Vancomycin therapeutic drug monitoring in paediatrics

Population pharmacokinetic analysis for dose regimen optimization of vancomycin in Southern Chinese children

Changes in physiological factors may result in large pharmacokinetic variability of vancomycin in pediatric patients, thereby leading to either supratherapeutic or subtherapeutic exposure and potentially affecting clinical outcomes. This study set out to characterize the disposition of vancomycin, quantify the exposure target and establish an optimal dosage regimen among the Southern Chinese pediatric population. Routine therapeutic drug monitoring data of 453 patients were available. We performed a retrospective population pharmacokinetic analysis of hospitalized children prescribed intravenous vancomycin using NONMEM® software. A one-compartment PPK model of vancomycin with body weight and renal functions as covariates based on a cutoff of 2 years old children was proposed in this study. Both internal and external validation showing acceptable and robust predictive performance of the model to estimate PK parameters. The value of area under the curve over 24 h to minimum inhibitory concentration ratio (AUC0-24/MIC) ≥ 260 was a significant predictor for therapeutic efficacy. Monte Carlo simulations served as a model-informed precision dosing approach and suggested that different optimal dose regimens in various scenarios should be considered rather than flat dosing. The evaluation of vancomycin exposure-efficacy relationship indicated that lower target level of AUC0-24/MIC may be needed to achieve clinical effectiveness in children, which was used to derive the recommended dosing regimen. Further prospective studies will be needed to corroborate and elucidate these results.

Vancomycin audit in the paediatric population: Patterns of use and appropriateness of therapeutic drug monitoring

AIMS

This study aims to investigate prescribing and therapeutic drug monitoring (TDM) practices for vancomycin in paediatrics at the Jordan University Hospital and to determine the impact of inaccuracies in TDM data on dosing decisions.

METHODS

Patterns of vancomycin prescriptions, appropriateness of vancomycin dosing, duration, TDM, and the accuracy of the recorded dosing/sampling times were determined prospectively based on prespecified criteria. Finally, Monte Carlo simulations were undertaken using the mrgsolve-package in R to assess the effect of inaccuracies in recording dosing/sampling times on subsequent dose adjustments.

RESULTS

Four hundred forty-two vancomycin courses were analysed. Vancomycin prescriptions were mainly empirical (77.4%). Initial vancomycin doses were appropriate in 73.1% of vancomycin courses. Prolonged use (>5 days) was found in 45.7% of admissions with negative cultures; this was related to the diagnosis of suspected sepsis unadjusted-OR: 1.8 (1.1-2.9). TDM was appropriately ordered in 90.7% of concentrations. Discrepancies between the recorded and actual times were noted in 83.9% and 82.7% of audited times of dose administration and sample collection, respectively. Based on simulations, these discrepancies were predicted to result in inappropriate dose adjustment in 37.9% of patients.

CONCLUSIONS

Inappropriate empirical and prolonged vancomycin use and inaccuracies in recording dosing/sampling times are important areas of improvement in the current clinical practice.

Vancomycin prescribing and therapeutic drug monitoring: Challenges of real clinical practice

BACKGROUND

Vancomycin prescription and monitoring guidelines have been reported to be poorly followed by various centers.

AIMS

Identifying barriers to compliance with vancomycin dosing and therapeutic drug monitoring guidelines (TDM) and possible ways to enhance compliance based on the healthcare providers' (HCPs) perspective.

METHODS

A qualitative study based on semi-structured interviews with HCP (physicians, pharmacists, and nurses) was conducted at two Jordanian Teaching Hospitals. Interviews were audio-recorded and analyzed through thematic analysis. The COREQ criteria for qualitative research were utilized to report the study findings.

RESULTS

A total of 34 HCPs were interviewed. HCP perceived several factors as barriers to guideline recommendation compliance. Such factors included negative perception towards prescription guidelines, lack of knowledge regarding TDM guidelines, the hierarchy of medication management, work pressure, and ineffective communication among healthcare providers. Potential strategies to optimize guidelines adaptation included providing HCPs with more training and decision support tools in addition to activating the role of clinical pharmacists.

CONCLUSIONS

The main barriers to guideline recommendations uptake were identified. Interventions should address those barriers related to the clinical environment, including enhancing interprofessional communication related to vancomycin prescription and TDM, reducing workload and providing support systems, promoting educational and training programs, in addition to adopting guidelines suitable for the local environment.

Optimal exposure targets for vancomycin in the treatment of neonatal coagulase-negative Staphylococcus infection: A retrospective study based on electronic medical records

BACKGROUND

The currently advocated ratio of area under the curve (AUC) over 24 h to minimum inhibitory concentration (AUC/MIC) > 400 and AUC < 600 mg h/L as the therapeutic drug monitoring (TDM) target of vancomycin is based on data from multiple observational studies in adult patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. It may not be applicable to newborns with coagulase-negative Staphylococcus (CoNS) infection. We conducted a retrospective study to identify the optimal exposure targets for vancomycin in the treatment of neonatal CoNS infection.

METHODS

Based on the inclusion and exclusion criteria, serum vancomycin concentration, demographics, clinical data, and related laboratory data of newborns who received vancomycin intravenous infusion from June 1, 2016 to February 1, 2021 were collected retrospectively. The AUC was calculated using the maximum a posteriori Bayesian (MAPB) method. The vancomycin exposure threshold of AUC/MIC for efficacy and AUC for toxicity (acute kidney injury, AKI) were determined based on receiver operating characteristic (ROC) curve analysis. The correlation between vancomycin exposure and both clinical effect and nephrotoxicity was analyzed using logistic multivariate regression.

RESULTS

In total, 153 patients and 245 vancomycin concentrations (160 trough and 85 peak concentrations) were included. The ROC curve analysis showed that the exposure thresholds of AUC/MIC for clinical efficacy and AUC for nephrotoxicity were 281 and 602 mg h/L, respectively. The multivariate regression analysis showed that AUC/MIC > 280 was a predictor of efficacy (OR: 13.960, 95% CI: 1.891-103.078, P < 0.05) and AUC > 600 mg h/L was associated with AKI (OR: 9.008, 95% CI: 2.706-29.983, P < 0.05). The vancomycin AUC/MIC threshold for treating neonatal CoNS infection with vancomycin is lower than the currently advocated AUC/MIC >400.

CONCLUSION

The optimal exposure targets for vancomycin in neonatal CoNS infection were AUC/MIC > 280 and AUC < 600 mg h/L.

Vancomycin in neonatal sepsis: predictive performance of a Chinese neonatal population pharmacokinetic model and clinical efficacy evaluation

BACKGROUND

In the neonatal population, individual calculation and adjustment of vancomycin (VCM) doses has been recommended based on population pharmacokinetics (PPK) methods.

OBJECTIVE

Our previous study established a Chinese neonatal VCM PPK model. The main goal of this study was to evaluate the predictive performance of this PPK model for VCM trough concentration.

METHODS

The data on neonatal severe infection patients treated with VCM were retrospectively collected. The predictive performance of this PPK model was expressed using mean prediction error (MPE), mean absolute prediction error (MAPE), sensitivity and specificity. Linear regression analysis was used to compare predicted and measured VCM concentrations. We drew the receiver operating characteristic (ROC) curve to evaluate the predictive efficacy of the ratio of area under the concentration-time curve over 24 hours to minimum inhibitory concentration (AUC_0-24/MIC) and trough concentration for clinical efficacy.

RESULTS

A total of 40 neonates with Gram-positive bacterial sepsis were included. After VCM treatment, 32 (80%) neonates were clinically cured. Eight cases were a clinical failure: the trough concentrations and AUC_0-24 were lower than that of the clinical cure patients (8.70±4.30 vs 14.30±4.50 mg/L, p=0.003; 404.30±122.80 vs 515.40±131.70, p=0.037). The measured and predicted trough concentration were 11.16 (5.96, 16.53) mg/L and 10.13 (6.61, 15.73) mg/L, respectively. The MPE and MAPE were 4.62% and 13.26% (5.30%, 25.88%), respectively. The proportion of MAPE <30% in the adjusted regimen was higher than the initial regimen (89.66% vs 65.00%, p=0.039). Predictions of sensitivity and specificity by this PPK model were 88.24% and 94.29%, respectively. The coefficients of determination of linear regression analysis were 0.9171 and 0.9009 for the initial and adjusted regimen, respectively. The AUC_0-24 was correlated with the trough concentration (r=0.587, p<0.001). The ROC curve indicated that the optimal cut-off points for predicting clinical efficacy were AUC_0-24/MIC >425.47 and trough concentration >9.45 mg/L.

CONCLUSION

This PPK model has good predictive performance in Chinese neonatal patients. Both AUC_0-24/MIC and trough concentration can predict the clinical efficacy of antibacterial treatment.

Clinical Application Value of Pharmacokinetic Parameters of Vancomycin in Children Treated in the Pediatric Intensive Care Unit

OBJECTIVE

To explore the efficacy and safety of vancomycin as measured by pharmacokinetic/pharmacodynamic parameters in children with severe infection in the Pediatric Intensive Care Unit (PICU) and to determine the appropriate threshold for avoiding nephrotoxicity.

METHODS

The medical records of hospitalized children with severe infection treated with vancomycin in the PICU of a tertiary pediatric hospital from September 2018 to January 2021 were retrospectively collected. Univariate analysis was used to assess the correlation between vancomycin pharmacokinetic/pharmacodynamic parameters and therapeutic efficacy or vancomycin-related nephrotoxicity. Binary logistic regression was used to analyze the risk factors for vancomycin-related nephrotoxicity. The vancomycin area under the concentration-time curve over 24 h (AUC_0-24) threshold was determined by receiver operating characteristic (ROC) curve analysis.

RESULTS

One hundred and 10 patients were included in this study. Seventy-six patients (69.1%) exhibited clinically effective response, while the rest exhibited clinically ineffective response. There were no significant differences in APACHE II score, steady-state trough concentration, peak concentration or AUC_0-24 of vancomycin between the effective and ineffective groups. Among the 110 patients, vancomycin-related nephrotoxicity occurred in 15 patients (13.6%). Multivariate analysis showed that vancomycin treatment duration, trough concentration, and AUC_0-24 were risk factors for vancomycin-related nephrotoxicity. The ROC curve indicated that AUC_0-24 < 537.18 mg.h/L was a suitable cutoff point for predicting vancomycin-related nephrotoxicity.

CONCLUSION

No significant correlations were found between the trough concentration or AUC_0-24 of vancomycin and therapeutic efficacy when the daily dose of vancomycin was approximately 40 mg/kg d, while the trough concentration and AUC_0-24 were both closely related to vancomycin-related nephrotoxicity. The combination of AUC_0-24 and trough concentration for therapeutic drug monitoring may reduce the risk of nephrotoxicity.

A Multicenter Retrospective Study of Vancomycin Dosing by Weight Measures in Children

OBJECTIVE

Vancomycin carries risks of treatment failure and emergent resistance with underexposure and renal toxicity with overexposure. Children with overweight or obesity may have altered pharmacokinetics. We aimed to examine how body weight metrics influence vancomycin serum concentrations and to evaluate alternative dosing strategies.

METHODS

This was a multicenter retrospective cohort study across 3 large, academic hospitals. Patients aged 2 to 18 years old who received ≥3 doses of intravenous vancomycin were included. Weight metrics included total body weight, adjusted body weight, ideal body weight, body surface area, and allometric weight. Outcomes included vancomycin concentration and ratios of area under the curve (AUC) to minimum inhibitory concentration (MIC). Regression analyses were used to examine which body-weight identifier predicted outcomes.

RESULTS

Of the 1099 children, 45% were girls, mean age was 9.0 (SD = 5.4) years, 14% had overweight, and 17% had obesity. Seventy-five percent of children had vancomycin concentrations in the subtherapeutic range by trough <10 µg/mL, and 63% had a ratio of AUC to MIC <400 μg-hr/mL. Three percent had a supratherapeutic initial trough >20 µg/mL or ratio of AUC to MIC >600 μg-hr/mL. Serum vancomycin concentrations were higher in children with overweight or obesity compared with children who were at a normal weight or underweight; the mean ratio of AUC to MIC also trended higher in the groups with overweight or obesity.

CONCLUSIONS

Most children received vancomycin regimens that produced suboptimal trough levels. Children with overweight or obesity experienced higher vancomycin trough levels than children of normal weight despite receiving lower total body weight dosing. Using the ratio of AUC to MIC was a better measure of drug exposure.

Vancomycin dosing and therapeutic drug monitoring practices: guidelines versus real-life

Background Correct dosing and therapeutic drug monitoring (TDM) practices are essential when aiming for optimal vancomycin treatment. Objective To assess target attainment after initial dosing and dose adjustments, and to determine compliance to dosing and TDM guidelines. Setting Tertiary care university hospital in Belgium. Method A chart review was performed in 150 patients, ranging from preterm infants to adults, treated intravenously with vancomycin. Patient characteristics, dosing and TDM data were compared to evidence-based hospital guidelines. Main outcome measures Target attainment of vancomycin after initial dosing and dose adjustments. Results Subtherapeutic concentrations were measured in 68% of adults, in 76% of children and in 52% of neonates after treatment initiation. Multiple dose adaptations (median 2, Q1 1-Q3 2) were required for target attainment, whilst more than 20% of children and neonates never reached targeted concentrations. Regarding compliance to the hospital guideline, some points of improvement were identified: omitted dose adjustment in adults with decreased renal function (53%), delayed sampling (16% in adults, 31% in children) and redundant sampling (34% of all samples in adults, 12% in children, 13% in neonates). Conclusion Target attainment for vancomycin with current dosing regimens and TDM is poor in all age groups. Besides, human factors should not be ignored when aiming for optimal treatment. This study reflects an ongoing challenge in clinical practice and highlights the need for optimization of vancomycin dosing strategies and improvement of awareness of all health care professionals involved.

Are vancomycin dosing guidelines followed? A mixed methods study of vancomycin prescribing practices

AIMS

Despite the availability of international consensus guidelines, vancomycin dosing and therapeutic drug monitoring (TDM) remain suboptimal. This study aimed to assess concordance of vancomycin dosing and TDM with institutional guidelines and to identify factors taken into consideration by clinicians when prescribing vancomycin.

METHODS

A retrospective audit of 163 patients receiving vancomycin therapy (≥48 hours) was undertaken. Data collected included patient characteristics, dosing history and plasma vancomycin and creatinine concentrations. Concordance of dosing and TDM with institutional guidelines was evaluated. Semi-structured interviews, including simulated prescribing scenarios, were undertaken with prescribers (n = 17) and transcripts analysed.

RESULTS

Plasma vancomycin concentrations (n = 1043) were collected during 179 courses of therapy. Only 24% of courses commenced with a loading dose with 72% lower than recommended. The initial maintenance dose was concordant in 42% of courses with 34% lower than recommended. Only 14% of TDM samples were trough vancomycin concentrations. Dose was not adjusted for 60% (21/35) of subtherapeutic and 43% (18/42) of supratherapeutic trough vancomycin concentrations, respectively. Interview participants reported that patient characteristics (including renal function), vancomycin concentrations, guidelines and expert advice influenced vancomycin prescribing decisions. Despite referring to guidelines when completing simulated prescribing scenarios, only 37% of prescribing decisions aligned with guideline recommendations.

CONCLUSION

Poor compliance with institutional vancomycin guidelines was observed, despite prescriber awareness of available guidelines. Multifaceted strategies to support prescriber decision-making are required to improve vancomycin dosing and monitoring.