High Single-dose Vancomycin Loading Is Not Associated With Increased Nephrotoxicity in Emergency Department Sepsis Patients

Impact of Limiting Vancomycin Loading Doses in Patients With Methicillin-resistant Staphylococcus aureus Infections After Hospital Protocol Revision

Background: Vancomycin loading doses are commonly used to quickly attain target serum concentrations; however, data supporting their effect on clinical patient outcomes is limited. In April 2020, our institution revised our pharmacist-driven vancomycin dosing protocol to reserve loading doses for hemodynamically unstable patients with suspected serious methicillin-resistant Staphylococcus aureus (MRSA) infections. Prior to the protocol update, all patients treated with vancomycin at our institution received a weight-based loading dose. The purpose of this study is to assess clinical efficacy and safety outcomes related to the use of vancomycin loading doses. Methods: A retrospective, quasi-experimental study was performed to compare clinical outcomes in adult patients treated with vancomycin for laboratory-confirmed MRSA infections. Patients who received vancomycin therapy prior to our institution's vancomycin dosing protocol revisions (pre-intervention) were compared to patients who received vancomycin after the revisions (post-intervention). The primary outcome was all-cause, inpatient mortality. Secondary outcomes included persistent signs and symptoms of infection ≥5 days after vancomycin initiation, switch to alternative anti-MRSA therapy, and nephrotoxicity. Results: A total of 122 patients (63 pre-intervention patients and 59 post-intervention patients) were included. Receipt of a vancomycin loading dose did not impact the rate of inpatient mortality (4.76%vs 6.78%; OR 1.46, 95% CI [0.31, 6.79]). All secondary outcomes were similar between the two groups, including persistent signs and symptoms of infection, switch to alternative anti-MRSA therapy, and nephrotoxicity. Conclusions: Routine use of vancomycin loading doses is not associated with improved outcomes in hemodynamically stable patients with MRSA infections.

Vancomycin Loading Doses and Nephrotoxicity on Medicine Teaching Services

Background

Infectious Disease Society of America (IDSA) guidelines recommend the usage of a loading dose when using vancomycin for seriously ill patients. While the relationship between vancomycin and nephrotoxicity is the focus of many studies, few studies have examined the relationship between vancomycin loading doses and nephrotoxicity.

Methods

We performed a retrospective cohort study examining vancomycin dosing for internal medicine teaching services' patients over the 2014-15 academic year at one academic medical center. We generated a list of all hospitalized patients aged 18-85 who received vancomycin and were admitted to a teaching service. Nephrotoxicity was determined by 7-day acute kidney injury (AKI) rate. Patients in the loading dose cohort were compared with those in the standard-dose cohort. Primary modeling used multivariable logistic regression with AKI as our outcome of interest.

Results

Four hundred and thirty-eight patients were included for analysis. The loading dose (n = 365, 83%) and standard dosing (n = 73, 17%) cohorts were not significantly different regarding demographics, GFR, nephrotoxic drug exposure, total vancomycin received, trough levels, or comorbidities and were only significantly different regarding body mass index (BMI). The 7-day AKI rate was not significantly different between the two arms (6.3% in the standard dosing arm and 8.2% in the loading dose arm, p = 0.6).

Conclusion

Few studies have examined the relationship between nephrotoxicity and vancomycin loading doses. The results of this study provide evidence that the use of loading doses is not significantly associated with increased 7-day AKI rate.

A Systematic Review on Clinical Safety and Efficacy of Vancomycin Loading Dose in Critically Ill Patients

Background: The clinical significance of utilizing a vancomycin loading dose in critically ill patients remains unclear. Objective: The main aim of this systematic review is to evaluate the clinical safety and efficacy of the vancomycin loading dose in critically ill patients. Methods: We performed a systematic review using PRISMA guidelines. PubMed, the Web of Science, MEDLINE, Scopus, Google Scholar, the Saudi Digital Library and other databases were searched. Studies that reported clinical outcomes among patients receiving the vancomycin LD were considered eligible. Data for this study were collected using PubMed, the Web of Science, MEDLINE, Scopus, Google Scholar and the Saudi Digital Library using the following terms: “vancomycin”, “safety”, “efficacy” and “loading dose” combined with the Boolean operator “AND” or “OR”. Results: A total of 17 articles, including 2 RCTs, 11 retrospective cohorts and 4 other studies, met the inclusion/exclusion criteria out of a total 1189 studies. Patients had different clinical characteristics representing a heterogenous group, including patients in critical condition, with renal impairment, sepsis, MRSA infection and hospitalized patients for hemodialysis or in the emergency department. Conclusions: The study shows that the target therapeutic level is achieved more easily among patients receiving a weight-based LD as compared to patients received the usual dose without an increased risk of new-onset adverse drug reactions.

Development and evaluation of a vancomycin dosing nomogram to achieve the target area under the concentration-time curve. A retrospective study

Although the superiority of vancomycin dosing based on area under the concentration-time curve (AUC_0-24) over that based on trough concentration has been reported, a dosing strategy to achieve the target AUC_0-24 has yet to be developed. The objective of this study was to develop a convenient useable nomogram for vancomycin dosing to obtain the target AUC_0-24 (400 μg h/mL). The nomogram was pharmacokinetically developed in a retrospective manner. The number of enrolled patients and concentrations was 166 and 309 for development of the nomogram, 99 and 181 for evaluation of the nomogram, respectively. The nomogram was developed as doses per personal body weight corresponding to each range of estimated glomerular filtration rate (eGFR), which was identified to be the covariate for vancomycin clearance by non-linear mixed effect modeling. The nomogram described the surrogate trough concentration for the target AUC_0-24 was calculatedly different for each eGFR range (9.3-15.0 μg/mL). The rate of attainment of therapeutic range using surrogate trough concentration to obtain the target AUC_0-24 was 63.8% in the evaluation period. We have developed and evaluated the first convenient useable nomogram of vancomycin dosing to obtain the target AUC_0-24.

Relationship Status between Vancomycin Loading Dose and Treatment Failure in Patients with MRSA Bacteremia: It's Complicated

INTRODUCTION

A one-time vancomycin loading dose of 25-30 mg/kg is recommended in the current iteration of the vancomycin consensus guidelines in order to more rapidly achieve target serum concentrations and hasten clinical improvement. However, there are few clinical data to support this practice, and the extents of its benefits are largely unknown.

METHODS

A multicenter, retrospective, cohort study was performed to assess the impact of a vancomycin loading dose (≥ 20 mg/kg) on clinical outcomes and rates of nephrotoxicity in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. The study matched patients in a 1:1 fashion based on age, Pitt bacteremia score, and bacteremia source. The primary outcome was composite treatment failure (30-day mortality, bacteremia duration ≥ 7 days after vancomycin initiation, persistent signs and symptoms of infection ≥ 7 days after vancomycin initiation, or switch to an alternative antimicrobial agent). Secondary outcomes included duration of bacteremia, length of stay post-bacteremia onset, and nephrotoxicity.

RESULTS

A total of 316 patients with MRSA bacteremia were included. Median first doses in the loading dose and non-loading dose groups were 23.0 mg/kg and 14.3 mg/kg, respectively (P < 0.001). No difference was found in composite failure rates between the non-loading dose and loading dose groups (40.5% vs. 36.7%; P = 0.488) or in the incidence of nephrotoxicity (12.7% vs. 16.5%; P = 0.347). While multivariable regression modeling showed receipt of a vancomycin loading dose on a mg/kg basis was not significantly associated with composite failure [aOR 0.612, 95% CI (0.368-1.019)]; post hoc analyses demonstrated that initial doses ≥ 1750 mg were independently protective against failure [aOR 0.506, 95% CI (0.284-0.902)] without increasing the risk for nephrotoxicity [aOR 0.909, 95% CI (0.432-1.911)].

CONCLUSION

These findings suggest that initial vancomycin doses above a certain threshold may decrease clinical failures without increasing toxicity and that weight-based dosing might not be the optimal strategy.

The clinical efficacy and safety of vancomycin loading dose: A systematic review and meta-analysis

BACKGROUND

The clinical significance of using vancomycin loading dose remains controversial. A systematic review and meta-analysis were performed to assess the clinical efficacy and safety of vancomycin loading dose in the treatment of infections.

METHODS

The Pubmed, Embase, Web of Science, and Cochrane Library databases were searched from their inception up to 5 May 2019. Randomized controlled trials (RCTs) and other observational studies were included if they provided clinical outcomes or trough concentrations of vancomycin loading dose (20-30 mg/kg) and conventional-dose (10-20 mg/kg) in the treatment of infections. Achievement of therapeutic concentration (serum trough concentrations of vancomycin reached 15-20 mg/L before the second dose), clinical response (clinical improvement or culture-negative), nephrotoxicity (serum creatinine increase ≥0.5 mg/dL or ≥50% increasing from the baseline), other adverse events (including pruritus, flushing, rash, and/or red man syndrome), and mortality were analyzed. Heterogeneity was identified using the Cochrane I statistic, and P-value <.10 or I-values >50% indicated significant heterogeneity. Pooled estimates of the intervention effects were determined by the odds ratios (ORs) and 95% confidence intervals (CIs) in Review Manager program, version 5.3.5.

RESULTS

Two RCTs and 7 cohort studies including 2816 infected patients were selected for the analysis, in which serum trough concentrations of vancomycin following the use of vancomycin loading dose or other outcomes were available. Loading dose group had a significantly higher compliance rate of serum trough concentration of 15 to 20 mg/L (OR = 3.06; 95% CI = 1.15-8.15; P = .03) and significantly lower incidence of nephrotoxicity (OR = 0.59, 95% CI = 0.40-0.87; P = .008; I = 29%) compared with control group. No significant difference was noted between loading dose group and control group in terms of other adverse events and clinical response (OR = 1.98, 95% CI = 0.80-4.93; P = .14; I = 0%). The use of vancomycin loading doses in patients can indeed increase the achievement of therapeutic concentration.

CONCLUSION

Vancomycin loading dose increases the achievement of therapeutic concentration without bringing extra risk of nephrotoxicity. However, well-designed large-scale RCTs remain needed to validate the clinical efficacy of vancomycin loading dose and to further evaluate other adverse reactions and mortality.PROSPERO registration number CRD42018093927.

An Evaluation of the Incidence of Nephrotoxicity After a Loading Dose of Vancomycin in Patients With Severe Renal Impairment

BACKGROUND

Loading doses of vancomycin assist in the rapid achievement of target trough concentrations. Patients with renal dysfunction have been excluded from studies evaluating loading doses.

OBJECTIVE

The purpose of this study was to investigate nephrotoxicity related to initial vancomycin dose in patients with severe renal dysfunction.

METHODS

A retrospective cohort study was approved by the Institutional Review Board of a large, academic health system. Adults were included if they received intravenous vancomycin in the emergency department and presented with creatinine clearance < 30 mL/min. Chronic dialysis patients were excluded. The primary outcome was incidence of nephrotoxicity after an initial high (>20 mg/kg) vs. low (≤20 mg/kg) dose of vancomycin. Secondary outcomes included dialysis, vancomycin concentrations, length of stay, in-hospital mortality, and a composite outcome of nephrotoxicity or dialysis.

RESULTS

Of the 927 patients included in the analysis, nephrotoxicity occurred in 7.2% and 13.8% of patients in the high- and low-dose groups, respectively (p < 0.01). Patients in the high-dose group had a reduced risk of nephrotoxicity (relative risk 0.53; 95% confidence interval 0.35-0.78). The reduction in risk remained after fitting a generalized linear model adjusting for weight, age, sex, initial serum creatinine, diabetes, and chronic kidney disease (relative risk 0.61; 95% confidence interval 0.39-0.93). Limitations of this study include its retrospective design and single-center population.

CONCLUSION

These data suggest that vancomycin loading doses do not increase nephrotoxicity compared with lower doses in patients with severe renal dysfunction. These patients should be included in future studies relating to vancomycin loading doses.

Pharmacotherapy options and drug development in managing periprosthetic joint infections in the elderly

INTRODUCTION

Prosthetic joint infections are an increasingly important problem among patients undergoing arthroplasty procedures, and are associated with significant morbidity, reduced quality of life, substantial healthcare costs, and even mortality. Arthroplasties are performed with increasing frequency in elderly patients, who present specific problems.

AREAS COVERED

Surgical therapy is clearly influenced by the clinical status of the patient, which in some case can contraindicate surgery. Antibiotic selection is also affected by comorbidities and underlying diseases, which in some cases reduce therapeutic options. The authors review this together with the changes in pharmacokinetics and pharmacodynamics in the elderly population and the prospects for future research on prevention and treatment.

EXPERT OPINION

The management of PJI in the elderly makes multidisciplinary teams even more mandatory than in other patients, because the complexity of these patients. A frequent scenario is that in which surgery is contraindicated with long-term suppressive treatment as the only available option. Treating physicians must consider the presence of multiple comorbidities, interactions with other treatments and secondary effects when choosing antibiotic treatment. An in-depth knowledge of the alterations in pharmacokinetics and pharmacodynamics in elderly patients is key for a proper treatment selection.

The dosing and monitoring of vancomycin: what is the best way forward?

We have evaluated the literature to review optimal dosing and monitoring of intravenous vancomycin in adults, in response to evolving understanding of targets associated with efficacy and toxicity. The area under the total concentration-time curve (0-24 h) divided by the minimum inhibitory concentration (AUC₂₄/MIC) is the most commonly accepted index to guide vancomycin dosing for the treatment of Staphylococcus aureus infections, with a value of 400 h a widely recommended target for efficacy. Upper limits of AUC₂₄ exposure of around 700 (mg/L).h have been proposed, based on the hypothesis that higher exposures of vancomycin are associated with an unacceptable risk of nephrotoxicity. If AUC₂₄/MIC targets are used, sources of variability in the assessment of both AUC₂₄ and MIC need to be considered. Current consensus guidelines recommend measuring trough vancomycin concentrations during intermittent dosing as a surrogate for the AUC₂₄. Trough concentrations are a misleading surrogate for AUC₂₄ and a poor end-point in themselves. AUC₂₄ estimation using log-linear pharmacokinetic methods based on two plasma concentrations, or Bayesian methods are superior. Alternatively, a single concentration measured during continuous infusion allows simple AUC₂₄ estimation and dose-adjustment. All of these methods have logistical challenges which must be overcome if they are to be adopted successfully.

Pharmacokinetic Assessment of Vancomycin Loading Dose in Critically Ill Patients

The vancomycin loading dose (LD) of 25 to 30 mg/kg is a frequently practiced strategy to achieve effective concentrations from the first-treatment dose. However, considering only the body weight for dosing might be inadequate in critically ill patients due to pharmacokinetics changes. We sought to assess achieving optimal trough serum levels of vancomycin and AUC_0-24/MIC in the first 24 h of treatment by using an LD based on population pharmacokinetic parameters of critically ill patients. We performed a concurrent cohort study over 22 months of patients with severe sepsis who received intravenous vancomycin. The patients were treated with three different strategies to initiate vancomycin: without an LD (group A), with an LD of 25 to 30 mg/kg (group B), and with an LD based on population pharmacokinetic parameters of the critically ill patient (group C). An optimal trough serum concentration was achieved in 5, 9, and 83% of patients in groups A, B, and C, respectively. The number of patients that reached optimal AUC_0-24 was 2 of 18 (11%), 5 of 11 (46%), and 11 of 12 (92%) in groups A, B, and C, respectively. The statistical analysis for both parameters revealed significant differences in group C with respect to other groups. The administration of the LD calculated from population pharmacokinetic parameters from the beginning of therapy is a more efficient strategy to obtain adequate trough serum concentrations and AUC_0-24/MIC in critical patients.

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.