Reduced Vancomycin Clearance Despite Unchanged Creatinine Clearance in Patients Treated With Vancomycin For Longer Than 4 Weeks

Pharmacokinetic variability of vancomycin in patients with nosocomial meningitis

WHAT IS KNOWN AND OBJECTIVE

High doses of vancomycin are required early in the treatment of nosocomial meningitis. However, the dosage is often reduced later during treatment, irrespective of renal function. This study was designed to investigate the pharmacokinetic variability of vancomycin and the associated factors throughout the treatment course for patients with nosocomial bacterial meningitis.

METHODS

This study included 17 patients who received vancomycin for nosocomial bacterial meningitis at the Tokyo Women's Medical University Yachiyo Medical Center from April 2013 to May 2020. All patients had their serum vancomycin concentrations and cerebrospinal fluid (CSF) parameters measured within 7 days of initiating treatment (early period) and after 8 days (later period) of treatment.

RESULTS AND DISCUSSION

The relative error between the predicted serum vancomycin concentration and the measured value was significantly higher in the later period than in the early period. In 13 patients who did not have their dosing interval shortened, the vancomycin dosage/serum vancomycin concentration/estimated glomerular filtration rate (D/C/eGFR) ratio significantly decreased in the later period. Moreover, the rate of change in the D/C/eGFR ratio significantly correlated with that in the CSF protein and C-reactive protein levels.

WHAT IS NEW AND CONCLUSION

This study suggests that the clinical condition and inflammatory response of a patient with meningitis influence the pharmacokinetics of vancomycin. Therefore, the vancomycin dosage for the treatment of nosocomial bacterial meningitis must be adjusted according to changes in the clinical condition and renal function of the patient, necessitating careful therapeutic drug monitoring.

Infective Endocarditis Following Chicken Pox: A Rare Association

A 38-year old immunocompetent male presented to us with chicken pox complicated by development of Guillain-Barre syndrome (GBS) and left-sided native valve endocarditis due to methicillin resistant Staphylococcus aureus (MRSA). This was further complicated by embolization to various vital organs including the brain. The patient was treated with vancomycin for four weeks but did not respond to the treatment. We present this case to highlight the rare complications associated with chicken pox and the challenges faced in management of such a case.

Time Course and Extent of Renal Function Changes in Patients Receiving Treatment for Staphylococcal Pneumonias: An Analysis Comparing Telavancin and Vancomycin from the ATTAIN Trials

STUDY OBJECTIVE

Telavancin and vancomycin are both approved for treatment of hospital-acquired and ventilator-associated bacterial pneumonias caused by Staphylococcus aureus, and both agents can cause renal dysfunction. The objective of this study was to assess renal function changes by performing renal shift table analyses of telavancin- and vancomycin-treated patients in phase III trials.

DESIGN

Retrospective, descriptive analysis of data from the safety population from the Assessment of Telavancin for Treatment of Hospital-Acquired Pneumonia (ATTAIN) trials.

PATIENTS

A total of 1503 adults with hospital-acquired or ventilator-associated bacterial pneumonia primarily caused by gram-positive pathogens and who received telavancin (n = 751) or vancomycin (n = 752).

MEASUREMENTS AND MAIN RESULTS

Decline or improvement in creatinine clearance (CrCl) across seven defined categories (≤30, >30-40, >40-50, >50-60, >60-70, >70-80, and >80 ml/min) was classified as negative or positive shifts, respectively. The number of categories crossed (either positive or negative) determined the grade of shift (of a potential grades 1-6, with crossing from one category to the next adjacent category defined as a grade 1 shift) at specific time points compared with baseline: day 4, day 7, and end of therapy (EOT). Approximately 77%-91.6% of patients had either no change or improvement of CrCl across all time points for both treatments. Negative shifts were consistent for telavancin (day 4, 19.3%; day 7, 19.0%; EOT, 23.0%) but increased over time for vancomycin (day 4, 8.4%; day 7, 12.3%; EOT, 19.3%). A significantly lower proportion of patients receiving vancomycin showed renal function decline on day 4 and day 7. At EOT, negative shift rates were similar between treatments (treatment difference 3.6% [95% CI -0.7 to 7.9]). At day 7 and EOT, a higher percentage of vancomycin-treated patients experienced high-grade negative shifts relative to telavancin (day 7, vancomycin 2.8% vs telavancin 1.9%; EOT, vancomycin 4.7% vs telavancin 4.1%), though differences were not statistically significant.

CONCLUSION

Use of shift tables revealed differences in timing of renal function changes in patients receiving telavancin and vancomycin. Telavancin-related declines in renal function were similar at day 4 and day 7, with a slight increase by EOT. This differed from vancomycin, which caused a steady increase in the percentage of patients with renal function decline over time. A significant difference in negative renal shifts between treatments occurred at day 4 and day 7 and favored vancomycin; however, the difference was minimal and not significant at EOT.

Vancomycin therapeutic drug monitoring and population pharmacokinetic models in special patient subpopulations

Vancomycin is a fundamental antibiotic in the management of severe Gram-positive infections. Inappropriate vancomycin dosing is associated with therapeutic failure, bacterial resistance and toxicity. Therapeutic drug monitoring (TDM) is acknowledged as an important part of the vancomycin therapy management, at least in specific patient subpopulations, but implementation in clinical practice has been difficult because there are no consensus and agglutinator documents. The aims of the present work are to present an overview of the current knowledge on vancomycin TDM and population pharmacokinetic (PPK) models relevant to specific patient subpopulations. Based on three published international guidelines (American, Japanese and Chinese) on vancomycin TDM and a bibliographic review on available PPK models for vancomycin in distinct subpopulations, an analysis of evidence was carried out and the current knowledge on this topic was summarized. The results of this work can be useful to redirect research efforts to address the detected knowledge gaps. Currently, TDM of vancomycin presents a moderate level of evidence and practical recommendations with great robustness in neonates, pediatric and patients with renal impairment. However, it is important to investigate in other subpopulations known to present altered vancomycin pharmacokinetics (eg neurosurgical, oncological and cystic fibrosis patients), where evidence is still unsufficient.

Vancomycin pharmacokinetic and pharmacodynamic models for critically ill patients with post-sternotomy mediastinitis

BACKGROUND AND OBJECTIVE

Vancomycin is commonly used to treat serious methicillin-resistant staphylococcal infections, especially post-sternotomy mediastinitis (PSM). However, information on pharmacokinetics and pharmacodynamics in intensive care unit (ICU) patients remains scarce. We conducted vancomycin pharmacokinetic-pharmacodynamic modeling for ICU patients with PSM.

METHODS

This cohort study included 30 consecutive patients who received multiple vancomycin doses during primary closed drainage of PSM with Redon catheters, targeting serum drug trough concentrations of 25-35 mg/L, and generating 359 serum vancomycin concentration-time values for analysis. Population pharmacodynamics served to describe the withdrawal of Redon catheters, i.e., the probability of in-ICU cure.

RESULTS

Vancomycin pharmacokinetics corresponded to a two-compartment open model with first-order elimination kinetics. Mean [between-subject variability] population estimates were 1.91 (men)/1.25 (women) [0.28] L/h for vancomycin elimination, with intercompartmental clearance of 5.71 [1.01] L/h, and respective central and peripheral distribution volumes of 21.9 and 68 [0.53] L. Vancomycin clearance increased with body weight and declined with severity at ICU admission and serum creatinine (SCr), thereby allowing the prediction of the vancomycin plateau. Intercompartmental clearance decreased with diabetes mellitus (-70 %). The probability of withdrawing all Redon catheters (patient cured) was dependent only on the area under the concentration-time curve to minimum inhibitory concentration (AUC/MIC) exposures ratio in plasma. Neither preoperative factors, antistaphylococcal co-treatments, nor the initial number of Redon catheters significantly influenced this probability. The AUC/MIC exposures ratio had no significant effect on SCr levels.

CONCLUSION

These modeling analysis results identified five clinically relevant covariates that influenced vancomycin pharmacokinetics and might achieve better individualization of vancomycin dosing for methicillin-resistant staphylococcal PSM in ICU patients.

Vancomycin-associated renal dysfunction: where are we now?

Vancomycin has been in clinical use for over 60 years, during which time renal toxicity has been well documented. Multiple risk factors and outcomes are associated with vancomycin-related nephrotoxicity. Risk factors include vancomycin exposure (trough levels 15 mg/L or higher, larger area under the curve, duration of therapy), host susceptibility to vancomycin (increased body weight, preexisting renal dysfunction, critical illness), and concurrent nephrotoxin therapy. Nephrotoxicity is associated with prolonged hospital stays, mortality, and the need for renal replacement therapy. To what degree vancomycin-associated nephrotoxicity exacerbates these adverse clinical outcomes remains unclear. This article reviews the current evidence on vancomycin-associated nephrotoxicity and explores future research directions with potential implications for improved patient safety.

Use of vancomycin pharmacokinetic-pharmacodynamic properties in the treatment of MRSA infections

Vancomycin is a commonly used antimicrobial in patients with methicillin-resistant Staphylococcus aureus (MRSA) infections. Increasing vancomycin MIC values in MRSA clinical isolates makes the optimization of vancomycin dosing pivotal to its continued use. Unfortunately, limited data exist regarding the optimal pharmacokinetic-pharmacodynamic (PK-PD) goal to improve bacterial killing and clinical outcomes with vancomycin. The hallmark study in this area suggests that achieving an AUC to MIC ratio of over 400 improves the likelihood of achieving these outcomes. Challenges in the implementation of PK-PD-based dosing for vancomycin include current methodologies utilized in microbiology laboratories, as well as intra- and interpatient pharmacokinetic variability. Individualized dosing based on MIC and specific patient factors is important to achieve optimal outcomes from vancomycin therapy.

Evaluation of glycopeptide prescription and therapeutic drug monitoring at a university hospital

The aim of this study was to assess the appropriateness of glycopeptide prescription almost 15 y after the publication of the Hospital Infection Control Practices Advisory Committee (HICPAC) guidelines. We also assessed the adequacy of dose regimen and therapeutic drug monitoring (TDM). All glycopeptide prescriptions were collected during a 3-month prospective study and evaluated by 2 independent infectious diseases experts. Appropriateness of prescription was assessed according to local guidelines based on the HICPAC recommendations. A total of 154 prescriptions were evaluated: 77% (69.1-83.0) were appropriate and 36% (28.2-43.8) were adequate with regard to dose regimen and loading dose. Multivariate analysis showed greater appropriateness for vancomycin than for teicoplanin (p=0.01). There was a wide discrepancy among units (p=0.04). TDM was appropriately performed in 40% (32.3-47.7) of glycopeptide treatments. When required, dose regimen adaptations occurred in 58% of cases. In conclusion, we show a satisfactory appropriateness of glycopeptide prescription. However, the adequacy of dose regimens must be improved. Finally, TDM does not comply with recent recommendations in most cases.