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This study aimed to characterize the population pharmacokinetics of sertraline in Mexican patients with psychiatric and substance use disorders. Fifty-nine patients (13 to 76 years old) treated with doses of sertraline between 12.5 and 100 mg/day were included. Plasma sertraline concentrations were determined in blood samples and five of the main substances of abuse were determined by rapid tests in urine samples. Demographic, clinical, and pharmacogenetic factors were also evaluated. Population pharmacokinetic analysis was performed using NONMEM software with first-order conditional estimation method. A one-compartment model with proportional residual error adequately described the sertraline concentrations versus time. CYP2D6*2 polymorphism and CYP2C19 phenotypes significantly influenced sertraline clearance, which had a population mean value of 66 L/h in the final model. The absorption constant and volume of distribution were fixed at 0.855 1/h and 20.2 L/kg, respectively. The model explained 11.3% of the interindividual variability in sertraline clearance. The presence of the CYP2D6*2 polymorphism caused a 23.1% decrease in sertraline clearance, whereas patients with intermediate and poor phenotype of CYP2C19 showed 19.06% and 48.26% decreases in sertraline clearance, respectively. The model was internally validated by bootstrap and visual predictive check. Finally, stochastic simulations were performed to propose dosing regimens to achieve therapeutic levels that contribute to improving treatment response.
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Citocromo P-450 CYP2C19 , Citocromo P-450 CYP2D6 , Sertralina , Transtornos Relacionados ao Uso de Substâncias , Humanos , Sertralina/farmacocinética , Sertralina/uso terapêutico , Sertralina/sangue , Masculino , Pessoa de Meia-Idade , Adulto , Feminino , Idoso , Citocromo P-450 CYP2D6/genética , Citocromo P-450 CYP2D6/metabolismo , Adolescente , Citocromo P-450 CYP2C19/genética , Citocromo P-450 CYP2C19/metabolismo , Transtornos Relacionados ao Uso de Substâncias/sangue , Adulto Jovem , Modelos Biológicos , Transtornos Mentais/tratamento farmacológico , Polimorfismo Genético , Inibidores Seletivos de Recaptação de Serotonina/farmacocinética , Inibidores Seletivos de Recaptação de Serotonina/sangue , Inibidores Seletivos de Recaptação de Serotonina/uso terapêutico , México , Antidepressivos/farmacocinética , Antidepressivos/uso terapêutico , Antidepressivos/sangueRESUMO
The present study aims to characterise the pharmacokinetics of rifampicin (RIF) in tuberculosis (TB) patients with and without HIV co-infection, considering the formation of 25-O-desacetylrifampicin (desRIF). It is hypothesised that the metabolite formation, HIV co-infection and drug formulation may further explain the interindividual variation in the exposure to RIF. Pharmacokinetic, clinical, and demographic data from TB patients with (TB-HIV+ group; n = 18) or without HIV (TB-HIV− group; n = 15) who were receiving RIF as part of a four-drug fixed-dose combination (FDC) regimen (RIF, isoniazid, pyrazinamide, and ethambutol) were analysed, along with the published literature data on the relative bioavailability of different formulations. A population pharmacokinetic model, including the formation of desRIF, was developed and compared to a model based solely on the parent drug. HIV co-infection does not alter the plasma exposure to RIF and the desRIF formation does not contribute to the observed variability in the RIF disposition. The relative bioavailability and RIF plasma exposure were significantly lower than previously reported for the standard regimen with FDC tablets. Furthermore, participants weighting less than 50 kg do not reach the same RIF plasma exposure as compared to those weighting >50 kg. In conclusion, as no covariate was identified other than body weight on CL/F and Vd/F, low systemic exposure to RIF is likely to be caused by the low bioavailability of the formulation.
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In individualized therapy, the Bayesian approach integrated with population pharmacokinetic models (PopPK) for predictions together with therapeutic drug monitoring (TDM) to maintain adequate objectives is useful to maximize the efficacy and minimize the probability of toxicity of vancomycin in critically ill patients. Although there are limitations to implementation, model-informed precision dosing (MIPD) is an approach to integrate these elements, which has the potential to optimize the TDM process and maximize the success of antibacterial therapy. The objective of this work was to present an app for individualized therapy and perform a validation of the implemented vancomycin PopPK models. A pragmatic approach was used for selecting the models of Llopis, Goti and Revilla for developing a Shiny app with R. Through ordinary differential equation (ODE)-based mixed effects models from the mlxR package, the app simulates the concentrations' behavior, estimates whether the model was simulated without variability and predicts whether the model was simulated with variability. Moreover, we evaluated the predictive performance with retrospective trough concentration data from patients admitted to the adult critical care unit. Although there were no significant differences in the performance of the estimates, the Llopis model showed better accuracy (mean 80.88%; SD 46.5%); however, it had greater bias (mean -34.47%, SD 63.38%) compared to the Revilla et al. (mean 10.61%, SD 66.37%) and Goti et al. (mean of 13.54%, SD 64.93%) models. With respect to the RMSE (root mean square error), the Llopis (mean of 10.69 mg/L, SD 12.23 mg/L) and Revilla models (mean of 10.65 mg/L, SD 12.81 mg/L) were comparable, and the lowest RMSE was found in the Goti model (mean 9.06 mg/L, SD 9 mg/L). Regarding the predictions, this behavior did not change, and the results varied relatively little. Although our results are satisfactory, the predictive performance in recent studies with vancomycin is heterogeneous, and although these three models have proven to be useful for clinical application, further research and adaptation of PopPK models is required, as well as implementation in the clinical practice of MIPD and TDM in real time.
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Meropenem pharmacokinetics in neonates exhibits large interindividual variability due to developmental changes occurring during the first month of life. The objective was to characterize meropenem pharmacokinetics through a population approach to determine effective dosing recommendations in neonates with severe nosocomial infections. Three blood samples from forty neonates were obtained once steady-state blood levels were achieved and plasma concentrations were determined with a validated chromatographic method. Data were used to develop and validate the one-compartment with first-order elimination population pharmacokinetic model obtained by non-linear mixed effect modeling. The final model was Clearance (L/h) = 2.23â¯×â¯Creatinine Clearance (L/h) and Volume of distribution(L) = 6.06â¯×â¯Body Surface Area(m2)â¯×â¯(1 + 0.60 if Fluticasone comedication). Doses should be adjusted based on said covariates to increase the likelihood of achieving therapeutic targets. This model explains 12.9% of the interindividual variability for meropenem clearance and 19.1% for volume of distribution. Stochastic simulations to establish initial dosing regimens to maximize the time above the MIC showed that the mean probabilities to achieve the PK/PD target (PTA) for microorganisms with a MIC of 2 and 8 µg/mL were 0.8 and 0.7 following i.v. bolus of 250 and 500 mg/m2/dose q8h, respectively. Meropenem extended 4h infusion would improve PTA in neonates with augmented creatinine clearance.
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Infecção Hospitalar , Antibacterianos/uso terapêutico , Infecção Hospitalar/tratamento farmacológico , Humanos , Recém-Nascido , Meropeném , Testes de Sensibilidade Microbiana , Método de Monte CarloRESUMO
AIMS: Gabapentin (GBP) is widely used to treat neuropathic pain, including diabetic neuropathic pain. Our objective was to evaluate the role of diabetes and glycaemic control on GBP population pharmacokinetics. METHODS: A clinical trial was conducted in patients with neuropathic pain (n = 29) due to type 2 diabetes (n = 19) or lumbar/cervical disc herniation (n = 10). All participants were treated with a single oral dose GBP. Blood was sampled up to 24 hours after GBP administration. Data were analysed with a population approach using the stochastic approximation expectation maximization algorithm. Weight, body mass index, sex, biomarkers of renal function and diabetes, and genotypes for the main genetic polymorphisms of SLC22A2 (rs316019) and SLC22A4 (rs1050152), the genes encoding the transporters for organic cations OCT2 and OCTN1, were tested as potential covariates. RESULTS: GBP drug disposition was described by a 1-compartment model with lag-time, first-order absorption and linear elimination. The total clearance was dependent on estimated glomerular filtration rate. Population estimates (between-subject variability in percentage) for lag time, first-order absorption rate, apparent volume of distribution and total clearance were 0.316 h (10.6%), 1.12 h-1 (10.7%), 140 L (7.7%) and 14.7 L/h (6.97%), respectively. No significant association was observed with hyperglycaemia, glycated haemoglobin, diabetes diagnosis, age, sex, weight, body mass index, SLC22A2 or SLC22A4 genotypes. CONCLUSION: This population pharmacokinetics model accurately estimated GBP concentrations in patients with neuropathic pain, using estimated glomerular filtrationrate as a covariate for total clearance. The distribution and excretion processes of GBP were not affected by hyperglycaemia or diabetes.
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Ácidos Cicloexanocarboxílicos , Diabetes Mellitus Tipo 2 , Neuralgia , Aminas , Analgésicos/uso terapêutico , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Gabapentina , Controle Glicêmico , Humanos , Neuralgia/tratamento farmacológicoRESUMO
BACKGROUND: The aim of this analysis was to characterize the pharmacokinetics (PK) of sublingual buprenorphine (BUP) and its metabolites (buprenorphine glucuronide; BUP-g, norbuprenorphine; Nor-BUP, and norbuprenorphine glucuronide; Nor-BUP-g) in opioid use disorder (OUD) patients in Puerto Rico (PR) as a first step of evidence-based BUP dosing strategies in this population. METHODS: BUP and metabolites concentrations were measured from 0 to 8 h after the administration of sublingual buprenorphine/naloxone films in 12 stable OUD subjects. RESULTS: PK non-compartmental characteristics showed considerable variability in parameters between the subjects over the 8-h sampling time (tmax = 1.5 ± 0.7 h, Co = 1.6 ± 1.4 ng/mL, Cmax= 7.1 ± 6 ng/mL, and AUC0-8h = 26.8 ± 17.8 h·ng/mL). Subjects had a significantly higher tendency towards CYP-mediated N-demethylation, with the AUC0-8h ratios of the molar concentrations of [Nor-BUP + Nor-BUP-g] to BUP being (3.4 ± 1.9) significantly higher compared with BUP-g to BUP (0.19 ± 0.2). A two-compartment population-PK model with linear absorption (ka = 2.54 h-1), distribution (k12= 2.34 h-1, k14 = 1.29 h-1), metabolism (k24 = 1.28 × 10-1 h-1, k23 = 6.43 × 10-2 h-1, k35 = 1.23 × 10-1 h-1, k45 = 8.73 × 10-1 h-1), and elimination (k30 = 3.81 × 10-3 h-1, k50 = 1.27 × 10-1 h-1) adequately described the time-course of BUP and its metabolites, which has been externally validated using published data. CONCLUSIONS: Although limited in sampling time and number of recruited subjects, this study presents specific BUP PK characteristics that evidenced the need for additional PK studies and subsequent modeling of the data for the development of evidence-based dosing approaches in Puerto Rico.
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Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease characterized by an abnormal activation of lung epithelium and fibroblasts, as well as an excessive accumulation of extracellular matrix. Pirfenidone was introduced as a therapeutic option for IPF and chronic hypersensitive pneumonitis (cHP), a related disease. However, high plasma concentrations, which can be achieved even at recommended doses, are frequently associated with adverse events. Hence, an extended release formulation (XP), yielding lower peak plasma concentrations, has been developed. The aim of this study was to compare the pharmacokinetic properties of XP with those of the immediate (IR) formulation in patients with IPF or cHP. Data were analyzed using two pharmacokinetic approaches, conventional non compartmental analysis and a population analysis using the nonlinear mixed effects model technique. Results observed with both approaches were consistent. Drug exposure was similar with both formulations. However, XP exhibited less concentration fluctuations and a longer mean resident time. These results suggest that XP could be a feasible option to reduce adverse events associated to pirfenidone elevated concentrations. Nevertheless, efficacy studies are required to fully document the therapeutic potential of XP.
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The aim of this study was to develop a population pharmacokinetic model of rifampicin (RMP) in Mexican patients with tuberculosis (TB) to evaluate the influence of anthropometric and clinical covariates, as well as genotypic variants associated with MDR1 and OATP1B1 transporters. A prospective study approved by Research Ethics Committee was performed at Hospital Central in San Luis Potosí, Mexico. TB patients under DOTS scheme and who signed informed consent were consecutively included. Anthropometric and clinical information was retrieved from medical records. Single nucleotide polymorphisms in MDR1 (C3435T) and SLCO1B1 (A388G and T521C) genes were evaluated. RMP plasma concentrations and time data were assessed with NONMEM software. A total of 71 Mexican TB patients from 18 to 72 years old were included for RMP quantification from 0.3 to 12 h after dose; 329 and 97 plasma concentrations were available for model development and validation, respectively. Sequential process includes a typical lag time of 0.25 h prior to absorption start with a Ka of 1.24 h-1 and a zero-order absorption of 0.62 h to characterize the gradual increase in RMP plasma concentrations. Final model includes total body weight in volume of distribution (0.7 L/kg, CV = 26.8%) and a total clearance of 5.96 L/h (CV = 38.5%). Bioavailability was modified according to time under treatment and generic formulation administration. In conclusion, a population pharmacokinetic model was developed to describe the variability in RMP plasma concentrations in Mexican TB patients. Genetic variants evaluated did not showed significant influence on pharmacokinetic parameters. Final model will allow therapeutic drug monitoring at early stages.
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Antibióticos Antituberculose/farmacocinética , Transportador 1 de Ânion Orgânico Específico do Fígado/genética , Modelos Biológicos , Variantes Farmacogenômicos , Polimorfismo de Nucleotídeo Único , Rifampina/farmacocinética , Tuberculose/tratamento farmacológico , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Adolescente , Adulto , Idoso , Antibióticos Antituberculose/administração & dosagem , Teorema de Bayes , Disponibilidade Biológica , Esquema de Medicação , Cálculos da Dosagem de Medicamento , Feminino , Humanos , Transportador 1 de Ânion Orgânico Específico do Fígado/metabolismo , Masculino , México/epidemiologia , Pessoa de Meia-Idade , Farmacogenética , Estudos Prospectivos , Reprodutibilidade dos Testes , Rifampina/administração & dosagem , Resultado do Tratamento , Tuberculose/diagnóstico , Tuberculose/etnologia , Tuberculose/microbiologia , Adulto JovemRESUMO
Background The standardized doses of isoniazid in therapy against tuberculosis are determined based on total body weight, without considering genetic polymorphisms of the metabolic enzyme N-acetyltransferase-2 that contribute to the wide pharmacokinetic variability of isoniazid. Objective The aim of this work was to build a population pharmacokinetic model of isoniazid in Mexican patients with tuberculosis to characterize typical estimates of pharmacokinetics, as well as inter-individual and residual variability of isoniazid considering the genetic factors associated with the N-acetyltransferase-2 enzyme. Setting A prospective study was conducted at the Department of Internal Medicine in Hospital Central, San Luis Potosí, México. Methods Plasma concentrations of isoniazid were measured by high performance liquid chromatography. The acetylator phenotype was predicted through single nucleotide polymorphisms in the N-acetyltransferase-2 gene. Genetic, anthropometric and clinical covariates were used to develop a pharmacokinetic model. Main outcome measure Isoniazid plasma concentration. Results A total of 69 patients with tuberculosis were included. Blood samples were drawn from 20 min to 12 h post dose to determinate the isoniazid plasma concentration. Typical pharmacokinetics parameters were characterized through two-compartment open model with first-order absorption and linear elimination. Clearance was different for each predicted N-acetyltransferase-2 phenotype being 11.4, 19.2 and 27.4 L/h for slow, intermediate and rapid acetylators, respectively. Central volume of distribution was determined as 1.5 * body mass index (L). Through the application of the model, external validation was performed and initial dose regimen of isoniazid is proposed based on stochastic simulations. Conclusion A validated population pharmacokinetic model of isoniazid was developed in Mexican patients with tuberculosis. Through the application of the final model, initial dose recommendations were provided considering body mass index and N-acetyltransferase-2 phenotype.
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Antituberculosos/administração & dosagem , Isoniazida/administração & dosagem , Modelos Biológicos , Tuberculose/tratamento farmacológico , Adolescente , Adulto , Idoso , Antituberculosos/farmacocinética , Arilamina N-Acetiltransferase/genética , Índice de Massa Corporal , Cromatografia Líquida de Alta Pressão , Relação Dose-Resposta a Droga , Feminino , Humanos , Isoniazida/farmacocinética , Masculino , México , Pessoa de Meia-Idade , Fenótipo , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , Adulto JovemRESUMO
BACKGROUND: Mycophenolic acid (MPA) is an effective oral immunosuppressive drug used to treat lupus nephritis (LN), which exhibits large pharmacokinetic variability. This study aimed to characterize MPA pharmacokinetic behaviour in Mexican LN patients and to develop a population pharmacokinetic model which identified factors that influence MPA pharmacokinetic variability. METHODS: Blood samples from LN patients treated with mycophenolate mofetil (MMF) were collected pre dose and up to six hours post dose. MPA concentrations were determined by a validated ultra-performance liquid chromatography tandem mass spectrometry technique. Patients were genotyped for polymorphisms in enzymes (UGT1A8, 1A9 and 2B7) and transporters (ABCC2 and SLCO1B3). The anthropometric, clinical, genetic and co-medication characteristics of each patient were considered as potential covariates to explain the variability. RESULTS: A total of 294 MPA concentrations from 40 LN patients were included in the development of the model. The data were analysed using NONMEM software and were best described by a two-compartment linear model. MPA CL, Vc, Vp, Ka and Q were 15.4 L/h, 22.86 L, 768 L, 1.28 h-1 and 20.3 L/h, respectively. Creatinine clearance and prednisone co-administration proved to have influence on clearance, while body weight influenced Vc. The model was internally validated, proving to be stable. MMF dosing guidelines were obtained through stochastic simulations performed with the final model. CONCLUSIONS: This is the first MPA population pharmacokinetic model to have found that co-administration of prednisone results in a considerable increase on clearance. Therefore, this and the other covariates should be taken into account when prescribing MMF in order to optimize the immunosuppressant therapy in patients with LN.
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Imunossupressores/farmacocinética , Nefrite Lúpica/tratamento farmacológico , Modelos Biológicos , Ácido Micofenólico/farmacocinética , Prednisona/farmacocinética , Adolescente , Adulto , Quimioterapia Combinada , Feminino , Humanos , Imunossupressores/administração & dosagem , Modelos Lineares , Nefrite Lúpica/sangue , Masculino , México , Pessoa de Meia-Idade , Proteína 2 Associada à Farmacorresistência Múltipla , Ácido Micofenólico/administração & dosagem , Prednisona/administração & dosagem , Software , Adulto JovemRESUMO
Dose individualization is essential in epilepsy treatment, especially in antiepileptic drugs that present high interindividual variability such as lamotrigine. We aimed an observational study to develop a population pharmacokinetic model for quantitative evaluation of the factors that influence lamotrigine pharmacokinetics in Mexican adults with epilepsy. Patients on stable treatment with lamotrigine therapy were included, plasma concentrations were analyzed by a high-performance liquid chromatography method and UGT2B7-161C > T polymorphism was determined. The data were analyzed by NONMEM® 7.3, model validation was performed using bootstrap approach and visual predictive check. Finally, stochastic simulations were carried out to propose dosage regimens. A total of 73 lamotrigine plasma concentrations from 2 h after last dose and up to 0.5 h prior to next administration were fitted to a one-compartment open model. The final population pharmacokinetic model for lamotrigine indicates that concomitant treatment with valproic acid and carbamazepine should be considered to individualize epilepsy treatment with this drug. Based on this model, we proposed dosage regimens to achieve trough lamotrigine concentrations within reference interval (2.5-15 mg/L). These results provide clinical useful data to give more rational anticonvulsant therapy in our population.
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Anticonvulsivantes , Epilepsia , Adulto , Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Humanos , Lamotrigina/uso terapêutico , Triazinas/uso terapêutico , Ácido ValproicoRESUMO
Mycophenolate mofetil (MMF) is typically used in combination with prednisone and tacrolimus to avoid graft rejection in kidney transplant patients. The aim of this study was to develop and validate a population pharmacokinetic model of mycophenolic acid (MPA) in kidney transplant patients to investigate the influence of clinical and genetic covariates and to propose a dosage regimen based on the final model. Adult kidney transplant patients (>18 years old) receiving combination of MMF, prednisone and tacrolimus regimen were included. The population pharmacokinetic model was built using a two-compartment model and First Order Conditional Estimation method with Interaction (FOCEI though NONMEM v.7.4.). A total of 343 MPA concentrations at steady state from 77 kidney transplant patients were included in the analysis. MPA CL/F, V1/F, Q/F, V2/F, and Ka were 12.4 L/h, 45.6 L, 29.9 L/h, 658 L, and 1.67 h-1, respectively. It was found that CL/F increases with serum creatinine and uric acid levels and V1/F is modified by blood urea nitrogen and the UGT1A9 genotype. In the final model the interindividual variabilities associated to CL/F and V1/F were 56.5% and 105.8%, respectively. The residual variability was 41.8%. Evaluation by bootstrapping showed that the final model was stable. The predictive performance was evaluated by goodness-of-fit plots and visual predictive check. Dosage regimens for MMF were proposed based on the final model and would be appropriate for a prospective evaluation. In conclusion, it was built a population pharmacokinetic model for MPA in kidney transplant patients, which include clinical and genetic covariates.
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Imunossupressores/farmacocinética , Transplante de Rim , Modelos Biológicos , Ácido Micofenólico/farmacocinética , Adolescente , Adulto , Idoso , Anti-Inflamatórios/uso terapêutico , Nitrogênio da Ureia Sanguínea , Creatinina/sangue , Interações Medicamentosas , Quimioterapia Combinada , Feminino , Glucuronosiltransferase/genética , Humanos , Imunossupressores/sangue , Imunossupressores/uso terapêutico , Masculino , Pessoa de Meia-Idade , Ácido Micofenólico/sangue , Ácido Micofenólico/uso terapêutico , Prednisona/uso terapêutico , Tacrolimo/uso terapêutico , UDP-Glucuronosiltransferase 1A , Ácido Úrico/sangue , Adulto JovemRESUMO
The aim of this work was to evaluate the pharmacokinetics of amikacin in Mexican patients with different renal functions receiving once-daily dosing regimens and the influence of clinical and demographical covariates that may influence the optimization of this antibiotic. A prospective study was performed in a total of 63 patients with at least one determination of amikacin plasma concentration. Population pharmacokinetic (PK) parameters were estimated by nonlinear mixed-effects modeling; validations were performed for dosing recommendation purposes based on PK/pharmacodynamic simulations. The concentration-versus-time data were best described by a one-compartment open model with proportional interindividual variability associated with amikacin clearance (CL) and volume of distribution (V); residual error followed a homoscedastic trend. Creatinine clearance (CLCR) and ideal body weight (IBW) demonstrated significant influence on amikacin CL and V, respectively. The final model [CL (liters/h) = 7.1 × (CLCR/130)0.84 and V (liters) = 20.3 × (IBW/68)2.9] showed a mean prediction error of 0.11 mg/liter (95% confidence interval, -3.34, 3.55) in the validation performed in a different group of patients with similar characteristics. There is a wide variability in amikacin PK parameters in Mexican patients. This leads to inadequate dosing regimens, especially in patients with augmented renal clearance (CLCR of >130 ml/min). Optimization based on the final population PK model in Mexican patients may be useful, since reliability and clinical applicability have been demonstrated in this study.
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Amicacina/sangue , Amicacina/farmacocinética , Antibacterianos/farmacocinética , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Testes de Função Renal , Adolescente , Adulto , Idoso , Amicacina/uso terapêutico , Antibacterianos/uso terapêutico , Vias de Eliminação de Fármacos/fisiologia , Feminino , Bactérias Gram-Negativas/efeitos dos fármacos , Humanos , Rim/fisiologia , Masculino , México , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto JovemRESUMO
PURPOSE: To develop and validate a population pharmacokinetic model of Methotrexate (MTX) in Mexican children with acute lymphoblastic leukemia (ALL) for the design of personalized dosage regimens based on the anthropometric and physiological characteristics of each patient. METHODS: A prospective study was developed in 50 children (1-15 years old) with ALL diagnosis attended at Pediatric Hemato-Oncology Service from Hospital Central "Dr. Ignacio Morones Prieto" and under treatment with high doses of MTX administered in 24-h continuous intravenous infusion. Plasma concentrations of MTX were determined in blood samples collected at 24, 36, 42 or 48 h post-infusion, by means of the CMIA immunoassay. The development of the population pharmacokinetic model was performed using the NONMEM® software evaluating the covariates that influence in clearance (CL), intercompartmental clearance (Q), central (Vc) and peripheral (Vp) volume of distribution of MTX. RESULTS: A two-compartment open model was selected to describe concentration-time data and body surface area (BSA) was the covariate that influences on MTX total CL. The population pharmacokinetic model obtained was: CL (L/h) = 6.5 × BSA0.62, Vc (L) = 0.36 × Weight, Q (L/h) = 0.41 and Vp (L) = 3.2. Internal validation was performed by bootstrap and visual predictive check. Predictive performance of final model was evaluated by external validation in a different group of patients. Initial MTX dosing regimens were established by stochastic simulation with final population pharmacokinetic model. CONCLUSIONS: The establishment of MTX dosing criteria in children with ALL should be adjusted based on the BSA of each patient to optimize oncological therapy and reduce the development of adverse effects. Therapeutic drug monitoring is an essential tool to individualize MTX doses to reduce toxicity and improve patients' outcomes.
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Antimetabólitos Antineoplásicos/farmacocinética , Antimetabólitos Antineoplásicos/uso terapêutico , Metotrexato/farmacocinética , Metotrexato/uso terapêutico , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , Adolescente , Superfície Corporal , Criança , Pré-Escolar , Monitoramento de Medicamentos , Feminino , Seguimentos , Humanos , Lactente , Masculino , México/epidemiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/epidemiologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Prognóstico , Estudos Prospectivos , Distribuição TecidualRESUMO
INTRODUCTION: Amikacin is commonly used in patients with pediatric cystic fibrosis (CF) for the treatment of pulmonary exacerbations. Amikacin efficacy is related to maximum plasma concentration/minimum inhibitory concentration (Cmax/MIC) ratio >8. Pharmacokinetic data in patients with pediatric CF are scarce. The aim of this study was to develop a population pharmacokinetic (PopPK) model describing amikacin disposition in patients with pediatric CF. METHODS: CF patients under 18 years of age with pulmonary exacerbation who received amikacin were enrolled. Patients received different amikacin regimens (30 mg-1 kg-1 day-1 every 8, 12, or 24 hours) depending on the patient's status and hospital protocols. Amikacin serum levels were obtained for therapeutic drug monitoring. PopPK model was developed using MONOLIX Suite-2018R1 (Lixoft). RESULTS: A total of 39 patients (114 amikacin concentrations) were included in this study. Population estimates for the elimination rate constant (k) and the volume of distribution (V) were 0.541 hours-1 and 0.451 L/kg, respectively. Between-subject and between-occasion variability were 53% and 16.5% for k and 31% and 22% for V, respectively. Bodyweight was a significant covariate associated with V. Based on simulations, almost 70% of the patients receiving 30 mg-1 kg-1 day-1 every 24 hours would achieve a Cmax/MIC ratio >8 which is an appropriate therapeutic goal while no patient in the other two groups (Q8 and Q12) would achieve that objective. CONCLUSIONS: The regimen of 30 mg-1 kg-1 day-1 every 24 hours more adequately fulfilled the therapeutic target for amikacin. Although all our patients had good clinical results and a good adverse-events profile, further studies are necessary to redefine the optimal treatment strategy.
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Amicacina/farmacocinética , Antibacterianos/farmacocinética , Fibrose Cística/metabolismo , Modelos Biológicos , Adolescente , Amicacina/sangue , Amicacina/uso terapêutico , Antibacterianos/sangue , Antibacterianos/uso terapêutico , Peso Corporal , Criança , Pré-Escolar , Fibrose Cística/sangue , Fibrose Cística/tratamento farmacológico , Feminino , Infecções por Bactérias Gram-Negativas/sangue , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/metabolismo , Humanos , Lactente , Masculino , Testes de Sensibilidade MicrobianaRESUMO
The aim of this study was to perform a population pharmacokinetic analysis of tacrolimus in Mexican adult kidney transplant patients to analyse the influence of clinical and genetic covariates to propose a dosage regimen. Kidney transplant patients (>18 years old) receiving oral tacrolimus treatment were included in the current study. The population pharmacokinetic model was built using a one-compartment model and the First Order Conditional Estimation method with Interaction (FOCEI via NONMEM v.7.3.). A total of 600 tacrolimus trough blood concentrations from 52 kidney transplant patients were analysed. Tacrolimus clearances were 26, 18.8 and 12.3 L/h, for patients with genetic polymorphisms CYP3A5*1*1, *1*3 and *3*3, respectively. The influence of haematocrit was inversely related to tacrolimus clearance, following an allometric power function. Total volume of distribution was 604 L. Interindividual variability associated with tacrolimus clearance and distribution volume for the final model was 33 and 63%, respectively, with a residual error of 2.5 ng/mL. Relative bioavailability was calculated between generic formulations A (0.53) and B (1) of tacrolimus. Internal validation was performed through bootstrap analysis to evaluate the stability of the final model; external validation was performed in a new group of patients (n = 13) to estimate residual errors on basic (57.8%) and final (34.8%) models. Finally, stochastic simulations were performed to propose a dosage regimen based on haematocrit, CYP3A5 genotype and generic formulation of tacrolimus. A stable and predictive population pharmacokinetic model of tacrolimus was developed for Mexican adult kidney transplant patients; additionally, the proposed dosage regimen of tacrolimus should be prospectively validated.
Assuntos
Transplante de Rim , Tacrolimo/farmacocinética , Administração Oral , Adulto , Idoso , Disponibilidade Biológica , Biomarcadores Farmacológicos/análise , Citocromo P-450 CYP3A/genética , Citocromo P-450 CYP3A/metabolismo , Feminino , Genótipo , Humanos , Imunossupressores/administração & dosagem , Imunossupressores/farmacocinética , Masculino , México , Pessoa de Meia-Idade , Modelos Biológicos , Farmacogenética , Polimorfismo Genético , Tacrolimo/administração & dosagem , Adulto JovemRESUMO
Gabapentin (GAB) is eliminated unchanged in urine, and organic cation transporters (OCT2 and OCTN1) have been shown to play a role in GAB renal excretion. This prospective clinical study aimed to evaluate the genetic polymorphisms effect on GAB pharmacokinetic (PK) variability using a population pharmacokinetic approach. Data were collected from 53 patients with chronic pain receiving multiple doses of GAB. Patients were genotyped for SLC22A2 c.808G>T and SLC22A4 c.1507C>T polymorphisms. Both polymorphisms' distribution followed the Hardy-Weinberg equilibrium. An one-compartment model with first-order absorption and linear elimination best described the data. The absorption rate constant, volume of distribution, and clearance estimated were 0.44 h-1 , 86 L, and 17.3 × (estimated glomerular filtration ratio/89.58)1.04 L/h, respectively. The genetic polymorphism SLC22A4 c.1507C>T did not have a significant influence on GAB absorption, distribution or elimination. Due to the low minor allelic frequency of SLC22A2 c.808G>T, further studies require higher number of participants to confirm its effect on GAB renal elimination. In conclusion, GAB clinical pharmacokinetics are strongly influenced by renal function and absorption process, but not by the OCTN1 (SLC22A4 c.1507C>T) polymorphism.
Assuntos
Dor Crônica/tratamento farmacológico , Dor Crônica/genética , Gabapentina/farmacocinética , Proteínas de Transporte de Cátions Orgânicos/genética , Transportador 2 de Cátion Orgânico/genética , Adulto , Idoso , Analgésicos/farmacocinética , Dor Crônica/metabolismo , Feminino , Frequência do Gene , Humanos , Masculino , Pessoa de Meia-Idade , Proteínas de Transporte de Cátions Orgânicos/metabolismo , Transportador 2 de Cátion Orgânico/metabolismo , Farmacogenética , Polimorfismo de Nucleotídeo Único , Estudos Prospectivos , SimportadoresRESUMO
PURPOSE: The main objective was to quantify any potential differences in pharmacokinetic (PK) parameters (AUC and Cmax) between RTXM83, a proposed rituximab biosimilar, and its reference product, using a population PK model approach. METHODS: Rituximab PK and PD data were obtained from a randomized, double-blind, phase III clinical study (RTXM83-AC-01-11) in patients with diffuse large B-cell lymphoma (DLBCL) that received 375 mg/m2 intravenous RTXM83 or its reference product with CHOP regimen, every 3 weeks, for six cycles. Rituximab levels were quantified by Meso Scale Discovery assay. PK analysis was performed using NONMEM 7.3.0. The effect of disease and patient covariates on RXTM83 PK was investigated. Model was evaluated using visual predictive check and non-parametric bootstrap. RESULTS: In total, 251 DLBCL patients (127 and 124 in RXTM83-CHOP and rituximab-CHOP arms, respectively) and 5341 serum concentrations (2703 for RXTM83 and 2638 for rituximab, respectively) were available for the population PK analysis. The volume of distribution of the central compartment (V1) and clearance of RXTM83 were estimated at 3.19 L and 12.5 mL/h, respectively. Body surface area allowed to explain the interindividual variability for V1. A statistical analysis showed that systemic exposure (AUC and Cmax) of RTXM83 was similar to rituximab. The 90% confidence intervals for all pairwise comparisons were within the predefined bioequivalence interval of 0.80-1.25. PD similarity of B-cell depletion and recovery was also observed. CONCLUSIONS: The time course of RTXM83 was well characterized by the model developed. The systemic exposure of RTXM83 and its associated variability were similar to those for rituximab reference in DLBCL patients, demonstrating PK similarity. The PD similarity of RTXM83 and rituximab reference product was also demonstrated.
Assuntos
Medicamentos Biossimilares , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Rituximab , Imunidade Adaptativa/efeitos dos fármacos , Administração Intravenosa , Anticorpos Monoclonais Humanizados/administração & dosagem , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/farmacocinética , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Antineoplásicos Imunológicos/farmacocinética , Área Sob a Curva , Medicamentos Biossimilares/administração & dosagem , Medicamentos Biossimilares/farmacocinética , Monitoramento de Medicamentos/métodos , Feminino , Humanos , Linfoma Difuso de Grandes Células B/patologia , Masculino , Modelos Estatísticos , Rituximab/administração & dosagem , Rituximab/efeitos adversos , Rituximab/química , Rituximab/farmacocinética , Equivalência Terapêutica , Resultado do TratamentoRESUMO
To make advances in the treatment of cryptococcal meningitis, it is crucial to know a given drug's free fraction that reaches the biophase. In the present study, we applied microdialysis (µD) as a tool to determine the free levels reached by voriconazole (VRC) in the brains of healthy and Cryptococcus neoformans-infected rats. The infection was induced by the intravenous (i.v.) administration of 1 × 105 CFU of yeast. The dose administered was 5 mg/kg (of body weight) of VRC, given i.v. Plasma and microdialysate samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and LC-UV methods. The free brain/free plasma ratio (fT) and population pharmacokinetic (popPK) analyses were performed to evaluate the impact of infection on PK parameters of the drug. The brain penetration ratio showed an increase on brain exposure in infected animals (fThealthy = 0.85 versus fTinfected = 1.86). The structural PK model with two compartments and Michaelis-Menten (MM) elimination describes the VRC concentration-time profile in plasma and tissue simultaneously. The covariate infection was included in volume of distribution in the peripheral compartment in healthy animals (V2) and maximum rate of metabolism (VM ). The levels reached in infected tissues were higher than the values described for MIC of VRC for Cryptococccus neoformans (0.03 to 0.5 µg ml-1), indicating its great potential to treat meningitis associated with C. neoformans.
Assuntos
Encéfalo/metabolismo , Voriconazol/farmacocinética , Voriconazol/uso terapêutico , Animais , Encéfalo/efeitos dos fármacos , Cryptococcus neoformans/efeitos dos fármacos , Cryptococcus neoformans/patogenicidade , Masculino , Meningite Criptocócica/tratamento farmacológico , Meningite Criptocócica/metabolismo , Microdiálise , Ratos , Ratos WistarRESUMO
Carvedilol, a drug available as a racemic mixture, is metabolised into hydroxyphenylcarvedilol (OHC) by CYP2D6 and O-desmethylcarvedilol (DMC) by CYP2C9 followed by conjugation to glucuronides. In contrast to other ß-adrenergic receptor antagonists, carvedilol does not induce insulin resistance or worsen glycaemic control in diabetic hypertensive patients. This study aims to investigate the implications of type 2 diabetes (T2DM) on the pharmacokinetics of carvedilol enantiomers using an integrated population pharmacokinetic modelling approach. In total, 14 T2DM patients with good glycaemic control receiving standard doses of metformin and glibenclamide were evaluated along with a control group of 13 healthy subjects. Serial blood samples were collected up to 24h after administration of a single 25mg dose of racemic carvedilol. A multicompartmental population pharmacokinetic model describing the enantioselective disposition of the parent compound, OHC and DMC was developed in NONMEM v7.2. Even though data are limited, it appears that despite inhibition of CYP2C9 due to long-term glibenclamide administration to T2DM patients, overall no differences are observed in the total clearance of carvedilol when compared to healthy subjects (43.1 vs. 45.9L/h for (S)-(-)-carvedilol and 29.0 vs. 33.1L/h for (R)-(+)-carvedilol). These results provide evidence of a compensatory mechanism for the inhibition of CYP2C9, with higher contribution of CYP2D6 activity to the elimination of carvedilol. Consequently, no dose adjustment is recommended for carvedilol in T2DM patients receiving glibenclamide and metformin.