significant and prolonged increase post- UFH bolus. The mean APTT was 261 seconds 102 ± 25 minutes post-UFH, representing a seven-fold increase from the mean baseline APTT (38 seconds). Anti- Xa assay levels were within the therapeutic range for TED management (0.35 to 0.7 IU/mL), or greater, at every post-UFH bolus timepoint. This prolonged UFH-effect was evident to nearly two hours post-UFH bolus, without concurrent UFH infusion. Age-related differences in UFH-response were evident for anti-Xa, anti-IIa and protamine titration results. Furthermore, during periods of high UFH concentration, the ratio of anti-Xa to anti-IIa activity in children less than one year of age significantly favoured UFH-mediated anti-Xa effect over anti-IIa effect (1.9), compared to teenagers (1.3).
This study demonstrated poor correlation between protamine titration and both the anti-Xa assay (r2 = 0.47) and APTT (r2 = 0.56). Use of the anti-Xa assay (0.35 to 0.7 IU/mL) or protamine titration assay (0.2 to 0.4 IU/mL) to establish APTT-based reference ranges for therapeutic management of TED resulted in APTT ranges with upper limits greater than 250 seconds.
No age-related quantitative differences in plasma levels of vitronectin or platelet factor 4 were identified across the childhood years. The addition of dextran sulphate (DS) to ex vivo study samples demonstrated no change in anti-Xa activity in samples collected within 20 minutes of UFH bolus, however a significant increase in anti-Xa activity following the addition of DS was evident at all later timepoints post-UFH bolus.
The measurement of TFPI before and after a single bolus dose of UFH demonstrated children have a similar immediate increase in TFPI activity following intravenous UFH compared to adults. However, the children in this series demonstrated a significantly prolonged level of increased TFPI activity, out to 102 ± 25 minutes post-UFH, compared to that reported in adult patients.
This study has developed the first paediatric-specific PK profile of UFH and has elucidated a number of age-dependent UFH-mechanisms of action that contribute to the previously reported age-dependent response to UFH in children. The results of this study support the hypothesis that developmental haemostasis influences both the action and effect of UFH in children of different ages.

Analysis of anticoagulant utilization in the Czech republic in the period from 2007 to 2016 Author: Zuzana Hochelová1 Supervisor: PharmDr. Eva Zimčíková, Ph.D.1 Consultant: PharmDr. Kateřina Malá, Ph.D.1 1 Department of Social and Clinical Pharmacy, Faculty of Pharmacy in Hradec Králové, Charles University, Czech Republic Introduction: Anticoagulants are drugs that reduce blood clotting and prevent the formation of blood clots. In the Czech Republic - antagonists of vitamin K-warfarin, direct oral inhibitors of factor Xa-rivaroxaban, apixaban, edoxaban, direct oral inhibitors trombin - dabigatran, parenteral anticoagulants - heparin, low-molecular heparin, fondaparinux, oral and parenteral hirudin are used. Objective: The objective of this diploma thesis was to assess the consumption of oral and parenteral anticoagulants in the Czech Republic from 01. 01. 2007 to 31. 12. 2016, based on the data from the State Institute of Drug Control (SIDC). Methods: ATC/DDD methodology was applied. The research consisted of a retrospective analysis of the SIDC database. All oral and parental anticoagulants approved in the CR were included in the study. Drug utilization was calculated as number of defined daily doses per thousands of inhabitants per day (DID). The data on the number of residents was acquired from...

Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de Medicina
Os Anticoagulantes Orais Diretos (DOACs) têm vindo a ganhar uma relevância importante em doentes com necessidade de terapêutica anticoagulante, tendo como vantagens relativamente à Varfarina o facto de ter doses terapêuticas fixas de acordo com a indicação e alguns critérios clínicos individuais, não sendo necessário o controlo do nível de anticoagulação através do Índice Internacional Normalizado (INR). Os testes comummente disponíveis para monitorizar estes doentes são o Tempo de Protrombina (PT) e o Tempo de Tromboplastina Parcial Ativado (APTT), mas estes testes são pouco sensíveis e específicos para os DOACs.Em relação ao controlo dos anticoagulados com DOACs, o Teste de Geração de Trombina (TGT) tem mostrado bons resultados, sendo útil para medir a capacidade do plasma de gerar trombina, resultado final da cascata de coagulação. Desta forma, o TGT pode ser utilizado para testar a capacidade de coagulação, para avaliar o risco trombótico e para comparar a eficácia entre medicamentos, tendo como resultado uma curva que descreve a quantidade de Trombina ao longo da cascata de coagulação. Uma vez que as doses de DOACs são fixas, sendo apenas ajustadas com alguns critérios clínicos, em teoria o nível de anticoagulação de cada doente seria o mesmo, após estes ajustes predeterminados.Neste projeto, pretendemos incluir doentes tratados com DOACs com doses correctamente ajustadas por critérios clínicos e avaliar, através do TGT, se os níveis de anticoagulação são os adequados. A nossa hipótese é que alguns doentes, com critérios clínicos específicos em associação, como baixo peso, idade avançada ou disfunção renal moderada a grave, poderão estar expostos a níveis superiores aos desejados de anticoagulação. Testámos ainda diferentes interações medicamentosas dos DOACs ao medir a sua concentração e função através do TGT. A nossa hipótese é que certos fármacos predispõem os doentes a risco hemorrágico ou trombótico, sendo estes pacientes candidatos a doses reduzidas.
The use of direct oral anticoagulants (DOACs) is increasing because its prescription in fixed doses does not require routine monitoring. However, assessment of the anticoagulant effect may be needed in specific situations to prevent ischemic or bleeding events. Traditional coagulation tests to monitor anticoagulant activity include prothrombin time (PT) and activated partial thromboplastin time (aPTT), which are very useful for following those under VKA and non-fractioned heparin therapy, respectively. The same principle does not apply for DOACs, since PT and aPTT use clot formation as their endpoint, making them incapable of assessing the whole coagulation system. A global coagulation test such as thrombin generation test (TGT) may be the answer since it measures total thrombin formation, the final result of the coagulation cascade, thus offering a more sensitive measurement of anticoagulation intensity for those medicated with DOACs. We aimed to assess the anticoagulant effect of DOACs on TGT and to compare the population under a full dose to patients with dose reduction in order to weigh TGT as a valuable clinical tool.We hypothesized that patients with clinically-driven dose reduction strategies had comparable levels of anticoagulation to patients without indication for dose reduction, due to the pharmacodynamic profile of DOACs. Additionally, we also wanted to specifically weight the DDIs of DOACs by measuring the concentration and function of anticoagulation through TGT. We theorized that some drugs enhance or diminish DOAC concentration and function, making patients who are taking these drugs candidates for tailored dosing.

Background: Warfarin is an anticoagulant that is used for the prophylactic and therapeutic treatment for a wide range of thrombo-embolic disorders. The prescribing and monitoring of warfarin therapy is challenging due to the fact that warfarin exhibits numerous interactions with other drugs and a variety of factors that influence the dosing of warfarin. Objective: The general objective of this study was to investigate the prevalence of drugs prescribed with warfarin that may have a potential drug-drug interaction (DDI) with warfarin. Methods: This was a cross-sectional, observational or qualitative study that was conducted on medicine claims data of a pharmaceutical benefit management company for patients receiving warfarin therapy for a six year period, ranging from 1 January 2005 to 31 December 2010. Drug products that were co-prescribed with warfarin were also identified from the medicine claims database. The total number of prescriptions for all drug products during the study period were analysed and compared to the warfarin dataset. This was done by means of the SAS 9.1® computer package (SAS Institute, 2004). The total number of prescriptions and medicine items claimed from the database during the study period were respectively 49 523 818 and 118 305 941. Potential DDls between warfarin and coprescribed drugs were identified and classified according to a clinically significant rating. The clinically significance ratings of potential DDls are described in three degrees of severity, identified as major, moderate and minor (Tatro, 2011 :xiv). Results: The database consisted of 427 238 warfarin prescriptions and 427 744 warfarin medicine items, which represented 0.9% of the total number of prescriptions and 0.4% of total number of medicine items. The total number of patients who claimed warfarin prescriptions through the database represented 0.9% (n=68 575) of the total number of patients who claimed prescriptions in the total database (2005-2010). General practitioners prescribed the highest frequency of warfarin medicine items, representing 58.3% (n=249 202) of the total number prescribed. The age group that claimed the highest frequency of warfarin prescriptions (n=327 592, 76.6%) and the highest frequency of warfarin medicine items (n=327 984, 76.7%) was age group 4 (consisting of patients 59 years and older). The distribution between females and males regarding warfarin prescriptions claimed (n=205 999, 48.2%; n=221 117, 51.8%) and warfarin medicine items claimed (n=206 232, 48.2%; n=221 390, 51.8%) were almost equal. General practitioners prescribed the highest average PDD (7.01 mg ± 9.86 mg) of warfarin medicine items. Paediatric cardiologists prescribed the lowest average PDD (4.61 mg ± 1.29 mg) of warfarin medicine items. A d-value of 0.1 indicates that there is no practical difference of the average PDD between general practitioners and paediatric cardiologists. The average PDD of warfarin medicine items between females (6.60 mg ± 9.06 mg) and males (6.74 mg± 8.41 mg) was almost equal. The age group who was prescribed the highest average PDD was age group 2 (consisting of patients 20 years to 39 years old) (7.42 mg± 7.42 mg). Age group 4 (consisting of patients 59 years and older) (6.50 mg± 8.90 mg) was prescribed the lowest average PDD of warfarin medicine items. A d-value of 0.1 indicates that there is no practical difference of the average PDDs of warfarin medicine items between these two age groups. The results revealed that drugs with a significance rating (SR) of 1 (n=155 066, 43.3%), 2 (n=30128, 8.4%), 4 (n=137144, 38.3%), and 5 (n=36144, 10.1%) were co-prescribed with warfarin in the six year study period. The five drugs that was co-prescribed with warfarin most frequently was aspirin (n=48 903, 13.6%), thyroxine (n=33 954, 9.5%), amiodarone (n=25 056, 7.0%), simvastatin (n=19 070, 5.3%) and celecoxib (n=10 794, 3.0%). These five drugs have a SR of 1. Conclusions: This study showed that the top five drugs most frequently prescribed with warfarin are aspirin, thyroxine, amiodarone, simvastatin and celecoxib. These drugs can potentially interact with warfarin. The potential interactions of these drugs are rated with a significance rating of 1. This concludes that drugs that can potentially cause life threatening effects and permanent damage are commonly co-prescribed with warfarin. Clinical data concerning the INR or PT must be obtained in order to evaluate whether or not warfarin therapy is changed when a potentially interacting drug is co-prescribed. The age of the patients as well as the duration of warfarin treatment should also be obtained in order to assess whether warfarin treatment is changed with the progression of age.
MPharm (Pharmacy Practice), North-West University, Potchefstroom Campus, 2013