Vancomycin loading doses: a systematic review

VANCOmycin dose adjustments comparing trough levels to the ratio of the area under de curve to the minimum inhibitory concentration method using a BAYESian approach: A feasibility study

WHAT IS KNOWN AND OBJECTIVE?: The latest published guidelines advocate for the area under the concentration-time curve to minimal inhibitory concentration (AUC_0-24h /MIC) estimated with bayesian calculations. This recommended pharmacokinetic monitoring transition is not based on randomized controlled prospective data. METHODS: In this open-label feasibility RCT, patients were assigned to have their vancomycin dosing adjusted based on bayesian-guided AUC_0-24h /MIC or trough levels. Primary outcomes were consent rate, number of patients recruited per month, compliance with blood sampling schedule and compliance with bayesian software recommendations. Secondary outcomes focused on target attainment, safety and operational impacts. RESULTS AND DISCUSSION: Forty-five patients underwent randomization (23 bayesian, 22 trough). Consent rate was 37,5% for an average of 9.8 patients recruited per month meeting pre-specified objectives of 30% (p = 0.073) and 10 (p = 0.74) respectively. A 74.8% compliance with blood sampling schedule was below the pre-specified objective of 80% (p = 0.038). There was no statistically significant difference between the 83.7% compliance with bayesian software recommendations and the pre-specified objective of 90% (p = 0.21). Although exploratory, key clinical results were significant increases in the bayesian group for proportion of levels at target (RR 1.32; 95% CI 1.01-1.72; P = 0.038), number of blood samplings for patients (p = 0.036) and pharmacists' time spent on monitoring (p < 0.0001). A tendency towards a reduced incidence of nephrotoxicity in the Bayesian group was observed (RR 0.57; 95% CI 0.16-2.12; p = 0.46). WHAT IS NEW AND CONCLUSIONS?: This trial demonstrates that it would be feasible to conduct a properly sized RCT comparing vancomycin Bayesian-guided AUC_0-24h /MIC to trough level monitoring. Although exploratory, this trial also showed a tendency towards reduced incidence of nephrotoxicity and an increased proportion of dosages at therapeutic targets with Bayesian monitoring.

Antimicrobial Therapy in Pediatric Sepsis: What Is the Best Strategy?

Pediatric sepsis is a relevant cause of morbidity and mortality in this age group. Children are affected differently in high and low-income countries. Antibiotics are crucial for the treatment of sepsis, but indiscriminate use can increase resistance worldwide. The choice of a correct empiric therapy takes into consideration the site of infection, local epidemiology, host comorbidities and recent antibiotic exposure. Antibiotics should be administered in the first hour for patients with septic shock, and always intravenously or via intraosseous access. Culture results and clinical improvement will guide de-escalation and length of treatment. New diagnostic methods can help improve the prescription of adequate treatment. Prevention of sepsis includes vaccination and prevention of healthcare-associated infections. More research and education for awareness of sepsis is needed to improve care.

Key articles and guidelines for the emergency medicine clinical pharmacist: 2011-2018 update

PURPOSE

To summarize recently published research reports and practice guidelines on emergency medicine (EM)-related pharmacotherapy.

SUMMARY

Our author group was composed of 14 EM pharmacists, who used a systematic process to determine main sections and topics for the update as well as pertinent literature for inclusion. Main sections and topics were determined using a modified Delphi method, author and peer reviewer groups were formed, and articles were selected based on a comprehensive literature review and several criteria for each author-reviewer pair. These criteria included the document "Oxford Centre for Evidence-based Medicine - Levels of Evidence (March 2009)" but also clinical implications, interest to reader, and belief that a publication was a "key article" for the practicing EM pharmacist. A total of 105 articles published from January 2011 through July 2018 were objectively selected for inclusion in this review. This was not intended as a complete representation of all available pertinent literature. The reviewed publications address the management of a wide variety of disease states and topic areas that are commonly found in the emergency department: analgesia and sedation, anticoagulation, cardiovascular emergencies, emergency preparedness, endocrine emergencies, infectious diseases, neurology, pharmacy services and patient safety, respiratory care, shock, substance abuse, toxicology, and trauma.

CONCLUSION

There are many important recent additions to the EM-related pharmacotherapy literature. As is evident with the surge of new studies, guidelines, and reviews in recent years, it is vital for the EM pharmacist to continue to stay current with advancing practice changes.

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.

Vancomycin in ICU Patients with Gram-Positive Infections: Initial Trough Levels and Mortality

Background

Vancomycin is one of the most common therapeutic agents for treating gram-positive infections, particularly in critically ill patients. The aim of this study was to identify factors associated with initial therapeutic vancomycin trough levels and mortality in a tertiary-care intensive care unit (ICU).

Methods

This retrospective study evaluated 301 adult ICU patients admitted to King Abdulaziz Medical City in Riyadh between October 1, 2017 and December 31, 2018 with confirmed gram-positive infections and received intravenous vancomycin. Vancomycin trough levels of 15–20 mg/L for severe infections and 10–15 mg/L for less severe infections were considered therapeutic.

Results

The patients were relatively older with a mean age of 60 (SD ±20) years. Initial vancomycin trough levels were therapeutic in 168 (55.8%). Factors associated with initial therapeutic vancomycin trough levels were female gender (adjusted odds ratio [aOR]=2.575), older age (aOR=1.024), receiving a loading dose (aOR=2.445), having bacteremia (aOR=2.061), and high platelet count (aOR=1.003). On the other hand, the increase of estimated glomerular filtration rate (eGFR) (aOR=0.993) and albumin levels (aOR=0.944) were associated with lower odds of initial therapeutic vancomycin trough levels. Factors associated with higher mortality were female gender (adjusted hazard ratio [aHR]=2.630), increased body weight (aHR=1.021), cancer (aHR=3.451), and high APACHE II score (aHR=1.068).

Conclusion

The study identified several factors associated with achieving initial therapeutic vancomycin trough levels (i.e. older age, female gender, receiving a loading dose, bacteremia, high platelets count, low eGFR and albumin level). These factors should be considered in the dosing of vancomycin in critically ill patients with gram-positive infections.

Effect of Vancomycin Loading Doses on the Attainment of Target Trough Concentrations in Hospitalized Children

OBJECTIVE

Subtherapeutic vancomycin trough concentrations are common in children and may be associated with suboptimal therapeutic response. Our objective was to determine if vancomycin loading doses safely increase the frequency of target trough attainment in hospitalized children.

METHODS

Patients (≥6 months and <18-years-old) who received a vancomycin loading dose between February 1, 2018, and January 30, 2019, were retrospectively enrolled. These patients were compared to a convenience cohort of patients hospitalized between January 1, 2015, and December 31, 2015, who received vancomycin without a loading dose. Target trough concentrations were defined as >15 mg/dL for invasive infections and >10 mg/dL for non-invasive infections.

RESULTS

A total of 151 patients were enrolled, with 77 in the control arm and 74 in the loading dose arm. There was no significant difference in the frequency of comorbidities or need for intensive care unit admission between the two arms. Those receiving a vancomycin loading dose were older (mean age 9.1 vs 5.2 years, p < 0.0001). Patients given a loading dose achieved higher mean initial trough values (13.0 mg/dL vs 9.2 mg/dL, p < 0.0001), were more likely to have an initial trough at or above target (37.0% vs 10.4%, p = 0.0001), were more likely to reach target trough values at any point during therapy (52.1% vs 32.9%, p = 0.0081), and attained a target trough concentration more quickly (mean 41.1 hours vs 58.8 hours, p = 0.0118). There were no significant differences in the frequency of serum creatinine elevation or oliguria at the end of therapy.

CONCLUSIONS

Vancomycin loading doses may improve the ability to safely obtain target trough values in hospitalized children.

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.

Correlation of the vancomycin 24-h area under the concentration-time curve (AUC24) and trough serum concentration in children with severe infection: A clinical pharmacokinetic study

BACKGROUND

Vancomycin is a common drug used in children with severe infection. In adults, at least 15 mg/L of the optimal vancomycin trough concentration (C_trough) is needed to generate the target 24-h area under the concentration-time curve (AUC₂₄) to the minimum inhibitory concentration (MIC) of 400 for a pathogen with the MIC ≤1 mg/L.

OBJECTIVES

To determine vancomycin PK in children with severe infection and to explore the correlation between vancomycin C_trough and AUC₂₄ in children, as well as to propose the appropriate vancomycin dosages using Monte Carlo simulation.

MATERIALS AND METHODS

Children aged 2-18 years who were admitted to Chiang Mai University Hospital and received intravenous vancomycin for severe infection were included in the study. Serum samples for vancomycin PK were obtained before and serially after the administration of the first dose according to the protocol. Pharmacokinetic analyses were performed using Phoenix WinNonlin® 7.0 and NLME™7.0.

RESULTS

Fourteen children with 64% males and age range from 2 to 13 years were included in this study. Non-compartmental analysis revealed the median volume of distribution, clearance, and elimination half-life of 0.58 L/kg, 2.82 mL/kg/min and 2.33 h, respectively. Vancomycin serum concentrations were best described by a two-compartmental model with first-order elimination.The observed C_trough at 6 h correlated well with the AUC₂₄. The median vancomycin C_trough at steady state that correlated with the AUC₂₄ ≥ 400 and <800 were 11.18, 9.50, 7.91 and 6.55 mg/L in simulated children receiving vancomycin 40, 60, 80 and 100 mg/kg/day, respectively.

CONCLUSION

Correlation between vancomycin C_trough and AUC₂₄ values in children has been observed. However, the values of C_trough that correlate with the target AUC₂₄≥400 in children are lower than the values observed and targeted in adults.

Vancomycin volume of distribution estimation in adults with class III obesity

PURPOSE

To compare methods of estimating vancomycin volume of distribution (V) in adults with class III obesity.

METHODS

A retrospective, multicenter pharmacokinetic analysis of adults treated with vancomycin and monitored through measurement of peak and trough concentrations was performed. Individual pharmacokinetic parameter estimates were obtained via maximum a posteriori Bayesian analysis. The relationship between V and body weight was assessed using linear regression. Mean bias and root-mean-square error (RMSE) were calculated to assess the precision of multiple methods of estimating V.

RESULTS

Of 241 patients included in the study sample, 159 (66.0%) had a body mass index (BMI) of 40.0-49.9 kg/m2, and 82 (34.0%) had a BMI of ≥50.0 kg/m2. The median (5th, 95th percentile) weight of patients was 136 (103, 204) kg, and baseline characteristics were similar between BMI groups. The mean ± S.D. V was lower in patients with a BMI of 40.0-49.9 kg/m2 than in those with a BMI of ≥50.0 kg/m2 (72.4 ± 19.6 L versus 79.3 ± 20.6 L, p = 0.009); however, body size poorly predicted V in regression analyses (R2 < 0.20). A fixed estimate of V (75 L) and use of a weight-based value (0.52 L/kg by total body weight [TBW]) yielded similar bias and error in this population.

CONCLUSION

Results of the largest analysis of vancomycin V in class III obesity to date indicated that use of a fixed V value (75 L) and use of a TBW-based estimate (0.52 L/kg) for estimation of vancomycin V in patients with a BMI of ≥40.0 kg/m2 have similar bias. Two postdistribution vancomycin concentrations are needed to accurately determine patient-specific pharmacokinetic parameters, estimate area under the curve, and improve the precision of vancomycin dosing in this patient population.

Is there still a role for vancomycin in skin and soft-tissue infections?

PURPOSE OF REVIEW

Skin and soft-tissue infections (SSIs) are among the commonest infections encountered in clinical practice. Spread of methicillin-resistant Staphylococcus aureus SSIs continues to increase in both health care and community settings and presents a challenge for the best treatment choice. Vancomycin has been the mainstay of SSIs treatment, but recently its use has been questioned because of concerns about its efficacy, tolerability, and unfavorable pharmacokinetic/pharmacodynamic profile. The purpose of this review is to establish the current role for vancomycin in light of the literature published from January 2007 to September 2017 on comparison with both old and new alternatives.

RECENT FINDINGS

Meta-analyses show better clinical and microbiological outcomes for drugs approved for the treatment of SSI, including those sustained by methicillin-resistant S. aureus, in the last 10 years than for vancomycin. The newer glycopeptides and linezolid decrease the total treatment costs compared with vancomycin, by reducing the length of stay or avoiding the hospitalization.

SUMMARY

Vancomycin is noninferior in efficacy and safety to all comparator drugs, including the newest on the market. However, the SSI treatment evidence base presents several shortcomings limiting the clinical applicability of the results. High-level clinical trials should be performed to obtain results that can be generalized and applied effectively in clinical practice.

Vancomycin population pharmacokinetics for adult patients with sepsis or septic shock: are current dosing regimens sufficient?

PURPOSE

Vancomycin is commonly used for the management of severe infections; however, vancomycin dosing may be challenging in critically ill patients. This observational study aims to describe the population pharmacokinetics of vancomycin in adult patients with sepsis or septic shock.

METHODS

A single-centre retrospective review of adult patients with sepsis or septic shock receiving vancomycin with therapeutic drug monitoring was undertaken. Blood samples taken 1 h after the vancomycin infusion cessation and 30 min prior to the next dose were assayed using the Vitros Crea Slide method. Vancomycin concentrations determined on different days were included. A pharmacokinetic model was developed using Pmetrics for R. Monte Carlo dosing simulations were performed using the final model.

RESULTS

Vancomycin concentrations were available for 27 adult patients admitted to the intensive care unit with sepsis or septic shock. A one-compartment pharmacokinetic model with inter-occasion variability of clearance and volume of distribution before and after 72 h adequately described the data. Creatinine clearance normalized to body surface area was included as a covariate on vancomycin clearance. The clearance and volume of distribution within 72 h of admission were 7.29 L/h and 54.20 L, respectively. Monte Carlo simulations suggested that for patients with a creatinine clearance of ≥ 80 mL/min/1.73 m², vancomycin doses of ≥ 2 g every 8 h are required to consistently achieve key therapeutic targets.

CONCLUSIONS

Vancomycin doses ≥ 2 g every 8 h in adult patients with sepsis or septic shock with a creatinine clearance ≥ 80 mL/min/1.73 m² are likely needed to achieve an optimal therapeutic exposure.

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.

Individualized Pharmacokinetic Dosing of Vancomycin Reduces Time to Therapeutic Trough Concentrations in Critically Ill Patients

Dosing vancomycin in critically ill patients often results in subtherapeutic and supratherapeutic trough concentrations. In this retrospective study, we compared the time to goal trough attainment and incidence of acute kidney injury in intensive care unit (ICU) patients whose vancomycin was dosed by a pharmacy pharmacokinetic (PK) dosing and monitoring service to the standard of care. Three-hundred fifty adult ICU patients at a Level 1 trauma, teaching hospital who received vancomycin for >24 hours from February 1, 2016, to November 30, 2016, were screened. Patients were included in the PK group if consecutive serum concentrations were used to calculate individualized PK and determine a dosing regimen. Patients who were dosed using troughs only were then matched 1-to-1 to the PK group by date of vancomycin initiation and included in the traditional group. Fifty patients were included in each group. Baseline characteristics were similar, except the PK group had more patients under the care of the neuromedical ICU service (42% vs 18%; P = .02) and fewer patients with a corrected creatinine clearance <30 mL/min/1.73 m² (22% vs 46%; P = .02). Attainment of goal trough concentrations for the PK and traditional groups were 84.4% and 29.4% by 48 hours (P = .0001), 88.4% and 60.7% by 72 hours (P = .009), and 92.9% and 77.8% by 96 hours (P = .1), respectively. Incidence of acute kidney injury between the PK and traditional groups was not statistically significant (8.3% vs 14%; P = .5). Utilization of individualized pharmacokinetic dosing of vancomycin in critically ill patients resulted in faster goal trough attainment without an increase in nephrotoxicity.

Serum trough level as a postmarketing quality measure of generic vancomycin products

BACKGROUND

The vancomycin trough level (VTL) is the most widely used pharmacokinetic parameter for monitoring its clinical efficacy. Whether the VTL is affected in patients receiving different vancomycin products has not previously been determined.

METHODS

From 2005 to 2015, five vancomycin products, including the innovator (designated as VAN-Lilly) and four generic versions (designated as VAN-A, VAN-B, VAN-C and VAN-D), were sequentially used in a teaching hospital. The initial VTLs were compared between patients who received different vancomycin products after propensity score (PS) weighting and matching for clinical covariates.

RESULTS

Among 8735 patients with initial VTL levels available for analysis, a significant association was identified between the VTL and different vancomycin products in children aged 1 month to 12 years (P < 0.0001). The PS weighting analysis in the paediatric group disclosed children on VAN-C had higher VTL compared to those on other four products (P = 0.0008). PS matching analysis revealed that children who received VAN-C had significantly higher VTLs than those who received VAN-Lily (P = 0.0001), VAN-A (P = 0.0008), VAN-B (P = 0.0002) or VAN-D (P = 0.0015). Furthermore, the coefficient of variation of the VTL was much greater in patients who received VAN-C than in those who received the other four versions, suggesting an unstable quality of this product.

CONCLUSION

A generic version of vancomycin generated significantly higher concentrations and greater variation of VTLs than the innovator and other generic vancomycin products in children. The VTL can serve as an indicator to monitor the quality of vancomycin products after marketing.

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.

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.

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.

Zunyimycins B and C, New Chloroanthrabenzoxocinones Antibiotics against Methicillin-Resistant Staphylococcus aureus and Enterococci from Streptomyces sp. FJS31-2

This study performed an optimization of the fermentation conditions to activate the expression of the zunyimycin family biosynthesis genes of the zunyimycin-producing streptomycetes strain Streptomyces sp. FJS31-2. Bioassay-guided isolation and purification by varied chromatographic methods yielded two new compounds of the zunyimycin derivatives, namely, 31-2-7 and 31-2-8, accompanied with three known anthrabenzoxocinones family members of zunyimycin A, BE24566B, and chloroanthrabenzoxocinone. Their structures were elucidated by NMR, HRESIMS, IR, UV, and CD. Results showed that these two compounds were structurally similar to the previously reported compound zunyimycin A but differed in positions and number of chlorine atom substitution. The two novel compounds were called zunyimycins B and C. Antibacterial activity assay indicated that zunyimycin C showed a good inhibitory effect on the methicillin-resistant Staphylococcus aureus and Enterococci.

Oral health promotion in patients with chronic renal failure admitted in the Intensive Care Unit

Oral hygiene deficiency is common in patients treated in ICUs and it enables biofilm colonization by microorganisms that lead to respiratory infections. A 30‐year‐old female patient with chronic renal failure was hospitalized. Dental procedures were performed in the ICU and contributed to the patient's health after a few days.

Pharmacist-led implementation of a vancomycin guideline across medical and surgical units: impact on clinical behavior and therapeutic drug monitoring outcomes

Background

Vancomycin is the antibiotic of choice for the treatment of serious infections such as methicillin-resistant Staphylococcus aureus (MRSA). Inappropriate prescribing of vancomycin can lead to therapeutic failure, antibiotic resistance, and drug toxicity.

Objective

To examine the effectiveness of pharmacist-led implementation of a clinical practice guideline for vancomycin dosing and monitoring in a teaching hospital.

Methods

An observational pre–post study design was undertaken to evaluate the implementation of the vancomycin guideline. The implementation strategy principally involved education, clinical vignettes, and provision of pocket guidelines to accompany release of the guideline to the hospital Intranet. The target cohort for clinical behavioral change was junior medical officers, as they perform the majority of prescribing and monitoring of vancomycin in hospitals. Assessment measures were recorded for vancomycin prescribing, therapeutic drug monitoring, and patient outcomes.

Results

Ninety-nine patients, 53 pre- and 46 post-implementation, were included in the study. Prescribing of a loading dose increased from 9% to 28% (P=0.02), and guideline adherence to starting maintenance dosing increased from 53% to 63% (P=0.32). Dose adjustment by doctors when blood concentrations were outside target increased from 53% to 71% (P=0.12), and correct timing of initial concentration measurement increased from 43% to 57% (P=0.23). Appropriately timed trough concentrations improved from 73% to 81% (P=0.08). Pre-dose (trough) concentrations in target range rose from 33% to 44% (P=0.10), while potentially toxic concentrations decreased from 32% to 21% (P=0.05) post-implementation. Infection cure rates for patients increased from 85% to 96% (P=0.11) after the guideline was implemented.

Conclusion

The implementation strategy employed in this study demonstrated potential effectiveness, and should prompt additional larger studies to optimize strategies that will translate into improved clinical practice using vancomycin.

Performance of a Divided-Load Intravenous Vancomycin Dosing Strategy for Obese Patients

Background: Current guidelines recommend vancomycin trough concentrations of 15 to 20 µg/mL in complicated infections and all trough concentrations >10 µg/mL to avoid developing microbial resistance. To date, no published protocol reliably meets these recommendations for obese patients. Objective: We assessed the performance of a novel, obese-specific, divided-load vancomycin protocol for attaining target trough concentrations within 12 to 24 hours of dosing initiation, and during maintenance dosing, in obese patients. Methods: The protocol was evaluated through prospective medical record review in 54 consecutive obese patients. Vancomycin serum concentrations were drawn before the third and fifth dose after initiation. Steady-state concentrations were drawn after the third dose once maintenance dosing was achieved and periodically thereafter. Results: Within 12 hours after dosing initiation, 48 (89%) study patients exhibited trough concentrations of 10 to 20 µg/mL averaging 14.5 ± 3.2 µg/mL; 51 (94%) study patients exhibited trough concentrations >10 µg/mL within 12 hours after dosing initiation, and 3 (6%) had trough concentrations >20 µg/mL. Thirty-one participants had second trough concentrations drawn within 24 hours of dosing initiation, averaging 15.0 ± 3.1 µg/mL; 24 patients had a total of 32 trough concentrations drawn during maintenance dosing, averaging 15.1 ± 2.5 µg/mL. Conclusion: Obese-specific, divided-load dosing achieved trough concentrations of 10 to 20 µg/mL for 89% of obese patients within 12 hours of initial dosing and 97% of obese patients within 24 hours of initial dosing while preventing doses given during supratherapeutic trough levels; 97% of troughs measured during steady state were within target range.