Drug dosing consideration in patients with acute and chronic kidney disease-a clinical update from Kidney Disease: Improving Global Outcomes (KDIGO). Kidney Int. 2011;80:1122-1137. [PMID: 21918498 DOI: 10.1038/ki.2011.322]

Clearance of chloroquine and hydroxychloroquine by the Seraph® 100 Microbinda Affinity Blood Filter -a device approved for the treatment of COVID-19 patients

On April 17 2020, the United States Food and Drug Administration granted Coronavirus Disease 2019 (COVID‐19) emergency use authorizations for the Seraph 100 Microbind Affinity Blood Filter. The medical device is aimed to treat critically ill COVID‐19 patients with confirmed or imminent respiratory failure. The aim of this life size in vitro pharmacokinetic study was to investigate the in vitro adsorption of chloroquine and hydroxychloroquine from human plasma using equipment that is also used at the bedside. After start of the hemoperfusion, Pre (C_pre) Seraph plasma levels were obtained at 5 (C₅), 10 (C₁₀), 15 (C₁₅), 30 (C₃₀), 60 (C₆₀), and 120 (C₁₂₀) minutes into the procedure. At two timepoints (5 and 120 minutes) post (C_post) Seraph plasma levels were determined that were used to calculate the plasma clearance of the Seraph. Both drugs were determined using a validated HPLC method. Median [IQR] plasma clearance of the Seraph for chloroquine/hydroxychloroquine was 1.71 [0.51‐4.38] mL/min/1.79 [0.21‐3.68] mL/min respectively. The lack of elimination was also confirmed by the fact that plasma levels did not change over the 120 minutes treatment. As neither chloroquine nor hydroxychloroquine were removed by the treatment with the Seraph dose adjustments in COVID‐19 patients undergoing this treatment are not necessary.

Pharmacokinetics in children with chronic kidney disease

In children, the main causes of chronic kidney disease (CKD) are congenital diseases and glomerular disorders. CKD is associated with multiple physiological changes and may therefore influence various pharmacokinetic (PK) parameters. A well-known consequence of CKD on pharmacokinetics is a reduction in renal clearance due to a decrease in the glomerular filtration rate. The impact of renal impairment on pharmacokinetics is, however, not limited to a decreased elimination of drugs excreted by the kidney. In fact, renal dysfunction may lead to modifications in absorption, distribution, transport, and metabolism as well. Currently, insufficient evidence is available to guide dosing decisions on many commonly used drugs. Moreover, the impact of maturation on drug disposition and action should be taken into account when selecting and dosing drugs in the pediatric population. Clinicians should take PK changes into consideration when selecting and dosing drugs in pediatric CKD patients in order to avoid toxicity and increase efficiency of drugs in this population. The aim of this review is to summarize known PK changes in relation to CKD and to extrapolate available knowledge to the pediatric CKD population to provide guidance for clinical practice.

Severe renal impairment and risk of bleeding during anticoagulation for venous thromboembolism

BACKGROUND

Detection of severe renal impairment in patients with venous thromboembolism (VTE) is mandatory both for selecting anticoagulant therapy and for evaluating major bleeding risk, increased by severe renal impairment.

OBJECTIVES

To determine whether the Cockcroft and Gault (CG) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formulas identify severe renal impairment in the same VTE patients presenting the same risk of major bleeding.

PATIENTS/METHODS

We compared clinical characteristics and outcomes during the first 3 months of anticoagulation between VTE patients in the RIETE registry with severe renal impairment according to the CG and/or CKD-EPI formula (estimated glomerular filtration rate <30 mL/min and <30 mL/min/1.73 m2 , respectively). The primary outcome was major bleeding.

RESULTS

Up to October 2017, 41 796 patients were included in RIETE. Among the 4676 patients with severe renal impairment according to at least one of the formulas, this was not confirmed by the other formula in 1904 (40.7%). Major bleeding risk was increased in every patient subgroup with severe renal impairment vs patients without this condition (CG or CKD-EPI < 30: odds ratio [OR] = 2.26, 95% confidence interval [CI 2.01-2.53], only CG < 30: OR = 1.72, 95% CI [1.37-2.13], only CKD-EPI < 30: OR = 2.34, 95% CI [1.77-3.05], CG+CKD-EPI < 30: OR = 2.47, 95% CI [2.16-2.83], all vs CG+CKD-EPI > 30).

CONCLUSION

The CG and CKD-EPI formulas identify different subgroups of patients with severe renal impairment, leading to discordant results in 40.7% of these patients. Irrespective of the formula used for their identification, patients with severe renal impairment have a higher risk of major bleeding under anticoagulant therapy.

The Impact of Multiple Renal Estimates on Pharmacist Dosing Recommendations: A Randomized Trial

Background:

Numerous equations are used for estimation of renal function, and many electronic medical records report multiple clearance estimates to assist with drug dosing. It is unknown whether the presence of multiple clearance estimates affects clinical decision-making.

Objective:

To determine whether the presence of multiple renal clearance estimates affects pharmacist drug dosing decisions.

Methods:

A randomized trial in the form of an electronic survey including 4 clinical vignettes was delivered to hospital pharmacists. Vignettes consisted of a patient presenting with an acute pulmonary embolism requiring enoxaparin therapy. Pharmacists were randomized to receive a single estimate of renal function or multiple estimates for all vignettes. The primary outcome was deviation from approved recommendations on at least 1 vignette. The χ2 test was used to detect differences in deviation rates between groups. Logistic regression was performed to adjust for the effects of potentially confounding variables.

Results:

A total of 154 studies were completed (73 in the multiple-estimate group and 81 in the single-estimate group). Pharmacists presented with multiple renal estimates were significantly more likely to deviate from recommended dosing regimens than pharmacists presented with a single estimate (54.7% vs 38.2%; P = 0.04). The results were driven primarily by the 2 vignettes that included discordance among Cockcroft-Gault equation creatinine clearance estimates. Logistic regression identified multiple estimates as the only independent predictor of deviation ( P = 0.04).

Conclusion and Relevance:

Pharmacists provided with a single renal clearance estimate were more likely to adhere to approved dosing recommendations than pharmacists provided with multiple estimates.

A Systematic Review of Vancomycin Dosing in Patients with Hematologic Malignancies or Neutropenia

Objective

To provide a comprehensive review of vancomycin dosing in patients with hematologic malignancies or neutropenia.

Methods

PubMed, Embase and the Cochrane Library were searched through April 2, 2020. Original studies relevant to vancomycin dosing regimen in adults with hematologic malignancies or neutropenia were included. No restriction was applied in study design and language. A descriptive analysis was performed.

Results

Twenty-three studies were included eventually, of which eighteen were case series studies, four were cohort studies and another one was a randomized controlled trial. Five case series studies made a clinical audit of conventional vancomycin dosing in patients with malignancies or neutropenia, showing that the proportion of patients with sub-therapeutic trough levels remained high, ranging from 32% to 88%. Seven case series studies and four cohort studies demonstrated that vancomycin clearance (CLva) tended to be higher in patients with hematologic malignancies or neutropenia, whereas volume of distribution (V) seemed to be comparable to the control group. Five studies proposed individualized initial dosing regimen per the pharmacokinetic changes; however, no prospective validation has been conducted in clinical setting. Additionally, four case series studies suggested that the correlation between vancomycin clearance and estimated creatinine clearance was relatively poor, bringing a great challenge to proper dosing strategy. A randomized controlled trial stated that therapeutic drug monitoring (TDM) of vancomycin could decrease the incidence of nephrotoxicity in immunocompromised febrile patients with hematologic malignancies.

Conclusion

The available evidence indicates that conventional vancomycin dosing leads to suboptimal concentration in patients with hematologic malignancy or neutropenia. TDM accompanied by pharmacokinetic interpretation can decrease the risk of nephrotoxicity. The individualization of the initial dosing regimen and mechanisms of augmented clearance require further research.

Chronic kidney disease and upper tract concerns after congenital and acquired urinary tract abnormalities: considerations for transition of care in teens and young adults

PURPOSE

To emphasize the burden that chronic kidney disease (CKD) and its complications place on overall health and well-being over the lifetime in individuals with congenital and acquired urinary tract abnormalities.

METHODS

Topic-based literature review was performed and professional opinion was obtained to describe the scope of medical challenges faced by both teens and adults and their health care providers in the context of congenital and acquired urinary tract abnormalities.

RESULTS

Challenges include accurate assessment of glomerular filtration rate; engaging for consistent surveillance of blood pressure, proteinuria, and medical complications of CKD that increase the risk of progression to end-stage renal disease and affect general health; achieving early referral to nephrology for better outcomes; managing renal complications within the unique limitations of lower urinary tract function; treating upper tract urolithiasis in the atypical urinary tract; and preparing for successful renal transplant.

CONCLUSION

In individuals with congenital or acquired abnormalities of the urinary tract, there is an inherent risk of CKD with its associated morbidity and increased mortality risk. Interplay between the upper and lower urinary tract impacts CKD progression. Collaborative management between urology and nephrology is highly recommended to address the unique challenges for each individual over the lifetime.

Bioelectrical Impedance Measurements for Assessment of Kidney Function in Critically Ill Patients

OBJECTIVES

To evaluate the use of multifrequency bioelectrical impedance analysis to predict creatinine/urea clearance based on 24 hours urine collection. A practical formula was developed, and its performance was compared with that of established formulas such as Cockcroft-Gault, Modification of Diet in Renal Disease, and Jelliffe's.

DESIGN

An open-label prospective observational cohort study.

SETTING

A 12-bed ICU at a nonuniversity major teaching hospital (Gelre ziekenhuizen Apeldoorn/Zutphen, The Netherlands).

PATIENTS

Adult critical care patients with an expected ICU length of stay at admission of at least 48 hours.

INTERVENTIONS

Each patient's body composition was assessed using a validated Quadscan 4000 analyzer (Bodystat, Isle of Man, British Isles). Twenty-four hours urine was collected, and laboratory variables in serum including creatinine, urea, and albumin were obtained at the beginning and end of the collection period.

MEASUREMENTS AND MAIN RESULTS

A total of 151 patients, stratified to an acute and nonacute ICU-group, were enrolled in the study over a 2-year period. A formula to predict creatinine/urea clearance based on 24 hours urine collection was developed using stepwise linear regression using a training data set of 75 patients. This formula was subsequently tested and compared with other relevant predictive equations using a validation data set of 76 patients. Serum creatinine values ranged from 40 to 446 µmol/L. With the predictive model based on estimated body cell mass and a "prediction marker" more than 71% of the observed variance in creatinine/urea clearance based on 24 hours urine collection could be explained. Predictive performance was superior to the other eight evaluated models (R = 0.39-0.55) and demonstrated to be constant over the whole range of creatinine/urea clearance based on 24 hours urine collection values.

CONCLUSIONS

Multifrequency bioelectrical impedance analysis measurements can be used to predict creatinine/urea clearance based on 24 hours urine collection with superior performance than currently established prediction models. This rapid, noninvasive method enables correction for influences of a patient's actual body composition and may prove valuable in daily clinical practice.

Development of Vancomycin Dose Individualization Strategy by Bayesian Prediction in Patients Receiving Continuous Renal Replacement Therapy

PURPOSE

Vancomycin (VCM) concentration is often out of therapeutic range (10-20 μg/ml) in patients receiving continuous renal replacement therapy (CRRT). The purposes of this study were to develop a practical VCM population pharmacokinetic (PPK) model and to evaluate the potential of Bayesian prediction-based therapeutic drug monitoring (Bayes-TDM) in VCM dose individualization for patients receiving CRRT.

METHODS

We developed a VCM PPK model using 80 therapeutic concentrations in 17 patients receiving CRRT. Bayes-TDM with the VCM PPK model was evaluated in 23 patients after PPK modeling.

RESULTS

We identified the covariates reduced urine output (RUO, <0.5 ml/kg/h) and effluent flow rate of CRRT for the VCM PPK model. The mean VCM non CRRT clearance (CL_nonCRRT) was 2.12 l/h. RUO lowered CL_nonCRRT to 0.34 l/h. The volume of distribution was 91.3 l/70 kg. The target concentration attainment rate by Bayes-TDM was higher (87.0%) than that by the PPK modeling period (53.8%, P = 0.046). The variance of the second measured concentrations by the Bayes-TDM was lower (11.5, standard deviation: 3.4 μg/ml) than that by the PPK modeling period (50.5, standard deviation: 7.1 μg/ml, P = 0.003).

CONCLUSIONS

Bayes-TDM could be a useful tool for VCM dose individualization in patients receiving CRRT.

In vitro elimination of anti-infective drugs by the Seraph® 100 Microbind® affinity blood filter

Background

In August 2019, the European Union licensed the first ever haemoperfusion device aimed to reduce pathogens in the blood. The core of the adsorber consists of ultra-high molecular weight polyethylene beads with endpoint-attached heparin. These beads utilize pathogen inherent adhesion mechanisms to reduce pathogen load. So far, it is unknown whether the device has an effect on anti-infective drug concentrations. The aim of this study was to investigate the in vitro adsorption of multiple anti-infective drugs from human plasma.

Methods

In this in vitro study, 18 anti-infective drugs were administered to human donor plasma and pumped through the heparin-coated pathogen adsorber (Seraph^® 100 Microbind^®Affinity Blood Filter; ExThera Medical Corp., Martinez, CA, USA) at a plasma flow rate of 250 mL/min for 60 min. Pre- and post-adsorber plasma samples were quantified after 5, 15, 30 and 60 min.

Results

We found a reduction ratio (RR) in anti-infective plasma levels between −1% and 62%. This decrease occurred mainly in the first 5 min of the experiment (RR_0–5 −4 to 62%). Mean plasma clearance rates ranged between –11.93 mL/min (fluconazole) and 4.86 mL/min (clindamycin). The highest RRs were measured for aminoglycosides (tobramycin 62% and gentamycin 59%).

Conclusions

The elimination of anti-infective drugs by the Seraph is neglectable in all but 2 of 18 of the investigated substances. Aminoglycosides may be adsorbed by the device during their first pass.

Predictors of Augmented Renal Clearance in a Heterogeneous ICU Population as Defined by Creatinine and Cystatin C

INTRODUCTION

The incidence of augmented renal clearance (ARC) in the intensive care unit (ICU) is highly variable, and identification of these patients remains challenging.

OBJECTIVE

The objective of this study was to define the incidence of ARC in a cohort of critically ill adults, using serum Cr and cystatin C, and to identify factors associated with its development.

METHODS

This is a retrospective cohort study of critically ill patients without stage 2 or 3 acute kidney injury with both serum Cr and cystatin C available. The incidence of ARC was defined as a Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)Cr-cystatin C-estimated glomerular filtration rate >130 mL/min. A multivariable logistic regression model using a penalized Lasso method was fit to identify independent predictors of ARC.

RESULTS

Among the 368 patients included in the study, indication for ICU admission was nonoperative in 55% of patients, and 9% of patients were admitted for major trauma. The overall incidence of ARC was low at 4.1%. In a multivariable logistic regression model, Charlson comorbidity index, major trauma, intracerebral hemorrhage, age, and Sequential Organ Failure Assessment score were found to predict ARC.

CONCLUSION

The incidence of ARC in this study was low, but prediction models identified several factors for early identification of patients with risk factors for or who develop ARC, particularly in a cohort with a low baseline risk of ARC. These factors could be used to help identify patients who may develop ARC.

Clearance Confusion: An Exploratory Analysis of Inpatient Dosing Discordances Between Renal Estimating Equations

Background:

Numerous equations exist for estimating renal clearance for drug dosing, and discordance rates may be as high as 40% in certain populations. However, the populations and types of equations used in these studies may not be generalizable to broader pharmacy practice.

Objectives:

To determine the dosing discordance rate between Cockcroft-Gault (C-G), Chronic Kidney Disease Epidemiology (CKD-EPI), and Modification of Diet in Renal Disease (MDRD) equations in a community hospital population.

Methods:

This was a cross-sectional analysis of inpatients who had documented renal function assessment over a 6-month period. Renal estimation was calculated using 5 equations (MDRD, CKD-EPI, and 3 C-G variants). Differences between equations were assessed using mean bias, dosing discordance, and agreement (κ statistic). Patients with acute kidney injury and those requiring renal replacement therapy were excluded.

Results:

A total of 466 patients were eligible for inclusion. Dosing discordance was evident between C-G variants and both MDRD and CKD-EPI equations in greater than 20% of patients. Agreement was highest between MDRD and CKD-EPI (κ = 0.93) and lowest between MDRD and C-G calculated using ideal body weight (κ = 0.33). The majority of discordant instances led to higher dosing recommendations when using MDRD and CKD-EPI equations compared with C-G variants. Dosing discordance exceeded 18% between the different C-G variants, with the highest discordance (36%) observed between total body weight and ideal body weight variants.

Conclusion and Relevance:

Dosing discordance between renal estimating equations is widespread. Practitioners and institutions should be aware of these differences when dosing medications and implementing renal dosing policies.

Mechanistic Models as Framework for Understanding Biomarker Disposition: Prediction of Creatinine-Drug Interactions

Creatinine is widely used as a biomarker of glomerular filtration, and, hence, renal function. However, transporter-mediated secretion also contributes to its renal clearance, albeit to a lesser degree. Inhibition of these transporters causes transient serum creatinine elevation, which can be mistaken as impaired renal function. The current study developed mechanistic models of creatinine kinetics within physiologically based framework accounting for multiple transporters involved in creatinine renal elimination, assuming either unidirectional or bidirectional-OCT2 transport (driven by electrochemical gradient). Robustness of creatinine models was assessed by predicting creatinine-drug interactions with 10 perpetrators; performance evaluation accounted for 5% intra-individual variability in serum creatinine. Models showed comparable predictive performances of the maximum steady-state effect regardless of OCT2 directionality assumptions. However, only the bidirectional-OCT2 model successfully predicted the minimal effect of ranitidine. The dynamic nature of models provides clear advantage to static approaches and most advanced framework for evaluating interplay between multiple processes in creatinine renal disposition.

How to determine kidney function in cancer patients?

A precise and efficient method for estimating kidney function in cancer patients is important to determine their eligibility for clinical trials and surgery and to allow for appropriate dose adjustment of anti-cancer drugs, especially toxic drugs with a narrow therapeutic index. Since direct measurement of glomerular filtration rate (GFR) is cumbersome, several formulae have been developed to estimate kidney function. Most of these are based on serum creatinine concentration. Though the CKD-EPI formula is recognised as being the most accurate, there is an ongoing debate on which is the optimal formula for cancer patients. In this review, we provide an overview of different GFR estimating equations for kidney function and the advantages and disadvantages of each method and compare their performance in cancer patients. We discuss the importance of body surface area-indexing and propose a framework for evaluating kidney function in cancer patients.

Managing the patient with epilepsy and renal impairment

PURPOSE

Epilepsy affects more than 50 million people worldwide and its management can be complicated by comorbidities such as impaired renal function. To optimize epilepsy control in patients with kidney disease, clinicians need to be aware of how antiepileptic drugs (AEDs) are affected by impaired renal function and how the kidneys are affected by epilepsy management strategies. Herein we present a narrative review with systematic literature search to discuss the use of AEDs in patients with renal impairment, including those undergoing dialysis, as well as the nephrotoxic effects of some AEDs. We finally conclude the article by providing practical tips about our approach to using AEDs in the setting of renal disease.

METHODS

A literature search targeting epilepsy management in patients with kidney disease was performed in MEDLINE database (1946 to 7th Jan 2019).

RESULTS

A total of 1193 articles were found. After duplicate removal, title and abstract screening followed by full text screening, a total of 110 references were included in this review. Additional information was included from drug product monographs.

CONCLUSION

The disposition of AEDs can be altered in patients with impaired renal function, leading to a higher risk of AED toxicity or therapy failure. Renal dosage adjustment and close monitoring is recommended. Although AED-induced nephrotoxicity is rare, it is unpredictable and clinicians need to vigilant about this possibility. In addition, AEDs renal adverse reactions and renal drug interactions should be considered when selecting an AED.

Medications Used Routinely in Primary Care to be Dose-Adjusted or Avoided in People With Chronic Kidney Disease: Results of a Modified Delphi Study

Background: Chronic kidney disease (CKD) affects up to 18% of those over the age of 65 years. Potentially inappropriate medication prescribing in people with CKD is common. Objectives: Develop a pragmatic list of medications used in primary care that required dose adjustment or avoidance in people with CKD, using a modified Delphi panel approach, followed by a consensus workshop. Methods: We conducted a comprehensive literature search to identify potential medications. A group of 17 experts participated in a 3-round modified Delphi panel to identify medications for inclusion. A subsequent consensus workshop of 8 experts reviewed this list to prioritize medications for the development of point-of-care knowledge translation materials for primary care. Results: After a comprehensive literature review, 59 medications were included for consideration by the Delphi panel, with a further 10 medications added after the initial round. On completion of the 3 Delphi rounds, 66 unique medications remained, 63 requiring dose adjustment and 16 medications requiring avoidance in one or more estimated glomerular filtration rate categories. The consensus workshop prioritized this list further to 24 medications that must be dose-adjusted or avoided, including baclofen, metformin, and digoxin, as well as the newer SGLT2 inhibitor agents. Conclusion and Relevance: We have developed a concise list of 24 medications commonly used in primary care that should be dose-adjusted or avoided in people with CKD to reduce harm. This list incorporates new and frequently prescribed medications and will inform an updated, easy to access source for primary care providers.

11. Microvascular Complications and Foot Care: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc20-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Effect of renal ischaemia/reperfusion-induced acute kidney injury on pharmacokinetics of midazolam in rats

OBJECTIVES

This study aimed to investigate the effects of renal ischaemia/reperfusion (I/R)-induced acute kidney injury (AKI) on the distribution of midazolam (MDZ), a probe drug for cytochrome P450 3A (CYP3A) activity.

METHODS

We established an AKI model inducing ischaemia of both renal pedicles for 60 min followed by 24-h reperfusion. MDZ was administered intravenously (i.v.) to the rats via the jugular vein, and then, blood samples were collected to determine the plasma concentration of MDZ.

KEY FINDINGS

While the plasma concentration of MDZ after i.v. administration was decreased in the I/R rats, the tissue concentration was not altered. In addition, the tissue-to-plasma (T/P) ratio of MDZ was increased in the I/R rats. The unbound fraction of MDZ and the level of indoxyl sulphate (IS) in plasma were elevated in the I/R rats. Furthermore, the unbound fraction of MDZ was significantly increased by the addition of IS.

CONCLUSIONS

These results indicated that the displacement of albumin-bound MDZ by IS changed the unbound fraction of MDZ and elevated the T/P ratio of MDZ in I/R rats.

How to adjust drug doses in chronic kidney disease

Drugs excreted by the kidney require dose reduction in chronic kidney disease. This adjustment depends on the severity of the disease and what proportion of the drug is eliminated by the kidneys

The estimated glomerular filtration rate can generally be used to guide dose adjustment in patients with stable kidney function. However, the formula can be misleading in some patient subsets and other approaches are required

At extremes of body mass, the estimated glomerular filtration rate can under- or overestimate kidney function. It may need to be adjusted for body surface area, particularly for drugs with a narrow therapeutic range or requiring a minimum concentration to be effective. Close monitoring of drug effect and toxicity is also needed and can be supported by therapeutic drug monitoring

For short courses of drugs with a wide therapeutic index, dose adjustment may not be needed

Alternative methods for quantifying kidney function include the Cockcroft-Gault formula (estimates creatinine clearance) or direct measures of glomerular filtration rate using exogenous isotope compounds. These are not commonly required

Comprehensive Assessment of Kidney Health in Acute Kidney Injury: Can It Be Achieved?

Acute kidney injury (AKI) is a frequent event in hospitalized patients, with an incidence that continues to rise, reaching as high as 70-80% in intensive care settings. The need for dialysis and progression to end-stage kidney disease (ESKD) after an episode of AKI is relatively low, from 5 to 20%. However, it is now recognized that patients with AKI may have very different kidney outcomes, varying from complete recovery, incipient chronic kidney disease (CKD), to progression to ESKD. Recent studies have shown that even mild AKI episodes can be associated with a 90% increased risk of developing CKD during long-term follow-up. There is a significant need to focus our efforts on factors that could mitigate the progression of kidney dysfunction and ultimately improve outcomes from AKI. The first step toward this goal encompasses a better understanding of tubular and glomerular alterations during and following an AKI episode. Our current approach, based solely on glomerular filtration rate (GFR), is flawed, since the loss of kidney function does not correspond to the degree of decline in estimated GFR (eGFR), and eGFR does not reflect tubular function. Changes in tubular concentration, reabsorptive and secretory capacity are recognized in AKI; however, they have not been incorporated in clinical assessments of overall kidney function. Here we review a few candidates to assess glomerular filtration/permeability, tubular dysfunction, and injury and how we expect these markers to alter during the development and recovery phase of AKI.

Maternal and environmental risk factors for neonatal AKI and its long-term consequences

Acute kidney injury (AKI) is a common and life-threatening complication in critically ill neonates. Gestational risk factors for AKI include premature birth, intrauterine growth restriction and low birthweight, which are associated with poor nephron development and are often the consequence of pre-gestational and gestational factors, such as poor nutritional status. Our understanding of how to best optimize renal development and prevent AKI is in its infancy; however, the identification of pre-gestational and gestational factors that increase the risk of adverse neonatal outcomes and the implementation of interventions, such as improving nutritional status early in pregnancy, have the potential to optimize fetal growth and reduce the risk of preterm birth, thereby improving kidney health. The overall risk of AKI among critically ill and premature neonates is exacerbated postnatally as these infants are often exposed to dehydration, septic shock and potentially nephrotoxic medications. Strategies to improve outcomes - for example, through careful evaluation of nephrotoxic drugs - may reduce the incidence of AKI and its consequences among this population. Management strategies and updated technology that will support neonates with AKI are greatly needed. Extremely premature infants and those who survive an episode of AKI should be screened for chronic kidney disease until early adulthood. Here, we provide an overview of our current understanding of neonatal AKI, focusing on its relationship to preterm birth and growth restriction. We describe factors that prevent optimal nephrogenesis during pregnancy and provide a framework for future explorations designed to maximize outcomes in this vulnerable population.

Mechanisms and treatment of organ failure in sepsis

Sepsis is a dysregulated immune response to an infection that leads to organ dysfunction. Knowledge of the pathophysiology of organ failure in sepsis is crucial for optimizing the management and treatment of patients and for the development of potential new therapies. In clinical practice, six major organ systems - the cardiovascular (including the microcirculation), respiratory, renal, neurological, haematological and hepatic systems - can be assessed and monitored, whereas others, such as the gut, are less accessible. Over the past 2 decades, considerable amounts of new data have helped improve our understanding of sepsis pathophysiology, including the regulation of inflammatory pathways and the role played by immune suppression during sepsis. The effects of impaired cellular function, including mitochondrial dysfunction and altered cell death mechanisms, on the development of organ dysfunction are also being unravelled. Insights have been gained into interactions between key organs (such as the kidneys and the gut) and organ-organ crosstalk during sepsis. The important role of the microcirculation in sepsis is increasingly apparent, and new techniques have been developed that make it possible to visualize the microcirculation at the bedside, although these techniques are only research tools at present.

Producing hybrid nanofiber-based on /PAN/Fe3 O4 /zeolite/nettle plant extract/urease and a deformed coaxial natural polymer to reduce toxicity materials in the blood of dialysis patients

On incidence of kidney failure, the concentration of urea increases and there is need for patients to visit the hospital all through the week for blood purification. However, current hemodialysis has been found to reduce only 66-75% urea in the blood of patients. The main goal of this article is to observe the effect of biocompatible and high mechanical hemodiafiltration in reducing urea and creatinine within the shortest time frame, using two methods of Nano electrospinning fiber (hybrid and coaxial). Hybrid electrospinning was made by zeolite 940-HOA(beta), Fe₃ O₄ , polyacrylonitrile as well as the addition of nettle plant's leaf extract. Dispersing solution and enzymes were added to two different syringes and was used in making hybrid nanofibers by the electrospinning process. Nessler's Reagent adsorption method was used for measuring the concentration of ammonia after urease enzyme activation. Second coaxial filter was made by the core-shell electrospinning system and cellulose acetate phthalate (CAP) as well as polyurethane (PU) were utilized. The data show hybrid hemodiafiltration with enzyme coating, decomposed urea and enzymes were activated for two days after electrospinning. The core-shell filtration can also reduce creatinine. Core-shell CAP-PU nanofiber was previously used for intravaginal drug delivery and PU was used as an artificial renal microfluidic chip. Thus, our study focused on using CAP-PU to reduce creatinine in dialysis patients. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1736-1743, 2019.

Optimizing Vancomycin Dosing in Chronic Kidney Disease by Deriving and Implementing a Web-Based Tool Using a Population Pharmacokinetics Analysis

Background: Chronic kidney disease (CKD) patients requiring intravenous vancomycin bear considerable risks of adverse outcomes both from the infection and vancomycin therapy itself, necessitating especially precise dosing to avoid sub- and supratherapeutic vancomycin exposure.

Methods: In this retrospective study, we performed a population pharmacokinetic analysis to construct a vancomycin dose prediction model for CKD patients who do not require renal replacement therapy. The model was externally validated on an independent cohort of patients to assess its prediction accuracy. The pharmacokinetic parameter estimates and the equations were productized into a Web application (VancApp) subsequently implemented in routine care. The association between VancApp-based dosing and time-to-target concentration attainment, 30-day mortality, and nephrotoxicity were assessed postimplementation.

Results: The model constructed from an initial cohort (n = 80) revealed a population clearance and volume of distribution of 1.30 L/h and 1.23 L/kg, respectively. External model validation (n = 112) demonstrated a mean absolute prediction error of 1.25 mg/L. Following 4 months of clinical implementation of VancApp as an optional alternative to usual care [VancApp (n = 22) vs. usual care (n = 21)], patients who had received VancApp-based dosing took a shorter time to reach target concentrations (median: 66 vs. 102 h, p = 0.187) and had fewer 30-day mortalities (14% vs. 24%, p = 0.457) compared to usual care. While statistical significance was not achieved, the clinical significance of these findings appear promising.

Conclusion: Clinical implementation of a population pharmacokinetic model for vancomycin in CKD can potentially improve dosing precision in CKD and could serve as a practical means to improve vital clinical outcomes.

The prominent impairment of liver/intestinal cytochrome P450 and intestinal drug transporters in sepsis-induced acute kidney injury over acute and chronic renal ischemia, a mouse model comparison

Drug dosing adjustment in sepsis-induced acute kidney injury (sepsis-AKI) is currently adjusted based on renal function. Sepsis is a multiorgan injury, and thus, drug metabolism in sepsis-AKI might be interfered by non-renal factors such as changes in functions of drug-metabolizing enzymes in the liver and functions of intestinal drug transporters. We compared the defect on mouse CYP3A11 (human CYP3A4 representative) in liver and intestine along with several intestinal drug transporters (MDR1a, MRP2, and OATP3) in three mouse models; chronic ischemic reperfusion injury (Chr I/R; 4-week), acute ischemic reperfusion injury (Acute I/R; 24-h), and cecal ligation and puncture (CLP; 24-h) as representative of sepsis-AKI. Decreased expression of CYP3A11 and drug transporters was demonstrated in all models. Among these models, sepsis-AKI had the least severe renal injury (increased BUN and Scr) with the most severe liver injury (increased ALT and changes in liver histopathology), the most severe intestinal leakage (increased serum (1→3)-β-D-glucan) and the highest increase in serum IL-6. A reduced expression and activity of liver and intestinal CYP3A11 along with intestinal efflux-drug transporter expressions (MDR1a and MRP2), but not drug uptake transporter (OATP3), was predominant in sepsis-AKI compared with acute I/R. Additionally, a reduction of CYP3A4 expression with IL-6 was demonstrated on HepG2 cells implying a direct injury of IL-6 on human liver cells. Differences in drug metabolism were reported between sepsis-AKI and ischemic-AKI confirming that drug dosing adjustment in sepsis-AKI depends not just only on renal function but also on several non-renal factors. Further studies are warranted.

Patterns of medication use and the burden of polypharmacy in patients with chronic kidney disease: the German Chronic Kidney Disease study

Background

Patients with chronic kidney disease (CKD) bear a substantial burden of comorbidities leading to the prescription of multiple drugs and a risk of polypharmacy. However, data on medication use in this population are scarce.

Methods

A total of 5217 adults with an estimated glomerular filtration rate (eGFR) between 30 and 60 mL/min/1.73 m² or an eGFR ≥60 mL/min/1.73m² and overt proteinuria (>500 mg/day) were studied. Self-reported data on current medication use were assessed at baseline (2010-12) and after 4 years of follow-up (FU). Prevalence and risk factors associated with polypharmacy (defined as the regular use of five or more drugs per day) as well as initiation or termination of polypharmacy were evaluated using multivariable logistic regression.

Results

The prevalence of polypharmacy at baseline and FU was almost 80%, ranging from 62% in patients with CKD Stage G1 to 86% in those with CKD Stage G3b. The median number of different medications taken per day was eight (range 0-27). β-blockers, angiotensin-converting enzyme inhibitors and statins were most frequently used. Increasing CKD G stage, age and body mass index, diabetes mellitus, cardiovascular disease and a history of smoking were significantly associated with both the prevalence of polypharmacy and its maintenance during FU. Diabetes mellitus was also significantly associated with the initiation of polypharmacy [odds ratio (OR) 2.46, (95% confidence interval 1.36-4.45); P = 0.003].

Conclusion

Medication burden in CKD patients is high. Further research appears warranted to address the implications of polypharmacy, risks of drug interactions and strategies for risk reduction in this vulnerable patient population.

Pharmacokinetic study of the oral fluorouracil antitumor agent S-1 in patients with impaired renal function

Although dose reduction of S-1 is recommended for patients with impaired renal function, dose modification for such patients has not been prospectively evaluated. The aim of the present study was to investigate the pharmacokinetic parameters of 5-fluorouracil, 5-chloro-2,4 dihydroxypyridine and oteracil potassium, and to review the recommended dose modification of S-1 in patients with renal impairment. We classified patients receiving S-1 into 4 groups according to their renal function, as measured using the Japanese estimated glomerular filtration rate (eGFR) equation. The daily S-1 dose was adjusted based on the patient's eGFR and body surface area. Blood samples were collected for pharmacokinetic analysis. A total of 33 patients were enrolled and classified into 4 groups as follows: 10 patients in cohort 1 (eGFR ≥ 80 mL/min/1.73 m² ), 10 patients in cohort 2 (eGFR = 50-79 mL/min/1.73 m² ), 10 patients in cohort 3 (eGFR = 30-49 mL/min/1.73 m² ), and 3 patients in cohort 4 (eGFR < 30 mL/min/1.73 m² ). Those in cohorts 3 and 4 treated with an adjusted dose of S-1 showed a similar area under the curve for 5-fluorouracil (941.9 ± 275.6 and 1043.5 ± 224.8 ng/mL, respectively) compared with cohort 2 (1034.9 ± 414.3 ng/mL). Notably, while there was a statistically significant difference between cohort 1 (689.6 ± 208.8 ng/mL) and 2 (P = 0.0474) treated with an equal dose of S-1, there was no significant difference observed in the toxicity profiles of the cohorts. In conclusion, dose adjustment of S-1 in patients with impaired renal function using eGFR is appropriate and safe.

Single dose oral ranolazine pharmacokinetics in patients receiving maintenance hemodialysis

Purpose: Ranolazine is a novel anti-angina treatment approved in the United States for chronic stable angina. Ranolazine pharmacokinetics have not been studied previously in patients who receive maintenance hemodialysis. This study describes the pharmacokinetics of ranolazine and three major metabolites (CVT-2738, CVT-2512, CVT-2514) in patients receiving thrice weekly hemodialysis.

Methods: Eight participants receiving maintenance hemodialysis completed this prospective, open-label study (study identifier NCT01435174 at Clinicaltrials.gov). Three participants received a single tablet of ranolazine 500 mg (followed by an interim analysis), and five received 2 tablets of ranolazine 500 mg. Blood samples were collected over 65 h to determine the pharmacokinetic characteristics during and between hemodialysis sessions. Non-compartmental analysis was used to determine the individual pharmacokinetic parameters.

Results: Ranolazine off-hemodialysis elimination phase half-lives were 3.6 and 3.9 h for 500 mg and 1000 mg doses, respectively. The time to maximum concentration ranged from 2 to 18 hours and the average maximum concentration was 0.65 ± 0.27 mcg/mL and 1.18 ± 0.48 mcg/mL for ranolazine 500 mg and 1000 mg dose, respectively. The mean hemodialysis percent reduction ratio for the ranolazine 500 mg dose was 52.3 ± 8.1% and for the ranolazine 1000 mg dose was 69.2 ± 37.6%.

Conclusions: Data on ranolazine dosing in patients receiving maintenance hemodialysis is almost non-existent. Given the extent of pharmacokinetic variability observed with the 500 mg and 1000 mg oral doses of ranolazine, neither can be recommended as a starting dose in patients receiving maintenance hemodialysis. Guided by the information gained form this study about the extent of hemodialytic drug clearance, further multi-dose clinical trials of ranolazine are needed to optimize therapeutic outcomes in this patient population.

Optimization of the treatment with beta-lactam antibiotics in critically ill patients-guidelines from the French Society of Pharmacology and Therapeutics (Société Française de Pharmacologie et Thérapeutique-SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (Société Française d'Anesthésie et Réanimation-SFAR)

BACKGROUND

Beta-lactam antibiotics (βLA) are the most commonly used antibiotics in the intensive care unit (ICU). ICU patients present many pathophysiological features that cause pharmacokinetic (PK) and pharmacodynamic (PD) specificities, leading to the risk of underdosage. The French Society of Pharmacology and Therapeutics (SFPT) and the French Society of Anaesthesia and Intensive Care Medicine (SFAR) have joined forces to provide guidelines on the optimization of beta-lactam treatment in ICU patients.

METHODS

A consensus committee of 18 experts from the two societies had the mission of producing these guidelines. The entire process was conducted independently of any industry funding. A list of questions formulated according to the PICO model (Population, Intervention, Comparison, and Outcomes) was drawn-up by the experts. Then, two bibliographic experts analysed the literature published since January 2000 using predefined keywords according to PRISMA recommendations. The quality of the data identified from the literature was assessed using the GRADE® methodology. Due to the lack of powerful studies having used mortality as main judgement criteria, it was decided, before drafting the recommendations, to formulate only "optional" recommendations.

RESULTS

After two rounds of rating and one amendment, a strong agreement was reached by the SFPT-SFAR guideline panel for 21 optional recommendations and a recapitulative algorithm for care covering four areas: (i) pharmacokinetic variability, (ii) PK-PD relationship, (iii) administration modalities, and (iv) therapeutic drug monitoring (TDM). The most important recommendations regarding βLA administration in ICU patients concerned (i) the consideration of the many sources of PK variability in this population; (ii) the definition of free plasma concentration between four and eight times the Minimal Inhibitory Concentration (MIC) of the causative bacteria for 100% of the dosing interval as PK-PD target to maximize bacteriological and clinical responses; (iii) the use of continuous or prolonged administration of βLA in the most severe patients, in case of high MIC bacteria and in case of lower respiratory tract infection to improve clinical cure; and (iv) the use of TDM to improve PK-PD target achievement.

CONCLUSIONS

The experts strongly suggest the use of personalized dosing, continuous or prolonged infusion and therapeutic drug monitoring when administering βLA in critically ill patients.

Evaluation of renal drug dosing adjustment in chronic kidney disease patients at two university hospitals in Lebanon

Background:

Inappropriate medication dosing in patients with chronic kidney disease can cause toxicity or ineffective therapy. Patients are at a high risk of developing related adverse events caused by the altered effect of drugs in conjunction with the use of polypharmacy to treat comorbid conditions. This necessitates adequate renal dosing adjustments.

Objective:

The current study aims at assessing whether appropriate dosing adjustments were made in hospitalized patients with chronic kidney disease.

Methods:

A retrospective descriptive study was conducted at two university hospitals in Beirut between January and December 2016. All adult CKD patients with creatinine clearance less than 60 ml/min and receiving at least one medication that require renal dosing adjustment were included. Kidney function was estimated from serum creatinine using Cockcroft-Gault equation, and dose appropriateness was determined by comparing practice with specific guidelines. The rates of renal drug dosing adjustment were investigated, in addition to the influence of possible determinants, such as the severity of renal impairment, reason of hospital admission, and other patient characteristics.

Results:

2138 patients admitted in 2016 were screened. 223 adults receiving 578 drug orders that require adjustment were included. Among the 578 orders, 215 (37%) were adjusted adequately, 284 (49%) were adjusted inadequately, and 79 (14%) were not adjusted at all. Beta-blockers were the most inadequately dosed (83.6%) class of medication, whereas lipid-lowering agents had the highest percentage of adequate dosing (65.1%). As per patient, 84.3% of patients appeared to be receiving at least one inappropriate drug dose.

Conclusions:

Our study confirms that physicians are not prescribing appropriate dosing adjustments in chronic kidney disease inpatients, which may have deleterious effects. This highlights the need for more nephrology consultation and the implementation of physician education programs.

Clinical Outcomes of Failing to Dose-Reduce Cephalosporin Antibiotics in Older Adults with CKD

BACKGROUND AND OBJECTIVES

Current dosing recommendations for cephalosporin antibiotics are on the basis of pharmacokinetic studies and are frequently ignored in practice. This study was undertaken to investigate the clinical outcomes of failing to dose-reduce cephalosporin antibiotics in CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Retrospective cohort study conducted in Ontario, Canada using linked population-based health care databases. Nine thousand three hundred forty-seven outpatients (median age 83; interquartile range, 77-88 years; 57% women) with an eGFR<30 ml/min per 1.73 m2 and no prior history of dialysis were dispensed oral cephalexin, cefuroxime, or cefprozil between April of 2007 and March of 2016. Two thirds of the patients (6253 of 9347) received a higher than recommended daily dose of cephalexin (>1000 mg), cefuroxime (>500 mg), or cefprozil (>500 mg). The primary outcome was a hospital encounter (emergency room visit or hospital admission) with a condition listed as a possible side-effect of cephalosporins. Secondary outcomes were antibiotic treatment failure and all-cause mortality. All measures were assessed in the 30 days after cephalosporin initiation.

RESULTS

Patients who received a higher than recommended dose of a cephalosporin antibiotic were similar in multiple indicators of baseline health to patients who received a reduced dose. Overall, 6% of patients presented to hospital with a possible cephalosporin side-effect, 13% failed antibiotic treatment, and 3% died. Compared with a reduced dose, receiving a higher dose of antibiotic was not associated with a different rate of side-effects (adjusted odds ratio, 1.00; 95% confidence interval, 0.84 to 1.20), treatment failure (1.01; 0.88 to 1.15), or death (0.99; 0.76 to 1.29).

CONCLUSIONS

In this study we failed to demonstrate any association between the dose of cephalosporin antibiotic administered to elderly patients with CKD and the risk of side-effects leading to hospitalization, treatment failure, or mortality.

High variability of teicoplanin concentration in patients with continuous venovenous hemodiafiltration

INTRODUCTION

Continuous venovenous hemodiafiltration (CVVHDF) may alter teicoplanin pharmacokinetics and increase the risk of incorrect dosing. The objective of this prospective observational study was to assess the effect of CVVHDF on the pharmacokinetics of teicoplanin as maintenance therapy.

METHODS

Blood, urine, and dialysate samples were collected to measure teicoplanin levels. CVVHDF clearance (CL_CVVHDF ), total clearance (CL_TOTAL ), and volume of distribution (Vd) were calculated by simplex-linear modeling. The influence of CVVHDF dose on teicoplanin pharmacokinetics was assessed.

FINDINGS

Ten samples from eight patients were studied. Creatinine clearance was 3.4 ± 5.1 ml/min/1.73 m² . Three patients were anuria. The dose for CVVHDF was 32.1 ± 7.0 mL/kg/h. Vd was 1.6 ± 0.7 L/kg. T1/2 was 100.1 ± 42.7 hours. CL_TOTAL of teicoplanin was 11.9 ± 5.4 mL/min and CL_CVVHDF was 5.8 ± 4.2 mL/min. Contribution of CL_CVVHDF to CL_TOTAL was 51.2% ± 23.6%. CL_CVVHDF of individual teicoplanin varied widely. Large intra-occasion differences were also observed. Dose of CL_CVVHDF did not influence overall CL_TOTAL , Vd, or half-life. The proportion of CL_TOTAL due to CL_CVVHDF varied widely. It was high in some cases.

DISCUSSION

In patients receiving CVVHDF, there is great variability in teicoplanin pharmacokinetics which complicates empiric approach to dosing, suggesting the need for therapeutic drug monitoring.

Differences in Kidney Function Estimates Based on Creatinine and/or Cystatin C in Non-Traumatic Amputation Patients and Their Impact on Drug Prescribing

Accurate kidney function estimates are necessary when prescribing renally-eliminated medications. Our objectives were to investigate how amputation affects estimated glomerular filtration rate (eGFR) and to determine if dosing recommendations differ among different eGFR equations. In a cohort study of non-traumatic amputation patients, eGFR based on creatinine and/or cystatin C were measured before and after amputation. Prescribed, renally-eliminated medications were compared with dosing guidelines in Renbase^®. Data from 38 patients with a median age of 75 years were analyzed. The median (range) eGFR was 65 (15⁻103), 38 (13⁻79), and 48 (13⁻86) mL/min/1.73 m² before amputation and 80 (22⁻107), 51 (13⁻95), and 62 (16⁻100) mL/min/1.73 m² after amputation for eGFR_Creatinine, eGFR_CystatinC, and eGFR_Combined, respectively (p < 0.01). From before to after amputation, eGFR increased on average by 8.5, 6.1, and 7.4 mL/min/1.73 m² for eGFR_Creatinine, eGFR_CystatinC, and eGFR_Combined (all p < 0.01), respectively. At least one renally-eliminated medication was prescribed at a higher dose than recommended in 37.8% of patients using eGFR_CystatinC, 17.6% using eGFR_Combined and 10.8% using eGFR_Creatinine. In conclusion, amputation affects eGFR regardless of the eGFR equations. The differences among equations would impact prescribing of renally-eliminated medications, particularly when switching from creatinine to cystatin C.

Medication Safety Principles and Practice in CKD

Ensuring patient safety is a priority of medical care because iatrogenic injury has been a primary concern. Medications are an important source of medical errors, and kidney disease is a thoroughfare of factors threatening safe administration of medicines. Principal among these is reduced kidney function because almost half of all medications used are eliminated via the kidney. Additionally, kidney patients often suffer from multimorbidity, including diabetes, hypertension, and heart failure, with a range of prescribers who often do not coordinate treatments. Patients with kidney disease are also susceptible to further kidney injury and metabolic derangements from medications, which can worsen the disease. In this review, we will present the key issues and threats to safe medication use in kidney disease, with a focus on predialysis CKD, as the scope of medication safety in ESKD and transplantation are unique and deserve their own consideration. We discuss drugs that need to be avoided or dose modified, and review the complications of a range of medications routinely administered in CKD, as these also call for cautious use.

Renal Complications Following Lung Transplantation and Heart Transplantation

Renal complications are common following heart and/or lung transplantation and lead to increased morbidity and mortality. Renal dysfunction is also associated with increased mortality for patients on the transplant wait list. Dialysis dependence is a relative contraindication for heart or lung transplantation at most centers, and such patients are often listed for a simultaneous kidney transplant. Several factors contribute to the impaired renal function in patients undergoing heart and/or lung transplantation, including the interplay between cardiopulmonary and renal hemodynamics, complex perioperative issues, and exposure to nephrotoxic medications, mainly calcineurin inhibitors.

Single-Center Pharmacokinetic Study and Simulation of a Low Meropenem Concentration in Brain-Dead Organ Donors

Meropenem is an ultrabroad-spectrum antibiotic of the carbapenem family. In brain-dead organ donors, administration of standard meropenem dosages does not reach therapeutic levels. Our objectives were to determine the plasma concentration of meropenem after the administration of standard meropenem dose and to estimate an improved dosage regimen for these patients. One gram of meropenem was administered as a 1-h infusion every 8 h for 1 to 3 days, and blood samples were collected. The plasma concentration of meropenem was measured and subjected to pharmacokinetic analysis. Simcyp simulation was performed to predict the optimum plasma levels and dosage based on the patients' individual pharmacokinetic parameters. The maximum plasma concentration of meropenem was 3.29 μg/ml, which was lower than four times the MIC of 8 μg/ml. Although the mean creatinine clearance of patients was moderately low (67.5 ml/min), the apparent volume of distribution at steady state (Vss) and time-averaged total body clearance (CL) of meropenem were markedly elevated (4.97 liters/kg and 2.06 liters/h/kg, respectively), owing to massive fluid loading to decrease the high sodium levels and to treat shock or dehydration. The simulation revealed that dose and infusion time of meropenem should be increased based on patients' Vss and CL, and a loading dose is recommended to reach rapidly the target concentration. In conclusion, a standard meropenem regimen is insufficient to achieve optimal drug levels in brain-dead patients, and an increase in dose and extended or continuous infusion with intravenous bolus administration of a loading dose are recommended for these patients.

Estimating Renal Function in Drug Development: Time to Take the Fork in the Road

Renal function is the most commonly applied patient-specific quantitative variable used to determine drug doses. Measurement of renal function is not practical in most clinical settings; therefore, clinicians often rely on estimates when making dosing decisions. Similarly, renal function estimates are used to assign subjects in phase 1 pharmacokinetic studies, which inform dosing in late-phase clinical trials and ultimately the product label. The Cockcroft-Gault estimate of creatinine clearance has been the standard renal function metric; however, this paradigm is shifting toward the Modification of Diet in Renal Diseases (MDRD) estimate of the glomerular filtration rate (GFR). The proportion of approved new drug labels with dosing recommendations based on the MDRD equation was 16.7% in 2015, 70.0% in 2016, and 46.7% in 2017. Disharmonious recommendations from the United States Food and Drug Administration and the European Medicines Agency will continue to increase this heterogeneity in the assessment of renal function in drug development and negatively impact industry, health systems, and clinicians. In this review, we discuss the current regulatory guidance for the conduct of renal impairment pharmacokinetic studies and review the implications of this guidance across the medication use system with 3 recently approved antibiotics: ceftazidime/avibactam, delafloxacin, and meropenem/vaborbactam. Finally, we suggest measuring GFR in phase 1 studies and employing the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation to integrate data across clinical trials. This will help to harmonize CKD staging, population pharmacokinetic analyses, and dosing by estimated renal function.

Use of Estimating Equations for Dosing Antimicrobials in Patients with Acute Kidney Injury Not Receiving Renal Replacement Therapy

Acute kidney injury (AKI) can potentially lead to the accumulation of antimicrobial drugs with significant renal clearance. Drug dosing adjustments are commonly made using the Cockcroft-Gault estimate of creatinine clearance (CLcr). The Modified Jelliffe equation is significantly better at estimating kidney function than the Cockcroft-Gault equation in the setting of AKI. The objective of this study is to assess the degree of antimicrobial dosing discordance using different glomerular filtration rate (GFR) estimating equations. This is a retrospective evaluation of antimicrobial dosing using different estimating equations for kidney function in AKI and comparison to Cockcroft-Gault estimation as a reference. Considering the Cockcroft-Gault estimate as the criterion standard, antimicrobials were appropriately adjusted at most 80.7% of the time. On average, kidney function changed by 30 mL/min over the course of an AKI episode. The median clearance at the peak serum creatinine was 27.4 (9.3–66.3) mL/min for Cockcroft Gault, 19.8 (9.8–47.0) mL/min/1.73 m² for MDRD and 20.5 (4.9–49.6) mL/min for the Modified Jelliffe equations. The discordance rate for antimicrobial dosing ranged from a minimum of 8.6% to a maximum of 16.4%. In the event of discordance, the dose administered was supra-therapeutic 100% of the time using the Modified Jelliffe equation. Use of estimating equations other than the Cockcroft Gault equation may significantly alter dosing of antimicrobials in AKI.

[Interactions between lung and kidney in the critically ill]

Interactions between lung and kidney can significantly affect the course of acute diseases, a phenomenon that was first observed in the 1950s by describing pulmonary dysfunction in uremic patients. From animal experiments there is ample evidence for remote lung injury following acute kidney injury (AKI), with an increased risk for the development of pulmonary edema and acute respiratory distress syndrome (ARDS). Coincident ARDS and AKI are associated with higher rates of intubation and mechanical ventilation, significantly prolonged weaning from mechanical ventilation and increased mortality. On the other hand, acute lung diseases and mechanical ventilation can promote the development of AKI and are associated with increased mortality when AKI is also present. These bidirectional interactions may include hemodynamic adverse effects during mechanical ventilation or volume overload as well as the release or decreased clearance and metabolism of proinflammatory mediators (e.g., interleukin-6 and tumor necrosis factor-α), which may induce and aggravate distant organ injury. The aim of this work is to examine the interactions between lung and the kidney in critically ill patients, as well as discuss potential preventive approaches.

Creatinine Versus Cystatin C: Differing Estimates of Renal Function in Hospitalized Veterans Receiving Anticoagulants

BACKGROUND

Current practice in anticoagulation dosing relies on kidney function estimated by serum creatinine using the Cockcroft-Gault equation. However, creatinine can be unreliable in patients with low or high muscle mass. Cystatin C provides an alternative estimation of glomerular filtration rate (eGFR) that is independent of muscle.

OBJECTIVE

We compared cystatin C-based eGFR (eGFR_cys) with multiple creatinine-based estimates of kidney function in hospitalized patients receiving anticoagulants, to assess for discordant results that could impact medication dosing.

DESIGN

Retrospective chart review of hospitalized patients over 1 year who received non-vitamin K antagonist anticoagulation, and who had same-day measurements of cystatin C and creatinine.

PARTICIPANTS

Seventy-five inpatient veterans (median age 68) at the San Francisco VA Medical Center (SFVAMC).

MAIN MEASURES

We compared the median difference between eGFR by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) study equation using cystatin C (eGFR_cys) and eGFRs using three creatinine-based equations: CKD-EPI (eGFR_EPI), Modified Diet in Renal Disease (eGFR_MDRD), and Cockcroft-Gault (eGFR_CG). We categorized patients into standard KDIGO kidney stages and into drug-dosing categories based on each creatinine equation and calculated proportions of patients reclassified across these categories based on cystatin C.

KEY RESULTS

Cystatin C predicted overall lower eGFR compared to creatinine-based equations, with a median difference of - 7.1 (IQR - 17.2, 2.6) mL/min/1.73 m² versus eGFR_EPI, - 21.2 (IQR - 43.7, - 8.1) mL/min/1.73 m² versus eGFR_MDRD, and - 25.9 (IQR - 46.8, - 8.7) mL/min/1.73 m² versus eGFR_CG. Thirty-one to 52% of patients were reclassified into lower drug-dosing categories using cystatin C compared to creatinine-based estimates.

CONCLUSIONS

We found substantial discordance in eGFR comparing cystatin C with creatinine in this group of anticoagulated inpatients. Our sample size was limited and included few women. Further investigation is needed to confirm these findings and evaluate implications for bleeding and other clinical outcomes.

NIH TRIAL REGISTRY NUMBER

Not applicable.