A randomized trial of loading vancomycin in the emergency department

Descriptive evaluation of patients receiving one-time intravenous vancomycin doses at a large academic medical center emergency department

BACKGROUND

Intravenous (IV) vancomycin is commonly used to treat a variety of infections caused by methicillin-resistant Staphylococcus aureus (MRSA). The practice of administering a single dose of IV vancomycin prior to emergency department (ED) discharge may be clinically ineffective and foster antimicrobial resistance. Furthermore, this practice introduces an unnecessary infection risk along with preventable adverse effects while potentially increasing ED length of stay (LOS). There is a paucity of literature identifying patient characteristics and objective findings in this patient population, which may foster future antimicrobial stewardship initiatives in the ED.

METHODS

This was a single-center, retrospective, descriptive analysis of adult patients seen in the ED between January 2020 and January 2023 who received a single dose of IV vancomycin and were subsequently discharged from the ED without hospital admission. Information was collected on patient demographics and select comorbidities, vancomycin indication and dosing, ED LOS, initial vitals and labs, concomitant antibiotics administered, culture results, 30-day return ED visits and admissions, and antibiotics prescribed at ED discharge.

RESULTS

A total of 295 patients met inclusion criteria. A total of 32.1% of patients met SIRS criteria. The most commonly selected order indication for IV vancomycin was "skin and skin structure infection" (41%). A total of 86.1% of patients received concomitant antibiotics in the ED and only 54.6% of patients were prescribed oral antibiotics at ED discharge. A total of 80% of patients had at least one culture obtained during the ED visit. In those who had at least one culture obtained, 78.4% of patients had negative cultures and 4.2% of patients had MRSA positive cultures, with MRSA skin cultures being the most common (3.1%). Return ED visits and admissions within 30 days were not statistically significantly different between patients who did and did not receive oral antibiotics at ED discharge.

CONCLUSIONS

Despite a lack of clinical efficacy reported in prior literature and the potential risks, administration of a one-time dose of IV vancomycin prior to ED discharge is commonly encountered in clinical practice. There are opportunities for enhanced antimicrobial stewardship related to IV vancomycin use in the ED. Areas of future focus include the utilization of oral antimicrobials when clinically appropriate, particularly for skin and soft tissue infections, and clarification of antibiotic allergies.

Association of vancomycin-induced acute kidney injury with trough versus AUC monitoring in patients receiving extended durations of therapy

Objective

Vancomycin therapy is associated with an increased risk of acute kidney injury (AKI). Previous studies suggest that area under the curve (AUC) monitoring reduces the risk of AKI, but literature is lacking to support this in patients receiving longer durations of vancomycin therapy.

Design

Retrospective cohort study.

Method

Patients ≥18 years old, admitted between August 2015 and July 2017 or October 2017 and September 2019, and received at least 14 days of intravenous (IV) vancomycin therapy were included in the study. Our primary outcome was the incidence of AKI between trough monitoring and AUC monitoring groups using Kidney Disease Improving Global Outcomes criteria. Secondary outcomes included inpatient mortality, median inpatient length of stay, and median intensive care unit length of stay.

Results

Overall, 582 patients were included in the study, with 318 patients included in the trough monitoring group and 264 included in the AUC monitoring group. The median duration of vancomycin therapy was 23 days (interquartile range, 16-39). Patients within the trough monitoring group had a higher incidence of AKI compared to the AUC monitoring group (45.6% vs 28.4%, p < 0.001). Furthermore, logistic regression analysis showed that AUC monitoring was associated with a 54% lower incidence of AKI (OR 0.46, 95% CI [0.31-0.69]). All-cause inpatient mortality was numerically higher in the trough monitoring group (12.9% vs 8.3%, p = 0.078).

Conclusions

In patients who received at least 14 days of IV vancomycin therapy, AUC monitoring was associated with a lower incidence of AKI.

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.

Assessment of an institutional guideline for vancomycin dosing and identification of predictive factors associated with dose and drug trough levels

OBJECTIVES

To evaluate the effectiveness of an antimicrobial guideline for vancomycin prescribing deployed using electronic prescribing aid and web/phone-based app. To define factors associated with guideline compliance and drug levels, and to investigate if antimicrobial dosing recommendations can be refined using routinely collected electronic healthcare record data.

METHODS

We used data from Oxford University Hospitals between 01-January-2016 and 01-June-2021 and multivariable regression models to investigate factors associated with dosing compliance, drug levels and acute kidney injury (AKI).

RESULTS

3767 patients received intravenous vancomycin for ≥24 h. Compliance with recommended loading and initial maintenance doses reached 84% and 70% respectively; 72% of subsequent maintenance doses were correctly adjusted. However, only 26% first and 32% subsequent levels reached the target range, and for patients with ongoing vancomycin treatment, 55-63% achieved target levels at 5 days. Drug levels were independently higher in older patients. Incidence of AKI was low (5.7%). Model estimates were used to propose updated age, weight and eGFR specific guidelines.

CONCLUSION

Despite good compliance with guidelines for vancomycin dosing, the proportion of drug levels achieving the target range remained suboptimal. Routinely collected electronic data can be used at scale to inform pharmacokinetic studies and could improve vancomycin dosing.

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.

Clinical Practice Guidelines for Therapeutic Drug Monitoring of Vancomycin in the Framework of Model-Informed Precision Dosing: A Consensus Review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring

Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.

Development of a decision flowchart to identify the patients need high-dose vancomycin in early phase of treatment

Background

The standard dose of vancomycin (VCM, 2 g/day) sometimes fails to achieve therapeutic concentration in patients with normal renal function. In this study, we aimed to identify factors to predict patients who require high-dose vancomycin (> 2 g/day) to achieve a therapeutic concentration and to develop a decision flowchart to select these patients prior to VCM administration.

Methods

Patients who had an estimated creatinine clearance using the Cockcroft–Gault equation (eCCr) of ≥50 mL/min and received intravenous VCM were divided into 2 cohorts: an estimation set (n = 146, from April to September 2016) and a validation set (n = 126, from October 2016 to March 2017). In each set, patients requiring ≤2 g/day of VCM to maintain the therapeutic trough concentration (10–20 μg/mL) were defined as standard-dose patients, while those who needed > 2 g/day were defined as high-dose patients. Univariate and multivariate logistic regression analysis was performed to identify the predictive factors for high-dose patients and decision tree analysis was performed to develop decision flowchart to identify high-dose patients.

Results

Among the covariates analyzed, age and eCCr were identified as independent predictors for high-dose patients. Further, the decision tree analysis revealed that eCCr (cut off value = 81.3 mL/min) is the top predictive factor and is followed by age (cut off value = 58 years). Based on these findings, a decision flowchart was constructed, in which patients with eCCr ≥81.3 mL/min and age < 58 years were designated as high-dose patients and other patients were designated as standard-dose patients. Subsequently, we applied this decision flowchart to the validation set and obtained good predictive performance (positive and negative predictive values are 77.6 and 84.4%, respectively).

Conclusion

These results suggest that the decision flowchart constructed in this study provides an important contribution for avoiding underdosing of VCM in patients with eCCr of ≥50 mL/min.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40780-021-00231-w.

Target serum concentration of vancomycin may be reached earlier with a loading dose

BACKGROUND

Vancomycin treatment failure against vancomycin-susceptible gram-positive cocci is not rare in the intensive care unit (ICU). One of the reasons for this is the substandard drug trough concentration. We aimed to examine the hypothesis that the target serum concentration could be reached earlier with a loading dose of vancomycin.

METHODS

This retrospective cohort study was conducted at our ICU between June 2018 and June 2020 and involved patients who were suspected of having, or confirmed to have, gram-positive cocci infection and treated with vancomycin. One group of the patients was administered a loading dose of vancomycin (loading group) and compared with the group that did not receive a loading dose (control group). The baseline characteristics, vancomycin serum concentrations, and clinical outcomes were collected and analyzed.

RESULTS

Fifty-five patients were finally included, of which 29 received a loading dose of vancomycin. The serum concentration of vancomycin before the second dose was significantly higher for the loading group than for the control group (10.3 ± 6.1 mg/L vs. 5.7 ± 4.4 mg/L, P = 0.002). The results for both groups were similar before the fifth dose (12.4 ± 7.3 mg/L vs. 10.3 ± 6.3 mg/L in the loading and the control groups, respectively; P = 0.251). The 28-day mortality was lower for the loading group than for the control group (6.7% vs. 34.6% in the loading and control groups, respectively; P = 0.026). No significant differences were observed in serum creatinine (Cr) concentrations of the two groups.

CONCLUSION

With the loading dose of vancomycin, the target serum concentration of vancomycin may be reached earlier without increasing the risk of acute kidney injury.

TRIAL REGISTRATION

https://www.chictr.org.cn; ChiCTR2000035369.

Candidates for area under the concentration-time curve (AUC)-guided dosing and risk reduction based on analyses of risk factors associated with nephrotoxicity in vancomycin-treated patients

OBJECTIVES

Compared with vancomycin trough concentration (C_min)-guided dosing, area under the concentration-time curve (AUC)-guided dosing is associated with decreased acute kidney injury (AKI). However, whether C_min-guided or AUC-guided dosing should be used in patients other than those with serious MRSA infections remains uncertain. The purposes of this multicentre study were to identify risk factors for early- and late-phase vancomycin-induced AKI and to identify candidates for AUC-guided dosing, rather than C_min-guided dosing, who require a more accurate dose titration to reduce the AKI risk.

METHODS

A multivariate logistic regression analysis was applied to identify risk factors for AKI. Additionally, the cut‑off day for AKI onset, cut-off C_min for AKI, safe C_min for reduced AKI risk and probability of AKI were calculated.

RESULTS

In total, 8.4% (159/1882) of patients developed AKI. AKI occurred within the first 7 days of therapy (early phase) in the vast majority of patients. Significant risk factors for AKI during the early phase were identified as C_min > 20 mg/L, ICU stay, concurrent diuretic or piperacillin/tazobactam use, and pre-existing renal dysfunction. A temporarily elevated C_min (>15-20 mg/L) was not associated with a greater risk of AKI. In patients with risk factors, the cut-off C_min for AKI and the estimated safe C_min for reduced AKI risk were 18.8-21.0 mg/L and <11.7-13.5 mg/L, respectively.

CONCLUSION

Patients with known AKI risk factors require a low target C_min. The presence of several risk factors for AKI may indicate a need for more accurate dose titration using AUC-guided dosing.

Evidence-based Guideline for Therapeutic Drug Monitoring of Vancomycin: 2020 Update by the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society

BACKGROUND

Clinical practice guidelines or recommendations often require timely and regular updating as new evidence emerges, because this can alter the risk-benefit trade-off. The scientific process of developing and updating guidelines accompanied by adequate implementation can improve outcomes. To promote better management of patients receiving vancomycin therapy, we updated the guideline for the therapeutic drug monitoring (TDM) of vancomycin published in 2015.

METHODS

Our updated recommendations complied with standards for developing trustworthy guidelines, including timeliness and rigor of the updating process, as well as the use of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. We also followed the methodology handbook published by the National Institute for Health and Clinical Excellence and the Spanish National Health System.

RESULTS

We partially updated the 2015 guideline. Apart from adults, the updated guideline also focuses on pediatric patients and neonates requiring intravenous vancomycin therapy. The guideline recommendations involve a broadened range of patients requiring TDM, modified index of TDM (both 24-hour area under the curve and trough concentration), addition regarding the necessity and timing of repeated TDM, and initial dose for specific subpopulations. Overall, 1 recommendation was deleted and 3 recommendations were modified. Eleven new recommendations were added, and no recommendation was made for 2 clinical questions.

CONCLUSIONS

We updated an evidence-based guideline regarding the TDM of vancomycin using a rigorous and multidisciplinary approach. The updated guideline provides more comprehensive recommendations to inform rational and optimized vancomycin use and is thus of greater applicability.

Efficacy and safety of vancomycin loading doses in critically ill patients with methicillin-resistant Staphylococcus aureus infection

Background

While vancomycin loading doses may facilitate earlier pharmacokinetic-pharmacodynamic target attainment, the impact of loading doses on clinical outcomes remains understudied. Critically ill patients are at highest risk of morbidity and mortality from methicillin resistant Staphylococcus aureus (MRSA) infection and hypothesized to most likely benefit from a loading dose. We sought to determine the association between receipt of a vancomycin loading dose and clinical outcomes in a cohort of critically ill adults.

Methods

Four hundred and forty-nine critically ill patients with MRSA cultures isolated from blood or respiratory specimens were eligible for the study. Cohorts were established by receipt of a loading dose (⩾20 mg/kg actual body weight) or not. The primary outcome was clinical failure, a composite outcome of death within 30 days of first MRSA culture, blood cultures positive ⩾7 days, white blood cell count up to 5 days from vancomycin initiation, temperature up to 5 days from vancomycin initiation, or substitution (or addition) of another MRSA agent.

Results

There was no difference in the percentage of patients experiencing clinical failure between the loading dose and no loading dose groups (74.8% versus 72.8%; p = 0.698). Secondary outcomes were also similar between groups, including mortality and acute kidney injury, as was subgroup analysis based on site of infection. Exploratory analyses, including assessment of loading dose based on quartiles and a multivariable logistic regression model showed no differences.

Conclusion

Use of vancomycin loading doses was not associated with improved clinical outcomes in critically ill patients with MRSA infection.

Impact of a computerised clinical decision support system on vancomycin loading and the risk of nephrotoxicity

BACKGROUND

A vancomycin loading dose is recommended for the treatment of serious methicillin-resistant Staphylococcus aureus (MRSA) infections. However, clinicians often do not adhere to these recommendations, mainly due to nephrotoxicity risk, unfamiliarity with the guideline, or complexity of calculating an individual dose. Therefore, we introduced a computerised clinical decision support system (CDSS) for vancomycin loading (hereafter Vancomycin CDSS) to promote the use of vancomycin loading dose.

METHODS

We describe a quasi-experimental study spanning 6 months before and 18 months after the deployment of a Vancomycin CDSS. The Vancomycin CDSS was integrated into the hospital's electronic medical record system in the form of a vancomycin order set. Our primary endpoint was the incidence of nephrotoxicity; the secondary endpoint was mean initial vancomycin trough levels. We also conducted a survey to evaluate the reasons why clinicians opted not to utilise a vancomycin loading dose.

RESULTS

After implementation of Vancomycin CDSS, 363 out of 746 patients (49 %) who were first administered vancomycin received a loading dose. We did not find significant differences in nephrotoxicity between the pre- and post-intervention groups, nor between the loading- and non-loading groups. In the pre-intervention group, the mean initial vancomycin trough level was 7.10 mg/L, which was significantly lower than that in the post-intervention group of 11.11 mg/L. In the vancomycin loading group, the mean initial trough level was 11.95 mg/L, compared to 7.55 mg/L in the non-loading group. The main reason stated for not prescribing a vancomycin loading dose was concern about nephrotoxicity.

CONCLUSION

Introduction of the Vancomycin CDSS did not increase nephrotoxicity and increased the mean initial dose and trough level of vancomycin.

Effect of vancomycin loading dose on clinical outcome in critically ill patients with methicillin-resistant Staphylococcus aureus pneumonia

Background

Vancomycin is the treatment of choice for serious methicillin-resistant Staphylococcus aureus (MRSA) infections. Current guidelines recommend giving an initial loading dose (LD) of 25–30 mg/kg to rapidly increase the serum concentration. However, high-quality evidence for the clinical benefit of LD is lacking. Herein, we aim to examine the association between vancomycin LD and clinical outcome.

Methods

A retrospective cohort study was conducted on adult patients treated for MRSA pneumonia with vancomycin in medical intensive care units from April 2016 to August 2018. MRSA pneumonia was defined by the Centers for Disease Control and National Healthcare Safety Network definition. The primary outcome was the clinical cure of pneumonia. Secondary outcome measures included time to pharmacokinetic (PK) target attainment, microbiological cure, acute kidney injury, and all-cause mortality.

Results

A total of 81 patients were included; of these 22 (27.2%) received LD. The mean initial dose was significantly higher in the LD group. Clinical cure was similar in both groups (68.2% vs. 66.1% in the LD and non-LD groups, respectively; P=0.860). No significant difference was observed in the microbiological cure, all-cause mortality, and incidence of acute kidney injury. Furthermore, no difference was observed in terms of time to PK target attainment (69.2 vs. 63.4 h in the LD and non-LD groups, respectively; P=0.624). Vancomycin minimum inhibitory concentration of <2 mg/L was identified as an independent predictive factor for clinical cure in multivariable analysis, whereas vancomycin LD was not.

Conclusions

Initial LD is not associated with better clinical outcome or rapid pharmacological target attainment in critically ill patients with MRSA pneumonia. Further studies are warranted to provide better evidence for this widely recommended practice.

Comparison of trough concentration and area under the curve of vancomycin associated with the incidence of nephrotoxicity and predictors of a high trough level

PURPOSE

A high vancomycin trough concentration during therapy is associated with increased nephrotoxicity, and the recent guidelines for therapeutic monitoring of vancomycin recommend target of the ratio of area under the curve (AUC) to minimum inhibitory concentration. We aimed to determine vancomycin trough concentration and AUC that induce nephrotoxicity and evaluate predictive factors associated with a high serum vancomycin trough level according to the initial dosing strategy.

METHODS

We conducted a retrospective cohort study in patients administered intravenous vancomycin from June 2013 to February 2017. Totally, 346 patients were included.

RESULTS

38 experienced nephrotoxicity during therapy. The both trough level and AUC were significant risk factors for the occurrence of vancomycin induced-nephrotoxicity (p < 0.001, p = 0.001). The exposure-response analysis revealed that the trough level of 15 μg/mL was associated with 12.0% nephrotoxicity incidence and AUC of 600 was associated with 12.9% nephrotoxicity incidence. During the treatment, 90 patients had an initial trough concentration of ≥15 μg/mL, and 124 patients had AUC of ≥600 μg h/mL. The multiple logistic regression analysis revealed body weight (p = 0.001), serum creatinine level (p = 0.028), daily vancomycin dose (p = 0.001), and ICU (p = 0.015) were independent predictive factors for a high trough concentration. And same factors were selected for the high AUC.

CONCLUSION

The risk factors for vancomycin induced nephrotoxicity were comparable in both trough concentration and AUC. The incidence of nephrotoxicity can be reduced by controlling vancomycin trough concentration similarly AUC and promoting antimicrobial stewardship.

Personalised dosing of vancomycin: A prospective and retrospective comparative quasi-experimental study

AIMS

The 2019 update to the US consensus guideline for vancomycin therapeutic monitoring advocates using Bayesian-guided personalised dosing to maximise efficacy and minimise toxicity of vancomycin. We conducted an observational cohort study of the implementation of bed-side Bayesian-guided vancomycin dosing in vascular surgery patients.

METHODS

Over a 9-month prospective study period, vascular surgery patients were dosed vancomycin using Bayesian-guided dosing decision tool (DoseMeRx) and compared retrospectively with a control group admitted to the same ward in the 14 months prior to the study and dosed using a standard algorithmic approach. Primary endpoints were proportion of patients achieving mean area under the curve in 24 hours (AUC₂₄ ) in the acceptable range 350-450 mg/L• h and percentage time in acceptable range (%TTR). Secondary endpoints focused on clinical outcomes including incidence of acute kidney injury.

RESULTS

A significantly higher proportion of DoseMeRx patients achieved mean AUC₂₄ values in the acceptable range compared to the control group; 71/104 (68.3%) vs 58/139 (41.7%), P < .005. The median %TTR was also greater in DoseMeRx patients compared to the control group (57.1 vs 30.0%, P < .00001). Patients in the DoseMeRx group missed an average of 0.23 doses per course compared to 1.04 doses in the control group (P < .00001). No difference was observed in secondary (clinical) outcomes between the 2 groups.

CONCLUSION

Bedside Bayesian-guided personalised dosing of vancomycin increases the proportion of patients achieving target AUC₂₄ and the %TTR.

Weight-based vancomycin loading strategy may not improve achievement of optimal vancomycin concentration in patients with preserved renal function

We performed a retrospective study to evaluate clinical effectiveness of vancomycin loading strategy and factors associated with achieving optimal C _min. Patients administered vancomycin for ≥72 h from January to June 2018 were enrolled. Patients were divided into two groups: loading (LD) and non-loading (NLD). LD was defined as initial vancomycin dose ≥20 mg/kg and ≥120% of maintenance dose. During study period, 70 and 71 received initial LD (24.2 ± 2.5 mg/kg) and NLD (17.3 ± 3.3 mg/kg) doses of vancomycin, respectively (p < .001). Achievement of optimal C _min was not different before administration of the third dose (24.4% in LD versus 18.2% in NLD, p = .484) and within 72 h (22.9% versus 28.2%, p = .759). Risk factors for failure to achieve optimal C _min before administration of the third dose were higher creatinine clearance and higher level of serum albumin. Therefore, more sufficient loading or patient-specific dose strategies should be used to achieve optimal serum vancomycin C _min.

Vancomycin loading dose is associated with increased early clinical response without attainment of initial target trough concentration at a steady state in patients with methicillin-resistant Staphylococcus aureus infections

WHAT IS KNOWN AND OBJECTIVE

Vancomycin therapeutic guidelines suggest a loading dose of 25-30 mg/kg for seriously ill patients. However, high-quality data to guide the use of loading doses are lacking. We aimed to evaluate whether a loading dose (a) achieved a target trough concentration at steady state and (b) improved early clinical response.

METHODS

Patients with an estimated glomerular filtration rate ≥ 90 mL/min/1.73 m² were included. A loading dose of 25 mg/kg vancomycin followed by 15 mg/kg twice daily was compared with traditional dosing. A C_min sample was obtained before the fifth dose. An early clinical response 48-72 hours after the start of therapy and clinical success at end of therapy (EOT) was evaluated in patients with methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant coagulase-negative Staphylococci or Enterococcus faecium.

RESULTS

There was no significant difference in C_min between the regimen with and without a loading dose (median: 10.4 and 10.2 µg/mL, P = .54). Proportions of patients achieving 10-20 and 15-20 µg/mL were 56.9% and 5.6%, respectively, in patients with a loading dose. Although there was no significant difference in success rate at EOT between groups, a loading dose was associated with increased early clinical response for all infections (adjusted odds ratio [OR]: 4.588, 95% confidence interval [CI]: 1.373-15.330) and MRSA infections (OR: 12.065, 95% CI: 1.821-79.959). Study limitations included no C_min measurements within 24 hours and the inclusion of less critically ill patients.

WHAT IS NEW AND CONCLUSION

A loading dose of 25 mg/kg followed by 15 mg/kg twice daily did not achieve the optimal Cmin at steady state in patients with normal renal function. However, more early clinical responses were obtained with a loading dose compared with traditional dosing, possibly because of a prompt albeit temporary achievement of a more effective concentration.

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.

Individualising Therapy to Minimize Bacterial Multidrug Resistance

The scourge of antibiotic resistance threatens modern healthcare delivery. A contributing factor to this significant issue may be antibiotic dosing, whereby standard antibiotic regimens are unable to suppress the emergence of antibiotic resistance. This article aims to review the role of pharmacokinetic and pharmacodynamic (PK/PD) measures for optimising antibiotic therapy to minimise resistance emergence. It also seeks to describe the utility of combination antibiotic therapy for suppression of resistance and summarise the role of biomarkers in individualising antibiotic therapy. Scientific journals indexed in PubMed and Web of Science were searched to identify relevant articles and summarise existing evidence. Studies suggest that optimising antibiotic dosing to attain defined PK/PD ratios may limit the emergence of resistance. A maximum aminoglycoside concentration to minimum inhibitory concentration (MIC) ratio of > 20, a fluoroquinolone area under the concentration-time curve to MIC ratio of > 285 and a β-lactam trough concentration of > 6 × MIC are likely required for resistance suppression. In vitro studies demonstrate a clear advantage for some antibiotic combinations. However, clinical evidence is limited, suggesting that the use of combination regimens should be assessed on an individual patient basis. Biomarkers, such as procalcitonin, may help to individualise and reduce the duration of antibiotic treatment, which may minimise antibiotic resistance emergence during therapy. Future studies should translate laboratory-based studies into clinical trials and validate the appropriate clinical PK/PD predictors required for resistance suppression in vivo. Other adjunct strategies, such as biomarker-guided therapy or the use of antibiotic combinations require further investigation.

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.

Vancomycin levels are frequently subtherapeutic in critically ill patients: a prospective observational study

Background

Appropriate utilization of vancomycin is important to attain therapeutic targets while avoiding clinical failure and the development of antimicrobial resistance. Our aim was to observe the use of vancomycin in an intensive care population, with the main focus on achievement of therapeutic serum concentrations (15–20 mg/l) and to evaluate how this was influenced by dose regimens, use of guidelines and therapeutic drug monitoring.

Methods

A prospective observational study was carried out in the intensive care units at two tertiary hospitals in Norway. Data were collected from 83 patients who received vancomycin therapy, half of these received continuous renal replacement therapy. Patients were followed for 72 h after initiation of therapy. Blood samples were drawn for analysis of trough serum concentrations. Urine was collected for calculations of creatinine clearance. Information was gathered from medical records and electronic health records.

Results

Less than 40% of the patients attained therapeutic trough serum concentrations during the first 3 days of therapy. Patients with augmented renal clearance had lower serum trough concentrations despite receiving higher maintenance doses and more loading doses. When trough serum concentrations were outside of therapeutic range, dose adjustments in accordance to therapeutic drug monitoring were made to less than half.

Conclusion

The present study reveals significant challenges in the utilization of vancomycin in critically ill patients. There is a need for clearer guidelines regarding dosing and therapeutic drug monitoring of vancomycin for patient subgroups.

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.

Optimizing the Clinical Use of Vancomycin

The increasing number of infections produced by beta-lactam-resistant Gram-positive bacteria and the morbidity secondary to these infections make it necessary to optimize the use of vancomycin. In 2009, the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, and the Society of Infectious Disease Pharmacists published specific guidelines about vancomycin dosage and monitoring. However, these guidelines have not been updated in the past 6 years. This review analyzes the new available information about vancomycin published in recent years regarding pharmacokinetics and pharmacodynamics, serum concentration monitoring, and optimal vancomycin dosing in special situations (obese people, burn patients, renal replacement therapy, among others). Vancomycin efficacy is linked to a correct dosage which should aim to reach an area under the curve (AUC)/MIC ratio of ≥400; serum trough levels of 15 to 20 mg/liter are considered a surrogate marker of an AUC/MIC ratio of ≥400 for a MIC of ≤1 mg/liter. For Staphylococcus aureus strains presenting with a MIC >1 mg/liter, an alternative agent should be considered. Vancomycin doses must be adjusted according to body weight and the plasma trough levels of the drug. Nephrotoxicity has been associated with target vancomycin trough levels above 15 mg/liter. Continuous infusion is an option, especially for patients at high risk of renal impairment or unstable vancomycin clearance. In such cases, vancomycin plasma steady-state level and creatinine monitoring are strongly indicated.

Towards Rational Dosing Algorithms for Vancomycin in Neonates and Infants Based on Population Pharmacokinetic Modeling

Because of the recent awareness that vancomycin doses should aim to meet a target area under the concentration-time curve (AUC) instead of trough concentrations, more aggressive dosing regimens are warranted also in the pediatric population. In this study, both neonatal and pediatric pharmacokinetic models for vancomycin were externally evaluated and subsequently used to derive model-based dosing algorithms for neonates, infants, and children. For the external validation, predictions from previously published pharmacokinetic models were compared to new data. Simulations were performed in order to evaluate current dosing regimens and to propose a model-based dosing algorithm. The AUC/MIC over 24 h (AUC24/MIC) was evaluated for all investigated dosing schedules (target of >400), without any concentration exceeding 40 mg/liter. Both the neonatal and pediatric models of vancomycin performed well in the external data sets, resulting in concentrations that were predicted correctly and without bias. For neonates, a dosing algorithm based on body weight at birth and postnatal age is proposed, with daily doses divided over three to four doses. For infants aged <1 year, doses between 32 and 60 mg/kg/day over four doses are proposed, while above 1 year of age, 60 mg/kg/day seems appropriate. As the time to reach steady-state concentrations varies from 155 h in preterm infants to 36 h in children aged >1 year, an initial loading dose is proposed. Based on the externally validated neonatal and pediatric vancomycin models, novel dosing algorithms are proposed for neonates and children aged <1 year. For children aged 1 year and older, the currently advised maintenance dose of 60 mg/kg/day seems appropriate.

Optimization of time to initial vancomycin target trough improves clinical outcomes

BACKGROUND

Outcomes data for the efficacy of interventions designed to decrease the time to initial target vancomycin troughs are sparse.

OBJECTIVE

A vancomycin therapeutic drug monitoring (TDM) program was initiated to reduce the time to initial target troughs and to examine the impact on clinical outcomes.

METHODS

Single-center, pre- and post-intervention observational study in a 250 bed teaching facility. Adult inpatients treated with physician-guided, vancomycin therapy (historical control, CTRL) were compared to high trough, pharmacist-guided vancomycin therapy (TDM). Nephrotoxicity analyses were conducted to the ensure safety of the TDM. Clinical outcome analysis was limited to patients with normal renal function and culture-confirmed gram positive infections and a pre-defined MRSA subset.

RESULTS

340 patients met initial inclusion criteria for the nephrotoxicity analysis (TDM, n = 173; CTRL, n = 167). Acute kidney injury occurrence was similar between the CTRL (n = 20) and TDM (n = 23) groups (p = 0.7). Further exclusions yielded 145 patients with gram positive infections for clinical outcomes evaluation (TDM, n = 66; CTRL, n = 75). The time to initial target trough was shorter in the TDM group (3 vs. 5 days, p < 0.001). Patients in the TDM group discharged from the hospital more rapidly, 7 vs. 14 days (Hazards Ratio (HR), 1.41; 95% Confidence Interval [CI] 1.08-1.83; p = 0.01), reached clinical stability faster, 4 vs. 8 days (HR, 1.51; 95% CI 1.08-2.11; p = 0.02), and had shorter courses of vancomycin, 4 vs. 7 days (HR, 1.5; 95% CI 1.15-1.95; p = 0.003). In the MRSA infection subset (TDM, n = 36; CTRL, n = 35), patients in the TDM group discharged from the hospital more rapidly, 7 vs. 16 days (HR, 1.89; 95% CI 1.08-3.3; p = 0.03), reached clinical stability faster, 4 vs. 6 days (HR, 2.69; 95% CI 1.27-5.7; p = 0.01), and had shorter courses of vancomycin, 5 vs. 8 days (HR, 2.52; 95% CI 1.38-4.6; p = 0.003). Attaining initial target troughs in <5 days versus ≥5 days was associated with improved clinical outcomes. All cause in-hospital mortality, and vancomycin treatment failure occurred at comparable rates between groups.

CONCLUSIONS

Interventions designed to decrease the time to reach initial target vancomycin troughs can improve clinical outcomes in gram positive infections, and in particular MRSA infections.

Vancomycin loading doses: a systematic review

OBJECTIVE

To systematically assess the literature to ascertain the pharmacokinetics, pharmacodynamics, and clinical efficacy and safety associated with administration of a vancomycin loading dose (LD).

DATA SOURCES

MEDLINE (1948-December 31, 2014), EMBASE (1980-December 31, 2014), Cochrane Central Register of Controlled Trials, International Pharmaceutical Abstracts (1970-December 31, 2014), Google and Google Scholar, and International Clinical Trials Registry Platform were searched using the following terms: vancomycin, glycopeptides, loading dose, dose-response relationship.

STUDY SELECTION AND DATA EXTRACTION

Pharmacokinetic, pharmacodynamic, and clinical efficacy studies using vancomycin LDs to achieve trough concentrations of 15 to 20 mg/L were included. Nonhuman, non-English, oral vancomycin, and dialysis patient studies were excluded. Abstracts were included. Study quality was ranked using US Preventative Services Task Force 1996 classification system. Data on study design, baseline characteristics, exclusion criteria, dosing, study outcomes, and conclusions were extracted.

DATA SYNTHESIS

A total of 8 studies (5 manuscripts [2 level I, 3 level II-3] and 3 abstracts) were cited. Of 6 adult studies, 4 concluded that administration of vancomycin LDs resulted in significantly more patients achieving troughs of 15 to 20 mg/L. Studies in children found that LDs did not lead to rapid attainment of vancomycin levels ≥15 mg/L. No studies assessed clinical or microbiological outcomes. Limitations included heterogeneity and inconsistent timing of concentration measurements.

CONCLUSIONS

High-quality data to guide the use of vancomycin LDs are lacking. LDs may more rapidly attain vancomycin troughs of 15 to 20 mg/L in adults, but information in pediatrics, obesity, and renal impairment is limited. Further studies are required to determine benefit of LDs on clinical and microbiological outcomes.