Augmented Renal Clearance in Critical Illness: An Important Consideration in Drug Dosing

Development and External Validation of an Online Clinical Prediction Model for Augmented Renal Clearance in Adult Mixed Critically Ill Patients: The Augmented Renal Clearance Predictor

OBJECTIVES

Augmented renal clearance might lead to subtherapeutic plasma levels of drugs with predominant renal clearance. Early identification of augmented renal clearance remains challenging for the ICU physician. We developed and validated our augmented renal clearance predictor, a clinical prediction model for augmented renal clearance on the next day during ICU stay, and made it available via an online calculator. We compared its predictive performance with that of two existing models for augmented renal clearance.

DESIGN

Multicenter retrospective registry-based cohort study.

SETTING

Three Belgian tertiary care academic hospitals.

PATIENTS

Adult medical, surgical, and cardiac surgery ICU patients.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Development of the prediction model was based on clinical information available during ICU stay. Out of 33,258 ICU days, we found augmented renal clearance on 19.6% of all ICU days in the development cohort. We retained six clinical variables in our augmented renal clearance predictor: day from ICU admission, age, sex, serum creatinine, trauma, and cardiac surgery. We assessed performance by measuring discrimination, calibration, and net benefit. We externally validated the final model in a single-center population (n = 10,259 ICU days). External validation confirmed good performance with an area under the curve of 0.88 (95% CI 0.87-0.88) and a sensitivity and specificity of 84.1 (95% CI 82.5-85.7) and 76.3 (95% CI 75.4-77.2) at the default threshold probability of 0.2, respectively.

CONCLUSIONS

Augmented renal clearance on the next day can be predicted with good performance during ICU stay, using routinely collected clinical information that is readily available at bedside. Our augmented renal clearance predictor is available at www.arcpredictor.com.

Design and conduct considerations for studies in patients with impaired renal function

An impaired renal function, including acute and chronic kidney disease and end‐stage renal disease, can be the result of aging, certain disease conditions, the use of some medications, or as a result of smoking. In patients with renal impairment (RI), the pharmacokinetics (PKs) of drugs or drug metabolites may change and result in increased safety risks or decreased efficacy. In order to make specific dose recommendations in the label of drugs for patients with RI, a clinical trial may have to be conducted or, when not feasible, modeling and simulations approaches, such as population PK modeling or physiologically‐based PK modelling may be applied. This tutorial aims to provide an overview of the global regulatory landscape and a practical guidance for successfully designing and conducting clinical RI trials or, alternatively, on applying modeling and simulation tools to come to a dose recommendation for patients with RI in the most efficient manner.

Augmented renal clearance: a retrospective, cohort study of urinary creatinine clearance in critically ill patients in the United Kingdom

OBJECTIVE

Augmented renal clearance (ARC) is associated with sub-therapeutic antibiotic, anti-epileptic, and anticoagulant serum concentrations leading to adverse patient outcomes. We aimed to describe the prevalence and associated risk factors for ARC development in a large, single-centre cohort in the United Kingdom.

METHODS

We conducted a retrospective observational study of critically unwell patients admitted to intensive care between 2014 and 2016. Urinary creatinine clearance was used to determine the ARC prevalence during the first 7 days of admission. Repeated measures logistic regression was used to determine risk factors for ARC development.

RESULTS

The ARC prevalence was 47.0% (95% confidence interval [95%CI]: 44.3%-49.7%). Age, sex, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and sepsis diagnosis were significantly associated with ARC. ARC was more prevalent in younger vs. older (odds ratio [OR] 0.95 [95%CI: 0.94-0.96]), male vs. female (OR 0.32 [95%CI: 0.26-0.40]) patients with lower vs. higher APACHE II scores (OR 0.94 [95%CI: 0.92-0.96]).

CONCLUSIONS

This patient group probably remains unknown to many clinicians because measuring urinary creatinine clearance is not usually indicated in this group. Clinicians should be aware of the ARC risk in this group and consider measurement of urinary creatinine clearance.

SARS-CoV-2 Renal Impairment in Critical Care: An Observational Study of 42 Cases (Kidney COVID)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to 5% to 16% hospitalization in intensive care units (ICU) and is associated with 23% to 75% of kidney impairments, including acute kidney injury (AKI). The current work aims to precisely characterize the renal impairment associated to SARS-CoV-2 in ICU patients. Forty-two patients consecutively admitted to the ICU of a French university hospital who tested positive for SARS-CoV-2 between 25 March 2020, and 29 April 2020, were included and classified in categories according to their renal function. Complete renal profiles and evolution during ICU stay were fully characterized in 34 patients. Univariate analyses were performed to determine risk factors associated with AKI. In a second step, we conducted a logistic regression model with inverse probability of treatment weighting (IPTW) analyses to assess major comorbidities as predictors of AKI. Thirty-two patients (94.1%) met diagnostic criteria for intrinsic renal injury with a mixed pattern of tubular and glomerular injuries within the first week of ICU admission, which lasted upon discharge. During their ICU stay, 24 patients (57.1%) presented AKI which was associated with increased mortality (p = 0.007), hemodynamic failure (p = 0.022), and more altered clearance at hospital discharge (p = 0.001). AKI occurrence was associated with lower pH (p = 0.024), higher PaCO₂ (CO₂ partial pressure in the arterial blood) (p = 0.027), PEEP (positive end-expiratory pressure) (p = 0.027), procalcitonin (p = 0.015), and CRP (C-reactive protein) (p = 0.045) on ICU admission. AKI was found to be independently associated with chronic kidney disease (adjusted OR (odd ratio) 5.97 (2.1-19.69), p = 0.00149). Critical SARS-CoV-2 infection is associated with persistent intrinsic renal injury and AKI, which is a risk factor of mortality. Mechanical ventilation settings seem to be a critical factor of kidney impairment.

Is Therapeutic Drug Monitoring of Lacosamide Needed in Patients with Seizures and Epilepsy?

Lacosamide is an antiepileptic drug (AED) that has linear pharmacokinetics, predictable blood concentrations, and few drug interactions, setting it apart from other AEDs that require vigorous therapeutic drug monitoring (TDM) such as phenytoin and carbamazepine. However, there have been reports of altered lacosamide pharmacokinetics in some populations. The purpose of this review is to determine whether lacosamide pharmacokinetics are altered in certain patient populations, suggesting the need for TDM. A literature search of Medline, Scopus, Embase, and Cochrane trials was conducted on January 3, 2019 (and then updated on September 2, 2019) to search for articles relevant to the TDM or pharmacokinetics of lacosamide. A total of 56 relevant articles were found and included in this review. Dose of lacosamide is linearly correlated with plasma concentrations and efficacy. However, currently there is no well-established reference range. Overall, the recommended reference ranges varied from 2.2 to 20 mg/L. Lacosamide has very few clinically relevant drug-drug interactions; however, there seems to be a significant drug interaction between lacosamide and enzyme-inducer AEDs. Based on available literature, it appears that lacosamide pharmacokinetics may be altered in severe renal dysfunction, in patients on dialysis and with extremes of age. More evidence is currently needed on lacosamide pharmacokinetics in pregnancy and critical illness. While it is not practical to utilize TDM for all patients, TDM may be useful in patients taking enzyme-inducer AEDs, in patients with decreased renal function or on dialysis, and older adults.

Augmented renal clearance. An unnoticed relevant event

Augmented renal clearance (ARC) is a phenomenon that can lead to a therapeutic failure of those drugs of renal clearance. The purpose of the study was to ascertain the prevalence of ARC in the critically ill patient, to study the glomerular filtration rate (GFR) throughout the follow-up and analyze the concordance between the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimation formula and measured GFR. Observational, prospective, multicenter study. ARC was defined as a creatinine clearance greater than 130 ml/min/1.73 m2. Eighteen hospitals were recruited. GFR measurements carried out twice weekly during a 2-month follow-up period. A total of 561 patients were included. ARC was found to have a non-negligible prevalence of 30%. More even, up to 10.7% already had ARC at intensive care unit (ICU) admission. No specific pattern of GFR was found during the follow-up. Patients in the ARC group were younger 56.5 (53.5-58.5) versus 66 (63.5-68.5) years than in the non-ARC group, p < 0.001. ICU mortality was lower in the ARC group, 6.9% versus 14.5%, p = 0.003. There was no concordance between the estimation of GFR by the CKD-EPI formula and GFR calculated from the 4-h urine. ARC is found in up to 30% of ICU patients, so renal removal drugs could be under dosed by up to 30%. And ARC is already detected on admission in 10%. It is a dynamic phenomenon without an established pattern that usually occurs in younger patients that can last for several weeks. And the CKD-EPI formula does not work to estimate the real creatinine clearance of these patients.

Augmented Renal Clearance in a Case of Sepsis Leading to Vancomycin Failure Despite Increasing Dose As per the Estimated Glomerular Filtration Rate

Augmented renal clearance (ARC) is a unique clinical scenario observed in critically ill patients. We present a case of a 30-year-old male with sepsis secondary to methicillin-resistant Staphylococcus aureus (MRSA) bacteremia treated with vancomycin. ARC was observed in the patient with a maximum estimated glomerular filtration rate (eGFR) of 161.9 ml/min/1.73 m², and therapeutic drug monitoring was used to adjust the vancomycin dosage. Despite the maximal recommended dose of vancomycin, the therapeutic vancomycin level was not achieved, leading to treatment failure and subsequent mortality. Our case report suggests the necessity of other strategies, such as early dose adjustment of vancomycin based on vancomycin clearance and continuous vancomycin infusion, not merely conventional adjustment based on eGFR and vancomycin levels.

Augmented renal clearance in critically ill patients with cancer (ARCCAN Study): A prospective observational study evaluating prevalence and risk factors

Augmented renal clearance (ARC) is a phenomenon that has been associated with enhanced excretion of renally eliminated drugs, such as antimicrobials, which may result in subtherapeutic levels and potentially therapeutic failure. There has been limited data on ARC in critically ill patients with cancer. This study aimed to evaluate the prevalence of ARC and to identify risk factors associated with ARC in this patient population. This was a prospective study at an oncologic intensive care unit (ICU) which included adult patients with normal renal function, defined as serum creatinine ≤1 mg/dl and urine output >0.5 ml/kg/hr. The 24‐hour creatinine clearance (ClCr) study was used to determine ClCr, starting on day 1 of ICU admission, for 5 days or until ICU transfer or death. ARC was defined as ClCr >130 ml/min/1.73 m². Univariate and multivariate logistic regression analyses were performed to identify risk factors for ARC. Over the study period, 363 patients were enrolled who completed an average of 2.8 ± 1.5(SD) days in the study and contributed 977 ClCr measurements. The mean age was 52 ± 16(SD) years old, the majority had solid tumors (n = 264, 73%), mean APACHE II was 21 ± 8(SD), and the major admission diagnosis was respiratory failure (n = 165, 45%). ARC was reported in 116 (32%) patients on at least one of the study days. Over the study period, the incidence of ARC ranged between 15.6% and 24.3%. Age was the only risk factor significantly associated with ARC (OR 1.028, 95% CI 1.005–1.051).

Population Pharmacokinetic and Pharmacokinetic/Pharmacodynamic Analyses of Cefiderocol, a Parenteral Siderophore Cephalosporin, in Patients with Pneumonia, Bloodstream Infection/Sepsis, or Complicated Urinary Tract Infection

Cefiderocol is a novel siderophore cephalosporin with antibacterial activity against Gram-negative bacteria, including carbapenem-resistant strains. The standard dosing regimen of cefiderocol is 2 g administered every 8 hours over 3 hours infusion in patients with creatinine clearance (CrCL) of 60 to 119 ml/min, and it is adjusted for patients with <60 ml/min or ≥120 ml/min CrCL. A population pharmacokinetic (PK) model was constructed using 3,427 plasma concentrations from 91 uninfected subjects and 425 infected patients with pneumonia, bloodstream infection/sepsis (BSI/sepsis), and complicated urinary tract infection (cUTI). Plasma cefiderocol concentrations were adequately described by the population PK model, and CrCL was the most significant covariate. No other factors, including infection sites and mechanical ventilation, were clinically relevant, although the effect of infection sites was identified as a statistically significant covariate in the population PK analysis. No clear pharmacokinetic/pharmacodynamic relationship was found for any of the microbiological outcome, clinical outcome, or vital status. This is because the estimated percentage of time for which free plasma concentrations exceed the minimum inhibitory concentration (MIC) over dosing interval (%fT>MIC) was 100% in most of the enrolled patients. The probability of target attainment (PTA) for 100% fT>MIC was >90% against MICs of ≤4 μg/ml for all infection sites and renal function groups except for BSI/sepsis patients with normal renal function (85%). These study results support adequate plasma exposure can be achieved at the cefiderocol recommended dosing regimen for the infected patients, including the patients with augmented renal function, ventilation, and/or severe illness.

Pharmacokinetics and Pharmacodynamics of Ceftolozane/Tazobactam in Critically Ill Patients With Augmented Renal Clearance

OBJECTIVE

To determine whether established ceftolozane/tazobactam (C/T) dosing is adequate for patients with augmented renal clearance (ARC) and bacterial infection.

METHODS

ARC (creatinine clearance [CrCl] ≥ 130 mL/min) was confirmed by directly measured CrCl in 11 critically ill patients in a phase 1 pharmacokinetics study. Patients received 3 g C/T (ceftolozane 2 g/tazobactam 1 g) as a 60-minute intravenous infusion. Pharmacokinetic sampling occurred at 0 (predose), 1, 2, 4, 6, and 8 hours after the start of the infusion. Noncompartmental analyses were conducted on concentration data. The following pharmacodynamic targets were evaluated: time that free (unbound) drug concentrations exceeded the minimum inhibitory concentration (fT>MIC) of 4 μg/mL for ceftolozane and time that the unbound concentration exceeded the 1 μg/mL target threshold (fT>threshold = 1 µg/mL) for > 20% of the dosing interval for tazobactam. Safety was evaluated.

RESULTS

Mean (SD) area under the plasma concentration-time curve from 0 to infinity, clearance and volume of distribution at steady state (V_ss) were 236 (118) h*µg/mL, 10.4 (4.5) L/h and 30.8 (10.8) L, respectively, for ceftolozane; and 35.5 (18.5) h*µg/mL, 35.3 (16.5) L/h and 54.8 (20.1) L, respectively, for tazobactam. Clearance and V_ss were higher for both ceftolozane and tazobactam in patients with ARC compared with healthy individuals. The mean estimated ceftolozane fT>MIC at 4 µg/mL was 86.4%; the mean estimated tazobactam fT>threshold = 1 µg/mL was 54.9%. Treatment-emergent adverse events were mild to moderate.

CONCLUSIONS

In patients with ARC, a 3 g C/T dose met respective pharmacodynamic targets for ceftolozane and tazobactam. CLINICALTRIALS.

GOV IDENTIFIER

NCT02387372.

Antimicrobial Stewardship in the Intensive Care Unit: The Role of Biomarkers, Pharmacokinetics, and Pharmacodynamics

The high prevalence of infectious diseases in the intensive care unit (ICU) and consequently elevated pressure for immediate and effective treatment have led to increased antimicrobial therapy consumption and misuse. Moreover, the emerging global threat of antimicrobial resistance and lack of novel antimicrobials justify the implementation of judicious antimicrobial stewardship programs (ASP) in the ICU. However, even though the importance of ASP is generally accepted, its implementation in the ICU is far from optimal and current evidence regarding strategies such as de-escalation remains controversial. The limitations of clinical guidance for antimicrobial therapy initiation and discontinuation have led to multiple studies for the evaluation of more objective tools, such as biomarkers as adjuncts for ASP. C-reactive protein and procalcitonin can be adequate for clinical use in acute infectious diseases, the latter being the most studied for ASP purposes. Although promising, current evidence highlights challenges in biomarker application and interpretation. Furthermore, the physiological alterations in the critically ill render pharmacokinetics and pharmacodynamics crucial parameters for adequate antimicrobial therapy use. Individual pharmacokinetic and pharmacodynamic targets can reduce antimicrobial therapy misuse and risk of antimicrobial resistance.

Ensuring Sufficient Trough Plasma Concentrations for Broad-Spectrum Beta-Lactam Antibiotics in Children With Malignancies: Beware of Augmented Renal Clearance!

Introduction: Broad-spectrum beta-lactams are commonly prescribed for empirical or selective treatment of bacterial infections in children with malignancies. In the immunocompromised, appropriate concentration exposure is crucial to ensure antimicrobial efficacy. Augmented renal clearance (ARC) is increasingly recognized in this population, and raises concern for unmet concentration targets. We conducted a retrospective evaluation of meropenem and piperacillin exposure in our hospital's pediatric hematology-oncology patients. Materials and Methods: We compared trough levels of meropenem and piperacillin in a cohort of unselected pediatric hematology-oncology patients stratified based on their estimated renal function as decreased, normal or with ARC, and on their neutrophil count. Results: Thirty-two children provided a total of 51 meropenem and 76 piperacillin samples. On standard intermittent intravenous regimen, 67% of all trough plasma concentrations were below targeted concentrations. In neutropenic children with bacterial infection, all meropenem and 60% of piperacillin levels were below target. Nearly two-thirds of total samples came from children with ARC. In these patients, antimicrobial exposure was insufficient in 85% of cases (compared to 36% in the decreased or normal renal function groups), despite a dosage sometimes exceeding the maximum recommended daily dose. Under continuous infusion of piperacillin, only 8% of plasma levels were insufficient. Discussion: Intermittent administration of meropenem and piperacillin often fails to ensure sufficient concentration exposure in children treated for malignancies, even at maximal recommended daily dosage. This can in part be attributed to ARC. We recommend thorough assessment of renal function, resolute dosage adjustment, continuous infusion whenever possible and systematic therapeutic drug monitoring.

[Therapeutic drug monitoring of antiinfectives in intensive care unit patients - what's new?]

Pharmacokinetic and pharmacodynamic changes in intensive care unit patients can increase the risk for therapeutic failure or adverse effects of anti-infective therapy. Therapeutic drug monitoring (TDM) can inform required dose adaptions. The present article reviews the current practice and outlines modern approaches for decision making such as model-informed precision dosing software using the area-under-the-concentration-time-curve as target in favor of simplistic decision making based on trough concentrations. Moreover, the current recommendations for performing TDM of beta-lactams, aminoglycosides, linezolid, glycopeptides and voriconazole are concisely summarized.

A higher dose of vancomycin is needed in critically ill patients with augmented renal clearance

Background

Using standard vancomycin dosage in critically ill patients might lead to therapy failure and worse patient outcomes, augmented renal clearance (ARC) may be the leading risk factor. In this study, we comprehensively investigated the pharmacokinetics-pharmacodynamics (PK-PD) of vancomycin in critically ill patients with ARC, hoping to explore the precise and accurate dose adjustment method for vancomycin.

Methods

All critically ill patients tested for steady-state trough vancomycin serum concentrations during the recent 6 years in a tertiary level hospital were collected retrospectively and divided into ARC and non-ARC groups, respectively, according to creatinine clearance (CLcr). Serum vancomycin concentrations were measured by the fluorescence polarization immunoassay method. PK-PD parameters of vancomycin were recorded or calculated. The desired daily dose successful in achieving the lower target trough levels (10 mg/L) of vancomycin were investigated correspondingly.

Results

A total of 280 vancomycin concentrations were eligible for analysis. The ARC group (n=139) contained more male patients (64.7%) with average age and CLcr of 40 years old (P<0.05) and 180.8 mL/min (P<0.001), respectively. Those patients exhibited higher clearance (CL) and lower trough serum concentrations than the non-ARC patients under comparable daily doses of vancomycin. All the ICU patients demonstrated lower AUC_24h values than the target level of 400 µg·h/mL, and this value showed a lower trend in the ARC group than the non-ARC group (232.9 vs. 316.2 µg·h/mL). Subtherapeutic trough concentrations of vancomycin (<10.0 mg/L) were observed in 77.7% and 68.8% of the ARC and non-ARC patients (P<0.05). The proportion of patients with a trough concentration of 10–15 and 15–20 mg/L was 17.9% and 4.3%, respectively, in the ARC group and 24.8% and 2.8%, respectively, in the non-ARC group., a daily dose of 46.0 and 35.5 mg/kg of vancomycin is needed, respectively, in the ARC and non-ARC group to achieve a target trough concentration of 10 mg/L.

Conclusions

A higher dose of vancomycin is needed in critically ill patients, especially those with ARC, and appropriate TDM-guided dose adjustment should be considered to achieve the targeted therapeutic range and to provide dosing guidance for this: patient population.

Population pharmacokinetics and dosing optimization of metformin in Chinese patients with type 2 diabetes mellitus

Approximately 35% of patients fail to attain ideal initial blood glucose control under metformin monotherapy. The objective of this observational study is to simulate the optimal protocol of metformin according to the different renal function.The population pharmacokinetics of metformin was performed in 125 subjects with type 2 diabetes mellitus. Plasma concentrations of metformin were quantified by high-performance liquid chromatography. A population pharmacokinetic model of metformin was developed using NONMEN (version 7.2, Icon Development Solutions, USA). Monte Carlo simulation was used to simulate the concentration-time profiles for doses of metformin for 1000 times at different stages of renal function.The mean population pharmacokinetic parameters were apparent clearance 53.0 L/h, apparent volume of distribution 438 L, absorption rate constant 1.4 hour and lag-time 0.91 hour. Covariate analyses revealed that estimated glomerular filtration rate (eGFR) and bodyweight as individual factors influencing the apparent oral clearance: CL/F = 53.0 × ( bodyweight/75) × (eGFR/102.5)EXP(0.1797). The results of the simulation showed that patients should be prescribed metformin 2550 mg/d (t.i.d.) vs 3000 mg/d (b.i.d.) as the minimum doses for patients with augmented renal clearance.eGFR had a significant impact on metformin pharmacokinetics. Patients administered metformin twice a day require higher total daily doses than those with a regimen of 3 times a day at each stage of kidney function.

Endotoxemia-Induced Release of Pro-inflammatory Mediators Are Associated With Increased Glomerular Filtration Rate in Humans in vivo

Introduction: Sepsis is the most prevalent cause of Acute Kidney Injury (AKI). Conversely, in some septic patients the glomerular filtration rate (GFR) is augmented. The role of the inflammatory response and blood pressure to induce this increased GFR is unknown. Herein, we relate inflammatory mediators and blood pressure to the iohexol clearance-derived “true” GFR and kidney injury markers during systemic inflammation in healthy volunteers.

Methods: Twelve healthy subjects underwent experimental endotoxemia (i.v. administration of 2 ng/kg Escherichia coli-derived lipopolysaccharide, LPS). As a gold-standard to determine the GFR, iohexol plasma clearance (GFR_iohexol) was calculated during a 6-h period on the day before (baseline) as well as 2 and 24 h after LPS administration. Intra-arterial blood pressure was recorded continuously using a radial artery catheter. Circulating inflammatory mediators and urinary excretion of kidney injury markers were serially measured.

Results: Experimental endotoxemia profoundly increased plasma concentrations of inflammatory mediators, including [mean ± SD or median [IQR] peak values (pg/mL) of tumor necrosis factor (TNF)-α: 92 ± 40, interleukin (IL)-6: 1,246 ± 605, IL-8: 374 ± 120, IL-10: 222 ± 119, IL-1 receptor antagonist (RA): 8,955 ± 2,429, macrophage chemoattractant protein (MCP)-1: 2,885 [2,706 – 3,765], vascular adhesion molecule (VCAM)-1: 296,105 ± 34,822, intercellular adhesion molecule (ICAM)-1: 25,0170 ± 41,764]. Mean arterial pressure decreased with 13 ± 11 mmHg (p < 0.0001). No significant increase in the urinary excretion of tubular injury markers was observed following LPS administration. GFR_iohexol increased from 97 ± 6 at baseline to 118 ± 10 mL/min/1.73m² (p < 0.0001) post-LPS administration and returned to baseline levels at 24 h post-LPS (99 ± 9 mL/min/1.73m²). Peak plasma concentrations of IL-6 (R² = 0.66, p = 0.001) and IL-8 (R² = 0.51, p = 0.009), MCP-1 (R² = 0.38, p = 0.03) and VCAM-1 levels (R² = 0.37, p = 0.04) correlated with the increase in GFR_iohexol, whereas a trend was observed for TNF-α (R² = 0.33, p = 0.0509) and IL-1RA (R² = 0.28, p = 0.08). None of the kidney injury markers or changes in blood pressure were associated with GFR_iohexol. In multiple linear regression analysis, both peak IL-6 (p = 0.002) and IL-8 (p = 0.01) concentrations remained significantly correlated with GFR_iohexol, without collinearity.

Discussion: Concentrations of pro-inflammatory cytokines, but not blood pressure, are correlated with the endotoxemia-induced increase in GFR in healthy volunteers. These findings may indicate that inflammatory mediators orchestrate the augmented GFR observed in a subgroup of sepsis patients.

Clinical Discussions in Antithrombotic Therapy Management in Patients With Atrial Fibrillation: A Delphi Consensus Panel

Background

In recent years, direct-acting oral anticoagulants (DOACs) have entered clinical practice for stroke prevention in non-valvular atrial fibrillation or prevention and treatment of venous thromboembolism. However, remaining uncertainty regarding DOAC use in some clinical scenarios commonly encountered in the real world has not been fully explored in clinical trials.

Methods

We report on use of a Delphi consensus process on DOAC use in non-valvular atrial fibrillation patients. The consensus process dealt with 9 main topics: (i) DOACs vs vitamin K antagonists in atrial fibrillation (AF) patients; (ii) therapeutic options for patients with stable total time in range treated with vitamin K antagonists; (iii) therapeutic options for patients aged > 85 years; (iv) therapeutic management of hyperfiltering patients; (v) pharmacologic interactions; (vi) therapeutic options in the long-term treatment (prevention) of patients with AF and acute coronary syndrome after the triple therapy; (vii) low doses of DOACs in AF patients; (viii) ischemic stroke in patients inappropriately treated with low doses of DOACs; (ix) management of patients taking DOACs with left atrial appendage thrombosis.

Results

A total of 101 physicians (cardiologists, internists, geriatricians, and hematologists) from Italy expressed their level of agreement on each statement by using a 5-point Likert scale (1 = strongly disagree; 2 = disagree; 3 = somewhat agree; 4 = agree; 5 = strongly agree). Votes 1-2 were considered to be disagreement; votes 3-5 were considered to be agreement. Agreement among the respondents of ≥ 66% for each statement was considered consensus. A brief discussion of the results for each topic is also reported.

Conclusions

In clinical practice, there is still uncertainty on DOAC use, especially in elderly, fragile, comorbid, and hyperfiltering patients.

Some Suggestions from PK/PD Principles to Contain Resistance in the Clinical Setting-Focus on ICU Patients and Gram-Negative Strains

The containment of the phenomenon of resistance towards antimicrobials is a priority, especially in preserving molecules acting against Gram-negative pathogens, which represent the isolates more frequently found in the fragile population of patients admitted to Intensive Care Units. Antimicrobial therapy aims to prevent resistance through several actions, which are collectively known as "antimicrobial stewardship", to be taken together, including the application of pharmacokinetic/pharmacodynamic (PK/PD) principles. PK/PD application has been shown to prevent the emergence of resistance in numerous experimental studies, although a straight translation to the clinical setting is not possible. Individualized antibiotic dosing and duration should be pursued in all patients, and even more especially when treating intensive care unit (ICU) septic patients in whom optimal exposure is both difficult to achieve and necessary. In this review, we report on the available data that support the application of PK/PD parameters to contain the development of resistance and we give some practical suggestions that can help to translate the benefit of PK/PD application to the bedside.

Pharmacodynamic evaluation of intermittent versus extended and continuous infusions of piperacillin/tazobactam in a hollow-fibre infection model against Klebsiella pneumoniae

OBJECTIVES

To compare bacterial killing and the emergence of resistance to piperacillin/tazobactam, administered by intermittent versus prolonged infusion (i.e. extended or continuous), for ceftriaxone-resistant Klebsiella pneumoniae clinical isolates in an in vitro dynamic hollow-fibre infection model (HFIM).

METHODS

K. pneumoniae 68 (Kp68; MIC = 8 mg/L, producing SHV-106 and DHA-1) and K. pneumoniae 69 (Kp69; MIC = 1 mg/L, producing CTX-M-14) were studied in the HFIM over 7 days (initial inoculum ~107 cfu/mL). Six piperacillin/tazobactam dosing regimens for Kp68 (4/0.5 g 8 hourly as 0.5 and 4 h infusions, 12/1.5 g/24 h continuous infusion, 4/0.5 g 6 hourly as 0.5 and 3 h infusions and 16/2 g/24 h continuous infusion) and three piperacillin/tazobactam dosing regimens for Kp69 (4/0.5 g 8 hourly as 0.5 and 4 h infusions and 12/1.5 g/24 h continuous infusion) were simulated (piperacillin clearance = 14 L/h, creatinine clearance = 100 mL/min). Total and resistant populations and MICs were quantified/determined.

RESULTS

For Kp68, all simulated dosing regimens exhibited approximately 4 log10 of bacterial killing at 8 h followed by regrowth to approximately 1011 cfu/mL within 24 h. The MICs for resistant subpopulations exceeded 256 mg/L at 72 h. Similarly, for Kp69, all simulated dosing regimens exhibited approximately 4 log10 of bacterial killing over 8 h; however, only the continuous infusion prevented bacterial regrowth.

CONCLUSIONS

Compared with intermittent infusion, prolonged infusion did not increase initial bacterial killing and suppression of regrowth of plasmid-mediated AmpC- and ESBL-producing K. pneumoniae. However, continuous infusion may suppress regrowth of some ESBL-producing susceptible K. pneumoniae, although more data are warranted to confirm this observation.

A simple scoring method to predict augmented renal clearance in haematologic malignancies

WHAT IS KNOWN AND OBJECTIVE

Augmented renal clearance (ARC; hyperfiltration with over 130 mL/min/1.73 m² of creatinine clearance (CL_cr )) commonly occurs in critically ill patients. Recent reports indicate that ARC also occurs in haematologic malignancies. However, the risk factors for ARC in haematologic malignancies remain unknown, and there is no established method to predict ARC in haematologic malignancies. Our objective was to explore the risk factors for ARC retrospectively and develop a scoring method to predict ARC.

METHODS

A single-centre, retrospective, observational cohort study was conducted at the Sendai Medical Center (Sendai, Japan); 133 patients (April 2017-March 2019) and 41 patients (April-November 2019) with haematopoietic tumours who were administered vancomycin were enrolled in the analysis and validation cohorts, respectively. To define ARC, we calculated the vancomycin serum concentration when CL_cr  = 130 mL/min/1.73 m² using a one-compartment model. Patients with ARC were defined as those whose actual concentration of vancomycin remained lower than the calculated concentration. Using the analysis cohort, we explored risk factors of ARC and developed a scoring method to predict ARC in haematologic malignancies. The reproducibility of the scoring system was demonstrated using the validation cohort.

RESULTS AND DISCUSSION

Through multivariate analysis, young age (P < .001), leukaemia (P = .001) and low serum creatinine (P < .001) were identified as risk factors. According to this result, we established the ARC detection method: age ≤ 50 years = 3 points, 50 years < age ≤65 years = 1 point, leukaemia = 2 points, low SCr = 2 points; patients scoring ≥ 5 points represent the ARC high-risk group. Using this scoring system, we could detect ARC with a sensitivity and specificity of 60.0% and 89.7% in the analysis cohort and 90.0% and 90.9% in the validation cohort, respectively.

WHAT IS NEW AND CONCLUSION

Our scoring method could predict ARC in haematologic malignancies and is useful as a simple screening tool for ARC.

Antimicrobial therapeutic drug monitoring in critically ill adult patients: a Position Paper

Purpose

This Position Paper aims to review and discuss the available data on therapeutic drug monitoring (TDM) of antibacterials, antifungals and antivirals in critically ill adult patients in the intensive care unit (ICU). This Position Paper also provides a practical guide on how TDM can be applied in routine clinical practice to improve therapeutic outcomes in critically ill adult patients.

Methods

Literature review and analysis were performed by Panel Members nominated by the endorsing organisations, European Society of Intensive Care Medicine (ESICM), Pharmacokinetic/Pharmacodynamic and Critically Ill Patient Study Groups of European Society of Clinical Microbiology and Infectious Diseases (ESCMID), International Association for Therapeutic Drug Monitoring and Clinical Toxicology (IATDMCT) and International Society of Antimicrobial Chemotherapy (ISAC). Panel members made recommendations for whether TDM should be applied clinically for different antimicrobials/classes.

Results

TDM-guided dosing has been shown to be clinically beneficial for aminoglycosides, voriconazole and ribavirin. For most common antibiotics and antifungals in the ICU, a clear therapeutic range has been established, and for these agents, routine TDM in critically ill patients appears meritorious. For the antivirals, research is needed to identify therapeutic targets and determine whether antiviral TDM is indeed meritorious in this patient population. The Panel Members recommend routine TDM to be performed for aminoglycosides, beta-lactam antibiotics, linezolid, teicoplanin, vancomycin and voriconazole in critically ill patients.

Conclusion

Although TDM should be the standard of care for most antimicrobials in every ICU, important barriers need to be addressed before routine TDM can be widely employed worldwide.

Electronic supplementary material

The online version of this article (10.1007/s00134-020-06050-1) contains supplementary material, which is available to authorized users.

Clinical Pharmacokinetics of Vancomycin in Critically Ill Children

BACKGROUND AND OBJECTIVE

Critically ill children exhibit altered pharmacokinetic parameters of vancomycin, mainly due to altered renal excretion and volume of distribution (as a result of altered plasma protein concentrations). We assessed the pharmacokinetic parameters of vancomycin in this subpopulation.

METHODS

Vancomycin trough concentrations in critically ill children were obtained following first dose and at steady state. Using a one-compartment model, clearance (CL), volume of distribution (Vd), elimination half-life (t_1/2), and area under the time-concentration curve for 24 h (AUC_0-24) were estimated. Subgroup analyses were carried out, with patients differentiated based on age, renal clearance, outcome, and renal dysfunction. Protein-free vancomycin concentrations were calculated using a previously reported formula.

RESULTS

Twenty-two samples were evaluated for first-dose and 182 for steady-state pharmacokinetics, and similar pharmacokinetic parameter values were observed at first dose and at steady state. Only 36.4% and 47.3% of the samples attained the recommended AUC_0-24 (mg·hr/L) of > 400 at first dose and at steady state, while 62.5% of the patients with renal dysfunction achieved this target. Nearly 40% of the patients had augmented renal clearance (ARC), which was associated with higher CL, shorter t_1/2, and lower AUC values. Amongst the patients with ARC, none had AUC_0-24 (mg·hr/L) > 400 at first dose, while 16% achieved this target at steady state. Volume of distribution was significantly higher in infants and a decreasing trend was observed in toddlers, children, and older children at steady state. Children with renal dysfunction had lower CL, prolonged t_1/2, and higher AUC values than patients with normal renal clearance at first dose. A good correlation was observed between trough concentration and AUC_0-24, as corroborated by the area under the receiver operating characteristic curve. The median fraction of protein-free vancomycin was around 77%.

CONCLUSION

Vancomycin dosing strategies in younger children should be revisited, and increased doses should be considered for critically ill children with ARC in order to achieve therapeutic concentrations of AUC_0-24.

Therapeutic Drug Monitoring of Meropenem and Piperacillin in Critical Illness-Experience and Recommendations from One Year in Routine Clinical Practice

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.

Antithrombotic therapy in patients with acute coronary syndrome complicated by cardiogenic shock or out-of-hospital cardiac arrest: a joint position paper from the European Society of Cardiology (ESC) Working Group on Thrombosis, in association with the Acute Cardiovascular Care Association (ACCA) and European Association of Percutaneous Cardiovascular Interventions (EAPCI)

Timely and effective antithrombotic therapy is critical to improving outcome, including survival, in patients with acute coronary syndrome (ACS). Achieving effective platelet inhibition and anticoagulation, with minimal risk, is particularly important in high-risk ACS patients, especially those with cardiogenic shock (CS) or those successfully resuscitated following out-of-hospital cardiac arrest (OHCA), who have a 30-50% risk of death or a recurrent ischaemic event over the subsequent 30 days. There are unique challenges to achieving effective and safe antithrombotic treatment in this cohort of patients that are not encountered in most other ACS patients. This position paper focuses on patients presenting with CS or immediately post-OHCA, of presumed ischaemic aetiology, and examines issues related to thrombosis and bleeding risk. Both the physical and pharmacological impacts of CS, namely impaired drug absorption, metabolism, altered distribution and/or excretion, associated multiorgan failure, co-morbidities and co-administered treatments such as opiates, targeted temperature management, renal replacement therapy and circulatory or left ventricular assist devices, can have major impact on the effectiveness and safety of antithrombotic drugs. Careful attention to the choice of antithrombotic agent(s), route of administration, drug-drug interactions, therapeutic drug monitoring and factors that affect drug efficacy and safety, may reduce the risk of sub- or supra-therapeutic dosing and associated adverse events. This paper provides expert opinion, based on best available evidence, and consensus statements on optimising antithrombotic therapy in these very high-risk patients, in whom minimising the risk of thrombosis and bleeding is critical to improving outcome.

Differences in Vancomycin Clearance between Trauma and Medical Intensive Care Unit Patients

Background

To identify the differences in the vancomycin pharmacokinetics between multiple trauma patients and medically ill patients in the intensive care unit (ICU) stratified by the use of continuous renal replacement therapy (CRRT), and the factors affecting vancomycin clearance (CL_van).

Materials and Methods

All the included patients received at least three consecutive doses of vancomycin, then, therapeutic drug monitoring was conducted. Patients' serum vancomycin trough levels and other clinical variables were identified retrospectively. The vancomycin pharmacokinetics and associated factors were compared and analyzed between trauma ICU (TICU) and medical ICU (MICU) patients.

Results

In the non-dialyzed group, the CL_van was higher among the TICU patients than the MICU patients. However, in the continuous renal replacement therapy group, there was no significant difference in the CL_van between the multiple trauma and medically ill patients. The only factor associated with CL_van in the non-dialyzed group was creatinine clearance; none of the factors was associated with CL_van in the CRRT group.

Conclusion

In the case of non-dialyzed patients in the TICU, vancomycin dosages must be adjusted, depending on the patient's actual body weight changes. In the case of patients undergoing CRRT in both ICUs, vancomycin can be infused with fixed doses regardless of the patients' characteristics.

Expert Discussion of the Role of Rate Constant Versus Clearance Approaches to Define Drug Pharmacokinetics: Theoretical and Clinical Considerations

This article provides a dialogue covering an ongoing controversy on the use of clearance versus rate constant approaches for model parameterization when assessing pharmacokinetic (PK) data. It reflects the differences in opinions that can exist among PK experts. Importantly, this discussion extends beyond theoretical arguments to demonstrate how these different approaches impact the analysis and interpretation of data acquired in clinical situations. By not shying away from such dialogues, this article showcases how dissimilarity in well-grounded perspectives can influence how one applies PK and mathematical principles.

Basic Principles of Antibiotics Dosing in Patients with Sepsis and Acute Kidney Damage Treated with Continuous Venovenous Hemodiafiltration

Sepsis is the leading cause of acute kidney damage in patients in intensive care units. Pathophysiological mechanisms of the development of acute kidney damage in patients with sepsis may be hemodynamic and non-hemodynamic. Patients with severe sepsis, septic shock and acute kidney damage are treated with continuous venovenous hemodiafiltration. Sepsis, acute kidney damage, and continuous venovenous hemodiafiltration have a significant effect on the pharmacokinetics and pharmacodynamics of antibiotics. The impact dose of antibiotics is increased due to the increased volume of distribution (increased administration of crystalloids, hypoalbuminemia, increased capillary permeability syndrome toproteins). The dose of antibiotic maintenance depends on renal, non-renal and extracorporeal clearance. In the early stage of sepsis, there is an increased renal clearance of antibiotics, caused by glomerular hyperfiltration, while in the late stage of sepsis, as the consequence of the development of acute renal damage, renal clearance of antibiotics is reduced. The extracorporeal clearance of antibiotics depends on the hydrosolubility and pharmacokinetic characteristics of the antibiotic, but also on the type of continuous dialysis modality, dialysis dose, membrane type, blood flow rate, dialysis flow rate, net filtration rate, and effluent flow rate. Early detection of sepsis and acute kidney damage, early target therapy, early administration of antibiotics at an appropriate dose, and early extracorporeal therapy for kidney replacement and removal of the inflammatory mediators can improve the outcome of patients with sepsis in intensive care units.

Indian consensus on the management of CRE infection in critically ill patients (ICONIC) - India

Background: The increasing burden of carbapenem-resistant Enterobacteriaceae (CRE) carriage and infection in different patient settings in India has created an acute need for guidance for clinicians regarding optimal strategies for the management of CRE infection in critically ill patients. Research design and methods: A multidisciplinary panel of 11 Indian experts in CRE infection assembled for comprehensive discussion and consensus development. The experts developed clinical statements through a systematic review of key literature. Main outcome measures: The panel voted anonymously on 60 clinically relevant questions, through a modified Delphi process. Results: Forty-six key clinical consensus statements (CCS) were proposed. The panel reached a consensus on several important issues, providing recommendations on surveillance, diagnosis, prevention, pharmacokinetic challenges, combination therapy, and cornerstone molecules in CRE infections. The panel also proposed a treatment algorithm for NDM-prevalent settings. Conclusion: These consensus statements may offer clinicians expert guidance on the management of CRE infections. There is a dearth of high-/moderate-level evidence on managing CRE infections; the recommendations presented herein are based on expert opinion.

Clinically relevant pharmacokinetic knowledge on antibiotic dosing among intensive care professionals is insufficient: a cross-sectional study

BACKGROUND

Antibiotic exposure in intensive care patients with sepsis is frequently inadequate and is associated with poorer outcomes. Antibiotic dosing is challenging in the intensive care, as critically ill patients have altered and fluctuating antibiotic pharmacokinetics that make current one-size-fits-all regimens unsatisfactory. Real-time bedside dosing software is not available yet, and therapeutic drug monitoring is typically used for few antibiotic classes and only allows for delayed dosing adaptation. Thus, adequate and timely antibiotic dosing continues to rely largely on the level of pharmacokinetic expertise in the ICU. Therefore, we set out to assess the level of knowledge on antibiotic pharmacokinetics among these intensive care professionals.

METHODS

In May 2018, we carried out a cross-sectional study by sending out an online survey on antibiotic dosing to more than 20,000 intensive care professionals. Questions were designed to cover relevant topics in pharmacokinetics related to intensive care antibiotic dosing. The preliminary pass mark was set by members of the examination committee for the European Diploma of Intensive Care using a modified Angoff approach. The final pass mark was corrected for clinical relevance as assessed for each question by international experts on pharmacokinetics.

RESULTS

A total of 1448 respondents completed the survey. Most of the respondents were intensivists (927 respondents, 64%) from 97 countries. Nearly all questions were considered clinically relevant by pharmacokinetic experts. The pass mark corrected for clinical relevance was 52.8 out of 93.7 points. Pass rates were 42.5% for intensivists, 36.1% for fellows, 24.8% for residents, and 5.8% for nurses. Scores without correction for clinical relevance were worse, indicating that respondents perform better on more relevant topics. Correct answers and concise clinical background are provided.

CONCLUSIONS

Clinically relevant pharmacokinetic knowledge on antibiotic dosing among intensive care professionals is insufficient. This should be addressed given the importance of adequate antibiotic exposure in critically ill patients with sepsis. Solutions include improved education, intensified pharmacy support, therapeutic drug monitoring, or the use of real-time bedside dosing software. Questions may provide useful for teaching purposes.

Augmented Renal Clearance

Augmented renal clearance (ARC) is a phenomenon in critically ill patients characterized by increased creatinine clearance and elimination of renally eliminated medications. Patients with severe neurologic injury, sepsis, trauma, and burns have been consistently identified as at risk of ARC, with mean creatinine clearances ranging from 170 ml/minute to more than 300 ml/minute. Several potential mechanisms may contribute to the occurrence of ARC including endogenous responses to increased metabolism and solute production, alterations in neurohormonal balance, and therapeutic maneuvers such as fluid resuscitation. Augmented renal clearance is associated with suboptimal exposure to critical medications, including β-lactams and vancomycin, increasing the risk of treatment failure. Although definitive screening tools are not yet known, critical care pharmacists must be vigilant in recognizing when ARC may be a contributing factor affecting expected treatment outcomes in individual patients. Optimizing dosing strategies in critically ill patients with ARC remains a goal of continued research. The current review discusses the clinical characteristics and methods of identifying patients at risk of ARC, potential mechanisms for ARC, and describes pharmacotherapy dosing considerations in patients with ARC.

Colistin Use in Patients with Extreme Renal Function: From Dialysis to Augmented Clearance

Background and objectives: Colistin is used for the treatment of multidrug-resistant (MDR) Gram-negative bacteria infection in critically ill patients. It is recommended to adjust the dose in cases of renal impairment but not in cases of augmented renal clearance (ARC). The aim of this study was to determine colistin use pattern in patients with different renal functional states. Materials and Methods: Adult patients admitted to intensive care units of single Latvian hospitals in the years 2015–2017 with an MDR Gram-negative bacterial infection and at least 72 h colistin therapy were included in this study. Data were collected retrospectively from medical notes. Colistin use pattern and outcomes were analyzed in patients with different renal function prior to colistin therapy: normal, ARC, impaired, and on renal replacement therapy (RRT). Results: 100 cases of colistin use met the inclusion criteria. The study group was heterogeneous, and patients had different renal function states prior to colistin therapy-from continuous RRT (18 cases) to ARC (16 cases). The standard colistin dose of 9 million units (MU) daily was the most common dose among the patients. In many cases (43%), colistin dose adjustment did not follow the recent recommendations of drug manufacturers-this was mainly in patients with renal impairment prior to colistin therapy. Eighteen cases of colistin acute kidney injury (AKI) were detected, mostly (10 cases) in patients with normal renal function and without ARC prior to colistin therapy. No patients with colistin AKI needed RRT. Conclusions: Colistin doses varied greatly among patients, and in patients with renal function impairment it was commonly not in accordance with the summary of product characteristics (SPC). Patients with ARC mostly received a standard colistin daily dose of 9 MU daily, but the cumulative dose had a tendency to be higher and duration of colistin therapy was longer in comparison with other patient groups. ARC’s role in the development of colistin nephrotoxicity is still unclear.

Outcomes in patients with infections and augmented renal clearance: A multicenter retrospective study

Recently, augmented renal clearance (ARC), which accelerates glomerular filtration of renally eliminated drugs thereby reducing the systemic exposure to these drugs, has started to receive attention. However, the clinical features associated with ARC are still not well understood, especially in the Japanese population. This study aimed to evaluate the clinical characteristics and outcomes of ARC patients with infections in Japanese intensive care unit (ICU) settings. We conducted a retrospective observational study from April 2013 to May 2017 at two tertiary level ICUs in Japan, which included 280 patients with infections (median age 74 years; interquartile range, 64–83 years). We evaluated the estimated glomerular filtration rate (eGFR) at ICU admission using the Japanese equation, and ARC was defined as eGFR >130 mL/min/1.73 m². Multivariable logistic regression analysis was performed to identify the independent risk factors for ARC and to determine if it was a predictor of ICU mortality. In addition, a receiver operating curve (ROC) analysis was performed, and the area under the ROC (AUROC) was determined to examine the significant variables that predict ARC. In total, 19 patients (6.8%) manifested ARC. Multivariable logistic regression analysis identified younger age as an independent risk factor for ARC (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.91–0.96). However, ARC was not found to be a predictor of ICU mortality (OR, 0.57; 95% CI, 0.11–2.92). In addition, the AUROC of age was 0.79 (95% CI, 0.68–0.91), and the optimal cut off age for ARC was ≤63 years (sensitivity, 68.4%; specificity, 78.9%). The incidence of ARC was, therefore, low among patients with infections in the Japanese ICUs. Although younger age was associated with the incidence of ARC, it was not an independent predictor of ICU mortality.

A Novel Method for the Determination of Vancomycin in Serum by High-Performance Liquid Chromatography-Tandem Mass Spectrometry and Its Application in Patients with Diabetic Foot Infections

A novel, precise, and accurate high-performance liquid chromatography-tandem mass spectrometry (Q-trap-MS) method was developed, optimized, and validated for determination of vancomycin in human serum using norvancomycin as an internal standard. Effect of different parameters on the analysis was evaluated. ZORBAX SB-C18 column (150 × 4.6 mm, 5 μm) using water (containing 0.1% formic acid, v/v)⁻acetonitrile (containing 0.1% formic acid, v/v) as a mobile phase was chosen. The calibration curve was linear over the concentration ranges of 1 to 2000 ng/mL for vancomycin. The limit of detection (LOD) and limit of quantification (LOQ) for vancomycin were 0.3 and 1.0 ng/mL. Recoveries were between 87.2 and 102.3%, which gave satisfactory precision. A total of 100 serum samples (from 50 patients with diabetic foot proven Gram-positive infection and 50 nondiabetic patients with pneumonia requiring hospitalization and antibiotic therapy) were analyzed by this method. The trough vancomycin concentrations of diabetic foot infection (DFI) patients and nondiabetic patients were 8.20 ± 2.83 μg/mL (range: 4.80⁻14.2 μg/mL) and 15.80 ± 5.43 μg/mL (range: 8.60⁻19.5 μg/mL), respectively. The method is sensitive, precise, and reproducible, it could be applied for routine laboratory analysis of vancomycin in serum samples.

Pharmacokinetics and Drug Metabolism in Canada: The Current Landscape-A Summary of This Indispensable Special Issue

Canadian Pharmaceutical Scientists have a rich history of groundbreaking research in pharmacokinetics and drug metabolism undertaken primarily throughout its Pharmacy Faculties and within the Pharmaceutical and Biotechnology industry.[...].