Vancomycin dosing and target attainment in children

Comparison of Vancomycin Trough-Based and 24-Hour Area Under the Curve Over Minimum Inhibitory Concentration (AUC/MIC)-Based Therapeutic Drug Monitoring in Pediatric Patients

OBJECTIVES

Vancomycin 24-hour area under the curve over minimum inhibitory concentration (AUC/MIC) monitoring has been recommended over trough-based monitoring in pediatric patients. This study compared the proportion of target attainment between vancomycin AUC/MIC and trough-based methods, and identified risk factors for subtherapeutic initial extrapolated targets.

METHODS

This was a retrospective, observational study conducted at KK Women's and Children's Hospital (KKH), Singapore. Patients aged 1 month to 18 years with stable renal function who received intravenous vancomycin between January 2014 and October 2017, with at least 2 vancomycin serum concentrations obtained after the first dose of vancomycin, were included. Using a pharmacokinetic software, namely Adult and Pediatric Kinetics (APK), initial extrapolated steady-state troughs and 24-hour AUC were determined by using a one-compartmental model. Statistical tests included Wilcoxon rank sum test, McNemar test, logistic regression, and classification and regression tree (CART) analysis.

RESULTS

Of the 82 pediatric patients included, a significantly larger proportion of patients achieved therapeutic targets when the AUC/MIC-based method (24, 29.3%) was used than with the trough-based method (9, 11.0%; p < 0.01). Patients with estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 or with age <13 years had an increased risk of obtaining subtherapeutic targets. However, empiric vancomycin doses of 60 mg/kg/day would be sufficient to achieve serum therapeutic targets, using the AUC/MIC-based method.

CONCLUSION

The AUC/MIC-based vancomycin monitoring may be preferred because a larger proportion of patients could achieve initial therapeutic targets. Future prospective studies with larger sample size will be required to determine the optimal vancomycin strategy for pediatric patients.

Acute bacterial skin and skin structure infections in pediatric patients: potential role of dalbavancin

INTRODUCTION

Acute bacterial skin and skin structure infections (ABSSSIs) are a subtype of skin and soft tissue infections (SSTI), usually sustained by Gram-positive bacteria, whose incidence is high among children. ABSSSIs are responsible for a considerable number of hospitalizations. Moreover, as multidrug resistant (MDR) pathogens become widespread, the pediatric category seems burdened with an increased risk of resistance and treatment failure.

AREAS COVERED

To obtain a view on the status of the field, we describe the clinical, epidemiological, and microbiological aspects of ABSSSI in children. Old and new treatment options were critically revised with a focus on the pharmacological characteristics of dalbavancin. Evidence on the use of dalbavancin in children was collected, analyzed, and summarized.

EXPERT OPINION

Many of the therapeutic options available at the moment are characterized by the need for hospitalization or repeated intravenous infusions, safety issues, possible drug-drug interactions, and reduced efficacy on MDRs. Dalbavancin, the first long-acting molecule with strong activity against methicillin-resistant and also many vancomycin-resistant pathogens represents a game changer for adult ABSSSI. In pediatric settings, the available literature is still limited, but a growing body of evidence supports dalbavancin use in children with ABSSSI, demonstrating this drug to be safe and highly efficacious.

Vancomycin dosing required to achieve a therapeutic level in children post-surgical correction of congenital heart disease

The vancomycin dosing range for safe and effective treatment remains uncertain for children who had corrective surgery for a congenital heart disease (CHD). We aimed to determine the vancomycin dosing requirements for this subgroup of patients. This prospective cohort study included children younger than 14 years old with CHD who received intravenous vancomycin for at least 3 days at the Pediatric Cardiology section of King Abdulaziz Medical City, Riyadh. In total, 140 pediatric patients with CHD were included with a median age of 0.57 years (interquartile range 0.21-2.2). The mean vancomycin total daily dose (TDD), 37.71 ± 6.8 mg/kg/day, was required to achieve a therapeutic trough concentration of 7-20 mg/L. The patient's age group and the care setting were significant predictors of the vancomycin dosing needs. Neonates required significantly lower doses of 34 ± 6.03 mg/kg/day (P = .002), and young children higher doses of 43.97 ± 9.4 mg/kg/day (P = .003). The dosage requirements were independent of the type of cardiac lesion, cardiopulmonary surgery exposure, sex, and BMI percentile. However, the patients in the pediatric cardiac ward required higher doses of vancomycin 41.08 ± 7.06 mg/kg/day (P = .039). After the treatment, 11 (8.5%) patients had an elevated Scr, and 3 (2.3%) patients developed AKI; however, none of the patients' sociodemographic factors or clinical variables, or vancomycin therapy characteristics was significantly associated with the renal dysfunction. Overall, the vancomycin TDD requirements are lower in pediatric post-cardiac surgery compared to non-cardiac patients and are modulated by several factors.

Relationship between Vancomycin Trough Serum Concentrations and Clinical Outcomes in Children: a Systematic Review and Meta-Analysis

To systematically evaluate the relationships between vancomycin trough serum concentrations and clinical outcomes in children using meta-analysis. Several databases, including PubMed, Elsevier, Web of Science, EMBASE, Medline, clinicaltrials.gov, the Cochrane Library, and three Chinese databases (Wanfang Data, China National Knowledge Infrastructure, and SINOMED), were comprehensively searched to obtain research articles on vancomycin use in children from inception through December 2021. All studies were screened and evaluated using the Cochrane systematic review method. Then, the feature information was extracted for meta-analysis. The evaluated results included clinical efficacy, vancomycin-associated nephrotoxicity, hepatotoxicity, ototoxicity, mortality, and microbial clearance. A total of 35 studies involving 4820 children were included in the analysis. The meta-analysis showed that compared with children with vancomycin trough concentrations <10 μg/mL, those with vancomycin trough concentrations ≥10 μg/mL had a higher clinical efficacy rate [OR: 2.23, 95% CI: 1.29 to 3.84, P = 0.004] and higher incidences of nephrotoxicity [OR: 2.76, 95% CI: 1.51 to 5.07, P = 0.001], ototoxicity [OR: 1.87, 95% CI: 1.08 to 3.23, P = 0.02] and microbial clearance [OR: 2.36, 95% CI: 1.53 to 3.64, P = 0.0001]. All-cause mortality [OR: 1.07, 95% CI: 0.45 to 2.53, P = 0.88] and hepatotoxicity [OR: 0.84, 95% CI: 0.46 to 1.53, P = 0.57] were similar between the two groups. Subgroup analysis showed that compared with children with vancomycin trough concentrations of 10 to 15 μg/mL, those with vancomycin trough concentrations >15 μg/mL had a higher incidence of nephrotoxicity [OR: 2.64, 95% CI: 1.28 to 5.43, P = 0.008], but there was no significant difference in clinical efficacy [OR: 0.85, 95% CI: 0.30 to 2.44, P = 0.76]. A vancomycin trough concentration of 10 to 15 μg/mL can improve clinical efficacy in children. Additionally, avoidance of trough concentrations >15 μg/mL can reduce the incidence of adverse reactions.

Effect of Initial Vancomycin Dose and Creatinine Clearance on the Attainment of Target Trough Concentration in Children

BACKGROUND

Vancomycin is a glycopeptide antibiotic that is used to treat serious grampositive infections. However, therapeutic drug monitoring for vancomycin is not performed routinely in Vietnam in clinical practices. Monitoring of serum vancomycin concentration or trough levels is necessary to ensure the efficacy and safety of vancomycin therapy.

OBJECTIVE

This study aims to determine the impact of initial vancomycin dose and creatinine clearance on target trough attainment in hospitalized Vietnamese children.

METHODS

A prospective study with patients who received vancomycin for at least three days was conducted. Subsequently, demographic data, clinical diagnosis, vancomycin dosage, and serum creatinine levels were recorded. The vancomycin trough level was collected and creatinine clearance and adjusted vancomycin doses were calculated.

RESULTS

A total of 40 eligible patients were enrolled. Patients' mean age, body weight, and height were 1.4 years old, 9.8 kg, and 75.5 cm, respectively. The mean vancomycin dose was 55.83 ± 19.34 mg/kg/day. The mean creatinine clearance was 80.18 ± 29.14 ml/min. The median trough level was 11.09 (7.84 - 16.46) μg/ml. There was no significant difference in the mean initial and the adjusted vancomycin doses (p = 0.062). However, there were statistically significant differences of initial (p = 0.004) or adjusted doses (p = 0.016) between groups of creatinine clearance. The trough vancomycin concentration was not statistically significant (p = 0.406) between these groups.

CONCLUSION

Target trough vancomycin level may be associated with creatinine clearance but did not proportionally correspond to the vancomycin dose. Therefore, monitoring vancomycin trough levels is necessary to achieve the target trough and to ensure vancomycin efficacy and safety in treating severely infected Vietnamese children.

Variation in vancomycin dosing and therapeutic drug monitoring practices in neonatal intensive care units

Background Vancomycin is a frequently used antibiotic in neonates. However, there is no consensus guideline on the optimal dosing regimen and therapeutic drug monitoring (TDM) practices in this patient population. Objective To document the variability in the current dosing and TDM practices in neonatal intensive care units (NICU). Setting Belgian and Dutch NICUs. Method An online questionnaire was disseminated by e-mail to potential respondents. Main outcome measure Differences in vancomycin dosing and TDM practices in comparison with a reference source, the Dutch Paediatric Formulary. Results Eighteen NICUs (response rate 62%) participated. Eleven different dosing regimens are applied, with 83% using intermittent dosing regimens. Stratifying covariates used to determine the (initial) dosage include gestational age, postnatal age, serum creatinine, concurrent use of non-steroidal anti-inflammatory drugs, birth weight and current weight. Large variability is observed with regard to TDM practice as well, both for the concentration target range and the times of (re)sampling. Dosing calculators are more commonly used in the Netherlands than Belgium. Conclusion Significant inter-centre variability in dosing and TDM practices was found. The development of international consensus guidelines is required to optimize therapy. Dosing calculators to guide dosing are not yet considered as part of standard-of-care.

Efficacy and Safety of Continuous Infusion of Vancomycin in Children: A Systematic Review

Vancomycin is used to treat a wide variety of infections within the pediatric population. In adults, continuous infusion of vancomycin (CIV) has been evaluated as an alternative to intermittent infusion of vancomycin (IIV) with potential advantages. In children, the use of CIV is increasing; however, data is currently limited. The objective is to provide efficacy and safety evidence for CIV within this population. The review was carried out following PRISMA guidelines. A bibliographic search was performed for studies on PubMed and EMBASE. Clinical trials and observational studies that reported clinical efficacy and/or target attainment of CIV in pediatrics were included. Articles were reviewed to assess their design and target population, characteristics of vancomycin treatment and the main findings in terms of safety and efficacy. A total of 359 articles were identified, of which seven met the inclusion criteria. All of them evaluated the target attainment, six assessed safety but only three assessed clinical efficacy. The best administration method for this antibiotic within the pediatric population is still unknown due to limited evidence. However, studies conducted thus far suggest pharmacokinetic advantages for CIV. Further investigation is required, in particular for studies comparing IIV with CIV for clinical efficacy and toxicity outcomes.

Impact of the Implementation of a Vancomycin Protocol on Trough Serum Vancomycin Concentrations in a Pediatric Intensive Care Unit

BACKGROUND

Vancomycin is an antibiotic that is widely used in pediatric intensive care, but the safe and effective use of this drug is challenging.

OBJECTIVE

This study aimed to assess the impact of a vancomycin protocol on trough serum concentrations.

METHODS

We conducted a retrospective quasiexperimental study in patients aged ≤ 18 years in intensive care who received vancomycin for at least 5 days. Patients were divided into two groups: before and after a protocol implemented in 2017 that suggested an initial vancomycin dose of 60 mg/kg/day, target serum levels of 15-20 μg/mL, and dose adjustments. We compared patient characteristics, target serum level achievement, and vancomycin levels over time.

RESULTS

Each group contained 65 patients; most were male infants with heart disease as the main reason for hospitalization. Only 29.2% of the patients had pretreatment cultures for bacteria identification recorded, with 1.5% identified as methicillin-resistant Staphylococcus aureus. For the first serum levels, 10.8% of patients in the pre-protocol group and 21.5% in the post-protocol group achieved the 15-20 μg/mL target (p = 0.153); during the first 5 days of treatment, this proportion significantly increased from 52.3 to 73.8% (p = 0.018). We observed a difference between the first and fifth levels: 8.9 μg/mL (95% confidence interval [CI] - 3.1 to 21) pre-protocol and 0.4 μg/mL (95% CI - 6.1 to 6.9) post-protocol (p = 0.175).

CONCLUSIONS

Reaching adequate trough vancomycin concentrations in critically ill pediatric patients remains a challenge, and clinical practice protocols allow better dose adjustment and control even when monitoring technologies are unavailable.

A Canadian perspective on the revised 2020 ASHP-IDSA-PIDS-SIDP guidelines for vancomycin AUC-based therapeutic drug monitoring for serious MRSA infections

BACKGROUND

A revised consensus guideline on therapeutic drug monitoring (TDM) of vancomycin for serious methicillin-resistant Staphylococcus aureus (MRSA) infections was recently published with endorsement of numerous American pharmacy and medical societies. Changing practice from trough TDM to area-under-the-curve-(AUC)-guided dosing was suggested.

METHODS

Recent literature was critically appraised to determine whether AUC TDM is appropriate for Canadian hospital practice.

RESULTS

Previous 2009 vancomycin consensus guidelines recommended trough levels of 15-20 mg/L for serious MRSA infections, based on relatively poor evidence for efficacy or safety. In the past decade, aggressive trough targets have led to unnecessary toxicity. Adoption of a TDM strategy using an alternative parameter (AUC) has been suggested, although the evidence for any outcome benefits is low quality. In addition, implementation would require greater resources at health care institutions in the forms of more frequent serum levels or acquisition of costly Bayesian software programs. Most studies on this subject have been observational and retrospective; therefore, relationships between TDM parameters and outcomes have not been convincingly and consistently demonstrated to be causal in nature. Despite claims to the contrary, based on few in silico experiments, available clinical data suggest correlation of trough levels and AUC is high. TDM with lower target trough levels is a simpler solution to reduce risk of toxicity.

CONCLUSIONS

There are serious concerns with adoption of AUC TDM of vancomycin into routine practice in Canada. Trough-based monitoring with modest reduction in target levels remains the most evidence-informed practice at this time.

AUCs and 123s: a critical appraisal of vancomycin therapeutic drug monitoring in paediatrics

The revised vancomycin guidelines recommend implementing AUC24-based therapeutic drug monitoring (TDM) using Bayesian methods in both adults and paediatrics. The motivation for this change was accumulating evidence showing aggressive dosing to achieve high troughs, as recommended in the first guidelines for adults and extrapolated to paediatrics, is associated with increased nephrotoxicity without improving clinical outcomes. AUC24-based TDM requires substantial resources that may need to be diverted from other valuable interventions. It can therefore be justified only after certain assumptions are shown to be true: (i) there is a clear relationship between vancomycin efficacy and/or toxicity and the proposed therapeutic range; and (ii) maintaining exposure within the target range with AUC24-based TDM improves clinical outcomes and/or decreases toxicity. In this review, we critically appraise the scientific basis for these assumptions. We find studies evaluating the relationship between vancomycin AUC24/MIC and efficacy in adults and children do not offer strong support for the recommended lower limit of the proposed therapeutic range (i.e. AUC24/MIC ≥400). Nephrotoxicity in children increases in a stepwise manner along the vancomycin exposure continuum but it is unclear if one parameter (AUC24 versus trough) is a superior predictor. Overall, evidence in children suggests good-to-excellent correlation between AUC24 and trough. Most importantly, there is no convincing evidence that the method of vancomycin TDM has a causal role in improving efficacy or reducing toxicity. These findings question the need to transition to resource-intensive AUC24-based TDM over retaining trough-based TDM with lower targets to minimize nephrotoxicity in paediatrics.

The optimal trough-guided monitoring of vancomycin in children: Systematic review and meta-analyses

We carried out a systematic review and meta-analysis exploring the relationship between vancomycin (VCM) trough concentrations and its effectiveness and nephrotoxicity in pediatric patients. We conducted our analysis using MEDLINE, Web of Sciences, and Cochrane Register of Controlled Trials as electronic databases (June 29, 2019). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. We identified 16 studies that were eligible for the meta-analysis. A total of 351 and 3,266 patients were included in the analysis for effectiveness and nephrotoxicity, respectively. Pediatric MRSA infection patients with VCM trough concentrations ≥ 10 μg/mL had significantly lower treatment failure rates (OR 0.54, 95% CI 0.30-0.96). The incidence of nephrotoxicity was significantly higher in trough concentrations ≥ 15 μg/mL than when they were < 15 μg/mL (OR 3.02, 95% CI 2.08-4.38). We identified the optimal VCM trough concentrations associated with effectiveness and nephrotoxicity in pediatric patients with MRSA infection. Further prospective studies are needed to find optimal dosing and monitoring strategy on VCM in pediatric population.

A whole blood microsampling assay for vancomycin: development, validation and application for pediatric clinical study

Background: Vancomycin is a commonly used antibiotic, which requires therapeutic drug monitoring to ensure optimal treatment. Microsampling assays are attractive tools for pediatric clinical research and therapeutic drug monitoring. Results: A LC-MS/MS method for the quantification of vancomycin in human whole blood employing volumetric absorptive microsampling (VAMS^®) devices (20 μl) was developed and validated. Vancomycin was stable in human whole blood VAMS under assay conditions. Stability for vancomycin was established for at least 160 days as dried microsamples at -78°C. Conclusion: This method is currently being utilized for the quantitation of vancomycin in whole blood VAMS for an ongoing pediatric clinical study and representative clinical data are reported.

Intravenous Vancomycin Therapeutic Drug Monitoring in Children: Evaluation of a Pharmacy-Driven Protocol and Collaborative Practice Agreement

BACKGROUND

Vancomycin optimization is challenging, requiring careful therapeutic drug monitoring (TDM) to avoid toxicity and ensure an efficacious concentration. Most prescriptions are empiric and often discontinued within 72 hours, which makes early TDM unnecessary. Although TDM using trough levels is common, the area under the concentration-time curve (AUC) is the preferred pharmacodynamic target. We studied the effect of a pharmacy-driven vancomycin collaborative practice agreement (CPA) at a children's hospital that delayed TDM up to 72 hours and targeted a 2-point 24-hour AUC of ≥400 mg × h/L.

METHODS

We retrospectively reviewed vancomycin courses in patients aged ≥30 days who received vancomycin between April 1, 2011, and August 30, 2017. We implemented the CPA on June 1, 2014. Outcomes included CPA use, use of TDM, dosage adjustments, and development of acute kidney injury; we compared courses given while monitoring only trough levels (TO-TDM) with those given while using the CPA (AUC-TDM). We performed interrupted time series analyses to account for preintervention trends.

RESULTS

We included 2379 courses in the TO-TDM period and 2155 in the AUC-TDM period. During AUC-TDM, 87% of the courses were managed by the CPA. In adjusted interrupted time series analyses, CPA implementation was associated with an initial change in level of -0.265 (95% confidence interval [CI], -0.336 to -0.189) TDM and an initial change in level of -0.332 (95% CI, -0.506 to -0.163) dosage adjustments. The 1-year risk of acute kidney injury decreased after CPA implementation (odds ratio, 0.695 [95% CI, 0.539-0.91]).

CONCLUSION

The pharmacy-driven vancomycin CPA resulted in less monitoring and fewer dose adjustments without increasing AKI.

Steady-state Pharmacokinetics of Vancomycin in Children Admitted to Pediatric Intensive Care Unit of a Tertiary Referral Center

Aims and objectives

Vancomycin is a drug of choice for various gram-positive bacterial (GPB) infections and is largely prescribed to pediatric intensive care unit (PICU) patients. Despite the different pathophysiology of these patients, limited data are available on pharmacokinetics of vancomycin. There are lack of data for critically ill Indian children; hence, study was conducted to assess the steady-state pharmacokinetics in children admitted to PICU.

Materials and methods

Twelve subjects (seven males, five females) aged 1–12 years were enrolled. Vancomycin (dose of 20 mg/kg per 8 hours) was infused for over 1 hour and steady-state pharmacokinetics was performed on day 3. Vancomycin concentrations were measured by the validated liquid chromatography mass spectrometry method. Pharmacokinetic parameters were calculated using Winnonlin (Version 6.3; Pharsight, St. Louis, MO).

Results

The steady-state mean C_ssmax was 40.94 μg/mL (±15.07), and mean AUC_{0–8 hours} was 124.15 μg/mL (±51.27). The mean t_1/2 was 4.82 hours (±2.71), Vd was 12.48 L (±4.43), and Cl was 2.08 mL/minute (±0.89). The mean AUC_0–24 among 12 subjects was 372.44 μg/mL (±153.82). Among 35 measured trough concentrations, 23 (65.71%) were below, 11 (31.43%) were within, and 1 (2.86%) was above the recommended range.

Conclusion

The pharmacokinetic parameters of vancomycin were comparable with previously reported studies. However, recommended trough levels (10–20 μg/mL) were not achievable with current recommended dosing of 60 mg/kg/day.

How to cite this article

Mali NB, Tullu MS, Wandalkar PP, Deshpande SP, Ingale VC, Deshmukh CT, et al. Steady-state Pharmacokinetics of Vancomycin in Children Admitted to Pediatric Intensive Care Unit of a Tertiary Referral Center. IJCCM 2019;23(11):497–502.

Early Bayesian Dose Adjustment of Vancomycin Continuous Infusion in Children: a Randomized Controlled Trial

Methicillin-resistant staphylococcal infections are a global burden. Area under the serum concentration-time curve to minimum inhibitory concentration (AUC/MIC) ratio is the pharmacokinetic (PK) parameter that best predicts vancomycin efficacy. Its therapeutic range is narrow, difficult to achieve because of a wide intersubject variability, especially in children, and is not routinely targeted since the AUC is rarely available. We investigated if an early Bayesian dose adjustment would increase the rate of vancomycin target attainment, in the first 24 hours of treatment (H24), in children.We conducted a single-centre randomized controlled trial in 4 pediatric departments of Necker-Enfants Malades hospital (Paris, France). Patients aged 3 months to 17 years for whom intravenous vancomycin was started were eligible and randomized in a 1:1 ratio: routine care were compared with an early vancomycin therapeutic drug monitoring (3h after treatment initiation) followed by an early Bayesian dose adjustment using a previously published population-based PK model that included age, bodyweight and serum creatinine as covariates. The primary outcome was the proportion of patients of each group achieving vancomycin therapeutic range at H24, defined by AUC_0-24/MIC≥400 and AUC_0-24 ≤800mg-h/L.Ninety-nine patients were enrolled: 49 were randomized to the Bayesian group and 50 to the control group. Modified intention-to-treat analysis included 82 patients: 85% of Bayesian group patients achieved H24 vancomycin target versus 57% of control group patients (p=0.007) with no difference regarding iatrogenic events. Early Bayesian dose adjustment increased the proportion of children achieving vancomycin target at H24, which may improve clinical outcomes of methicillin-resistant staphylococcal infections.

Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA) Infections in Children: a Reappraisal of Vancomycin

PURPOSE OF REVIEW

In the last 50 years, vancomycin has been the agent of choice to treat infections due to methicillin-resistant Staphylococcus aureus (MRSA). However, vancomycin treatment failure is not uncommon, even when MRSA strains are fully susceptible to vancomycin. Treatment with vancomycin requires careful monitoring of drug levels as there is a potential for nephrotoxicity. Resistance to clindamycin is not infrequent, which also limits therapeutic options for treating infections due to MRSA in children. This paper reviews the current data on pharmacokinetics and pharmacodynamics and clinical efficacy of vancomycin in children.

RECENT FINDINGS

Resistance to vancomycin in MRSA (MIC >2 mg/L) is infrequent; there is increasing evidence in the literature that vancomycin maybe ineffective against increasing proportion of isolates with MICs between 1 and 2 mg/L. Recent studies and meta-analyses have demonstrated that strains with high vancomycin MICs are associated with poor outcomes especially in patients with bacteremia and deep tissue infections due to MRSA. This gradual increase in vancomycin MIC has been reported as MIC creep or vancomycin heteroresistance. Patients infected with MRSA isolates that exhibit MIC creep experience poorer clinical outcomes, including delayed treatment response, increased mortality, increase rate of relapse, and extended hospitalization. There are limited data to guide vancomycin dosing in children with MRSA. Although the vancomycin area under the curve AUC₂₄/MIC ratio > 400 has been shown to predict clinical efficacy in adults, this relationship has not been documented very well for treatment outcomes in MRSA infections in children. Use of higher vancomycin dosages in attempts to achieve higher trough concentrations has been associated with increased nephrotoxicity. New recently approved antibiotics including ceftaroline, dalbavancin, and tedizolid offer a number of advantages over vancomycin to treat staphylococcal infections: improved antimicrobial activity, superior pharmacokinetics, pharmacodynamics, tolerability, and dosing, including once-daily and weekly regimens, and less need for monitoring drug levels.

Vancomycin-associated Nephrotoxicity and Risk Factors in Critically Ill Children Without Preexisting Renal Injury

BACKGROUND

A recent systematic review concluded that critically ill pediatric patients have higher odds of vancomycin-related nephrotoxicity [odds ratio (OR): 3.61, 95% CI: 1.21-10.74]. We aimed to assess the incidence and risk factors for vancomycin-associated nephrotoxicity in critically ill children without preexisting renal injury.

METHODS

A cohort of children admitted to a pediatric intensive care unit, from 2011 to 2016 treated with vancomycin without preexisting renal injury. The main diagnosis, therapeutic interventions and medications administered in this period were evaluated. Generalized estimating equation models were used to assess the association between clinical covariates and the dependent variable pediatric risk, injury, failure, loss, end-stage renal disease (pRIFLE).

RESULTS

Hundred ten patients, representing 1177 vancomycin days, were analyzed. Vancomycin-associated nephrotoxicity was seen in 11.8%. In a multivariate model, higher vancomycin doses were not associated with poorer renal function (P = 0.08). Higher serum vancomycin levels were weakly associated with pRIFLE classification (OR: 1.05, 95% CI: 1.02-1.07). Furosemide or amphotericin B in addition to the vancomycin treatment was associated with impaired renal function (OR: 2.56, 95% CI: 1.38-4.8 and OR: 7.7 95% CI: 2.55-23, respectively).

CONCLUSIONS

Vancomycin-associated nephrotoxicity in acute ill children without preexisting renal injury, measured with pRIFLE, is close to 11.8%. Furosemide and amphotericin B in addition to the vancomycin treatment are strong predictors of worse pRIFLE scores. The influence of acute kidney injury status at pediatric intensive care unit admission and the method used for renal function assessment might influence the incidence of vancomycin-associated nephrotoxicity and its associated risk factors.

Vancomycin Treatment Failure in Children With Methicillin-Resistant Staphylococcus aureus Bacteremia

OBJECTIVES

Limited data exist regarding clinical outcomes of invasive methicillin-resistant Staphylococcus aureus (MRSA) infections in children treated with vancomycin. Treatment success in adults correlates best with an area under the curve/minimum inhibitory concentration (AUC₂₄/MIC) ratio ≥400. It is unknown if this relationship is useful in children.

METHODS

Charts of children who received vancomycin ≥5 days for MRSA bacteremia with a steady state trough were reviewed. AUC₂₄/MIC ratios were estimated using 2 different vancomycin clearance equations. Vancomycin treatment failure was defined as persistent bacteremia ≥7 days, recurrent bacteremia within 30 days, or 30-day mortality.

RESULTS

There were 67 bacteremia episodes in 65 patients. Nine (13.4%) met failure criteria: persistent bacteremia (n = 6), recurrent bacteremia (n = 2), 30-day mortality (n = 1). There were no differences between patients receiving <60 mg/kg/day and ≥60 mg/kg/day of vancomycin in median trough (11.9 versus 12.3 mg/L, p = 0.1). Troughs did not correlate well with AUC₂₄/MIC ratios (R ² = 0.32 and 0.22). Patients receiving ≥60 mg/kg/day had greater probability of achieving ratios ≥400. There were no significant differences in median dose (p = 0.8), trough (p = 0.24), or AUC₂₄/MIC ratios (p = 0.07 and p = 0.6) between patients with treatment success and failure.

CONCLUSIONS

Treatment failure was lower than previously reported in children. AUC₂₄/MIC ratios ≥400 were frequently achieved but were not associated with treatment success, dose, or troughs. Prospective studies using standard definitions of vancomycin treatment failure are needed to understand treatment failure in children with MRSA bacteremia.

Vancomycin Therapeutic Regime Adjustment in Newborns and Infants with Bacterial Infection: Case Series

Background:

Vancomycin is used mostly to overcome infections caused by methicillinresistant microorganisms. There are no well-established administration protocols for neonates and infants, so the leak of a specific administration regime in that population may lead to serum concentrations beyond the specified range.

Objective:

This case series evaluated the pharmacokinetics adjustment from a vancomycin therapeutic regimen prescribed to neonates and infants with bacterial infection at a neonatal public hospital intensive- care-unit, with the primary purpose to verify cases of nephrotoxicity.

Methods:

Three neonates and four infants taking vancomycin therapy, hospitalized in a public hospital from November 2014 to March 2015, were included in the study. Vancomycin serum concentrations were determined by particle-enhanced-turbidimetric inhibition-immunoassay. The vancomycin concentrations were used for dose adjustment by USC*Pack-PC-Collection®, a non-parametric maximization program. The trough serum concentration range of 10 to 20mg.L-1 was considered therapeutic.

Results:

Three patients had serum concentration outside the reference-range, one with subtherapeutic, and two with supratherapeutic concentrations. All patients had concomitant use of drugs which interfered with vancomycin distribution and excretion pharmacokinetics parameters, including drugs that may enhance nephrotoxicity. One patient showed signs of acute renal damage, by low vancomycin and creatinine estimated clearances.

Conclusion:

The pharmacokinetic adjustment has been proven to be a useful and necessary tool to increase therapeutic efficacy and treatment benefits. The standard dose of vancomycin can be used to initiate therapy in neonates and infants admitted to the ICU, but after reaching the drug steady state, the dosing regimen should be individualized and guided by pharmacokinetic parameters.

The Relationship Between Vancomycin Trough Concentrations and AUC/MIC Ratios in Pediatric Patients: A Qualitative Systematic Review

BACKGROUND

In adults, the area under the concentration-time curve (AUC) divided by the minimum inhibitory concentration (MIC) is associated with better clinical and bacteriological response to vancomycin in patients with methicillin-resistant Staphylococcus aureus who achieve target AUC/MIC ≥ 400. This target is often extrapolated to pediatric patients despite the lack of similar evidence. The impracticalities of calculating the AUC in practice means vancomycin trough concentrations are used to predict the AUC/MIC.

OBJECTIVE

This review aimed to determine the relationship between vancomycin trough concentrations and AUC/MIC in pediatric patients.

METHODS

We searched the MEDLINE and Embase databases, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials using the medical subject heading (MeSH) terms vancomycin and AUC and pediatric* or paediatric*. Articles were included if they were published in English and reported a relationship between vancomycin trough concentrations and AUC/MIC.

RESULTS

Of 122 articles retrieved, 11 met the inclusion criteria. One trial reported a relationship between vancomycin trough concentrations, AUC/MIC, and clinical outcomes but was likely underpowered. Five studies found troughs 6-10 mg/l were sufficient to attain an AUC/MIC > 400 in most general hospitalized pediatric patients. One study in patients undergoing cardiothoracic surgery found a trough of 18.4 mg/l achieved an AUC/MIC > 400. Two oncology studies reported troughs ≥ 15 mg/l likely attained an AUC/MIC ≥ 400. In critical care patients: one study found a trough of 9 mg/l did not attain the AUC/MIC target; another found 7 mg/l corresponded to an AUC/MIC of 400.

CONCLUSIONS

Potential vancomycin targets varied based on the population studied but, for general hospitalized pediatric patients, troughs of 6-10 mg/l are likely sufficient to achieve AUC/MIC ≥ 400. For MIC ≥ 2 mg/l, higher troughs are likely necessary to achieve an AUC/MIC ≥ 400. More research is needed to determine the relationships between vancomycin trough concentrations, AUC/MIC, and clinical outcomes.

Continuous intravenous vancomycin in children with normal renal function hospitalized in hematology-oncology: prospective validation of a dosing regimen optimizing steady-state concentration

Continuous intravenous (IV) infusion has been shown to be the best option to administer vancomycin because of its time-dependent bactericidal activity. Available IV vancomycin dosing guidelines in pediatrics with normal renal function leads to less than 50% of patients achieving a vancomycin serum concentration (Css) in the target range (15-20 mg/L). The primary objective of this study was to prospectively validate an age-based dosing regimen in pediatric oncology-hematology. The secondary objective was to investigate the influence on Css attainment of different variables. A continuous IV dosing nomogram was built by retrospective study (2000-2010) on Bayesian dosing adjustments performed in 161 patients. This study assessed the prospective validation of this age-based nomogram and the influence on Css attainment of variables as the gender, underlying disease (oncology or hematology), and hematopoietic stem cell transplantation (HSCT) before receiving vancomycin therapy. A total of 94 patients aged from 4.3 months to 17.9 years old with normal renal function were eligible for the prospective validation. Fifty-five of those patients (58.5%) achieved the target range of vancomycin Css. There was no significant difference between age groups (P = 0.816) and no influence of gender (P = 0.500). There was a nonsignificant trend to a better target attainment in oncology patients (69.2% vs. hematology 54.4%, P = 0.142) and patients who did not undergo HSCT (63.3% vs. 33.3%, P = 0.031). This study proposed an age-based nomogram prospectively validated which near 60% of patients of each age class achieving the target range of Css.

The Impact of Pediatric-Specific Vancomycin Dosing Guidelines: A Quality Improvement Initiative

BACKGROUND AND OBJECTIVES

There are limited data guiding vancomycin dosing practices in the pediatric population to target the goal troughs recommended by national vancomycin guidelines. In this study, we sought to improve adherence to guideline trough targets through a quality improvement intervention.

METHODS

A retrospective analysis was first conducted to assess baseline performance. A multidisciplinary team then developed and implemented a standardized dosing algorithm recommending 15 mg/kg per dose for mild and moderate infections (goal trough: 10-15 µg/mL) and 20 mg/kg per dose for severe infections (goal trough: 15-20 µg/mL), both delivered every 6 hours (maximum single dose: 750 mg). The impact of the intervention was evaluated prospectively using standard statistics and quality improvement methodology. The outcome measures included the percentage of patients with an initial therapeutic trough and the time to therapeutic trough.

RESULTS

A total of 116 patients (49 preintervention, 67 postintervention) were included. Postintervention, there was a significant increase in the percentage of patients with an initial therapeutic trough (6.1% to 20.9%, P = .03) and in the percentage of patients with initial troughs between 10 and 20 µg/mL (8.2% to 40.3%, P < .001). The time to therapeutic trough decreased from 2.78 to 1.56 days (P = .001), with the process control chart showing improved control postintervention. Vancomycin-related toxicity was unchanged by the intervention (6.1% versus 4.5%; P = .70).

CONCLUSIONS

Using quality improvement methodology with standardized higher initial vancomycin doses, we demonstrated improved adherence to national trough guidelines without noted safety detriment.