scholarly journals Does Critical Illness Change Levofloxacin Pharmacokinetics?

2015 ◽  
Vol 60 (3) ◽  
pp. 1459-1463 ◽  
Author(s):  
Jason A. Roberts ◽  
Menino Osbert Cotta ◽  
Piergiorgio Cojutti ◽  
Manuela Lugano ◽  
Giorgio Della Rocca ◽  
...  
Keyword(s):  
Renal Function ◽  
Critical Illness ◽  
Creatinine Clearance ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Clinical Indication ◽  
Independent Effect ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
The Mean

Levofloxacin is commonly used in critically ill patients for which existing data suggest nonstandard dosing regimens should be used. The objective of this study was to compare the population pharmacokinetics of levofloxacin in critically ill and in non-critically ill patients. Adult patients with a clinical indication for levofloxacin were eligible for participation in this prospective pharmacokinetic study. Patients were given 500 mg or 750 mg daily by intravenous administration with up to 11 blood samples taken on day 1 or 2 of therapy. Plasma samples were analyzed and population pharmacokinetic analysis was undertaken using Pmetrics. Thirty-five patients (18 critically ill) were included. The mean (standard deviation [SD]) age, weight, and Cockcroft-Gault creatinine clearance for the critically ill and for the non-critically ill patients were 60.3 (16.4) and 72.0 (11.6) years, 78.5 (14.8) and 70.9 (15.8) kg, and 71.9 (65.8) and 68.2 (30.1) ml/min, respectively. A two-compartment linear model best described the data. Increasing creatinine clearance was the only covariate associated with increasing drug clearance. The presence of critical illness did not significantly affect any pharmacokinetic parameter. The mean (SD) parameter estimates were as follows: clearance, 8.66 (3.85) liters/h; volume of the central compartment (Vc), 41.5 (24.5) liters; intercompartmental clearance constants from central to peripheral, 2.58 (3.51) liters/h; and peripheral to central compartments, 0.90 (0.58) liters/h. Monte Carlo dosing simulations demonstrated that achievement of therapeutic exposures was dependent on renal function, pathogen, and MIC. Critical illness appears to have no independent effect on levofloxacin pharmacokinetics that cannot be explained by altered renal function.

scholarly journals Population Pharmacokinetics of Fosfomycin in Critically Ill Patients

2015 ◽  
Vol 59 (10) ◽  
pp. 6471-6476 ◽  
Author(s):  
Suzanne L. Parker ◽  
Frantzeska Frantzeskaki ◽  
Steven C. Wallis ◽  
Chryssa Diakaki ◽  
Helen Giamarellou ◽  
...  
Keyword(s):  
Population Pharmacokinetics ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Pharmacokinetic Analysis ◽  
Peripheral Compartment ◽  
Population Pharmacokinetic ◽  
Parameter Estimates ◽  
Blood Samples ◽  
The Mean ◽  
Dosing Intervals

ABSTRACTThis study describes the population pharmacokinetics of fosfomycin in critically ill patients. In this observational study, serial blood samples were taken over several dosing intervals of intravenous fosfomycin treatment. Blood samples were analyzed using a validated liquid chromatography-tandem mass spectrometry technique. A population pharmacokinetic analysis was performed using nonlinear mixed-effects modeling. Five hundred fifteen blood samples were collected over one to six dosing intervals from 12 patients. The mean (standard deviation) age was 62 (17) years, 67% of patients were male, and creatinine clearance (CLCR) ranged from 30 to 300 ml/min. A two-compartment model with between-subject variability on clearance and volume of distribution of the central compartment (Vc) described the data adequately. Calculated CLCRwas supported as a covariate on fosfomycin clearance. The mean parameter estimates for clearance on the first day were 2.06 liters/h,Vcof 27.2 liters, intercompartmental clearance of 19.8 liters/h, and volume of the peripheral compartment of 22.3 liters. We found significant pharmacokinetic variability for fosfomycin in this heterogeneous patient sample, which may be explained somewhat by the observed variations in renal function.

scholarly journals Influence of Renal Replacement Modalities on Amikacin Population Pharmacokinetics in Critically Ill Patients on Continuous Renal Replacement Therapy

2016 ◽  
Vol 60 (8) ◽  
pp. 4901-4909 ◽  
Author(s):  
Claire Roger ◽  
Steven C. Wallis ◽  
Laurent Muller ◽  
Gilbert Saissi ◽  
Jeffrey Lipman ◽  
...  
Keyword(s):  
Renal Replacement Therapy ◽  
Continuous Renal Replacement Therapy ◽  
Replacement Therapy ◽  
Critically Ill ◽  
Rate Constant ◽  
Critically Ill Patients ◽  
Drug Distribution ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
The Mean

ABSTRACTThe objective of this study was to describe amikacin pharmacokinetics (PK) in critically ill patients receiving equal doses (30 ml/kg of body weight/h) of continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodiafiltration (CVVHDF). Patients receiving amikacin and undergoing CVVH or CVVHDF were eligible. Population pharmacokinetic analysis and Monte Carlo simulation were undertaken using the Pmetrics software package for R. Sixteen patients (9 undergoing CVVH, 11 undergoing CVVHDF) and 20 sampling intervals were analyzed. A two-compartment linear model best described the data. Patient weight was the only covariate that was associated with drug clearance. The mean ± standard deviation parameter estimates were 25.2 ± 17.3 liters for the central volume, 0.89 ± 1.17 h−1for the rate constant for the drug distribution from the central to the peripheral compartment, 2.38 ± 6.60 h−1for the rate constant for the drug distribution from the peripheral to the central compartment, 4.45 ± 2.35 liters/h for hemodiafiltration clearance, and 4.69 ± 2.42 liters/h for hemofiltration clearance. Dosing simulations for amikacin supported the use of high dosing regimens (≥25 mg/kg) and extended intervals (36 to 48 h) for most patients when considering PK/pharmacodynamic (PD) targets of a maximum concentration in plasma (Cmax)/MIC ratio of ≥8 and a minimal concentration of ≤2.5 mg/liter at the end of the dosing interval. The mean clearance of amikacin was 1.8 ± 1.3 liters/h by CVVHDF and 1.3 ± 1 liters/h by CVVH. On the basis of simulations, a strategy of an extended-interval high loading dose of amikacin (25 mg/kg every 48 h) associated with therapeutic drug monitoring (TDM) should be the preferred approach for aminoglycoside treatment in critically ill patients receiving continuous renal replacement therapy (CRRT). (This study is a substudy of a trial registered at ClinicalTrials.gov under number NCT01403220.)

scholarly journals Neutrophil Gelatinase-Associated Lipocalin as a Marker for Renal Dysfunction Detection in Critically Ill Patients with Increased Intraabdominal Pressure

2017 ◽  
Vol 3 (1) ◽  
pp. 24-28
Author(s):  
Claudiu Puiac ◽  
Janos Szederjesi ◽  
Alexandra Lazăr ◽  
Codruța Bad ◽  
Lucian Pușcașiu
Keyword(s):  
Renal Function ◽  
Intensive Care ◽  
Creatinine Clearance ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Abdominal Cavity ◽  
Intraabdominal Pressure ◽  
Abdominal Pressure ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Neutrophil Gelatinase

Abstract Introduction: Elevated intraabdominal pressure (IAP) it is known to have an impact on renal function trough the pressure transmitted from the abdominal cavity to the vasculature responsible for the renal blood flow. Intraabdominal pressure is found to be frequent in intensive care patients and also to be a predictor of mortality. Intra-abdominal high pressure is an entity that can have serious impact on intensive care admitted patients, studies concluding that if this condition progresses to abdominal compartment syndrome mortality is as high as 80%. Aim: The aim of this study was to observe if a link between increased intraabdominal pressure and modification in renal function exists (NGAL, creatinine clearance). Material and Method: The study enrolled 30 critically ill patients admitted in the Intensive Care Unit of SCJU Tîrgu Mures between November 2015 and August 2016. The study enrolled adult, hemodynamically stable patients admitted in intensive critical care - defined by a normal blood pressure maintained without any vasopressor or inotropic support, invasive monitoring using PICCO device and abdominal pressure monitoring. Results: The patients were divided into two groups based on the intraabdominal pressure values: normal intraabdominal pressure group= 52 values and increased intraabdominal group= 35 values. We compared the groups in the light of NGAL values, 24 hours diuresis, GFR and creatinine clearance. The groups are significantly different when compared in the light of NGAL values and GFR values. We obtained a statistically significant correlation between NGAL value and 24 hour diuresis. No other significant correlations were encountered between the studied items. Conclusions: NGAL values are increased in patients with high intraabdominal pressure which may suggest its utility as a cut off marker for patients with increased intraabdominal pressure. There is a significant decreased GFR in patient with elevated intraabdominal pressure, observation which can help in early detection of renal injury in patients due to high intraabdominal pressure. No correlation was found between creatinine clearance and increased intraabdominal pressure.

scholarly journals Influence of Mechanical Ventilation on the Pharmacokinetics of Vancomycin Administered by Continuous Infusion in Critically Ill Patients

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Susanna Edith Medellín-Garibay ◽  
Silvia Romano-Moreno ◽  
Pilar Tejedor-Prado ◽  
Noelia Rubio-Álvaro ◽  
Aida Rueda-Naharro ◽  
...  
Keyword(s):  
Mechanical Ventilation ◽  
Creatinine Clearance ◽  
Continuous Infusion ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Population Pharmacokinetic Model ◽  
Pharmacokinetic Model ◽  
Volume Of Distribution ◽  
Stochastic Simulations ◽  
Population Pharmacokinetic

ABSTRACT Pathophysiological changes involved in drug disposition in critically ill patients should be considered in order to optimize the dosing of vancomycin administered by continuous infusion, and certain strategies must be applied to reach therapeutic targets on the first day of treatment. The aim of this study was to develop a population pharmacokinetic model of vancomycin to determine clinical covariates, including mechanical ventilation, that influence the wide variability of this antimicrobial. Plasma vancomycin concentrations from 54 critically ill patients were analyzed simultaneously by a population pharmacokinetic approach. A nomogram for dosing recommendations was developed and was internally evaluated through stochastic simulations. The plasma vancomycin concentration-versus-time data were best described by a one-compartment open model with exponential interindividual variability associated with vancomycin clearance and the volume of distribution. Residual error followed a homoscedastic trend. Creatinine clearance and body weight significantly dropped the objective function value, showing their influence on vancomycin clearance and the volume of distribution, respectively. Characterization based on the presence of mechanical ventilation demonstrated a 20% decrease in vancomycin clearance. External validation (n = 18) was performed to evaluate the predictive ability of the model; median bias and precision values were 0.7 mg/liter (95% confidence interval [CI], −0.4, 1.7) and 5.9 mg/liter (95% CI, 5.4, 6.4), respectively. A population pharmacokinetic model was developed for the administration of vancomycin by continuous infusion to critically ill patients, demonstrating the influence of creatinine clearance and mechanical ventilation on vancomycin clearance, as well as the implications for targeting dosing rates to reach the therapeutic range (20 to 30 mg/liter).

scholarly journals Population Pharmacokinetic Analysis of Vancomycin Using Serum Cystatin C as a Marker of Renal Function

2009 ◽  
Vol 54 (2) ◽  
pp. 778-782 ◽  
Author(s):  
Akihiro Tanaka ◽  
Tetsuya Aiba ◽  
Takashi Otsuka ◽  
Katsuya Suemaru ◽  
Tatsuya Nishimiya ◽  
...  
Keyword(s):  
Renal Function ◽  
Cystatin C ◽  
Predictive Performance ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Population Pharmacokinetic ◽  
Serum Cystatin C ◽  
Serum Cystatin ◽  
New Model ◽  
The Mean

ABSTRACT We determined the population pharmacokinetics of vancomycin (VAN) using the glomerular filtration rate (GFR) estimated from the serum cystatin C concentration. We examined the predictive performance of the trough serum VAN concentration for determination of the initial dose by using a new model for the analysis of the population pharmacokinetic parameters. Data for 86 patients were used to estimate the values of the population pharmacokinetic parameters. Analysis with a nonlinear mixed-effects modeling program was done by using a one-compartment model. Data for 78 patients were used to evaluate the predictive performance of the new model for the analysis of population pharmacokinetic parameters. The estimated GFR values determined by using Hoek's formula correlated linearly with VAN clearance (VAN clearance [ml/min] = 0.825 × GFR). The mean volume of distribution was 0.864 (liters/kg). The interindividual variability of VAN clearance was 19.8%. The accuracy of the prediction determined by use of the new model was statistically better than that determined by use of the Japanese nomogram-based model because the 95% confidence interval (−3.45 to −1.38) of the difference in each value of the mean absolute error (−2.41) did not include 0. Use of the serum cystatin C concentration as a marker of renal function for prediction of serum VAN concentrations may be useful.

scholarly journals Population Pharmacokinetic Analysis of Colistin Methanesulfonate and Colistin after Intravenous Administration in Critically Ill Patients with Infections Caused by Gram-Negative Bacteria

2009 ◽  
Vol 53 (8) ◽  
pp. 3430-3436 ◽  
Author(s):  
D. Plachouras ◽  
M. Karvanen ◽  
L. E. Friberg ◽  
E. Papadomichelakis ◽  
A. Antoniadou ◽  
...  
Keyword(s):  
Steady State ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Compartment Model ◽  
Population Pharmacokinetic Analysis ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Colistin Methanesulfonate

ABSTRACT Colistin is used to treat infections caused by multidrug-resistant gram-negative bacteria (MDR-GNB). It is administered intravenously in the form of colistin methanesulfonate (CMS), which is hydrolyzed in vivo to the active drug. However, pharmacokinetic data are limited. The aim of the present study was to characterize the pharmacokinetics of CMS and colistin in a population of critically ill patients. Patients receiving colistin for the treatment of infections caused by MDR-GNB were enrolled in the study; however, patients receiving a renal replacement therapy were excluded. CMS was administered at a dose of 3 million units (240 mg) every 8 h. Venous blood was collected immediately before and at multiple occasions after the first and the fourth infusions. Plasma CMS and colistin concentrations were determined by a novel liquid chromatography-tandem mass spectrometry method after a rapid precipitation step that avoids the significant degradation of CMS and colistin. Population pharmacokinetic analysis was performed with the NONMEM program. Eighteen patients (6 females; mean age, 63.6 years; mean creatinine clearance, 82.3 ml/min) were included in the study. For CMS, a two-compartment model best described the pharmacokinetics, and the half-lives of the two phases were estimated to be 0.046 h and 2.3 h, respectively. The clearance of CMS was 13.7 liters/h. For colistin, a one-compartment model was sufficient to describe the data, and the estimated half-life was 14.4 h. The predicted maximum concentrations of drug in plasma were 0.60 mg/liter and 2.3 mg/liter for the first dose and at steady state, respectively. Colistin displayed a half-life that was significantly long in relation to the dosing interval. The implications of these findings are that the plasma colistin concentrations are insufficient before steady state and raise the question of whether the administration of a loading dose would benefit critically ill patients.

scholarly journals Population Pharmacokinetics of Piperacillin in Nonobese, Obese, and Morbidly Obese Critically Ill Patients

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Abdulaziz S. Alobaid ◽  
Steven C. Wallis ◽  
Paul Jarrett ◽  
Therese Starr ◽  
Janine Stuart ◽  
...  
Keyword(s):  
Critical Illness ◽  
Population Pharmacokinetics ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Central Compartment ◽  
Pharmacokinetic Analysis ◽  
Peripheral Compartment ◽  
Morbidly Obese ◽  
Obese Patients ◽  
Intercompartmental Clearance

ABSTRACT The treatment of infections in critically ill obese and morbidly obese patients is challenging because of the combined physiological changes that result from obesity and critical illness. The aim of this study was to describe the population pharmacokinetics of piperacillin in a cohort of critically ill patients, including obese and morbidly obese patients. Critically ill patients who received piperacillin-tazobactam were classified according to their body mass index (BMI) as nonobese, obese, and morbidly obese. Plasma samples were collected, and piperacillin concentrations were determined by a validated chromatographic method. Population pharmacokinetic analysis and Monte Carlo dosing simulations were performed using Pmetrics software. Thirty-seven critically ill patients (including 12 obese patients and 12 morbidly obese patients) were enrolled. The patients' mean ± standard deviation age, weight, and BMI were 50 ± 15 years, 104 ± 35 kg, and 38.0 ± 15.0 kg/m2, respectively. The concentration-time data were best described by a two-compartment linear model. The mean ± SD parameter estimates for the final covariate model were a clearance of 14.0 ± 7.1 liters/h, a volume of distribution of the central compartment of 49.0 ± 19.0 liters, an intercompartmental clearance from the central compartment to the peripheral compartment of 0.9 ± 0.6 liters · h−1, and an intercompartmental clearance from the peripheral compartment to the central compartment of 2.3 ± 2.8 liters · h−1. A higher measured creatinine clearance and shorter-duration infusions were associated with a lower likelihood of achieving therapeutic piperacillin exposures in patients in all BMI categories. Piperacillin pharmacokinetics are altered in the presence of obesity and critical illness. As with nonobese patients, prolonged infusions increase the likelihood of achieving therapeutic concentrations.

scholarly journals New Colistin Population Pharmacokinetic Data in Critically Ill Patients Suggesting an Alternative Loading Dose Rationale

2014 ◽  
Vol 58 (12) ◽  
pp. 7324-7330 ◽  
Author(s):  
N. Grégoire ◽  
O. Mimoz ◽  
B. Mégarbane ◽  
E. Comets ◽  
D. Chatelier ◽  
...  
Keyword(s):  
Steady State ◽  
Critically Ill ◽  
Critically Ill Patients ◽  
Plasma Concentrations ◽  
Multidrug Resistant ◽  
Pharmacokinetic Analysis ◽  
Population Pharmacokinetic ◽  
Pharmacokinetic Data ◽  
Loading Dose ◽  
Liquid Chromatography Tandem Mass

ABSTRACTColistin is an old antibiotic that has recently gained a considerable renewal of interest as the last-line defense therapy against multidrug-resistant Gram-negative bacteria. It is administered as colistin methanesulfonate (CMS), an inactive prodrug, and it was shown that due to slow CMS conversion, colistin plasma concentrations increase very slowly after treatment initiation, which constitutes the rationale for a loading dose in critically ill patients. However, faster CMS conversion was observed in healthy volunteers but using a different CMS brand, which may also have a major impact on colistin pharmacokinetics. Seventy-three critically ill patients not undergoing dialysis received multiple doses of CMS. The CMS concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and a pharmacokinetic analysis was conducted using a population approach. We confirmed that CMS renal clearance and colistin concentrations at steady state are mostly governed by creatinine clearance, but we predict a typical maximum concentration of drug in serum (Cmax) of colistin close to 2 mg/liter, occurring 3 h after an initial dose of 2 million international units (MIU) of CMS. Accordingly, the estimated colistin half-life (t1/2) was relatively short (3.1 h), with rapid attainment of steady state. Our results are only partially consistent with other recently published results. We confirm that the CMS maintenance dose should be adjusted according to renal function in critically ill patients. However, much higher than expected colistin concentrations were observed after the initial CMS dose, with rapid steady-state achievement. These discrepancies challenge the pharmacokinetic rationale for a loading dose, which may still be appropriate for rapid bacterial eradication and an improved clinical cure rate.

scholarly journals Area under the Curve-Based Dosing of Vancomycin in Critically Ill Patients Using 6-Hour Urine Creatinine Clearance Measurement

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Bita Shahrami ◽  
Farhad Najmeddin ◽  
Saeideh Ghaffari ◽  
Atabak Najafi ◽  
Mohammad Reza Rouini ◽  
...  
Keyword(s):  
Renal Function ◽  
Creatinine Clearance ◽  
Critically Ill ◽  
Normal Renal Function ◽  
Critically Ill Patients ◽  
Area Under The Curve ◽  
Total Daily Dose ◽  
Pharmacokinetic Parameters ◽  
Concentration Data ◽  
Urine Creatinine

Background. The area under the curve- (AUC-) guided vancomycin dosing is the best strategy for individualized therapy in critical illnesses. Since AUC can be calculated directly using drug clearance (CLvan), any parameter estimating CLvan will be able to achieve the goal of 24-hour AUC (AUC24 h). The present study was aimed to determine CLvan based on 6-hour urine creatinine clearance measurement in critically ill patients with normal renal function. Method. 23 adult critically ill patients with an estimated glomerular filtration rate (eGFR) ≥60 mL/min who received vancomycin infusion were enrolled in this pilot study. Vancomycin pharmacokinetic parameters were determined for each patient using serum concentration data and a one-compartment model provided by MONOLIX software using stochastic approximation expectation-maximization (SAEM) algorithm. Correlation of CLvan with the measured creatinine clearance in 6-hour urine collection (CL6 h) and estimated creatinine clearance by the Cockcroft–Gault formula (CLCG) was investigated. Results. Data analysis revealed that CL6 h had a stronger correlation with CLvan rather than CLCG (r = 0.823 vs. 0.594; p < 0.001 vs. 0.003). The relationship between CLvan and CL6 h was utilized to develop the following equation for estimating CLvan: CLvan (mL/min) = ─137.4 + CL6 h (mL/min) + 2.5 IBW (kg) (R2 = 0.826, p < 0.001 ). Regarding the described model, the following equation can be used to calculate the empirical dose of vancomycin for achieving the therapeutic goals in critically ill patients without renal impairment: total daily dose of vancomycin (mg) = (─137.4CL6-h (mL/min) + 2.5 IBW (kg)) × 0.06 AUC24 h (mg.hr/L). Conclusion. For AUC estimation, CLvan can be obtained by collecting urine in a 6-hour period with good approximation in critically ill patients with normal renal function.

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