scholarly journals Protein Binding of β-Lactam Antibiotics in Critically Ill Patients: Can We Successfully Predict Unbound Concentrations?

2013 ◽  
Vol 57 (12) ◽  
pp. 6165-6170 ◽  
Author(s):  
Gloria Wong ◽  
Scott Briscoe ◽  
Syamhanin Adnan ◽  
Brett McWhinney ◽  
Jacobus Ungerer ◽  
...  

ABSTRACTThe use of therapeutic drug monitoring (TDM) to optimize beta-lactam dosing in critically ill patients is growing in popularity, although there are limited data describing the potential impact of altered protein binding on achievement of target concentrations. The aim of this study was to compare the measured unbound concentration to the unbound concentration predicted from published protein binding values for seven beta-lactams using data from blood samples obtained from critically ill patients. From 161 eligible patients, we obtained 228 and 220 plasma samples at the midpoint of the dosing interval and trough, respectively, for ceftriaxone, cefazolin, meropenem, piperacillin, ampicillin, benzylpenicillin, and flucloxacillin. The total and unbound beta-lactam concentrations were measured using validated methods. Variabilities in both unbound and total concentrations were marked for all antibiotics, with significant differences being present between measured and predicted unbound concentrations for ceftriaxone and for flucloxacillin at the mid-dosing interval (P< 0.05). The predictive performance for calculating unbound concentrations using published protein binding values was poor, with bias for overprediction of unbound concentrations for ceftriaxone (83.3%), flucloxacillin (56.8%), and benzylpenicillin (25%) and underprediction for meropenem (12.1%). Linear correlations between the measured total and unbound concentrations were observed for all beta-lactams (R2= 0.81 to 1.00;P< 0.05) except ceftriaxone and flucloxacillin. The percent protein binding of flucloxacillin and the plasma albumin concentration were also found to be linearly correlated (R2= 0.776;P< 0.01). In conclusion, significant differences between measured and predicted unbound drug concentrations were found only for the highly protein-bound beta-lactams ceftriaxone and flucloxacillin. However, direct measurement of unbound drug in research and clinical practice is suggested for selected beta-lactams.

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Brandon Ferlas ◽  
Kristina Nelson ◽  
Milind Junghare ◽  
Kimberly Boeser

Background: Literature has demonstrated proper antibiotic selection and prompt initiation of antibiotics are associated with lower morbidity and mortality. Septic patients have altered pharmacokinetics and often require continuous renal replacement therapy which contributes to altered drug clearance and metabolism. The current study evaluates the pharmacokinetics of meropenem and piperacillin/tazobactam in critically-ill patients requiring continuous veno-venous hemodiafiltration. Purpose: This observational, prospective, single-center, nonrandomized study evaluated the pharmacokinetics of meropenem and piperacillin/tazobactam in critically-ill patients requiring continuous veno-venous hemodiafiltration. Methods: Plasma drug concentrations were determined via high-performance liquid chromatography using three post-dose blood samples after steady-state antimicrobial agent administration. Results: Meropenem peak drug concentrations ranged from 35.9 to 61 mcg/mL, while trough concentrations ranged from 3.9 to 16.7 mcg/mL. Piperacillin peak drug concentrations ranged from 240 to 331.8 mcg/mL, while trough concentrations ranged from 152.7 to 194.9 mcg/mL. Both drugs examined displayed peak concentrations relatively consistent with those expected from the literature, but observed trough concentrations for meropenem and piperacillin were uniformly high. Conclusions: Intravenous doses of meropenem and piperacillin result in peak drug concentrations similar to those previously reported and trough concentrations significantly greater than those in the literature. While concentrations above an organism’s MIC are desirable given the time-dependent nature of these beta-lactam antibiotics, decreased renal clearance of patients maintained on CVVHDF therapy while receiving higher doses of antimicrobials creates a situation in which drug accumulation and toxicity may occur. Given the complex nature of ICU patient care, increased pharmacovigilance and therapeutic drug monitoring are necessary in this unique population.   Type: Original Research


Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1311
Author(s):  
Milo Gatti ◽  
Pier Giorgio Cojutti ◽  
Renato Pascale ◽  
Tommaso Tonetti ◽  
Cristiana Laici ◽  
...  

Background: Emerging data suggest that more aggressive beta-lactam PK/PD targets could minimize the occurrence of microbiological failure and/or resistance development. This study aims to assess whether a PK/PD target threshold of continuous infusion (CI) beta-lactams may be useful in preventing microbiological failure and/or resistance development in critically ill patients affected by documented Gram-negative infections. Methods: Patients admitted to intensive care units from December 2020 to July 2021 receiving continuous infusion beta-lactams for documented Gram-negative infections and having at least one therapeutic drug monitoring in the first 72 h of treatment were included. A receiver operating characteristic (ROC) curve analysis was performed using the ratio between steady-state concentration and minimum inhibitory concentration (Css/MIC) ratio as the test variable and occurrence of microbiological failure as the state variable. Area under the curve (AUC) and 95% confidence interval (CI) were calculated. Independent risk factors for the occurrence of microbiological failure were investigated using logistic regression. Results: Overall, 116 patients were included. Microbiological failure occurred in 26 cases (22.4%). A Css/MIC ratio ≤ 5 was identified as PK/PD target cut-off with sensitivity of 80.8% (CI 60.6–93.4%) and specificity of 90.5% (CI 74.2–94.4%), and with an AUC of 0.868 (95%CI 0.793–0.924; p < 0.001). At multivariate regression, independent predictors of microbiological failure were Css/MIC ratio ≤ 5 (odds ratio [OR] 34.54; 95%CI 7.45–160.11; p < 0.001) and Pseudomonas aeruginosa infection (OR 4.79; 95%CI 1.11–20.79; p = 0.036). Conclusions: Early targeting of CI beta-lactams at Css/MIC ratio > 5 during the treatment of documented Gram-negative infections may be helpful in preventing microbiological failure and/or resistance development in critically ill patients.


2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Alan Abdulla ◽  
Puck van den Broek ◽  
Tim M.J. Ewoldt ◽  
Anouk E. Muller ◽  
Henrik Endeman ◽  
...  

2007 ◽  
Vol 51 (9) ◽  
pp. 3304-3310 ◽  
Author(s):  
Samir G. Sakka ◽  
Anna K. Glauner ◽  
Jürgen B. Bulitta ◽  
Martina Kinzig-Schippers ◽  
Wolfgang Pfister ◽  
...  

ABSTRACT Beta-lactams are regularly administered in intermittent short-term infusions. The percentage of the dosing interval during which free drug concentrations exceed the MIC (fT >MIC) is the measure of drug exposure that best correlates with clinical outcome for beta-lactams. Therefore, administration by continuous infusion has gained increasing interest recently. We studied 20 critically ill patients with nosocomial pneumonia and investigated whether continuous infusion with a reduced total dose, compared to the standard regimen of intermittent short-term infusion, results in a superior probability of target attainment as assessed by the fT >MIC value of imipenem. In this prospective, randomized, controlled clinical study, patients received either a loading dose of 1 g/1 g imipenem and cilastatin (as a short-term infusion) at time zero, followed by 2 g/2 g imipenem-cilastatin per 24 h as a continuous infusion for 3 days (n = 10), or 1 g/1 g imipenem-cilastatin three times per day as a short-term infusion for 3 days (total daily dose, 3 g/3 g; n = 10). Imipenem concentrations in plasma were determined by using a validated liquid chromatography-tandem mass spectrometry assay. A two-compartment open model was employed for population pharmacokinetic modeling. We simulated 10,000 intensive-care-unit patients via Monte Carlo simulations for pharmacodynamic evaluation using the target 40% fT >MIC. The probability of target attainment by MIC for intermittent infusion was robust (>90%) up to MICs of 1 to 2 mg/liter. The corresponding value for continuous infusion was 2 to 4 mg/liter. Although all 20 patients had an fT >MIC of 100%, 3 patients died. Patient survival was best described by employing a sepsis-related organ failure assessment score as a covariate in a logistic regression analysis. Larger clinical trials are warranted for evaluation of continuous infusions at a reduced dose of imipenem for critically ill patients.


Author(s):  
Heleen Aardema ◽  
Wouter Bult ◽  
Kai van Hateren ◽  
Willem Dieperink ◽  
Daan J Touw ◽  
...  

Abstract Background In critical care patients, reaching optimal β-lactam concentrations poses challenges, as infections are caused more often by microorganisms associated with higher MICs, and critically ill patients typically have an unpredictable pharmacokinetic/pharmacodynamic profile. Conventional intermittent dosing frequently yields inadequate drug concentrations, while continuous dosing might result in better target attainment. Few studies address cefotaxime concentrations in this population. Objectives To assess total and unbound serum levels of cefotaxime and an active metabolite, desacetylcefotaxime, in critically ill patients treated with either continuously or intermittently dosed cefotaxime. Methods Adult critical care patients with indication for treatment with cefotaxime were randomized to treatment with either intermittent dosing (1 g every 6 h) or continuous dosing (4 g/24 h, after a loading dose of 1 g). We defined a preset target of reaching and maintaining a total cefotaxime concentration of 4 mg/L from 1 h after start of treatment. CCMO trial registration number NL50809.042.14, Clinicaltrials.gov NCT02560207. Results Twenty-nine and 30 patients, respectively, were included in the continuous dosing group and the intermittent dosing group. A total of 642 samples were available for analysis. In the continuous dosing arm, 89.3% met our preset target, compared with 50% in the intermittent dosing arm. Patients not reaching this target had a significantly higher creatinine clearance on the day of admission. Conclusions These results support the application of a continuous dosing strategy of β-lactams in critical care patients and the practice of therapeutic drug monitoring in a subset of patients with higher renal clearance and need for prolonged treatment for further optimization, where using total cefotaxime concentrations should suffice.


Antibiotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 131
Author(s):  
Christina Scharf ◽  
Michael Paal ◽  
Ines Schroeder ◽  
Michael Vogeser ◽  
Rika Draenert ◽  
...  

Various studies have reported insufficient beta-lactam concentrations in critically ill patients. The extent to which therapeutic drug monitoring (TDM) in clinical practice can reduce insufficient antibiotic concentrations is an ongoing matter of investigation. We retrospectively evaluated routine meropenem and piperacillin measurements in critically ill patients who received antibiotics as short infusions in the first year after initiating a beta-lactam TDM program. Total trough concentrations above 8.0 mg/L for meropenem and above 22.5 mg/L for piperacillin were defined as the breakpoints for target attainment. We included 1832 meropenem samples and 636 piperacillin samples. We found that 39.3% of meropenem and 33.6% of piperacillin samples did not reach the target concentrations. We observed a clear correlation between renal function and antibiotic concentration (meropenem, r = 0.53; piperacillin, r = 0.63). Patients with renal replacement therapy or creatinine clearance (CrCl) of <70 mL/min had high rates of target attainment with the standard dosing regimens. There was a low number of patients with a CrCl >100 mL/min that achieved the target concentrations with the maximum recommended dosage. Patients with impaired renal function only required TDM if toxic side effects were noted. In contrast, patients with normal renal function required different dosage regimens and TDM-guided therapy to reach the breakpoints of target attainment.


2020 ◽  
Author(s):  
Chien-Huei Huang ◽  
Ching-Yao Shih ◽  
Meng Keng Tsay ◽  
Shen-Pei Hsuan ◽  
Yung-Hsin Tseng ◽  
...  

Abstract Background: The pathophysiologic changes during critical illness and high minimal inhibitory concentration (MIC) pathogens are important risk factors of mortality and bacterial eradication in critical care. Beta-lactam antibiotics have a time-dependent effect on bactericidal activity. The continuous infusion (CIF) of beta-lactam antibiotics achieves sufficient drug concentration above the MIC, especially for critically ill patients. However, the superiority of CIF over intermittent infusion (IIF) of beta-lactam antibiotics is yet to be clearly established. Thus, we aimed to investigate the effects on mortality of CIF of beta-lactams antibiotics in comparison to those of IIF of beta-lactams antibiotics in patients with sepsis admitted to the intensive care unit (ICU).Methods: We systematically searched PUBMED, MEDLINE, Cochrane Library, EMBASE, Web of Science, and ICTRP for randomized controlled trials (RCTs) comparing CIF with IIF of beta-lactam antibiotics in critically ill populations. All RCTs published until October 2019 were eligible. The primary outcome measure was the relative risk (RR) of mortality, while the secondary outcome measures were bacterial eradication rate, length of ICU stay, and length of admission. Results: In total, 6 RCTs comprising 974 patients were analyzed. We found a significantly lower mortality for critically ill patients on CIF (RR: 0.79; 95% CI: 0.63, 0.98) compared with those on IIF of beta-lactam antibiotics. The pooled RR for the bacterial eradication rate was 1.16 (95% CI: 1.03, 1.29) for CIF compared with IIF administration. Conclusion: CIF of beta-lactam antibiotics for critically ill patients significantly reduces mortality and yields a better bacterial eradication rate than IIF. These findings support the clinical and bacterial eradication benefits in adult critically ill patients, and may guide clinical discussions and decisions.


2019 ◽  
Vol 76 (18) ◽  
pp. 1383-1394 ◽  
Author(s):  
Melanie Chen ◽  
Valerie Buurma ◽  
Monica Shah ◽  
Germin Fahim

AbstractPurposeTo summarize the current literature on the use and clinical efficacy of extended-infusion (EI) beta-lactam antibiotics, including piperacillin–tazobactam, meropenem, and cefepime.SummaryGram-negative infections are a serious concern among hospitalized patients and require innovative pharmacokinetic dosing strategies to achieve clinical success, especially as the emergence of resistant gram-negative pathogens has outpaced the development of new antibiotics. Beta-lactam antibiotics exhibit time-dependent activity, which means that optimal efficacy is achieved when free drug concentrations stay above the minimum inhibitory concentration for an extended duration of the recommended dosage interval. EI piperacillin–tazobactam therapy has demonstrated improved clinical outcomes and decrease mortality in critically ill patients with gram-negative infections, particularly Pseudomonas aeruginosa infections. EI meropenem has shown higher therapeutic success rates for patients with febrile neutropenia and shorter intensive care unit (ICU) length of stay (LOS) with a reduction in ventilator days in patients with multidrug-resistant ventilator-associated pneumonia. However, a larger study showed no difference in clinical outcomes between standard-infusion and EI meropenem. EI cefepime has been associated with decreased mortality and shorter ICU LOS in patients with Pseudomonas aeruginosa infections. Common challenges associated with EI beta-lactam antibiotics include Y-site incompatibilities, lack of intravenous access, and tubing residuals. It is important to note that factors such as diverse patient populations and study methodology, along with various antibiotic dose regimens, may have contributed to conflicting data on EI beta-lactam therapy.ConclusionBased on most published literature, there appears to be a favorable trend toward use of EI beta-lactam therapy in clinical practice, particularly in critically ill patients with gram-negative infections.


2019 ◽  
Vol 64 (1) ◽  
Author(s):  
Stijn Jonckheere ◽  
Nikolaas De Neve ◽  
Jan Verbeke ◽  
Koen De Decker ◽  
Inger Brandt ◽  
...  

ABSTRACT Attainment of appropriate pharmacokinetic-pharmacodynamic (PK-PD) targets for antimicrobial treatment is challenging in critically ill patients, particularly for cefepime, which exhibits a relative narrow therapeutic-toxic window compared to other beta-lactam antibiotics. Target-controlled infusion (TCI) systems, which deliver drugs to achieve specific target drug concentrations, have successfully been implemented for improved dosing of sedatives and analgesics in anesthesia. We conducted a clinical trial in an intensive care unit (ICU) to investigate the performance of TCI for adequate target attainment of cefepime. Twenty-one patients treated with cefepime according to the standard of care were included. Cefepime was administered through continuous infusion using TCI for a median duration of 4.5 days. TCI was based on a previously developed population PK model incorporating the estimated creatinine clearance based on the Cockcroft-Gault formula as the input variable to calculate cefepime clearance. A cefepime blood concentration of 16 mg/liter was targeted. To evaluate the measured versus predicted plasma concentrations, blood samples were taken (median of 10 samples per patient), and total cefepime concentrations were measured using ultraperformance liquid chromatography-tandem mass spectrometry. The performance of the TCI system was evaluated using Varvel criteria. Half (50.3%) of the measured cefepime concentrations were within ±30% around the target value of 16 mg liter−1. The wobble was 11.4%, the median performance error (MdPE) was 21.1%, the median absolute performance error (MdAPE) was 32.0%, and the divergence was −3.72% h−1. Based on these results, we conclude that TCI is useful for dose optimization of cefepime in ICU patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02688582.)


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