Randomized Controlled Trial to Determine the Efficacy of Early Switch From Vancomycin to Vancomycin Alternatives as a Strategy to Prevent Nephrotoxicity in Patients With Multiple Risk Factors for Adverse Renal Outcomes (STOP-NT)

The Influence of a Therapeutic Drug Monitoring Service on Vancomycin-Associated Nephrotoxicity

Vancomycin's widespread use as the mainstay antibiotic against methicillin-resistant Staphylococcus aureus infections is complicated by its narrow therapeutic index. Therapeutic drug monitoring using area under the concentration-time curve (AUC)-guided dosing is recommended to optimize therapy and prevent vancomycin-associated nephrotoxicity (VAN). In 2018, a consultative therapeutic drug monitoring Advisory Service (the Service) was piloted at an Australian hospital to enable AUC-guided vancomycin dosing. This study sought to compare the incidence of VAN pre- and post-Service implementation. A 4-year retrospective observational study of intravenous vancomycin therapy (greater than 48 hours) in adults (aged 18 years or older), spanning 3 years before and 1-year after implementation of the Service was undertaken. Nephrotoxicity was defined as an increase in serum creatinine concentrations of 26.5 μmol/L or greater or 50% or more from baseline, on 2 or more consecutive days. Univariate analysis was performed to compare patients before and after implementation, and with and without VAN. Independent factors associated with VAN were identified using a multivariate model. In total, 971 courses of vancomycin therapy, administered to 781 patients, were included: 764 courses (603 patients) before implementation and 207 courses (163 patients) after implementation. The incidence of VAN decreased by 5% after Service implementation (15% before implementation vs 10% after implementation; P = .075). Independent factors associated with VAN were sepsis, heart failure, solid-organ transplant, concomitant piperacillin-tazobactam, and average vancomycin AUC during therapy. In conclusion, there was a nonsignificant trend toward a reduced incidence of VAN after the Service. Larger prospective studies are needed to confirm the efficacy of the Service.

Pharmacokinetics and pharmacodynamics of peptide antibiotics

Antimicrobial resistance is a major global health challenge. As few new efficacious antibiotics will become available in the near future, peptide antibiotics continue to be major therapeutic options for treating infections caused by multidrug-resistant pathogens. Rational use of antibiotics requires optimisation of the pharmacokinetics and pharmacodynamics for the treatment of different types of infections. Toxicodynamics must also be considered to improve the safety of antibiotic use and, where appropriate, to guide therapeutic drug monitoring. This review focuses on the pharmacokinetics/pharmacodynamics/toxicodynamics of peptide antibiotics against multidrug-resistant Gram-negative and Gram-positive pathogens. Optimising antibiotic exposure at the infection site is essential for improving their efficacy and minimising emergence of resistance.

Relationship of vancomycin trough levels with acute kidney injury risk: an exposure–toxicity meta-analysis

Objectives

Nephrotoxicity represents a major complication of vancomycin administration, leading to high rates of morbidity and treatment failure. The aim of this meta-analysis was to evaluate the association between trough levels and risk of renal impairment, by defining an exposure–toxicity relationship and assessing its accuracy in predicting the development of acute kidney injury (AKI).

Methods

Medline, Scopus, CENTRAL, Clinicaltrials.gov and Google Scholar databases were systematically searched from inception. Studies examining the effects of trough levels on nephrotoxicity risk in adult patients were deemed eligible.

Results

The meta-analysis was based on 60 studies, including 13 304 patients. The development of AKI was significantly linked to both higher initial [standardized mean difference (SMD): 0.82; 95% CI: 0.65–0.98] and maximum (SMD: 1.06; 95% CI: 0.82–1.29) trough levels. Dose–response analysis indicated a curvilinear relationship between trough levels and nephrotoxicity risk (χ2 = 127.1; P value < 0.0001). A cut-off of 15 mg/L detected AKI with a sensitivity of 62.6% (95% CI: 55.6–69.2) and a specificity of 65.5% (95% CI: 58.9–71.6), while applying a 20 mg/L threshold resulted in a sensitivity of 42.9% (95% CI: 34–52.2) and a specificity of 82.5% (95% CI: 73.9–88.8).

Conclusions

The present findings suggest that the development of vancomycin-induced AKI is significantly associated with higher initial and maximum trough levels. An exposure–response relationship was defined, indicating that increasing trough levels correlate with a significant rise of nephrotoxicity risk. Future studies should verify the effectiveness of individualized pharmacokinetic tools that would enable the attainment of trough level targets and minimize the risk of renal toxicity.

Drug-Induced Kidney Disease Associated With Selected Antibiotics

Structural and functional degeneration of the kidneys occur as the human body ages, making oler people especially susceptible to the consequences of acute kidney injury. Furthermore, the use of nephrotoxic agents, combined with the increased incidence of acute kidney injury and likelihood of an intensive-care unit admission, makes geriatric patients prone to develop drug-induced kidney disease. Vancomycin is routinely used as the first-line treatment for methicillin-resistant Staphylococcus aureus, but is known to be nephrotoxic; studies have shown that an early switch from vancomycin to alternatives does not necessarily prevent renal insult. Therefore, we aim to discuss the mechanisms of drug-induced kidney disease with regard to vancomycin, daptomycin, and ceftaroline and to provide insight as to their safety profiles with regard to older people. A clear understanding of this topic will aid clinicians in selecting drug therapy and may lead to shortened hospital stays, lower hospital costs, and improved outcomes of critically ill older people.

Worldwide clinical practices in perioperative antibiotic therapy for lung transplantation

Background

Infection is the most common cause of mortality within the first year after lung transplantation (LTx). The management of perioperative antibiotic therapy is a major issue, but little is known about worldwide practices.

Methods

We sent by email a survey dealing with 5 daily clinical vignettes concerning perioperative antibiotic therapy to 180 LTx centers around the world. The invitation and a weekly reminder were sent to lung transplant specialists for a single consensus answer per center during a 3-month period.

Results

We received a total of 99 responses from 24 countries, mostly from Western Europe (n = 46) and the USA (n = 34). Systematic screening for bronchial recipient colonization before LTx was mostly performed with sputum samples (72%), regardless of the underlying lung disease. In recipients without colonization, antibiotics with activity against gram-negative bacteria resistant strains (piperacillin / tazobactam, cefepime, ceftazidime, carbapenems) were reported in 72% of the centers, and antibiotics with activity against methicillin-resistant Staphylococcus aureus (mainly vancomycin) were reported in 38% of the centers. For these recipients, the duration of antibiotics reported was 7 days (33%) or less (26%) or stopped when cultures of donor and recipients were reported negatives (12%). In recipients with previous colonization, antibiotics were adapted to the susceptibility of the most resistant strain and given for at least 14 days (67%).

Conclusion

Practices vary widely around the world, but resistant bacterial strains are mostly targeted even if no colonization occurs. The antibiotic duration reported was longer for colonized recipients.

Acute kidney injury following the concurrent administration of antipseudomonal β-lactams and vancomycin: a network meta-analysis

BACKGROUND

Acute kidney injury is a major complication of vancomycin treatment, especially when it is co-administered with other nephrotoxins.

OBJECTIVES

This meta-analysis aims to comparatively assess the nephrotoxicity of antipseudomonal β-lactams when combined with vancomycin.

DATA SOURCES

Medline, Scopus, CENTRAL and Clinicaltrials.gov databases were systematically searched from inception through 20 August 2019.

STUDY ELIGIBILITY CRITERIA

Studies evaluating acute kidney injury risk following the concurrent use of antipseudomonal β-lactams and vancomycin were selected.

PARTICIPANTS

Adult and paediatric patients treated in hospital or intensive care unit.

INTERVENTIONS

Administration of vancomycin combined with any antipseudomonal β-lactam.

METHODS

Acute kidney injury incidence was defined as the primary outcome. Secondary outcomes included severity, onset, duration, need of renal replacement therapy, length of hospitalization and mortality. Quality of evidence was assessed using the ROBINS-I tool and the Confidence In Network Meta-Analysis approach.

RESULTS

Forty-seven cohort studies were included, with a total of 56 984 patients. In the adult population, the combination of piperacillin-tazobactam and vancomycin resulted in significantly higher nephrotoxicity rates than vancomycin monotherapy (odds ratio (OR) 2.05, 95% confidence intervals (CI) 1.17-3.46) and its concurrent use with meropenem (OR 1.84, 95% CI 1.02-3.10) or cefepime (OR 1.80, 95% CI 1.13-2.77). In paediatric patients, acute kidney injury was significantly higher with vancomycin plus piperacillin-tazobactam than vancomycin alone (OR 4.18, 95% CI 1.01-17.29) or vancomycin plus cefepime OR 3.71, 95% CI 1.08-11.24). No significant differences were estimated for the secondary outcomes. Credibility of outcomes was judged as moderate, mainly due to imprecision and inter-study heterogeneity.

CONCLUSIONS

The combination of vancomycin and piperacillin-tazobactam is associated with higher acute kidney injury rates than its parallel use with meropenem or cefepime. Current evidence is exclusively observational and is limited by inter-study heterogeneity. Randomized controlled trials are needed to verify these results and define preventive strategies to minimize nephrotoxicity risk.

Vancomycin-associated acute kidney injury in Hong Kong in 2012-2016

Background

To study the incidence of vancomycin-associated acute kidney injury (VA-AKI) in Hong Kong and identify risk factors for VA-AKI.

Method

Patients with vancomycin prescription and blood level measurement in 2012–2016 were identified using the Hong Kong Hospital Authority Clinical Data Analysis and Reporting System. Acute kidney injury was defined using KDIGO criteria. Patients without creatinine measurements, steady-state trough vancomycin level or who had vancomycin treatment < 3 days were excluded. Results were analyzed using SPSS version 22.0. Logistic regression was used to identify the predictors for VA-AKI. Odds ratio and 95% confidence interval were estimated.

Results

One thousand four hundred fifty patients were identified as VA-AKI from 12,758 records in Hong Kong in 2012–2016. The incidence was respectively 10.6, 10.9, 11.3, 12.2, 11.2% from 2012 to 2016. The incidence of VA-AKI was 16.3, 12.2, 11.3 and 6.2% in patients aged 1–12, 12–60, elderly aged > 60 and newborn and infants, respectively. Baseline creatinine, serum trough vancomycin level, systematic disease history including respiratory failure, hypertension, congestive heart failure, chronic renal failure, anemia and type II diabetes, and concomitant diuretics, piperacillin-tazobactam (PTZ) and meropenem prescription were significantly higher in VA-AKI patients older than 12 years. Logistic regression showed that older age group, higher baseline creatinine, serum trough vancomycin level, respiratory failure, chronic renal failure and congestive heart failure, concomitant diuretics, PTZ and meropenem prescription, and longer hospital stay were all associated with increased risk of VA-AKI.

Conclusion

The incidence of VA-AKI in Hong Kong is low but shows no decline. Patients with higher baseline creatinine, multi-organ diseases and multiple drugs administration should have their vancomycin level monitored to decrease the risk of VA-AKI.

Vancomycin Area Under the Curve and Acute Kidney Injury: A Meta-analysis

BACKGROUND

This study analyzed the relationship between vancomycin area under the concentration-time curve (AUC) and acute kidney injury (AKI) reported across recent studies.

METHODS

A systematic review of PubMed, Medline, Scopus, and compiled references was conducted. We included randomized cohort and case-control studies that reported vancomycin AUCs and risk of AKI (from 1990 to 2018). The primary outcome was AKI, defined as an increase in serum creatinine of ≥0.5 mg/L or a 50% increase from baseline on ≥2 consecutive measurements. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Primary analyses compared the impact of AUC cutpoint (greater than ~650 mg × hour/L) and AKI. Additional analysis compared AUC vs trough-guided monitoring on AKI incidence.

RESULTS

Eight observational studies met inclusion/exclusion criteria with data for 2491 patients. Five studies reported first-24-hour AUCs (AUC0-24) and AKI, 2 studies reported 24- to 48-hour AUCs (AUC24-48) and AKI, and 2 studies reported AKI associated with AUC- vs trough-guided monitoring. AUC less than approximately 650 mg × hour/L was associated with decreased AKI for AUC0-24 (OR, 0.36 [95% CI, .23-.56]) as well as AUC24-48 (OR, 0.45 [95% CI, .27-.75]). AKI associated with the AUC monitoring strategy was significantly lower than trough-guided monitoring (OR, 0.68 [95% CI, .46-.99]).

CONCLUSIONS

AUCs measured in the first or second 24 hours and lower than approximately 650 mg × hour/L may result in a decreased risk of AKI. Vancomycin AUC monitoring strategy may result in less vancomycin-associated AKI. Additional investigations are warranted.

Utilizing the Patient Care Process to Minimize the Risk of Vancomycin-Associated Nephrotoxicity

Vancomycin-associated acute kidney injury (AKI) is a popular topic in the medical literature with few clear answers. While many studies evaluate the risk of AKI associated with vancomycin, few data are high quality and/or long in duration of follow-up. This review takes the clinician through an approach to evaluate a patient for risk of AKI. This evaluation should include patient assessment, antibiotic prescription, duration, and monitoring. Patient assessment involves evaluating severity of illness, baseline renal function, hypotension/vasopressor use, and concomitant nephrotoxins. Evaluation of antibiotic prescription includes evaluating the need for methicillin-resistant Staphylococcus aureus (MRSA) coverage and/or vancomycin use. Duration of therapy has been shown to increase the risk of AKI. Efforts to de-escalate vancomycin from the antimicrobial regimen, including MRSA nasal swabs and rapid diagnostics, should be used to lessen the likelihood of AKI. Adequate monitoring includes therapeutic drug monitoring, ongoing fluid status evaluations, and a continual reassessment of AKI risk. The issues with serum creatinine make the timely evaluation of renal function and diagnosis of the cause of AKI problematic. Most notably, concomitant piperacillin-tazobactam can increase serum creatinine via tubular secretion, resulting in higher rates of AKI being reported. The few studies evaluating the long-term prognosis of AKI in patients receiving vancomycin have found that few patients require renal replacement therapy and that the long-term risk of death is unaffected for patients surviving after the initial 28-day period.

Acute kidney injury during daptomycin versus vancomycin treatment in cardiovascular critically ill patients: a propensity score matched analysis

Background

Gram-positive organisms are a leading cause of infection in cardiovascular surgery. Furthermore, these patients have a high risk of developing postoperative renal failure in intensive care unit (ICU). Some antibiotic drugs are known to impair renal function. The aim of the study was to evaluate whether patients treated for Gram-positive cardiovascular infection with daptomycin (DAP) experienced a lower incidence of acute kidney injury (AKI) when compared to patients treated with vancomycin (VAN), with comparable efficacy.

Methods

ICU patients who received either DAP or VAN, prior to or after cardiovascular surgery or mechanical circulatory support, from January 2010 to December 2012, were included in this observational retrospective cohort study. We excluded patients with end stage renal disease and antibiotic prophylaxis. The primary endpoint was the incidence of AKI within the first week of treatment. Secondary endpoints were the incidence of AKI within the first 14 days of treatment, the severity of AKI including renal replacement therapy (RRT), the rates of clinical failure (unsuccessful infection treatment) and of premature discontinuation and mortality. To minimize selection bias, we used a propensity score to compare the 2 groups. Univariate and multivariate analysis were performed to determine factors associated with AKI.

Results

Seventy two patients, treated for infective endocarditis, cardiovascular foreign body infection, or surgical site infection were included (DAP, n = 28 and VAN, n = 44). AKI at day 7 was observed in 28 (64%) versus 6 (21%) of the VAN and DAP patients, respectively (p = 0.001). In the multivariate analysis adjusted to the propensity score, vancomycin treatment was the only factor associated with AKI (Odds Ratio 4.42; 95% CI: 1.39–15.34; p = 0.014). RRT was required for 2 (7%) DAP patients and 13 (30%) VAN patients, p = 0.035. Premature discontinuation and clinical failure occurred more frequently in VAN group than in DAP group (25% versus 4%, p = 0.022 and 42% versus 12%, respectively, p = 0.027).

Conclusions

Daptomycin appears to be safer than vancomycin in terms of AKI risk in ICU patients treated for cardiovascular procedure-related infection. Daptomycin could be considered as a first line treatment to prevent AKI in high-risk patients.

Vancomycin-Associated Acute Kidney Injury in a Large Veteran Population

BACKGROUND

To determine the association of vancomycin with acute kidney injury (AKI) in relation to its serum concentration value and to examine the risk of AKI in patients treated with vancomycin when compared with a matched cohort of patients receiving non-glycopeptide antibiotics (linezolid/daptomycin).

METHODS

From a cohort of > 3 million US veterans with baseline estimated glomerular filtration rate ≥60 mL/min/1.73 m2, we identified 33,527 patients who received either intravenous vancomycin (n = 22,057) or non-glycopeptide antibiotics (linezolid/daptomycin, n = 11,470). We examined the association of the serum trough vancomycin level recorded within the first 48 h of administration with subsequent AKI in all patients treated with vancomycin and association of vancomycin vs. non-glycopeptide antibiotics use with the risk of incident AKI.

RESULTS

The overall multivariable adjusted ORs of AKI stages 1, 2, and 3 in patients on vancomycin vs. non-glycopeptides were 1.1 (1.1-1.2), 1.2 (1-1.4), and 1.4 (1.1-1.7), respectively. When examined in strata divided by vancomycin trough level, the odds of AKI were similar or lower in patients receiving vancomycin compared to non-glycopeptide antibiotics as long as serum vancomycin levels were ≤20 mg/L. However, in patients with serum vancomycin levels > 20 mg/L, the ORs of AKI stages 1, 2, and 3 in patients on vancomycin vs. non-glycopeptide antibiotics were 1.5 (1.4-1.7), 1.9 (1.5-2.3), and 2.7 (2-3.5), respectively.

CONCLUSIONS

Vancomycin use is associated with a higher risk of AKI when serum levels exceed > 20 mg/L.

Comparative incidence and excess risk of acute kidney injury in hospitalised patients receiving vancomycin and piperacillin/tazobactam in combination or as monotherapy

Combination therapy with vancomycin and piperacillin/tazobactam (TZP) has been associated with increased risk of acute kidney injury (AKI) compared with monotherapy with either agent. This retrospective, matched cohort study was conducted to assess the comparative incidence of AKI due to combination therapy in patients receiving vancomycin and TZP in combination or as monotherapy. Patients aged ≥18 years admitted to Albany Medical Center (Albany, NY) between September 2013 and August 2014 who had received therapy for at least two consecutive days were included. Patients who were pregnant, neutropenic, had AKI on admission or with cystic fibrosis were excluded. Patients were matched on baseline risk of AKI. The main outcome of interest was AKI, defined as an increase in serum creatinine of ≥0.3 mg/L or ≥50% within 48 h. Secondary outcomes evaluated were length of hospital and ICU stay and inpatient mortality associated with AKI. The risk of AKI was 7.0%, 8.5% and 26.8% in the vancomycin monotherapy, TZP monotherapy and combination groups, respectively (P < 0.001). In the multivariate analysis, combination therapy was independently associated with an increased odds of AKI (adjusted odds ratio = 4.406, 95% confidence interval 1.472-13.188) compared with vancomycin monotherapy. The excess risk of combination therapy was 11.3%. In this matched cohort study, there was an increased incidence of AKI in patients receiving vancomycin and TZP combination therapy. Further research is needed to determine the individual strategies to best prevent inpatient AKI in patients receiving this combination therapy.

Drug-induced kidney disease in the ICU: mechanisms, susceptibility, diagnosis and management strategies

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common complication in the critically ill population, is multifactorial and associated with increased mortality. Drug-induced kidney injury is a significant contributor to the development of AKI. The purpose of this review is to provide updates in the epidemiology, susceptibility and management of drug-induced kidney disease (DIKD).

RECENT FINDINGS

Recent changes in guidelines for the management of serious infections in the critically ill have resulted in an increased frequency of DIKD. Varying definitions employed in clinical trials has complicated the awareness of this adverse event. Causality assessment is often missing from studies as it is complicated by the need to evaluate competing AKI risk factors. This has led to uncertainty in the nephrotoxic risk of commonly used drugs.

SUMMARY

Standard criteria for DIKD should be applied in clinical trials to improve our understanding of the frequency of these events. Adjudication of these events will improve the clinician's ability to evaluate the causal relationship and relative contribution of specific drugs to the AKI event.

Risk of acute kidney injury in critically ill surgical patients with presumed pneumonia is not impacted by choice of methicillin-resistant staphylococcus aureus therapy

Background

Vancomycin and linezolid are standard treatment options for nosocomial methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. While acute kidney injury (AKI) is commonly attributed to vancomycin, existing data has not definitely confirmed vancomycin as an independent risk factor for AKI.

Aims

This study aimed to quantify the incidence of AKI in Surgical Intensive Care Unit (ICU) patients receiving empiric vancomycin or linezolid for nosocomial pneumonia and to identify risk factors for AKI with a focus on MRSA antibiotic therapy.

Materials and Methods

A retrospective cohort analysis of surgical ICU patients who received at least 48 h of vancomycin or linezolid for pneumonia was performed. Patients who received vancomycin were compared to those who received linezolid with a primary endpoint of AKI as defined by the risk/injury/failure/loss/end-stage renal disease (RIFLE) criteria. A modified RIFLE criteria assessing only changes in serum creatinine was also used.

Results

One hundred one patients were evaluated (63 vancomycin and 38 linezolid). AKI occurred in 51 (81.0%) and 32 (84.2%) patients in the vancomycin and linezolid groups (P = 0.79), respectively. Using the modified RIFLE criteria, AKI occurred in 19 (30.2%) and 14 (36.8%) patients in the vancomycin and linezolid groups (P = 0.448). After adjustment for age, diabetes mellitus, Charlson comorbidity index, and concomitant nephrotoxins, there was no difference in risk of AKI between groups (P = 0.773).

Conclusions

Patients who received empiric vancomycin or linezolid for nosocomial pneumonia experienced high, but similar rates of AKI. The results suggest MRSA antibacterial therapy in this setting may not be independently indicative of AKI risk, rather the risk is likely multifactorial.

Significant Publications on Infectious Diseases Pharmacotherapy in 2016

PURPOSE

This is a summary of the most important articles on infectious diseases (ID) pharmacotherapy published in peer-reviewed literature in 2016 as selected by clinical pharmacists with ID expertise.

SUMMARY

The Houston Infectious Diseases Network (HIDN) was asked to identify articles published in peer-reviewed literature in 2016 that were believed to contribute significantly to ID pharmacotherapy, including human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS). A list of 46 articles on general ID pharmacotherapy and 8 articles on HIV/AIDS were nominated. Members of the Society of Infectious Diseases Pharmacists (SIDP) were surveyed to select 10 general ID articles believed to have made a significant impact on general ID pharmacotherapy and 1 article most significant to HIV/AIDS pharmacotherapy. Of 445 SIDP members surveyed, 212 (47.6%) and 95 (21.3%) members voted for general ID pharmacotherapy- and HIV/AIDS-related articles, respectively. The 11 highest-ranked papers (10 general ID-related articles and 1 HIV/AIDS-related article) are summarized here.

CONCLUSION

With the large number of ID-related articles published each year, it can be challenging to stay current with the most relevant ID publications. This review of significant publications in 2016 may provide a starting point for that process.

The Whole Price of Vancomycin: Toxicities, Troughs, and Time

Vancomycin is a glycopeptide antibiotic that is active against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Nephrotoxicity, which is usually reversible, is the most serious common adverse effect of vancomycin. Vancomycin-associated nephrotoxicity prolongs hospital stays, imposes a need for additional antibiotics and, in rare circumstances, dialysis treatment, and increases medical costs and mortality. Risk factors for nephrotoxicity include the dose and duration of vancomycin treatment, serum trough concentration, patient characteristics, and concomitant receipt of nephrotoxins. Contemporary guidelines recommend targeting vancomycin trough concentrations of ≥10 mg/L to prevent resistance and trough concentrations of 15-20 mg/L to optimize outcomes. There is significant correlation between vancomycin trough serum concentrations and the incidence of vancomycin-associated nephrotoxicity; however, evidence of an association between trough concentrations and efficacy is less convincing. Routine monitoring of serum vancomycin concentrations consumes time and limited healthcare resources and may not be cost effective. The use of alternative antibacterial agents that do not require monitoring would free up pharmacy resources. This time could then be devoted to initiatives such as pharmacist-led antibiotic stewardship programs that are known to reduce antibiotic use and promote improved patient outcomes.

Intravenous Vancomycin Associated With the Development of Nephrotoxicity in Patients With Class III Obesity

Background:A consensus statement recommends initial intravenous (IV) vancomycin dosing of 15-20 mg/kg every 8- 24 hours, with an optional 25- to 30-mg/kg loading dose. Although some studies have shown an association between weight and the development of vancomycin-associated nephrotoxicity, results have been inconsistent. Objective: To evaluate the correlation between incidence of nephrotoxicity associated with weight-based IV vancomycin dosing strategies in nonobese and obese patients. Methods: This retrospective cohort study evaluated hospitalized adult patients admitted who received IV vancomycin. Patients were stratified into nonobese (body mass index [BMI] <25 kg/m2), obesity class I and II (BMI 30-39.9kg/m2), and obesity class III (BMI≥40 kg/m2) groups; patients who were overweight but not obese were excluded. Incidence of nephrotoxicity and serum vancomycin trough concentrations were evaluated. Results: Of a total of 62 documented cases of nephrotoxicity (15.1%), 13 (8.7%), 23 (14.3%), and 26 (26.3%) cases were observed in nonobese, obesity class I and II, and obesity class III groups, respectively ( P=0.002). Longer durations of therapy ( P<0.0001), higher initial maintenance doses in both total milligrams/day ( P=0.0137) and milligrams/kilogram ( P=0.0307), and any trough level >20 mg/L ( P<0.0001) were identified as predictors of development of nephrotoxicity. Concomitant administration of piperacillin/tazobactam, diuretics, and IV contrast were associated with development of nephrotoxicity ( P<0.005, all). Patients with class III obesity were 3-times as likely to develop nephrotoxicity when compared with nonobese patients (odds ratio [OR]=2.99; CI=1.12-7.94) and obesity class I and II patients (OR=3.14; CI=1.27-7.75). Conclusions: Obesity and other factors are associated with a higher risk of vancomycin-associated nephrotoxicity.

The Nephrotoxicity of Vancomycin

Vancomycin use is often associated with nephrotoxicity. It remains uncertain, however, to what extent vancomycin is directly responsible, as numerous potential risk factors for acute kidney injury frequently coexist. Herein, we critically examine available data in adult patients pertinent to this question. We review the pharmacokinetics/pharmacodynamics of vancomycin metabolism. Efficacy and safety data are discussed. The pathophysiology of vancomycin nephrotoxicity is considered. Risk factors for nephrotoxicity are enumerated, including the potential synergistic nephrotoxicity of vancomycin and piperacillin‐tazobactam. Suggestions for clinical practice and future research are given.