scholarly journals Pharmacokinetic Modelling to Predict FVIII:C Response to Desmopressin and Its Reproducibility in Nonsevere Haemophilia A Patients

2018 ◽  
Vol 47 (04) ◽  
pp. 621-629 ◽  
Author(s):  
Lisette Schütte ◽  
Reinier van Hest ◽  
Sara Stoof ◽  
Frank Leebeek ◽  
Marjon Cnossen ◽  
...  
Keyword(s):  
Compartment Model ◽  
Volume Of Distribution ◽  
Time Profile ◽  
Small Subset ◽  
Population Pharmacokinetic ◽  
Haemophilia A ◽  
Mixed Effect ◽  
Large Variability ◽  
Nonlinear Mixed Effect ◽  
Two Compartment Model

Background Nonsevere haemophilia A (HA) patients can be treated with desmopressin. Response of factor VIII activity (FVIII:C) differs between patients and is difficult to predict. Objectives Our aims were to describe FVIII:C response after desmopressin and its reproducibility by population pharmacokinetic (PK) modelling. Patients and Methods Retrospective data of 128 nonsevere HA patients (age 7–75 years) receiving an intravenous or intranasal dose of desmopressin were used. PK modelling of FVIII:C was performed by nonlinear mixed effect modelling. Reproducibility of FVIII:C response was defined as less than 25% difference in peak FVIII:C between administrations. Results A total of 623 FVIII:C measurements from 142 desmopressin administrations were available; 14 patients had received two administrations at different occasions. The FVIII:C time profile was best described by a two-compartment model with first-order absorption and elimination. Interindividual variability of the estimated baseline FVIII:C, central volume of distribution and clearance were 37, 43 and 50%, respectively. The most recently measured FVIII:C (FVIII-recent) was significantly associated with FVIII:C response to desmopressin (p < 0.001). Desmopressin administration resulted in an absolute FVIII:C increase of 0.47 IU/mL (median, interquartile range: 0.32–0.65 IU/mL, n = 142). FVIII:C response was reproducible in 6 out of 14 patients receiving two desmopressin administrations. Conclusion FVIII:C response to desmopressin in nonsevere HA patients was adequately described by a population PK model. Large variability in FVIII:C response was observed, which could only partially be explained by FVIII-recent. FVIII:C response was not reproducible in a small subset of patients. Therefore, monitoring FVIII:C around surgeries or bleeding might be considered. Research is needed to study this further.

scholarly journals 1573. Population Pharmacokinetic Analyses for Cefepime in Adult and Pediatric Patients

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S574-S575
Author(s):  
Jiajun Liu ◽  
Michael Neely ◽  
Jeffrey Lipman ◽  
Fekade B Sime ◽  
Jason Roberts ◽  
...  
Keyword(s):  
Rate Constant ◽  
Pediatric Patients ◽  
Validation Cohort ◽  
External Validation ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Information Criteria ◽  
Population Pharmacokinetic ◽  
Final Model ◽  
Two Compartment Model

Abstract Background Cefepime (CEF) is commonly used for adult and pediatric infections. Several studies have examined CEF’s pharmacokinetics (PK) in various populations; however, a unifying PK model for adult and pediatric subjects does not yet exist. We developed a combined population model for adult and pediatric patients and validated the model. Methods The initial model includes adult and pediatric patients with a rich cefepime sampling design. All adults received 2 g CEF while pediatric subjects received a mean of 49 (SD 5) mg/kg. One- and two-compartment models were considered as base models and were fit using a non-parametric adaptive grid algorithm within the Pmetrics package 1.5.2 (Los Angeles, CA) for R 3.5.1. Compartmental model selection was based on Akaike information criteria (AIC). Covariate relationships with PK parameters were visually inspected and mathematically assessed. Predictive performance was evaluated using bias and imprecision of the population and individual prediction models. External validation was conducted using a separate adult cohort. Results A total of 45 subjects (n = 9 adults; n = 36 pediatrics) were included in the initial PK model build and 12 subjects in the external validation cohort. Overall, the data were best described using a two-compartment model with volume of distribution (V) normalized to total body weight (TBW/70 kg) and an allometric scaled elimination rate constant (Ke) for pediatric subjects (AIC = 4,138.36). Final model observed vs. predicted plots demonstrated good fit (population R2 = 0.87, individual R2 = 0.97, Figure 1a and b). For the final model, the population median parameter values (95% credibility interval) were V0 (total volume of distribution), 11.7 L (10.2–14.6); Ke for adult, 0.66 hour−1 (0.38–0.78), Ke for pediatrics, 0.82 hour−1 (0.64–0.85), KCP (rate constant from central to peripheral compartment), 1.4 hour−1 (1.3–1.8), KPC (rate constant from peripheral to central compartment), 1.6 hour−1 (1.2–1.8). The validation cohort has 12 subjects, and the final model fit the data well (individual R2 = 0.75). Conclusion In this diverse group of adult and pediatrics, a two-compartment model described CEF PK well and was externally validated with a unique cohort. This model can serve as a population prior for real-time PK software algorithms. Disclosures All authors: No reported disclosures.

scholarly journals Fluconazole Population Pharmacokinetics and Dosing for Prevention and Treatment of Invasive Candidiasis in Children Supported with Extracorporeal Membrane Oxygenation

2015 ◽  
Vol 59 (7) ◽  
pp. 3935-3943 ◽  
Author(s):  
Kevin M. Watt ◽  
Daniel Gonzalez ◽  
Daniel K. Benjamin ◽  
Kim L. R. Brouwer ◽  
Kelly C. Wade ◽  
...  
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Mixed Effect ◽  
Final Model ◽  
Content Type ◽  
Membrane Oxygenation ◽  
Nonlinear Mixed Effect ◽  
Nonlinear Mixed Effect Modeling ◽  
Drug Pharmacokinetics

ABSTRACTCandidainfections are a leading cause of infectious disease-related death in children supported by extracorporeal membrane oxygenation (ECMO). The ECMO circuit can alter drug pharmacokinetics (PK); thus, standard fluconazole dosing may result in suboptimal drug exposures. The objective of our study was to determine the PK of fluconazole in children on ECMO. Forty children with 367 PK samples were included in the analysis. The PK data were analyzed using nonlinear mixed-effect modeling (NONMEM). A one-compartment model best described the data. Weight was included in the base model for clearance (CL) and volume of distribution (V). The final model included the effect of serum creatinine (SCR) level on CL and the effect of ECMO onVas follows: CL (in liters per hour) = 0.019 × weight × (SCR/0.4)−0.29× exp(ηCL) andV(in liters) = 0.93 × weight × 1.4ECMO× exp(ηV). The fluconazoleVwas increased in children supported by ECMO. Consequently, children on ECMO require a higher fluconazole loading dose for prophylaxis (12 mg/kg of body weight) and treatment (35 mg/kg) paired with standard maintenance doses to achieve exposures similar to those of children not on ECMO.

scholarly journals Population Pharmacokinetic/Pharmacogenetic Model for Optimization of Efavirenz Therapy in Caucasian HIV-Infected Patients

2011 ◽  
Vol 55 (11) ◽  
pp. 5314-5324 ◽  
Author(s):  
Almudena Sánchez ◽  
Salvador Cabrera ◽  
Dolores Santos ◽  
M. Paz Valverde ◽  
Aurelio Fuertes ◽  
...  
Keyword(s):  
High Performance ◽  
Plasma Concentrations ◽  
Compartment Model ◽  
Population Pharmacokinetic ◽  
Nucleotide Polymorphisms ◽  
Mixed Effect ◽  
Factors Affecting ◽  
Nonlinear Mixed Effect ◽  
Study Population ◽  
Major Factors

ABSTRACTDespite extensive clinical experience with efavirenz (EFV), unpredictable interindividual variabilities in efficacy and toxicity remain important limitations associated with the use of this antiretroviral. The purpose of this study was to determine the factors affecting EFV pharmacokinetics and to develop a pharmacokinetic/pharmacogenetic (PK/PG) model in a Caucasian population of HIV-infected patients. In total, 869 EFV plasma concentrations from 128 HIV-infected patients treated with EFV were quantitatively assessed using a validated high-performance liquid chromatography technique. All patients were genotyped for 90 single nucleotide polymorphisms (SNPs) in genes coding for proteins involved in the metabolism and transport of EFV, using a MassArray platform provided by Sequenom. The influence of these polymorphisms on EFV pharmacokinetics and the effects of demographic, clinical, biochemical, lifestyle, and concurrent drug covariates were evaluated. Plasma concentrations were fitted by a one-compartment model, with first-order absorption and elimination using nonlinear mixed-effect modeling (NONMEM program). The CYP2B6*6 allele, multidrug resistance-associated protein 4 (MRP4) 1497C→T, and gamma-glutamyltranspeptidase (GGT) were identified as major factors influencing the apparent EFV oral clearance (CL/F), reducing the initial interindividual variability by 54.8%, according to the model CL/F = (12.2 − 0.00279·GGT)·0.602CYP2B6*6 [G/T]·0.354CYP2B6*6 [T/T]·0.793MRP4 1497C→T, where CYP2B6*6 [G/T], CYP2B6*6 [T/T], and MRP4 1497C→T take values of 0 or 1 to indicate the absence or presence of polymorphisms. The detailed genetic analysis conducted in this study identified two of 90 SNPs that significantly impacted CL/F, which might indicate that the remaining SNPs analyzed do not influence this PK parameter, at least in Caucasian populations with characteristics similar to those of our study population.

scholarly journals 1540. A Population Pharmacokinetic Model for Vancomycin in Korean Patients Receiving Extracorporeal Membrane Oxygenation Therapy: A Prospective Study

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S562-S562
Author(s):  
Younghee Jung ◽  
Dong-Hwan Lee ◽  
Hyoung Soo Kim
Keyword(s):  
Extracorporeal Membrane Oxygenation ◽  
Creatinine Clearance ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Population Pharmacokinetic ◽  
Test Model ◽  
Mixed Effect ◽  
Korean Patients ◽  
Membrane Oxygenation ◽  
Population Pk

Abstract Background There is no literature on population pharmacokinetics (PK) of vancomycin in Korean patients receiving extracorporeal membrane oxygenation (ECMO) therapy. The aim of this study was to develop a population PK model for vancomycin in Korean ECMO patients. Methods We prospectively enrolled adult patients who were undergoing ECMO and receiving vancomycin from July 2018 to April 2019. After initial dose of vancomycin was administrated, serial blood samples (seven to nine times per patient) were drawn before the next dose. A population PK model for vancomycin was developed using a nonlinear mixed-effect modeling. Age, sex, creatinine clearance, and body weight were tested as potential covariates in the model. Model selection was based on log-likelihood test, model diagnostic plots, and clinical plausibility. Results Fourteen patients were included over the period. Ten received venovenous, three venoarterial, and one both type ECMO. Eleven were men and the median age was 54 (interquartile range 45–66.3). Mean estimated glomerular filtration rate (eGFR) was 69 ± 46 mL/minute/1.73m2 by the modification of diet in renal disease equation. A total of 123 vancomycin concentrations from the patients were included in the analysis. The population PK of vancomycin was best described by a two-compartment model with a proportional residual error model. The typical value (%between-subject variability) for total clearance was estimated to be 4.33 L/h (21.6%), central volume of distribution was 9.22 L, the intercompartmental clearance was 10.75 L/hr (34.9%) and the peripheral volume of distribution was 19.6 L (26.6%). The proportional residual variability was 8.81%. Creatinine clearance significantly influenced vancomycin clearance (CL). The proposed equation to estimate vancomycin clearance in Korean ECMO patients was CL = 4.33 + 0.199 × (eGFR – 56). Conclusion A two-compartment population PK model successfully describes vancomycin PK profiles in Korean ECMO patients. The model could be used to optimize the dosing regimen if more data become available from currently ongoing clinical study. Disclosures All authors: No reported disclosures.

scholarly journals Population Analysis of Weight-, Age-, and Sex-Related Differences in the Pharmacokinetics of Lopinavir in Children from Birth to 18 Years

2006 ◽  
Vol 50 (11) ◽  
pp. 3548-3555 ◽  
Author(s):  
Vincent Jullien ◽  
Saïk Urien ◽  
Déborah Hirt ◽  
Constance Delaugerre ◽  
Elisabeth Rey ◽  
...  
Keyword(s):  
Population Analysis ◽  
Combined Treatment ◽  
Elimination Rate ◽  
Compartment Model ◽  
Apparent Volume ◽  
Volume Of Distribution ◽  
Mixed Effect ◽  
Nonlinear Mixed Effect ◽  
Nonlinear Mixed Effect Modeling ◽  
Age And Sex

ABSTRACT The pharmacokinetics of lopinavir were investigated by the use of a population approach performed with the nonlinear mixed effect modeling program NONMEM and 157 children ranging in age from 3 days to 18 years. The pharmacokinetics of lopinavir were well described by a one-compartment model in which the absorption and the elimination rate constants were equal. Typical population estimates of the apparent volume of distribution (V/F) and plasma clearance (CL/F) were 24.6 liters and 2.58 liters/h, respectively. The lopinavir V/F and CL/F were both related to body weight (BW), with an important increase in weight-normalized CL/F for the lowest BW. Combined treatment with lopinavir and nevirapine was found to increase the CL/F. The lopinavir CL/F was also age and sex related, as a 39% increase was observed after the age of 12 years for boys compared to the CL/F for girls. The consequences of these pharmacokinetic discrepancies and the necessity to modify the currently recommended dosage regimen should be further investigated.

Population pharmacokinetics and dosing simulations of amoxicillin in obese adults receiving co-amoxiclav

2020 ◽  
Vol 75 (12) ◽  
pp. 3611-3618
Author(s):  
G Mellon ◽  
K Hammas ◽  
C Burdet ◽  
X Duval ◽  
C Carette ◽  
...  
Keyword(s):  
Compartment Model ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Open Label ◽  
Mixed Effect ◽  
Mean Values ◽  
Two Compartment Model ◽  
Amoxicillin Clavulanate ◽  
Dosing Regimens ◽  
Obese Subjects

Abstract Background Pneumonia, skin and soft tissue infections are more frequent in obese patients and are most often treated by co-amoxiclav, using similar dosing regimens to those used for non-obese subjects. No data are available on amoxicillin pharmacokinetics among obese subjects receiving co-amoxiclav. Materials and methods Prospective, single-centre, open-label, non-randomized, crossover pharmacokinetic trial having enrolled obese otherwise healthy adult subjects. A first dose of co-amoxiclav (amoxicillin/clavulanate 1000/200 mg) was infused IV over 30 min, followed by a second dose (1000/125 mg) administered orally, separated by a washout period of ≥24 h. We assayed concentrations of amoxicillin by a validated ultra HPLC–tandem MS technique. We estimated population pharmacokinetic parameters of amoxicillin by non-linear mixed-effect modelling using the SAEM algorithm developed by Monolix. Results Twenty-seven subjects were included in the IV study, with 24 included in the oral part of the study. Median body weight and BMI were 109.3 kg and 40.6 kg/m2, respectively. Amoxicillin pharmacokinetics were best described by a two-compartment model with first-order elimination. Mean values for clearance, central volume, intercompartmental clearance and peripheral volume were, respectively, 14.6 L/h, 9.0 L, 4.2 L/h and 6.4 L for amoxicillin. Oral bioavailability of amoxicillin was 79.7%. Amoxicillin Cmax after oral administration significantly reduced with weight (P = 0.013). Dosing simulations for amoxicillin predicted that most of the population will achieve the pharmacodynamic target of fT&gt;MIC ≥40% with the regimen of co-amoxiclav 1000/200 mg (IV) or 1000/125 mg (oral) q8h for MICs titrated up to 0.5 mg/L (IV) and 1 mg/L (oral). Conclusions Pharmacokinetic/pharmacodynamic goals for amoxicillin can be obtained in obese subjects.

Cefepime precision dosing tool: From Standard to Precise Dose Using Nonparametric Population Pharmacokinetics

2021 ◽  
Author(s):  
Mohammad H. Alshaer ◽  
Sylvain Goutelle ◽  
Barbara Santevecchi ◽  
Bethany Shoulders ◽  
Veena Venugopalan ◽  
...  
Keyword(s):  
Compartment Model ◽  
Volume Of Distribution ◽  
Target Range ◽  
Population Pharmacokinetic ◽  
Support Points ◽  
Two Compartment Model ◽  
Central Volume ◽  
Model Support ◽  
Median Rate ◽  
Concentration Prediction

Cefepime is the second most common cephalosporin used in U.S. hospitals. We aim to develop and validate cefepime population pharmacokinetic (PK) model and integrate into precision dosing tool for implementation. Two datasets (680 patients) were used to build cefepime PK model in Pmetrics, and three datasets (34 patients) were used for the validation. A separate application dataset (115 patients) was used for the implementation and validation of a precision dosing tool. The model support points and covariates were used to generate the optimal initial dose (OID). Cefepime PK was described by a two-compartment model including weight and creatinine clearance (CrCl) as covariates. The median rate of elimination was 0.30 hr −1 (adults) and 0.96 hr −1 (pediatrics), central volume of distribution 13.85 L, and rate of transfer from the central to the peripheral compartments 1.22 hr −1 and from the peripheral to the central compartments 1.38 hr −1 . After integration in BestDose, the observed vs. predicted cefepime concentration fit using the application dataset was excellent (R 2 >0.98) and the median difference between observed and what BestDose predicted in a second occasion was 4%. For OID, cefepime 0.5-1g 4-hour infusion q8-24hr with CrCl<70 mL/min was needed to achieve a target range of free trough:MIC 1-4 at MIC 8 mg/L, while continuous infusion was needed for higher CrCl and weight values. In conclusion, we developed and validated a cefepime model for clinical application. The model was integrated in a precision dosing tool for implementation and the median concentration prediction bias was 4%. OID algorithm was provided.

scholarly journals Clinical Application of Vancomycin PPK Model in Patients with Neutropenia

2021 ◽  
Author(s):  
Xiangjun Fu ◽  
Li Huang ◽  
Li Guo ◽  
Liangmo Lin
Keyword(s):  
Clinical Application ◽  
Compartment Model ◽  
Empiric Therapy ◽  
Model Group ◽  
Target Concentration ◽  
Mixed Effect ◽  
Model Study ◽  
Nonlinear Mixed Effect ◽  
Two Compartment Model ◽  
Stability And Accuracy

Abstract Background: To explore the clinical application of a population pharmacokinetics (PPK) model of vancomycin in patients with hematological diseases who developed neutropenia.Methods: Patients with neutropenia treated at the Department of Hematology in our hospital were included in the PPK model study. A nonlinear mixed effect modeling approach (NONMEM) was used to establish the PPK model of those patients. Monte Carlo simulation was also carried out. A total of 64 patients were divided into model group and non-model group for clinical application research. The model group was given the first dose of 1g q8h, and the non-model group was given 1g q12h as the empiric therapy; the follow-up dose adjustment was made according to the concentration results.Results: This two-compartment model showed good stability and accuracy. The average concentrations in the model group and the non-model group were significantly different, i.e., 13.45±4.07 μg/ml, 60.71% reaching the target concentration vs. 9.85±3.76 μg/ml, 27.78% reaching the target concentration, respectively (all P<0.05). This suggested that for patients with neutropenia and CLCR≥90 ml/min/1.73m2, the first dose of 1g q8h may help to reach the target concentration as soon as possible.Conclusions: Our PPK model of vancomycin in patients with hematologic diseases who developed neutropenia can be used to realize the individualized application of vancomycin in this population.

scholarly journals Rapidly maturing fentanyl clearance in preterm neonates

2019 ◽  
Vol 104 (6) ◽  
pp. F598-F603 ◽  
Author(s):  
Swantje Völler ◽  
Robert B Flint ◽  
Peter Andriessen ◽  
Karel Allegaert ◽  
Luc J I Zimmermann ◽  
...  
Keyword(s):  
Gestational Age ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Preterm Neonates ◽  
Population Pharmacokinetic ◽  
Additional Information ◽  
Two Compartment Model ◽  
Require Dose ◽  
Preterm Newborns ◽  
Pharmacodynamic Data

BackgroundFentanyl is frequently used off-label in preterm newborns. Due to very limited pharmacokinetic and pharmacodynamic data, fentanyl dosing is mostly based on bodyweight. This study describes the maturation of the pharmacokinetics in preterm neonates born before 32 weeks of gestation.Methods442 plasma samples from 98 preterm neonates (median gestational age: 26.9 (range 23.9–31.9) weeks, postnatal age: 3 (range 0–68) days, bodyweight 1.00 (range 0.39–2.37) kg) were collected in an opportunistic trial and fentanyl plasma levels were determined. NONMEM V.7.3 was used to develop a population pharmacokinetic model and to perform simulations.ResultsFentanyl pharmacokinetics was best described by a two-compartment model. A pronounced non-linear influence of postnatal and gestational age on clearance was identified. Clearance (L/hour/kg) increased threefold, 1.3-fold and 1.01-fold in the first, second and third weeks of life, respectively. In addition, clearance (L/hour/kg) was 1.4-fold and 1.7-fold higher in case of a gestational age of 28 and 31 weeks, respectively, compared with 25 weeks. Volume of distribution changed linearly with bodyweight and was 8.7 L/kg. To achieve similar exposure across the entire population, a continuous infusion (µg/kg/hour) dose should be reduced by 50% and 25% in preterm neonates with a postnatal age of 0–4 days and 5–9 days in comparison to 10 days and older.ConclusionBecause of low clearance, bodyweight-based dosages may result in fentanyl accumulation in neonates with the lowest postnatal and gestational ages which may require dose reduction. Together with additional information on the pharmacodynamics, the results of this study can be used to guide dosing.

scholarly journals P72 Maturation of sildenafil clearance in prematurely born infants with BPD associated pulmonary hypertension

2019 ◽  
Vol 104 (6) ◽  
pp. e47.1-e47
Author(s):  
H Nikrawesh ◽  
AGJ Engbers ◽  
S Völler ◽  
SHP Simons ◽  
BCP Koch ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Compartment Model ◽  
Volume Of Distribution ◽  
Limited Information ◽  
Mixed Effect ◽  
Time Profiles ◽  
Nonlinear Mixed Effect ◽  
Postmenstrual Age ◽  
Oral Doses ◽  
Prematurely Born Infants

BackgroundSildenafil is used as an off-label treatment for bronchopulmonary dysplasia (BPD) associated pulmonary hypertension in prematurely born infants. As there is only limited information on the pharmacokinetics (PK) of sildenafil in this population, the aim of this study is to investigate the PK of sildenafil in prematurely born infants with BPD associated pulmonary hypertension.MethodIn this multicentre study, a population PK model for sildenafil in prematurely born infants was developed based on samples obtained using opportunistic sampling during clinical use of sildenafil. Data of seven subjects (42 plasma samples) were analysed by nonlinear mixed-effect modelling (NONMEM®7.3). Median (range) gestational age (GA) was 26.1 (24.1–27.6) weeks, current bodyweight 1960 (632–3157) grams, birthweight 635 (465–1125) grams and postnatal age (PNA) at start of therapy 64.9 (10.9–89) days. The median (range) treatment duration was 4.9 (1.6–13.1) weeks, with six subjects receiving oral doses of median 2.6 mg/kg/day (1.5–5.3) in three doses and one subject receiving oral and intravenous doses of 6.7 mg/kg/day in two doses.ResultsThe plasma concentration time profiles of sildenafil were best described by a one compartment model. Clearance (CL) and volume of distribution (Vd) for a child with a PNA of 64.9 days and bodyweight of 1.96 kg was 4.42 L/h ((RSE) 11%) and 29.5 L (32%), respectively. PNA was found to significantly influence CL, resulting in an increase of 10.7% in a week, and 43% in a month for a 65-day old infant. No other covariates (i.e. bodyweight, birthweight, GA, postmenstrual age and sex) were identified for CL or Vd.ConclusionIn this PK study, we characterised the pharmacokinetics of sildenafil in prematurely born infants and found that clearance increases with PNA. Due to the limited sample size in this study, further research in a larger population is needed to extend these findings.Disclosure(s)Nothing to disclose

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