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Effects of cardiopulmonary bypass on propofol pharmacokinetics and bispectral index during coronary surgery

BARBOSA, Ricardo Antonio G.; SANTOS, Silvia Regina C. Jorge; WHITE, Paul F.; PEREIRA, Valéria A.; SILVA FILHO, Carlos R.; MALBOUISSON, Luiz M. S.; CARMONA, Maria José C.
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica
ENG
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36.71065%
PURPOSE: Cardiopulmonary bypass is known to alter propofol pharmacokinetics in patients undergoing cardiac surgery. However, few studies have evaluated the impact of these alterations on postoperative pharmacodynamics. This study was designed to test the hypothesis that changes in propofol pharmacokinetics increase hypnotic effects after cardiopulmonary bypass. METHODS: Twenty patients scheduled for on-pump coronary artery bypass graft (group, n=10) or off-pump coronary artery bypass graft (group, n=10) coronary artery bypass grafts were anesthetized with sufentanil and a propofol target controlled infusion (2.0 µg/mL). Depth of hypnosis was monitored using the bispectral index. Blood samples were collected from the induction of anesthesia up to 12 hours after the end of propofol infusion, at predetermined intervals. Plasma propofol concentrations were measured using high-performance liquid chromatography, followed by a non-compartmental propofol pharmacokinetic analysis. Data were analyzed using ANOVA, considering p<0.05 as significant. RESULTS: After cardiopulmonary bypass, despite similar plasma propofol concentrations in both groups, bispectral index values were lower in the on-pump coronary artery bypass graft group. Time to extubation after the end of propofol infusion was greater in the on-pump coronary artery bypass graft group (334 ± 117 vs. 216 ± 85 min...

Effect of cardiopulmonary bypass on the pharmacokinetics of propranolol and atenolol

CARMONA, M.J.C.; PEREIRA, V.A.; MALBOUISSON, L.M.S.; AULER JR., J.O.C.; SANTOS, S.R.C.J.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.76767%
The pharmacokinetics of some β-blockers are altered by cardiopulmonary bypass (CPB). The objective of this study was to compare the effect of coronary artery bypass graft (CABG) surgery employing CPB on the pharmacokinetics of propranolol and atenolol. We studied patients receiving oral propranolol with doses ranging from 80 to 240 mg (N = 11) or atenolol with doses ranging from 25 to 100 mg (N = 8) in the pre- and postoperative period of CABG with moderately hypothermic CPB (32°C). On the day before and on the first day after surgery, blood samples were collected before β-blocker administration and every 2 h thereafter. Plasma levels were determined using high-performance liquid chromatography and data were treated by pharmacokinetics-modelling. Statistical analysis was performed using ANOVA or the Friedman test, as appropriate, and P < 0.05 was considered to be significant. A prolongation of propranolol biological half-life from 5.41 ± 0.75 to 11.46 ± 1.66 h (P = 0.0028) and an increase in propranolol volume of distribution from 8.70 ± 2.83 to 19.33 ± 6.52 L/kg (P = 0.0032) were observed after CABG with CPB. No significant changes were observed in either atenolol biological half-life (from 11.20 ± 1.60 to 11.44 ± 2.89 h) or atenolol volume of distribution (from 2.90 ± 0.36 to 3.83 ± 0.72 L/kg). Total clearance was not changed by surgery. These CPB-induced alterations in propranolol pharmacokinetics may promote unexpected long-lasting effects in the postoperative period while the effects of atenolol were not modified by CPB surgery.; FAPESP

Influência do Diabetes mellitus e da insuficiência renal crônica em tratamento dialítico na farmacocinética e farmacodinâmica do carvedilol em pacientes hipertensos; Influence of Diabetes mellitus and chronic renal failure on continuous ambulatory peritoneal dialysis on the pharmacokinetics and pharmacodynamics of carvedilol in hypertensive patients

Silva, Flávia Garcez da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/08/2008 PT
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36.71065%
O carvedilol é um fármaco utilizado na terapêutica da hipertensão e da insuficiência cardíaca congestiva. É disponível para uso clínico como racemato e seus enantiômeros apresentam atividade semelhante sobre os receptores 1-adrenérgicos, sendo que o enantiômero S-(-) é mais ativo como antagonista dos receptores adrenérgicos. O presente estudo visa investigar a influência do Diabetes mellitus (DM) tipo 2 e da insuficiência renal crônica (IRC) em pacientes em diálise peritoneal ambulatorial contínua (DPAC) na farmacocinética enantiosseletiva e na farmacodinâmica do carvedilol em pacientes hipertensos. Os pacientes hipertensos investigados divididos nos grupos controle (n=8), DM tipo 2 (n=8) e IRC em DPAC (n=6) receberam dose única p.o. de 25 mg de carvedilol racêmico. Os enantiômeros do carvedilol e metabólitos 4-hidroxifenil e O-desmetilcarvedilol foram analisados no sistema LC-MS/MS empregando coluna quiral e fase móvel constituída por mistura de metanol: ácido acético: dietilamina. O método foi linear no intervalo de concentrações de 0,1-100 ng de cada enantiômero do carvedilol/mL de líquido de diálise, 0,2-200 ng de cada enantiômero do carvedilol/mL de plasma, 2,5-2500 ng de cada enantiômero do carvedilol...

Monitoramento terapêutico e modelagem farmacocinética de antimicrobianos em pacientes queimados da unidade de terapia intensiva; Therapeutic drug monitoring and pharmacokinetics of antimicrobial agents in burn patients from the Intensive care unit

Vera López, Karin Jannet
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/09/2009 PT
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36.810786%
A sepse após a injúria térmica é a maior causa de morbidade e mortalidade em pacientes queimados, uma vez que profundas alterações ocorrem na farmacocinética de agentes antimicrobianos. Investigaram-se trinta e um pacientes, portadores de sepse documentada e apresentando lesões ativas; utilizou-se o tratamento empírico conforme seguem os regimes de dose: 1 g, 12/12 h para a vancomicina, 1 g, 6/6 h para o imipenem e 2 g, 8/8 h para o cefepime. Sete coletas seriadas de sangue foram realizadas através de cateter venoso (2 mL/cada); o plasma foi obtido pela centrifugação e armazenado no congelador (-80o C) até o ensaio. A concentração plasmática dos antimicrobianos foi determinada simultaneamente pela aplicação do método bioanalítico desenvolvido no estudo. O método de cromatografia líquida de alta eficiência demonstrou boa linearidade, precisão e exatidão para a determinação simultânea da vancomicina, cefepime e imipenem plasmáticos; a plicação desse método bioanalítico permitiu o monitoramento plasmático terapêutico e o estudo farmacocinético. Com base nos resultados obtidos de concentração plasmática versus tempo, aplicou-se a modelagem para investigar a farmacocinética desses agentes antimicrobianos nos pacientes queimados. Os parâmetros cinéticos foram estimados com base no modelo aberto de um compartimento pela aplicação do programa PK Solutions v. 2.0; a estatística foi realizada pela utilização do programa GraphPad Prism v. 4.0. Com base na farmacocinética alterada...

Influência da doença renal crônica e da hemodiálise na farmacodinâmica e farmacocinética dos isômeros do nebivolol em pacientes hipertensos; Influence of chronic kidney disease and hemodialysis on the pharmacodynamics and pharmacokinetics of nebivolol isomers in hypertensive patients

Neves, Daniel Valente
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 20/05/2013 PT
Relevância na Pesquisa
36.71065%
A doença renal crônica (DRC) está associada com inibição de sistemas enzimáticos e de transportadores de fármacos. O nebivolol, um bloqueador de terceira geração, seletivo para receptores 1 adrenérgicos e com atividade vasodiladora, é metabolizado principalmente por hidroxilação aromática dependente do CYP2D6, hidroxilação alicíclica e por glicuronidação. O estudo avalia a influência da DRC estágios 3 e 4 e da hemodiálise na farmacodinâmica e na farmacocinética dos isômeros do nebivolol. Os pacientes investigados divididos nos Grupos controle (n=12), DRC estágios 3 e 4 (n=12) e Hemodiálise (n=11) receberam dose única p.o. de 10 mg de nebivolol racêmico. As amostras seriadas de sangue foram coletadas até 48h após a administração do fármaco. Em cada tempo de colheita de sangue, a frequência cardíaca foi avaliada na situação de exercício isométrico durante 2 min com o handgrip, a 30% da contratilidade voluntária máxima. Todos os pacientes foram fenotipados como metabolizadores rápidos do metoprolol, exceto um paciente do Grupo controle fenotipado como metabolizador lento. Os isômeros do nebivolol foram analisados em plasma como concentração total empregando LC-MS/MS e coluna de fase quiral. O método foi linear no intervalo de concentrações de 25-2500 pg de cada isômero do nebivolol/mL de plasma. Os parâmetros farmacocinéticos foram calculados empregando o programa WinNonlin. O teste de Wilcoxon foi empregado para avaliar as razões isoméricas diferentes da unidade (p<0...

Influência do verapamil na farmacocinética e na perfusão cerebral da oxcarbazepina e dos enantiômeros do metabólito 10-hidroxicarbazepina em voluntários sadios; Influence of verapamil on the pharmacokinetics and cerebral perfusion of oxcarbazepine and the enantiomers of its metabolite 10- hydroxycarbazepine in healthy volunteers

Antunes, Natalicia de Jesus
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 25/11/2014 PT
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36.871653%
A oxcarbazepina (OXC) é indicada como terapia adjuvante ou monoterapia no tratamento de crises epilépticas parciais ou crises tônico-clônicas generalizadas em adultos e crianças. A OXC sofre rápida eliminação pré-sistêmica com formação do metabólito ativo 10-hidroxicarbazepina (MHD), o qual possui como enantiômeros o R-(-)- e o S-(+)-MHD. A OXC e o MHD são substratos da glicoproteína-P (P-gp), que pode ser inibida pelo verapamil. O presente estudo avalia a influência do verapamil na farmacocinética e perfusão cerebral da OXC e dos enantiômeros do MHD em voluntários sadios. Os voluntários sadios (n=12) receberam em uma ocasião doses de 300 mg/12h de OXC e em outra ocasião doses de 300 mg/12h de OXC associadas com 80 mg/8h de verapamil. As amostras de sangue foram coletadas no estado de equilíbrio durante 12 horas e a avaliação da perfusão cerebral realizada utilizando a tomografia computadorizada por emissão de fóton único (SPECT) antes do início do tratamento e nos tempos 4, 6 ou 12h após a administração da OXC. As concentrações plasmáticas total e livre da OXC e dos enantiômeros do MHD foram avaliadas por LC-MS/MS. A análise farmacocinética não compartimental foi realizada com o programa WinNonlin e a farmacocinética populacional foi desenvolvida utilizando a modelagem não-linear de efeitos mistos com o programa NONMEM. Os limites de quantificação obtidos foram de 12...

Influência do diabetes mellitus tipo 2 na farmacocinética da nifedipina em gestantes hipertensas; Influence of type 2 diabetes mellitus on pharmacokinetics of nifedipine in hypertensive pregnant women

Filgueira, Gabriela Campos de Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/11/2014 PT
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36.76767%
A nifedipina é uma dihidropiridina, antagonista de canal de cálcio utilizada no tratamento hipertensão arterial na gravidez. O presente estudo visa avaliar a influência do DM2 na farmacocinética da nifedipina em gestantes hipertensas. Foram avaliadas 12 gestantes hipertensas (grupo controle) e 10 gestantes hipertensas portadoras de DM 2 controlado (grupo DM), em uso de nifedipina retard (20 mg, 12/12 horas). A partir da 34ª semana de gestação foram coletadas amostras seriadas de sangue para a análise farmacocinética nos tempos zero, 10, 20, 30, 60, 90, 120, 150, 180, 240, 300, 360, 420, 480, 540, 600, 660 e 720 minutos após a administração do medicamento. Na resolução da gravidez coletou-se sangue materno e fetal para determinar a taxa de transferência placentária da nifedipina. Foram coletadas também alíquotas de sangue do espaço interviloso e de líquido amniótico para a determinação da distribuição do fármaco nestes compartimentos. As concentrações de nifedipina em plasma e líquido amniótico foram analisadas por LC-MS/MS. Os parâmetros farmacocinéticos e de transferência placentária da nifedipina, reportados como mediana foram comparados usando o teste Mann-Whitney, com nível de significância fixado em p<0...

Influência da variação dos hormônios femininos (estrógeno e progesterona) na farmacocinética do etanol; The gender influences and the variation of female hormones (estrogen and progesterone) on the pharmacokinetics of ethanol

Corrêa, Cristiana Leslie
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 24/09/2001 PT
Relevância na Pesquisa
36.71065%
O uso de álcool entre mulheres é uma questão atual e preocupante, face a maior vulnerabilidade destas aos danos hepáticos, cerebrais, entre outros, quando comparadas aos homens com padrões semelhantes de consumo. Sendo assim, investigaram-se as possíveis variações na farmacocinética do etanol em mulheres, considerando duas fases do ciclo menstrual (pré-folicular e lútea), bem como o uso de anticoncepcionais orais (AO). Participaram voluntários dos sexos feminino (n=22) e masculino (n=14), administrando-lhes 0,3 g/kg de etanol, na forma de uísque. Os resultados indicaram: a) os parâmetros farmacocinéticos do etanol não variam em função do ciclo menstrual (fase pré-folicular e lútea); b) as mulheres que tomavam AO levam menos tempo para atingir a concentração máxima e eliminam o etanol mais rapidamente do que as que não faziam uso; c) não houve diferença nos parâmetros farmacocinéticos entre o grupo de homens e o de mulheres que utilizavam AO, porém os homens apresentam maior velocidade de eliminação do que as mulheres que não faziam uso e d) os parâmetros farmacocinéticos relacionados com a biodisponibilidade (área sob a curva) e com o volume de distribuição não apresentaram diferenças entre os grupos analisados.; After drinking equivalent amounts of alcohol...

Age effects on the pharmacokinetics of tityustoxin from Tityus serrulatus scorpion venom in rats

Nunan,E.A.; Arya,V.; Hochhaus,G.; Cardoso,V.N.; Moraes-Santos,T.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2004 EN
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36.71065%
The pharmacokinetics of scorpion venom and its toxins has been investigated in experimental models using adult animals, although, severe scorpion accidents are associated more frequently with children. We compared the effect of age on the pharmacokinetics of tityustoxin, one of the most active principles of Tityus serrulatus venom, in young male/female rats (21-22 days old, N = 5-8) and in adult male rats (150-160 days old, N = 5-8). Tityustoxin (6 µg) labeled with 99mTechnetium was administered subcutaneously to young and adult rats. The plasma concentration vs time data were subjected to non-compartmental pharmacokinetic analysis to obtain estimates of various pharmacokinetic parameters such as total body clearance (CL/F), distribution volume (Vd/F), area under the curve (AUC), and mean residence time. The data were analyzed with and without considering body weight. The data without correction for body weight showed a higher Cmax (62.30 ± 7.07 vs 12.71 ± 2.11 ng/ml, P < 0.05) and AUC (296.49 ± 21.09 vs 55.96 ± 5.41 ng h-1 ml-1, P < 0.05) and lower Tmax (0.64 ± 0.19 vs 2.44 ± 0.49 h, P < 0.05) in young rats. Furthermore, Vd/F (0.15 vs 0.42 l/kg) and CL/F (0.02 ± 0.001 vs 0.11 ± 0.01 l h-1 kg-1, P < 0.05) were lower in young rats. However...

Cardiopulmonary bypass alters the pharmacokinetics of propranolol in patients undergoing cardiac surgery

Carmona,M.J.C.; Malbouisson,L.M.S.; Pereira,V.A.; Bertoline,M.A.; Omosako,C.E.K.; Le Bihan,K.B.; Auler Jr.,J.O.C.; Santos,S.R.C.J.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2005 EN
Relevância na Pesquisa
36.71065%
The pharmacokinetics of propranolol may be altered by hypothermic cardiopulmonary bypass (CPB), resulting in unpredictable postoperative hemodynamic responses to usual doses. The objective of the present study was to investigate the pharmacokinetics of propranolol in patients undergoing coronary artery bypass grafting (CABG) by CPB under moderate hypothermia. We evaluated 11 patients, 4 women and 7 men (mean age 57 ± 8 years, mean weight 75.4 ± 11.9 kg and mean body surface area 1.83 ± 0.19 m²), receiving propranolol before surgery (80-240 mg a day) and postoperatively (10 mg a day). Plasma propranolol levels were measured before and after CPB by high-performance liquid chromatography. Pharmacokinetic Solutions 2.0 software was used to estimate the pharmacokinetic parameters after administration of the drug pre- and postoperatively. There was an increase of biological half-life from 4.5 (95% CI = 3.9-6.9) to 10.6 h (95% CI = 8.2-14.7; P < 0.01) and an increase in volume of distribution from 4.9 (95% CI = 3.2-14.3) to 8.3 l/kg (95% CI = 6.5-32.1; P < 0.05), while total clearance remained unchanged 9.2 (95% CI = 7.7-24.6) vs 10.7 ml min-1 kg-1 (95% CI = 7.7-26.6; NS) after surgery. In conclusion, increases in drug distribution could be explained in part by hemodilution during CPB. On the other hand...

Effect of cardiopulmonary bypass on the pharmacokinetics of propranolol and atenolol

Carmona,M.J.C.; Pereira,V.A.; Malbouisson,L.M.S.; Auler Jr.,J.O.C.; Santos,S.R.C.J.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2009 EN
Relevância na Pesquisa
36.76767%
The pharmacokinetics of some β-blockers are altered by cardiopulmonary bypass (CPB). The objective of this study was to compare the effect of coronary artery bypass graft (CABG) surgery employing CPB on the pharmacokinetics of propranolol and atenolol. We studied patients receiving oral propranolol with doses ranging from 80 to 240 mg (N = 11) or atenolol with doses ranging from 25 to 100 mg (N = 8) in the pre- and postoperative period of CABG with moderately hypothermic CPB (32°C). On the day before and on the first day after surgery, blood samples were collected before β-blocker administration and every 2 h thereafter. Plasma levels were determined using high-performance liquid chromatography and data were treated by pharmacokinetics-modelling. Statistical analysis was performed using ANOVA or the Friedman test, as appropriate, and P < 0.05 was considered to be significant. A prolongation of propranolol biological half-life from 5.41 ± 0.75 to 11.46 ± 1.66 h (P = 0.0028) and an increase in propranolol volume of distribution from 8.70 ± 2.83 to 19.33 ± 6.52 L/kg (P = 0.0032) were observed after CABG with CPB. No significant changes were observed in either atenolol biological half-life (from 11.20 ± 1.60 to 11.44 ± 2.89 h) or atenolol volume of distribution (from 2.90 ± 0.36 to 3.83 ± 0.72 L/kg). Total clearance was not changed by surgery. These CPB-induced alterations in propranolol pharmacokinetics may promote unexpected long-lasting effects in the postoperative period while the effects of atenolol were not modified by CPB surgery.

Effects of cardiopulmonary bypass on propofol pharmacokinetics and bispectral index during coronary surgery

Barbosa,Ricardo Antonio G.; Santos,Silvia Regina C. Jorge; White,Paul F.; Pereira,Valéria A.; Silva Filho,Carlos R.; Malbouisson,Luiz M. S.; Carmona,Maria José C.
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2009 EN
Relevância na Pesquisa
36.71065%
PURPOSE: Cardiopulmonary bypass is known to alter propofol pharmacokinetics in patients undergoing cardiac surgery. However, few studies have evaluated the impact of these alterations on postoperative pharmacodynamics. This study was designed to test the hypothesis that changes in propofol pharmacokinetics increase hypnotic effects after cardiopulmonary bypass. METHODS: Twenty patients scheduled for on-pump coronary artery bypass graft (group, n=10) or off-pump coronary artery bypass graft (group, n=10) coronary artery bypass grafts were anesthetized with sufentanil and a propofol target controlled infusion (2.0 µg/mL). Depth of hypnosis was monitored using the bispectral index. Blood samples were collected from the induction of anesthesia up to 12 hours after the end of propofol infusion, at predetermined intervals. Plasma propofol concentrations were measured using high-performance liquid chromatography, followed by a non-compartmental propofol pharmacokinetic analysis. Data were analyzed using ANOVA, considering p<0.05 as significant. RESULTS: After cardiopulmonary bypass, despite similar plasma propofol concentrations in both groups, bispectral index values were lower in the on-pump coronary artery bypass graft group. Time to extubation after the end of propofol infusion was greater in the on-pump coronary artery bypass graft group (334 ± 117 vs. 216 ± 85 min...

Clinical pharmacokinetics of vancomycin in the neonate: a review

Pacifici,Gian Maria; Allegaert,Karel
Fonte: Faculdade de Medicina / USP Publicador: Faculdade de Medicina / USP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2012 EN
Relevância na Pesquisa
36.71065%
Neonatal sepsis is common and is a major cause of morbidity and mortality. Vancomycin is the preferred treatment of several neonatal staphylococcal infections. The aim of this study was to review published data on vancomycin pharmacokinetics in neonates and to provide a critical analysis of the literature. A bibliographic search was performed using PubMed and Embase, and articles with a publication date of August 2011 or earlier were included in the analysis. Vancomycin pharmacokinetic estimates, which are different in neonates compared with adults, also exhibit extensive inter-neonatal variability. In neonates, several vancomycin dosing schedules have been proposed, mainly based on age (i.e., postmenstrual and postnatal), body weight or serum creatinine level. Other covariates [e.g., extracorporeal membrane oxygenation (ECMO), indomethacin or ibuprofen, and growth restriction] of vancomycin pharmacokinetics have been reported in neonates. Finally, vancomycin penetrates cerebrospinal fluid (range = 7-42%). Renal function drives vancomycin pharmacokinetics. Because either age or weight is the most relevant covariate of renal maturation, these covariates should be considered first in neonatal vancomycin dosing guidelines and further adjusted by renal dysfunction indicators (e.g....

Developmental pharmacokinetics of ciclosporin – a population pharmacokinetic study in paediatric renal transplant candidates

Fanta, S; Jönsson, S; Backman, J T; Karlsson, M O; Hoppu, K
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.71065%
What is already known about this subjectCiclosporin is an immunosuppressant drug with a narrow therapeutic index and large variability in pharmacokinetics.It is likely that the inter- and intraindividual variability in ciclosporin pharmacokinetics and dose requirements is even larger in children than in adults as a result of variation in biological maturation status.However, data on the developmental pharmacokinetics of ciclosporin, as well as other CYP3A4 substrate drugs, in children are scarce.What this study addsAdult CYP3A4 activity seems to be reached by the age of 6–12 months, and allometrically scaled body weight is a good predictor of the hepatic clearance of ciclosporin, a CYP3A4 substrate.Ciclosporin oral bioavailability, known previously to display large interindividual variability, is not influenced by age.These conclusions were reached using a robust modelling approach (NONMEM) with rich paediatric pharmacokinetic data collected after full i.v. and p.o. profiles.

Lack of tacrolimus circadian pharmacokinetics and CYP3A5 pharmacogenetics in the early and maintenance stages in Japanese renal transplant recipients

Satoh, Shigeru; Kagaya, Hideaki; Saito, Mitsuru; Inoue, Takamitsu; Miura, Masatomo; Inoue, Kazuyuki; Numakura, Kazuyuki; Tsuchiya, Norihiko; Tada, Hitoshi; Suzuki, Toshio; Habuchi, Tomonori
Fonte: Blackwell Science Inc Publicador: Blackwell Science Inc
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.810786%
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECTCircadian variations of tacrolimus pharmacokinetics are controversial.Also, the pharmacokinetics has time-dependent variability, such as a decrease in oral clearance and increase in the dose-adjusted AUC after transplantation.Although the CYP3A5 polymorphism is associated with tacrolimus pharmacokinetics, differences in the influence of this gene on the pharmacokinetics between the early and maintenance stages have not yet been clarified.WHAT THIS STUDY ADDSTacrolimus pharmacokinetics did not show circadian variation in either the early or maintenance stage with our designated-time administration strategy.Based on previous results and our own findings, the interval between food consumption and tacrolimus administration might influence the interindividual and interinstitutional variability of tacrolimus chronopharmacokinetics.The CYP3A5 polymorphism may be associated with the time-dependent changes in tacrolimus oral clearance.

In vivo cerebral pharmacokinetics and pharmacodynamics of diazepam and midazolam after short intravenous infusion administration in sheep

Upton, R.; Ludbrook, G.; Grant, C.; Martinez, A.
Fonte: Kluwer Academic/Plenum Publ Publicador: Kluwer Academic/Plenum Publ
Tipo: Artigo de Revista Científica
Publicado em //2001 EN
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36.71065%
The cerebral pharmacokinetics and pharmacodynamics of midazolam and diazepam were examined in chronically instrumented sheep via measurements of their arterio-venous concentration difference across the brain during and after 2-min iv infusions. Diazepam (30 mg) or midazolam (10 mg) were administered on 5 separate occasions to 4 sheep. For both drugs, rapid cerebral uptake occurred during the infusion, which quickly turned to elution in the postinfusion period. However, this process was more rapid for midazolam than diazepam. The cerebral pharmacokinetics of both was better described by a kinetic model with slight membrane limitation rather than flow limitation. For diazepam, the estimated brain:plasma partition coefficient was 2.67, and the first and second compartments filled with half-lives of 2.2 and 0.5 min, respectively. For midazolam, these values were 0.27, 0.26 and 1.34 min, respectively. In a subset of sheep, pulmonary arterial–arterial gradients were too small to measure suggesting limited metabolism and small distribution volumes for both drugs in the lungs. Simultaneous dynamic measurements of cerebral blood flow and algesimetry lagged behind both the arterial and sagittal sinus blood concentrations. The changes in cerebral blood flow were best described by a previously published a dynamic model that incorporated long half-lives for drug dissociation from the benzodiazepine receptor (13.3 and 5.5 min for midazolam and diazepam...

The pharmacokinetics pharmacodynamics safety and tolerability of NN2211 a new long-acting GLP-1 derivative in healthy men

Agerso, H.; Jensen, L.; Elbrond, B.; Rolan, P.; Zdravkovic, M.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em //2002 EN
Relevância na Pesquisa
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AIMS/HYPOTHESIS: Glucagon-like peptide-1 (GLP-1), a polypeptide hormone secreted by the l-cells in the gastrointestinal tract, has shown promising effects as a new treatment modality for patients with Type II (non-insulin-dependent) diabetes mellitus. However, the pharmacokinetic profile of native GLP-1 with a rapid elimination has limited its therapeutic potential. NN2211 is a fatty acid derivative of GLP-1, which pre-clinically has shown a protracted pharmacokinetic profile, while maintaining its biological activity. This study aimed to investigate the safety, tolerability, pharmacokinetics and pharmacodynamics of NN2211 in healthy male subjects following seven days treatment. METHODS: In a double-blind, randomized, dose escalation, placebo controlled study, healthy male subjects were enrolled at five consecutive dose levels of NN2211 (1.25, 5.0, 7.5, 10.0, 12.5 μg/kg). Six subjects were allocated at random at each dose level to active or placebo treatment with a ratio of 2:1. Dosing with NN2211 was performed on day 1, and days 5–11. The 84-h pharmacokinetics and 24-h glucose and insulin profiles were assessed on day 1 and day 11. Results: Following s. c. administration the half-life of NN2211 was found to be 12.6 ± 1.1 h, with a subsequent accumulation index after a daily dose for seven days of 1.4–1.5. There were dose-proportional increases in exposure (AUC and Cmax) with increasing doses. Overall...

The stereoselective pharmacokinetics of the enantiomers of perhexiline in poor and extensive metabolisers of the cytochrome P450 2D6.

Davies, Benjamin James Lloyd
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2008
Relevância na Pesquisa
36.76767%
Perhexiline maleate was first introduced for the prophylaxis of exertional angina in the 1970s but reports of adverse reactions, including potentially fatal hepatotoxicity, increasingly restricted its application. By 1988 Australia and New Zealand were the only countries permitting its use, limited to the treatment of refractory angina pectoris conditional upon the therapeutic monitoring of patients, due to recognition of the concentration dependent nature of its efficacy and toxicity. An understanding of the extreme interindividual variability in the pharmacokinetics of perhexiline due to metabolism by the polymorphic Cytochrome P450 2D6 (CYP2D6) has prompted a recent resurgence of its use in Australasia and Europe. Perhexiline is a chiral molecule and is administered as a racemic mixture. Prior to the publication of the papers that are the topic of this thesis the characterisation of the clinical pharmacology of the enantiomers of perhexiline had been limited to one pharmacokinetic study that suggested that the (+) enantiomer of perhexiline may display a smaller polymorphic effect in its metabolism than its optical antipode. The four publications that comprise this thesis describe a comprehensive investigation of the pharmacokinetics and metabolism of the enantiomers of perhexiline in extensive and poor metabolisers (EM and PM...

Untersuchung der Nikotinkinetik in Abhängigkeit von biologischen und rauchanamnestischen Variablen; Examination of nicotine pharmacokinetics dependent on biological and anamnestic smoking-related variables

Bannier, Oliver
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
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Die Tabakabhängigkeit stellt nach wie vor das bedeutendste einzelne Gesundheitsrisiko und die führende Ursache frühzeitiger Sterblichkeit dar (WHO-Kollaborationszentrum für Tabakkontrolle im Deutschen Krebsforschungszentrum 2006). Um die Tabakabhängigkeit besser behandeln zu können, ist es von großer Bedeutung, ein umfassendes Wissen über die Ursachen der Tabakabhängigkeit und die Nikotinkinetik zu erlangen. Fragestellung: Ziel dieser Studie war die Untersuchung möglicher biologischer und rauchanamnestischer Einflussfaktoren auf den Nikotinmetabolismus. Dafür wurden 28 Raucher (22w/6m) hinsichtlich Alter, Geschlecht, Gewicht, Zigaretten pro Tag, Rauchdauer, FTND-Gesamtwert und CYP2A6-Genotyp untersucht. In einer Nebenfragestellung wurde geprüft, wie sich das mittels Questionnaire on Smoking Urges (QSU) und visueller Analogskala (VACS) gemessene subjektive Rauchverlangen (Craving) über den Zeitraum der vierstündigen Nikotinkinetikstudie veränderte. Methoden: 28 Studienteilnehmern wurden, nach mindestens achtstündiger Nikotinkarenz, 8 mg Nikotin in Form von Sublingualtabletten verabreicht, um die individuelle Nikotinkinetik untersuchen zu können. Den Probanden wurde insgesamt zwölfmal Blut entnommen, um den Verlauf des Nikotin- bzw. Cotininmetabolismus bestimmen zu können. Um das Craving zu dokumentieren wurden die Probanden gebeten...

The intravenous pharmacokinetics of diminazene in healthy dogs

Naidoo,V; Mulders,M S G; Swan,G E
Fonte: Journal of the South African Veterinary Association Publicador: Journal of the South African Veterinary Association
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
36.76767%
Diminazene remains one of South Africa's most commonly used antiprotozoal agents for the management of babesiosis in dogs . Although the drug has been on the market for over 40 years, its intravenous pharmacokinetics are poorly known. To better understand the pharmacokinetics of the drug Berenil®, it was reconstituted in sterile water and administered intravenously to 6 adult German shepherd dogs. All 6 dogs demonstrated the previously described secondary peak in the plasma concentration versus time profile. The plasma pharmacokinetics for diminazene are described by both non-compartmental and compartmental models. From non-compartmental analysis, the area under curve to the last sample point (AUQast), clearance (CL) and volume of distribution (Vz) were 4.65 ± 1.95 ng/ml/h, 0.77 ± 0.18 l/kg/h and2.28 ± 0.60 l/kg respectively. For compartmental modelling, the plasma concentrations were fitted to both a 2-compartmental open model and a recirculatory enterohepatic model. From the recirculation model, the rate of release and re-entry into the central compartment varied markedly with the rate of release from the gall bladder (Ttom) being estimated at 27 ± 20.90 h. Once released, drug re-entry into the central compartment was variable at 9.70 ± 5.48 h. With normal biliary excretion time being about 2 h...