scholarly journals In VivoMicrodialysis To Determine Subcutaneous Interstitial Fluid Penetration and Pharmacokinetics of Fluconazole in Intensive Care Unit Patients with Sepsis

2015 ◽  
Vol 60 (2) ◽  
pp. 827-832 ◽  
Author(s):  
Mahipal G. Sinnollareddy ◽  
Michael S. Roberts ◽  
Jeffrey Lipman ◽  
Melissa Lassig-Smith ◽  
Therese Starr ◽  
...  
Keyword(s):  
Intensive Care ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
High Performance ◽  
Interstitial Fluid ◽  
Drug Exposure ◽  
Pharmacokinetic Analysis ◽  
Time Curve ◽  
Fluid Penetration

ABSTRACTThe objective of the study was to describe the subcutaneous interstitial fluid (ISF) pharmacokinetics of fluconazole in critically ill patients with sepsis. This prospective observational study was conducted at two tertiary intensive care units in Australia. Serial fluconazole concentrations were measured over 24 h in plasma and subcutaneous ISF using microdialysis. The concentrations in plasma and microdialysate were measured using a validated high-performance liquid chromatography system with electrospray mass spectrometer detector method. Noncompartmental pharmacokinetic analysis was performed. Twelve critically ill patients with sepsis were enrolled. The meanin vivofluconazole recovery rates ± standard deviation (SD) for microdialysis were 51.4% ± 16.1% with a mean (±SD) fluconazole ISF penetration ratio of 0.52 ± 0.30 (coefficient of variation, 58%). The median free plasma area under the concentration-time curve from 0 to 24 h (AUC0–24) was significantly higher than the median ISF AUC0–24(340.4 versus 141.1 mg · h/liter;P= 0.004). There was no statistical difference in median fluconazole ISF penetration between patients receiving and not receiving vasopressors (median, 0.28 versus 0.78;P= 0.106). Both minimum and the maximum concentrations of drug in serum (CmaxandCmin) showed a significant correlation with the fluconazole plasma exposure (Cmax,R2=0.86,P< 0.0001;Cmin,R2= 0.75,P< 0.001). Our data suggest that fluconazole was distributed variably, but incompletely, from plasma into subcutaneous interstitial fluid in this cohort of critically ill patients with sepsis. Given the variability of fluconazole interstitial fluid exposures and lack of clinically identifiable factors by which to recognize patients with reduced distribution/exposure, we suggest higher than standard doses to ensure that drug exposure is adequate at the site of infection.

scholarly journals Low Caspofungin Exposure in Patients in Intensive Care Units

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Kim C. M. van der Elst ◽  
Anette Veringa ◽  
Jan G. Zijlstra ◽  
Albertus Beishuizen ◽  
Rob Klont ◽  
...  
Keyword(s):  
Intensive Care ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Drug Exposure ◽  
Standard Dose ◽  
Drug Distribution ◽  
Volume Of Distribution ◽  
Primary Objective ◽  
Time Curve ◽  
Icu Patients

ABSTRACT In critically ill patients, drug exposure may be influenced by altered drug distribution and clearance. Earlier studies showed that the variability in caspofungin exposure was high in intensive care unit (ICU) patients. The primary objective of this study was to determine if the standard dose of caspofungin resulted in adequate exposure in critically ill patients. A multicenter prospective study in ICU patients with (suspected) invasive candidiasis was conducted in the Netherlands from November 2013 to October 2015. Patients received standard caspofungin treatment, and the exposure was determined on day 3 of treatment. An area under the concentration-time curve from 0 to 24 h (AUC0–24) of 98 mg · h/liter was considered adequate exposure. In case of low exposure (i.e., <79 mg · h/liter, a ≥20% lower AUC0–24), the caspofungin dose was increased and the exposure reevaluated. Twenty patients were included in the study, of whom 5 had a positive blood culture. The median caspofungin AUC0–24 at day 3 was 78 mg · h/liter (interquartile range [IQR], 69 to 97 mg · h/liter). A low AUC0–24 (<79 mg · h/liter) was seen in 10 patients. The AUC0–24 was significantly and positively correlated with the caspofungin dose in mg/kg/day (P = 0.011). The median AUC0–24 with a caspofungin dose of 1 mg/kg was estimated using a pharmacokinetic model and was 114.9 mg · h/liter (IQR, 103.2 to 143.5 mg · h/liter). In conclusion, the caspofungin exposure in ICU patients in this study was low compared with that in healthy volunteers and other (non)critically ill patients, most likely due to a larger volume of distribution. A weight-based dose regimen is probably more suitable for patients with substantially altered drug distribution. (This study has been registered at ClinicalTrials.gov under registration no. NCT01994096.)

In vivo Elimination of Clonidine by Continuous Venovenous Hemofiltration in Critically Ill Patients

2020 ◽  
Vol 49 (5) ◽  
pp. 622-626
Author(s):  
Huub L.A. van den Oever ◽  
Marieke Zeeman ◽  
Polina Nassikovker ◽  
Carmen Bles ◽  
Fred A.L. van Steveninck ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Continuous Venovenous Hemofiltration ◽  
Kidney Dysfunction ◽  
Sieving Coefficient ◽  
The Mean ◽  
Ventilated Patients

Background: Clonidine is an α2-agonist that is commonly used for sedation in the intensive care unit. When patients are on continuous venovenous hemofiltration (CVVH) in the presence of kidney dysfunction, the sieving coefficient of clonidine is required to estimate how much drug is removed by CVVH. In the present study, we measured the sieving coefficient of clonidine in critically ill, ventilated patients receiving CVVH. Methods: A total of 20 samples of plasma and ultrafiltrate of 3 patients on CVVH, using a standard 1.5 m2 polyacrylonitrile AN69 membrane, during continuous clonidine infusion were collected. After correction for the effect of predilution, we calculated the sieving coefficient for clonidine. Results: The mean sieving coefficient of clonidine was 0.52 (SD 0.097). Conclusion: Using a polyacrylonitrile AN69 membrane in a CVVH machine, the in vivo sieving coefficient of clonidine was 0.52.

scholarly journals Optimization of fluconazole dosing for the prevention and treatment of invasive candidiasis based on the pharmacokinetics of fluconazole in critically-ill patients

2020 ◽  
Author(s):  
J. M. Boonstra ◽  
A. G. Märtson ◽  
I Sandaradura ◽  
J. G. Kosterink ◽  
T. S. van der Werf ◽  
...  
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Plasma Concentrations ◽  
Organ Transplant ◽  
Compartment Model ◽  
Pharmacokinetic Analysis ◽  
Solid Organ ◽  
Time Curve ◽  
Final Population ◽  
The Mean

Background: The efficacy of fluconazole is related to the area under the plasma concentration-time curve over the minimum inhibitory concentration of the microorganism. Physiological changes in critically ill patients may affect the exposure of fluconazole and therefore dosing adjustments might be needed. Objective: The aim of this study was to evaluate variability in fluconazole drug concentration in ICU patients and to develop a pharmacokinetic model to support personalized fluconazole dosing. Methods: A prospective observational pharmacokinetic study was performed in critically ill patients receiving fluconazole either as prophylaxis or as treatment. The association between fluconazole exposure and patient variables was studied. Pharmacokinetic modeling was performed with nonparametric adaptive grid (NPAG) algorithm using R package Pmetrics. Results: Data from 33 patients were available for pharmacokinetic analysis. Patients on dialysis and solid organ transplant patients had a significantly lower exposure to fluconazole. The population was best described with a one-compartment model, where the mean volume of distribution was 51.52 L (SD 19.81) and the mean clearance was 0.767 L/h (SD 0.46). Creatinine clearance was tested as a potential covariate in the model, but was not included in the final population model. A significant positive correlation was found between the fluconazole exposure (AUC) and the Cmin. Conclusion: Substantial variability in fluconazole plasma concentrations in critically-ill adults was observed, where the majority of patients were underexposed. Fluconazole Cmin TDM guided dosing can be used to optimize therapy in critically ill patients.

scholarly journals Pharmacokinetics of Ganciclovir during Continuous Venovenous Hemodiafiltration in Critically Ill Patients

2013 ◽  
Vol 58 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Thomas Horvatits ◽  
Reinhard Kitzberger ◽  
Andreas Drolz ◽  
Christian Zauner ◽  
Walter Jäger ◽  
...  
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
High Performance ◽  
Area Under The Curve ◽  
Antiviral Agent ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Target Area ◽  
Continuous Venovenous Hemodiafiltration

ABSTRACTGanciclovir is an antiviral agent that is frequently used in critically ill patients with cytomegalovirus (CMV) infections. Continuous venovenous hemodiafiltration (CVVHDF) is a common extracorporeal renal replacement therapy in intensive care unit patients. The aim of this study was to investigate the pharmacokinetics of ganciclovir in anuric patients undergoing CVVHDF. Population pharmacokinetic analysis was performed for nine critically ill patients with proven or suspected CMV infection who were undergoing CVVHDF. All patients received a single dose of ganciclovir at 5 mg/kg of body weight intravenously. Serum and ultradiafiltrate concentrations were assessed by high-performance liquid chromatography, and these data were used for pharmacokinetic analysis. Mean peak and trough prefilter ganciclovir concentrations were 11.8 ± 3.5 mg/liter and 2.4 ± 0.7 mg/liter, respectively. The pharmacokinetic parameters elimination half-life (24.2 ± 7.6 h), volume of distribution (81.2 ± 38.3 liters), sieving coefficient (0.76 ± 0.1), total clearance (2.7 ± 1.2 liters/h), and clearance of CVVHDF (1.5 ± 0.2 liters/h) were determined. Based on population pharmacokinetic simulations with respect to a target area under the curve (AUC) of 50 mg · h/liter and a trough level of 2 mg/liter, a ganciclovir dose of 2.5 mg/kg once daily seems to be adequate for anuric critically ill patients during CVVHDF.

scholarly journals Pharmacokinetics of Unbound Linezolid in Plasma and Tissue Interstitium of Critically Ill Patients after Multiple Dosing Using Microdialysis

2006 ◽  
Vol 50 (7) ◽  
pp. 2455-2463 ◽  
Author(s):  
Cornelia Buerger ◽  
Nele Plock ◽  
Pejman Dehghanyar ◽  
Christian Joukhadar ◽  
Charlotte Kloft
Keyword(s):  
Steady State ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
High Performance ◽  
Time Course ◽  
Geometric Mean ◽  
Integrated Model ◽  
Multiple Dosing ◽  
Chromatography Method

ABSTRACT The antimicrobial agent linezolid is approved for the treatment of severe infections caused by, e.g., methicillin-resistant Staphylococcus strains. In order to evaluate the penetration of linezolid into the interstitial space fluid (ISF) of subcutaneous adipose tissue and skeletal muscle of the target population, a microdialysis study was performed with 12 patients with sepsis or septic shock after multiple intravenous infusions. Unbound linezolid concentrations were determined for plasma and microdialysates by use of a validated high-performance liquid chromatography method. Individual compartmental pharmacokinetic (PK) analysis was performed using WinNonlin. In vivo microdialysis was found to be feasible for the determination of unbound linezolid concentrations at steady state in the ISF of critically ill patients. On average, linezolid showed good distribution into ISF but with high interindividual variability. A two-compartment model was fitted to unbound concentrations in plasma with a geometric mean distribution volume of 62.9 liters and a mean clearance of 9.18 liters/h at steady state. However, disposition characteristics changed intraindividually within the time course. In addition, an integrated model for simultaneous prediction of concentrations in all matrices was developed and revealed similar results. Based on the model-predicted unbound concentrations in ISF, a scheme of more-frequent daily dosing of linezolid for some critically ill patients might be taken into consideration to avoid subinhibitory unbound concentrations in the infected tissue. The developed integrated model will be a valuable basis for further PK data analysis to explore refined dosing guidelines that achieve effective antimicrobial therapy in all patients by use of the population PK approach.

scholarly journals Population Pharmacokinetics of Doripenem in Critically Ill Patients with Sepsis in a Malaysian Intensive Care Unit

2015 ◽  
Vol 60 (1) ◽  
pp. 206-214 ◽  
Author(s):  
Mohd H. Abdul-Aziz ◽  
Azrin N. Abd Rahman ◽  
Mohd-Basri Mat-Nor ◽  
Helmi Sulaiman ◽  
Steven C. Wallis ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Monte Carlo ◽  
Intensive Care ◽  
Population Pharmacokinetics ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Population Pharmacokinetic Analysis ◽  
Volume Of Distribution ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic

ABSTRACTDoripenem has been recently introduced in Malaysia and is used for severe infections in the intensive care unit. However, limited data currently exist to guide optimal dosing in this scenario. We aimed to describe the population pharmacokinetics of doripenem in Malaysian critically ill patients with sepsis and use Monte Carlo dosing simulations to develop clinically relevant dosing guidelines for these patients. In this pharmacokinetic study, 12 critically ill adult patients with sepsis receiving 500 mg of doripenem every 8 h as a 1-hour infusion were enrolled. Serial blood samples were collected on 2 different days, and population pharmacokinetic analysis was performed using a nonlinear mixed-effects modeling approach. A two-compartment linear model with between-subject and between-occasion variability on clearance was adequate in describing the data. The typical volume of distribution and clearance of doripenem in this cohort were 0.47 liters/kg and 0.14 liters/kg/h, respectively. Doripenem clearance was significantly influenced by patients' creatinine clearance (CLCR), such that a 30-ml/min increase in the estimated CLCRwould increase doripenem CL by 52%. Monte Carlo dosing simulations suggested that, for pathogens with a MIC of 8 mg/liter, a dose of 1,000 mg every 8 h as a 4-h infusion is optimal for patients with a CLCRof 30 to 100 ml/min, while a dose of 2,000 mg every 8 h as a 4-h infusion is best for patients manifesting a CLCRof >100 ml/min. Findings from this study suggest that, for doripenem usage in Malaysian critically ill patients, an alternative dosing approach may be meritorious, particularly when multidrug resistance pathogens are involved.

The use of population modeling to optimize dosing of drugs used in anaesthesiology and intensive care

2021 ◽  
Vol 8 ◽  
pp. 18-23
Author(s):  
Agnieszka Borsuk-De Moor ◽  
Paweł Wiczling
Keyword(s):  
Intensive Care ◽  
Critically Ill ◽  
Intravenous Administration ◽  
Critically Ill Patients ◽  
Drug Exposure ◽  
Population Modeling ◽  
Population Models ◽  
Metabolic Clearance ◽  
Pharmacokinetics And Pharmacodynamics ◽  
Drug Pharmacokinetics

Effective pharmacotherapy requires an adequate drug dose that maximizes the effectiveness of therapy while minimizing adverse effects. Difficulties in dose selection arise from interindividual differences in drug pharmacokinetics and pharmacodynamics. Population modeling describes pharmacokinetic and pharmacodynamic processes in a population, taking into account the relationships in each patient, differences between patients, and the influence of covariates on drug pharmacokinetics and pharmacodynamics. The aim of this study was to develop population models for drugs used in anesthesiology and intensive care in special patient populations. The pharmacokinetics of sufentanil was described in infants and children after epidural and intravenous administration. The estimated absorption rate constant from the epidural space suggests slow systemic absorption of sufentanil and the possibility of flip-flop kinetics, which results in a slower decline in plasma concentrations at the end of drug administration compared with intravenous administration. The dependence of metabolic clearance on body weight and age was also demonstrated. A population model for the pharmacokinetics of tigecycline was developed for patients with sepsis or septic shock. No relationship between pharmacokinetic parameters and patient characteristics was detected, and the estimated interindividual and inter-occasion variability for clearance was small. This suggests that a universal dose is sufficient to achieve homogeneous drug exposure in critically ill patients. The pharmacokinetics of caspofungin was described in critically ill patients. The clearance and volume of central compartment showed systematic increase over time that was not explained by the covariates. The estimated increase in clearance values for three consecutive doses results in a clinically relevant reduction in drug exposure. The developed population models extend the knowledge of the pharmacokinetics of sufentanyl, tigecycline, and caspofungin. Simulations based on these models can aid the dosing decision-making process.

Methodological Approaches to Evaluate Fetal Drug Exposure

2019 ◽  
Vol 25 (5) ◽  
pp. 496-504 ◽  
Author(s):  
Naïm Bouazza ◽  
Frantz Foissac ◽  
Déborah Hirt ◽  
Saïk Urien ◽  
Sihem Benaboud ◽  
...  
Keyword(s):  
Cord Blood ◽  
Drug Exposure ◽  
Placental Transfer ◽  
Ex Vivo ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Pbpk Models ◽  
Drug Concentrations ◽  
Fetal Drug Exposure

Background: Drug prescriptions are usual during pregnancy, however, women and their fetuses still remain an orphan population with regard to drugs efficacy and safety. Most xenobiotics diffuse through the placenta and some of them can alter fetus development resulting in structural abnormalities, growth or functional deficiencies. Methods: To summarize the different methodologies developed towards the prediction of fetal drug exposure. Results: Neonatal cord blood concentration is the most specific measurement of the transplacental drug transfer at the end of pregnancy. Using the cord blood and mother drug concentrations altogether, drug exchanges between the mother and fetus can be modeled and quantified via a population pharmacokinetic analysis. Thereafter, it is possible to estimate the fetus exposure and the fetus-to-mother exposure ratio. However, the prediction of placental transfer before any administration to pregnant women is desirable. Animal studies remain difficult to interpret due to structural and functional inter-species placenta differences. The ex-vivo perfusion of the human placental cotyledon is the method of reference to study the human placental transfer of drugs because it is thought to mimic the functional placental tissue. However, extrapolation of data to in vivo situation remains difficult. Some research groups have extensively worked on physiologically based models (PBPK) to predict fetal drug exposure and showed very encouraging results. Conclusion: PBPK models appeared to be a very promising tool in order to predict fetal drug exposure in-silico. However, these models mainly picture the end of pregnancy and knowledge regarding both, development of the placental permeability and transporters is strongly needed.

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