High dose vancomycin for osteomyelitis: continuous vs. intermittent infusion

Determining steady-state trough range in vancomycin drug dosing using machine learning

BACKGROUND

Vancomycin is a renally eliminated, nephrotoxic, glycopeptide antibiotic with a narrow therapeutic window, widely used in intensive care units (ICU). We aimed to predict the risk of inappropriate vancomycin trough levels and appropriate dosing for each ICU patient.

METHODS

Observed vancomycin trough levels were categorized into sub-therapeutic, therapeutic, and supra-therapeutic levels to train and compare different classification models. We included adult ICU patients (≥ 18 years) with at least one vancomycin concentration measurement during hospitalization at Mayo Clinic, Rochester, MN, from January 2007 to December 2017.

RESULT

The final cohort consisted of 5337 vancomycin courses. The XGBoost models outperformed other machine learning models with the AUC-ROC of 0.85 and 0.83, specificity of 53% and 47%, and sensitivity of 94% and 94% for sub- and supra-therapeutic categories, respectively. Kinetic estimated glomerular filtration rate and other creatinine-based measurements, vancomycin regimen (dose and interval), comorbidities, body mass index, age, sex, and blood pressure were among the most important variables in the models.

CONCLUSION

We developed models to assess the risk of sub- and supra-therapeutic vancomycin trough levels to improve the accuracy of drug dosing in critically ill patients.

Is It Still Beneficial to Monitor the Trough Concentration of Vancomycin? A Quantitative Meta-Analysis of Nephrotoxicity and Efficacy

This study conducted a quantitative meta-analysis to investigate the association of vancomycin indicators, particularly area under the curve over 24 h (AUC24) and trough concentrations (Ctrough), and their relationship with both nephrotoxicity and efficacy. Literature research was performed in PubMed and Web of Science on vancomycin nephrotoxicity and efficacy in adult inpatients. Vancomycin Ctrough, AUC24, AUC24/minimum inhibitory concentration (MIC), nephrotoxicity evaluation and treatment outcomes were extracted. Logistic regression and Emax models were conducted, stratified by evaluation criterion for nephrotoxicity and primary outcomes for efficacy. Among 100 publications on nephrotoxicity, 29 focused on AUC24 and 97 on Ctrough, while of 74 publications on efficacy, 27 reported AUC24/MIC and 68 reported Ctrough. The logistic regression analysis indicated a significant association between nephrotoxicity and vancomycin Ctrough (odds ratio = 2.193; 95% CI 1.582-3.442, p < 0.001). The receiver operating characteristic curve had an area of 0.90, with a cut-off point of 14.55 mg/L. Additionally, 92.3% of the groups with a mean AUC24 within 400-600 mg·h/L showed a mean Ctrough of 10-20 mg/L. However, a subtle, non-statistically significant association was observed between the AUC24 and nephrotoxicity, as well as between AUC24/MIC and Ctrough concerning treatment outcomes. Our findings suggest that monitoring vancomycin Ctrough remains a beneficial and valuable approach to proactively identifying patients at risk of nephrotoxicity, particularly when Ctrough exceeds 15 mg/L. Ctrough can serve as a surrogate for AUC24 to some extent. However, no definitive cut-off values were identified for AUC24 concerning nephrotoxicity or for Ctrough and AUC24/MIC regarding efficacy.

Patient safety outcomes for continuous infusion vancomycin as outpatient parenteral antimicrobial therapy

BACKGROUND

Administration of vancomycin as a continuous infusion has been associated with reduced nephrotoxicity. Given limited published experience with continuous infusion vancomycin in outpatient parenteral antimicrobial therapy (OPAT) programs, we reviewed outcomes from our center.

METHODS

This was a retrospective, single-center study of adult patients receiving vancomycin OPAT as continuous or intermittent infusion for an intended treatment duration of at least 7 days. The primary outcome was time to nephrotoxicity with continuous versus intermittent infusion vancomycin while on OPAT; additional outcomes included time to any vancomycin-associated adverse event, time to 60-day death or readmission, and time to 60-day emergency department encounter. Proportional hazards modeling was used to identify variables independently associated with outcomes, as well as assess the strength of association of continuous infusion with each outcome.

RESULTS

Four-hundred ninety-two patients were included: 118 treated with continuous and 374 with intermittent vancomycin infusion. Continuous infusion was not associated with lower rates of nephrotoxicity compared to intermittent infusion (adjusted hazard ratio (aHR) 0.72, 95% CI: 0.35-1.50). There were no advantages of continuous over intermittent infusion in the rates of any adverse event (aHR 0.93, 95% CI: 0.56-1.53), 60-day death or readmission (aHR 1.04, 95% CI: 0.68-1.61), or 60-day emergency department encounter (aHR 1.17, 95% CI: 0.68-1.99). Vancomycin area under the concentration-time curve (AUC) at discharge was the only modifiable factor identified that was independently associated with patient safety outcomes.

CONCLUSION

There was no appreciable benefit of continuous infusion vancomycin on outpatient safety outcomes. AUC-centered dosing approaches warrant further investigation as strategies to improve vancomycin safety in OPAT programs.

A review of evidence, antimicrobial stability, and feasibility considerations for OPAT continuous infusion

Outpatient parenteral antimicrobial therapy (OPAT) has been widely used in clinical practice for many decades because of its associated cost savings, reductions in inpatient hospital days, and decreases in hospital-associated infections. Despite this long history, evolving practice patterns and new drug delivery devices continue to present challenges as well as opportunities for clinicians when designing appropriate outpatient antimicrobial regimens. One such change is the increasing use of extended and continuous infusion (CI) of antimicrobials to optimize the achievement of pharmacokinetic and pharmacodynamic targets. Elastomeric devices are also becoming increasingly popular in OPAT, including for the delivery of CI. In this article, we review the clinical evidence for CI in OPAT, as well as practical considerations of patient preferences, cost, and antimicrobial stability.

Pharmacokinetic/Pharmacodynamic Target Attainment of Vancomycin, at Three Reported Infusion Modes, for Methicillin-Resistant Staphylococcus aureus (MRSA) Bloodstream Infections in Critically Ill Patients: Focus on Novel Infusion Mode

Objective

The study aimed to evaluate and compare the pharmacokinetic/pharmacodynamic (PK/PD) exposure to vancomycin in the novel optimal two-step infusion (OTSI) vs. intermittent infusion (II) vs. continuous infusion (CI) mode, for MRSA bloodstream infections occurring in critical patients.

Methods

With PK/PD modeling and Monte Carlo simulations, the PK/PD exposure of 15 OTSI, 13 II, and 6 CI regimens for vancomycin, at 1, 2, 3, 4, 5, and 6 g daily dose, was evaluated. Using the Monte Carlo simulations, the vancomycin population PK parameters derived from critical patients, the PD parameter for MRSA isolates [i.e., minimum inhibitory concentration (MIC)], and the dosing parameters of these regimens were integrated into a robust mdel of vancomycin PK/PD index, defined as a ratio of the daily area under the curve (AUC0–24) to MIC (i.e., AUC0–24/MIC), to estimate the probability of target attainment (PTA) of these regimens against MRSA isolates with an MIC of 0.5, 1, 2, 4, and 8 mg/L in patients with varying renal function. The PTA at an AUC0–24/MIC ratio of &gt;400, 400–600, and &gt;600 was estimated. A regimen with a PTA of ≥90% at an AUC0–24/MIC ratio of 400–600, which is supposed to maximize both efficacy and safety, was considered optimal.

Results

At the same daily dose, almost only the OTSI regimens showed a PTA of ≥90% at an AUC0–24/MIC ratio of 400–600, and this profile seems evident especially in patients with creatinine clearance (CLcr) of ≥60 ml/min and for isolates with an MIC of ≤2 mg/L. However, for patients with CLcr of &lt;60 ml/min and for isolates with an MIC of ≥4 mg/L, the II regimens often displayed a higher or even ≥90% PTA at an AUC0–24/MIC ratio of &gt;400 and of &gt;600. The CI regimens frequently afforded a reduced PTA at an AUC0–24/MIC ratio of &gt;400 and of &gt;600, regardless of CLcr and MIC.

Conclusions

The data indicated that the OTSI regimens allowed preferred PK/PD exposure in terms of both efficacy and safety, and thus should be focused more on, especially in patients with CLcr of ≥60 ml/min and for isolates with an MIC of ≤2 mg/L.

When There Is No Trough: Use and Outcomes of Continuous-Infusion Vancomycin at a Free-Standing Children's Hospital

OBJECTIVE

There is minimal published literature regarding the use of continuous-infusion vancomycin (CIV) in children. The objective of this study was to describe the use, dosing requirements, and outcomes of CIV at a free-standing children's hospital.

METHODS

This is a retrospective review of patients who received CIV while admitted to Nationwide Children's Hospital between July 1, 2010, and June 30, 2020. The total daily dose (TDD) of vancomycin required to attain a target serum vancomycin concentration (SVC) was compared between CIV and intermittent-infusion vancomycin (IIV) administration regimens. Safety outcomes and treatment failure were also explored.

RESULTS

Fourteen patients (77% male) with a median age of 7 years (IQR = 1, 10 years) were included. Most patients (71%) were started on CIV in anticipation of outpatient parenteral antimicrobial therapy. The median TDD required to achieve a target SVC was higher with IIV compared with CIV (82.4 mg/kg/day vs 50.5 mg/kg/day; p = 0.02). Despite higher TDD with IIV, median SVC with IIV was similar to SVC with CIV (16.6 mg/L vs 17.6 mg/L; p = 2.00). There were no safety concerns or therapeutic failures identified with CIV.

CONCLUSIONS

Continuous-infusion vancomycin was a well-tolerated and effective alternative to IIV for the patients included in this study. The TDD of vancomycin required to achieve a target SVC was lower in patients receiving CIV compared with those receiving IIV.

A Systematic Review on Clinical Safety and Efficacy of Vancomycin Loading Dose in Critically Ill Patients

Background: The clinical significance of utilizing a vancomycin loading dose in critically ill patients remains unclear. Objective: The main aim of this systematic review is to evaluate the clinical safety and efficacy of the vancomycin loading dose in critically ill patients. Methods: We performed a systematic review using PRISMA guidelines. PubMed, the Web of Science, MEDLINE, Scopus, Google Scholar, the Saudi Digital Library and other databases were searched. Studies that reported clinical outcomes among patients receiving the vancomycin LD were considered eligible. Data for this study were collected using PubMed, the Web of Science, MEDLINE, Scopus, Google Scholar and the Saudi Digital Library using the following terms: “vancomycin”, “safety”, “efficacy” and “loading dose” combined with the Boolean operator “AND” or “OR”. Results: A total of 17 articles, including 2 RCTs, 11 retrospective cohorts and 4 other studies, met the inclusion/exclusion criteria out of a total 1189 studies. Patients had different clinical characteristics representing a heterogenous group, including patients in critical condition, with renal impairment, sepsis, MRSA infection and hospitalized patients for hemodialysis or in the emergency department. Conclusions: The study shows that the target therapeutic level is achieved more easily among patients receiving a weight-based LD as compared to patients received the usual dose without an increased risk of new-onset adverse drug reactions.

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

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

The impact of early target attainment of vancomycin in critically ill patients with confirmed Gram-positive infection: A retrospective cohort study

BACKGROUND

Vancomycin is a commonly used antibiotic in critically ill patients for various indications. Critical illness imposes pharmacokinetic-pharmacodynamics challenges, which makes optimizing vancomycin in this population cumbersome. Data are scarce on the clinical impact of time to therapeutic trough levels of vancomycin in critically ill patients.  This study aims to evaluate the timing to achieve therapeutic trough level of vancomycin on 30-day mortality in critically ill patients.

METHOD

A retrospective cohort study was conducted for all adult critically ill patients with confirmed Gram-positive infection who received IV vancomycin between January 1, 2017, and December 31, 2020. We compared early (< 48 h) versus late (≥ 48 h) attainment of vancomycin therapeutic trough levels. The primary outcome was the 30-day mortality in critically ill patients. Secondary outcomes were the development of resistant organisms, microorganisms eradication within 4-5 days of vancomycin initiation, acute kidney injury (AKI), and length of stay (LOS). Propensity score-matched (1:1 ratio) used based on patient's age, serum creatinine, and albumin values at baseline.

RESULTS

A total of 326 patients were included; 110 patients attained the therapeutic trough levels within 48 h of vancomycin initiation. Late achievement of the therapeutic trough levels was associated with higher 30-day mortality (HR: 2.54; 95% CI [1.24-5.22]; p = 0.01). Additionally, patients who achieved therapeutic trough levels of vancomycin late were more likely to develop AKI (OR = 2.59; 95% CI [1.01-6.65]; p = 0.04). Other outcomes were not statistically significant between the two groups.

CONCLUSION

Early achievement of vancomycin therapeutic levels in patients with confirmed Gram-positive infection was associated with possible survival benefits.

Retrospective multicentre matched cohort study comparing safety and efficacy outcomes of intermittent-infusion versus continuous-infusion vancomycin

BACKGROUND

Patients with good renal function receiving intermittent-infusion vancomycin (IIV) may require total daily doses ≥4 g to achieve trough concentrations of 15-20 mg/L, increasing the risk of vancomycin-associated nephrotoxicity. Continuous-infusion vancomycin (CIV) may be associated with a lower risk of vancomycin-associated nephrotoxicity compared with IIV, but studies comparing safety of both dosing strategies are lacking.

OBJECTIVES

To compare the risk of nephrotoxicity with CIV versus IIV when target concentration ranges were the same with both dosing modalities.

METHODS

A retrospective multicentre matched cohort study of admitted patients between 1 January 2010 and 31 December 2016 was completed. Adult patients who received ≥48 h of vancomycin with at least one steady-state vancomycin concentration were eligible. The primary outcome was to compare the rates of nephrotoxic risk and renal injury, defined by the RIFLE criteria, between CIV and IIV.

RESULTS

Of 2136 patients who received vancomycin during the study period, 146 CIV patients were eligible and matched to 146 IIV patients. After adjustment of potential confounders, CIV was found to have a lower odds of developing nephrotoxic risk (OR 0.42, 95% CI 0.21-0.98, P = 0.025) and renal injury (OR 0.19, 95% CI 0.05-0.59, P = 0.004).

CONCLUSIONS

CIV is associated with a lower odds of nephrotoxicity compared with IIV when targeting the same concentration range and should be an alternative dosing strategy for patients who will receive prolonged therapy or require >4 g/day to achieve therapeutic levels.

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.

Prolonged versus intermittent β-lactam antibiotics intravenous infusion strategy in sepsis or septic shock patients: a systematic review with meta-analysis and trial sequential analysis of randomized trials

Background

The prolonged β-lactam infusion strategy has emerged as the standard treatment for sepsis or septic shock despite its unknown efficacy. This study aimed to assess the efficacy of prolonged versus intermittent β-lactam antibiotics infusion on outcomes in sepsis or septic shock patients by conducting a systematic review and meta-analysis.

Methods

A thorough search was conducted on MEDLINE, the Cochrane Central Register of Controlled Trials, and the Igaku Chuo Zasshi databases. Randomized controlled trials (RCTs) comparing mortality between prolonged and intermittent infusion in adult patients with sepsis or septic shock were included. The primary outcome was hospital mortality. The secondary outcomes were the attainment of the target plasma concentration, clinical cure, adverse events, and occurrence of antibiotic-resistant bacteria. We performed a subgroup analysis stratified according to the year of publication before or after 2015 and a trial sequential analysis (TSA). The Der Simonian–Laird random-effects models were subsequently used to report the pooled risk ratios (RR) with confidence intervals (CI).

Results

We identified 2869 studies from the 3 databases, and 13 studies were included in the meta-analysis. Hospital mortality did not decrease (RR 0.69 [95%CI 0.47–1.02]) in the prolonged infusion group. The attainment of the target plasma concentration and clinical cure significantly improved (RR 0.40 [95%CI 0.21–0.75] and RR 0.84 [95%CI 0.73–0.97], respectively) in the prolonged infusion group. There were, however, no significant differences in the adverse events and the occurrence of antibiotic-resistant bacteria between the groups (RR 1.01 (95%CI 0.95–1.06) and RR 0.53 [95%CI 0.10–2.83], respectively). For the subgroup analysis, a significant improvement in hospital mortality or clinical cure was reported in studies published in or after 2015 (RR 0.66 [95%CI 0.44–0.98] and RR 0.67 [95%CI 0.50–0.90], respectively). The results of the TSA indicated an insufficient number of studies for a definitive analysis.

Conclusions

The prolonged infusion of β-lactam antibiotics significantly improved upon attaining the target plasma concentration and clinical cure without increasing the adverse event or the occurrence of antibiotic-resistant bacteria. Prolonged infusion could not improve hospital mortality although an improvement was shown for studies published in or after 2015. Further studies are warranted as suggested by our TSA results.

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.

Minocycline Combined with Vancomycin for the Treatment of Methicillin-Resistant Coagulase-Negative Staphylococcal Prosthetic Joint Infection Managed with Exchange Arthroplasty

Introduction: Treatment of methicillin-resistant (MR) staphylococcal prosthetic joint infections (PJIs) remains a matter of discussion, with vancomycin-rifampin combination therapy being the preferred treatment for DAIR and one-stage exchange arthroplasty strategies. This study analyzes the outcomes of patients with chronic methicillin-resistant coagulase-negative staphylococcal PJIs treated with vancomycin-minocycline combination therapy.

Methods: This prospective, single center cohort study included all chronic MR coagulase-negative staphylococcal PJIs (01/2004-12/2014) treated with exchange arthroplasty and at least 4 weeks of minocycline-vancomycin. The following endpoints were considered: reinfection including relapse (same microorganism) and a new infection (different microorganism) and PJI-related deaths. Their outcomes were compared with PJIs treated with rifampin-vancomycin during the same period.

Results: Thirty-four patients (median age, 69 years) with 22 hip and 12 knee arthroplasty infections were included. Sixteen (47%) had previously been managed in another center. Median vancomycin MIC of strains was 3 mg/L. Nineteen underwent one-stage, 15 two-stage exchange arthroplasty. After a median [IQR] follow-up of 43 [26-68] months, 2 patients relapsed and 6 developed a new PJI. Compared to 36 rifampin-vancomycin treated PJIs, relapse- or reinfection-free survival rates didn't differ, but more new infections developed in the minocycline group (6 vs 3; P 0.3).

Conclusions: Minocycline-vancomycin combination therapy for chronic MR coagulase-negative staphylococcal PJIs seems to be an interesting therapeutic alternative.

Clinical and Pharmacokinetic Outcomes of Peak-Trough-Based Versus Trough-Based Vancomycin Therapeutic Drug Monitoring Approaches: A Pragmatic Randomized Controlled Trial

Background

Vancomycin therapeutic drug monitoring (TDM) is based on achieving 24-h area under the concentration–time curve to minimum inhibitory concentration cure breakpoints (AUC₂₄/MIC). Approaches to vancomycin TDM vary, with no head-to-head randomized controlled trial (RCT) comparisons to date.

Objectives

We aimed to compare clinical and pharmacokinetic outcomes between peak–trough-based and trough-only-based vancomycin TDM approaches and to determine the relationship between vancomycin AUC₂₄/MIC and cure rates.

Methods

A multicentered pragmatic parallel-group RCT was conducted in Hamad Medical Corporation hospitals in Qatar. Adult non-dialysis patients initiated on vancomycin were randomized to peak–trough-based or trough-only-based vancomycin TDM. Primary endpoints included vancomycin AUC₂₄/MIC ratio breakpoint for cure and clinical effectiveness (therapeutic cure vs therapeutic failure). Descriptive, inferential, and classification and regression tree (CART) statistical analyses were applied. NONMEM.v.7.3 was used to conduct population pharmacokinetic analyses and AUC₂₄ calculations.

Results

Sixty-five patients were enrolled [trough-only-based-TDM (n = 35) and peak–trough-based-TDM (n = 30)]. Peak–trough-based TDM was significantly associated with higher therapeutic cure rates compared to trough-only-based TDM [76.7% vs 48.6%; p value = 0.02]. No statistically significant differences were observed for all-cause mortality, neutropenia, or nephrotoxicity between the two groups. Compared to trough-only-based TDM, peak–trough-based TDM was associated with less vancomycin total daily doses by 12.05 mg/kg/day (p value = 0.027). CART identified creatinine clearance (CL_CR), AUC₂₄/MIC, and TDM approach as significant determinants of therapeutic outcomes. All patients [n = 19,100%] with CL_CR ≤ 7.85 L/h, AUC₂₄/MIC ≤ 1256, who received peak–trough-based TDM achieved therapeutic cure. AUC₂₄/MIC > 565 was identified to be correlated with cure in trough-only-based TDM recipients [n = 11,84.6%]. No minimum AUC₂₄/MIC breakpoint was detected by CART in the peak–trough-based group.

Conclusion

Maintenance of target vancomycin exposures and implementation of peak–trough-based vancomycin TDM may improve vancomycin-associated cure rates. Larger scale RCTs are warranted to confirm these findings.

The clinical efficacy and safety of vancomycin loading dose: A systematic review and meta-analysis

BACKGROUND

The clinical significance of using vancomycin loading dose remains controversial. A systematic review and meta-analysis were performed to assess the clinical efficacy and safety of vancomycin loading dose in the treatment of infections.

METHODS

The Pubmed, Embase, Web of Science, and Cochrane Library databases were searched from their inception up to 5 May 2019. Randomized controlled trials (RCTs) and other observational studies were included if they provided clinical outcomes or trough concentrations of vancomycin loading dose (20-30 mg/kg) and conventional-dose (10-20 mg/kg) in the treatment of infections. Achievement of therapeutic concentration (serum trough concentrations of vancomycin reached 15-20 mg/L before the second dose), clinical response (clinical improvement or culture-negative), nephrotoxicity (serum creatinine increase ≥0.5 mg/dL or ≥50% increasing from the baseline), other adverse events (including pruritus, flushing, rash, and/or red man syndrome), and mortality were analyzed. Heterogeneity was identified using the Cochrane I statistic, and P-value <.10 or I-values >50% indicated significant heterogeneity. Pooled estimates of the intervention effects were determined by the odds ratios (ORs) and 95% confidence intervals (CIs) in Review Manager program, version 5.3.5.

RESULTS

Two RCTs and 7 cohort studies including 2816 infected patients were selected for the analysis, in which serum trough concentrations of vancomycin following the use of vancomycin loading dose or other outcomes were available. Loading dose group had a significantly higher compliance rate of serum trough concentration of 15 to 20 mg/L (OR = 3.06; 95% CI = 1.15-8.15; P = .03) and significantly lower incidence of nephrotoxicity (OR = 0.59, 95% CI = 0.40-0.87; P = .008; I = 29%) compared with control group. No significant difference was noted between loading dose group and control group in terms of other adverse events and clinical response (OR = 1.98, 95% CI = 0.80-4.93; P = .14; I = 0%). The use of vancomycin loading doses in patients can indeed increase the achievement of therapeutic concentration.

CONCLUSION

Vancomycin loading dose increases the achievement of therapeutic concentration without bringing extra risk of nephrotoxicity. However, well-designed large-scale RCTs remain needed to validate the clinical efficacy of vancomycin loading dose and to further evaluate other adverse reactions and mortality.PROSPERO registration number CRD42018093927.

Vancomycin dose optimisation comparing a pharmacokinetic/pharmacodynamic model versus the pharmacokinetic model

Objectives

To compare vancomycin dosage adjustment by evaluating trough concentrations (Ctrough) of vancomycin and its pharmacokinetic/pharmacodynamic (PK/PD) correlation (AUC/MIC ≥400).

Methods

A retrospective study of 52 adult haematological patients and 29 ICU patients was carried out. Dosage adjustment was performed in routine clinical practice with Ctrough​​ and then compared using a PK/PD model. The probability of achieving the PK/PD target associated with the success of antimicrobial therapy was evaluated. When the susceptibility of the organism responsible for infection is not known, Monte Carlo simulation calculates the cumulative fraction of response (CFR) from the distribution of MIC values. Values of CFR >90% represent an optimal achieved regimen against a population of microorganisms.

Results

According to dosage adjustment performed ​​with Ctrough, in haematological patients the dose of vancomycin was increased in 65.4% compared with an increase in 53.8% of patients with the PK/PD model. No dose adjustment was needed in 21.1% of patients using Ctrough compared with 7.7% with the PK/PD model and in 13.5% of patients using Ctrough determination and in 38.5% of patients with the PK/PD model the dose was reduced. For ICU patients the dosage adjustment made ​​with Ctrough resulted in an increased dose of vancomycin in 79.4% of patients compared with 41.4% with the PK/PD model. No dose adjustment was needed in 3.4% of patients using Ctrough in comparison with 13.8% with the PK/PD model, and the dose was reduced in 17.2% of patients using Ctrough determination and in 44.8% with the PK/PD model.

Conclusions

Data for bacterial susceptibility combined with measured data for antibiotic concentrations using a PK/PD model predict and improve the dosage adjustment for individual patients. A larger study with more complete datasets are needed for validation before it can be fully introduced into clinical practice.

Experience with Continuous Infusion Vancomycin Dosing in a Large Pediatric Hospital

BACKGROUND

There is a paucity of data on dosing of continuous infusion of vancomycin (CIV) in pediatric patients, despite it being an attractive treatment option for limiting escalating doses of intermittent infusion of vancomycin. The purpose of this study was to determine the total daily dose of CIV required to attain therapeutic serum vancomycin concentrations (SVCs) in pediatric patients according to age (≥31 days to <2 years, 2 to <8 years, and 8 to <18 years).

METHODS

We retrospectively evaluated patients who were transitioned from intermittent infusion of vancomycin to CIV between January 2013 and December 2016. Demographic data, vancomycin data (indication, dosing, steady-state SVCs, and time to reach goal SVC), and adverse-effect data (infusion reactions and serum creatinine level) were collected.

RESULTS

Of the 240 patients included, 76 had a goal SVC of 10 to 15 µg/mL and 164 had a goal of 15 to 20 µg/mL. The dose of CIV required to reach an SVC of 10 to 15 µg/mL in the youngest age group was 48.4 mg/kg per day versus 45.6 and 39.4 mg/kg per day in the older age groups (P < .005). The 2 younger age groups of patients with a goal SVC of 15 to 20 µg/mL required 50.2 and 50.6 mg/kg per day, respectively, whereas patients aged ≥8 years required 44.7 mg/kg per day (P = .008). One patient experienced renal injury, and 1 experienced renal failure.

CONCLUSIONS

CIV is an effective method for attaining a therapeutic SVC in pediatric patients. Patients <8 years of age require higher dosing than older pediatric patients to reach the goal SVCs of 10 to 15 and 15 to 20 µg/mL.

Vancomycin Dosing and Monitoring: Critical Evaluation of the Current Practice

After more than six decades of its use as the mainstay antibiotic for the treatment of multidrug-resistant Gram-positive bacterial infections, dosing and monitoring of vancomycin therapy have not been optimized. The current vancomycin therapeutic guidelines recommend empiric doses of 15-20 mg/kg administered by intermittent infusion every 8-12 h in patients with normal kidney function. Additionally, the guidelines recommend trough concentration of 15-20 mg/L as a therapeutic goal for adult patients with severe infections. This review critically discusses the current guidelines considering the basic pharmacokinetics and pharmacodynamics of vancomycin and the recent published reports from clinical studies. More in-depth discussion will be focused on (1) providing evidence of advantages of administering vancomycin by continuous infusion compared to intermittent infusion; (2) revising the current practice of trough-only monitoring versus the area under concentration-time curve (AUC); and (3) assessing the current practice of weight-based dosing versus AUC-based dosing. Using the gathered information presented in this paper, two user-friendly and scientifically based dosing strategies are proposed to improve the efficiency of vancomycin dosing while avoiding the risk of nephrotoxicity and minimizing the cost of therapeutic drug monitoring.

Influence of Mechanical Ventilation on the Pharmacokinetics of Vancomycin Administered by Continuous Infusion in Critically Ill Patients

Pathophysiological changes involved in drug disposition in critically ill patients should be considered in order to optimize the dosing of vancomycin administered by continuous infusion, and certain strategies must be applied to reach therapeutic targets on the first day of treatment. The aim of this study was to develop a population pharmacokinetic model of vancomycin to determine clinical covariates, including mechanical ventilation, that influence the wide variability of this antimicrobial. Plasma vancomycin concentrations from 54 critically ill patients were analyzed simultaneously by a population pharmacokinetic approach. A nomogram for dosing recommendations was developed and was internally evaluated through stochastic simulations. The plasma vancomycin concentration-versus-time data were best described by a one-compartment open model with exponential interindividual variability associated with vancomycin clearance and the volume of distribution. Residual error followed a homoscedastic trend. Creatinine clearance and body weight significantly dropped the objective function value, showing their influence on vancomycin clearance and the volume of distribution, respectively. Characterization based on the presence of mechanical ventilation demonstrated a 20% decrease in vancomycin clearance. External validation (n = 18) was performed to evaluate the predictive ability of the model; median bias and precision values were 0.7 mg/liter (95% confidence interval [CI], -0.4, 1.7) and 5.9 mg/liter (95% CI, 5.4, 6.4), respectively. A population pharmacokinetic model was developed for the administration of vancomycin by continuous infusion to critically ill patients, demonstrating the influence of creatinine clearance and mechanical ventilation on vancomycin clearance, as well as the implications for targeting dosing rates to reach the therapeutic range (20 to 30 mg/liter).

A simulation of loading doses for vancomycin continuous infusion regimens in intensive care

BACKGROUND

Delayed achievement of target vancomycin serum concentrations may adversely affect clinical outcomes. The objective of this retrospective study was to compare the prediction accuracy of different body weight descriptors for volume of distribution and to propose an optimal loading dose (LD) for continuous infusion regimens in adults.

METHODS

Pharmacokinetic variables were computed using one-compartmental analysis. Simulated LDs of vancomycin were evaluated for each patient.

RESULTS

Volume of distribution, clearance, and half-life median values (interquartile range) for vancomycin in the study population (n = 30) were 0.45 (0.39-0.61) L.kg^-1, 0.026 (0.015-0.040) L.h^-1.kg^-1, and 10.3 (7.7-21.3) h, respectively. The observed volume of distribution was better predicted by total body weight (TBW) than by the ideal body weight or the adjusted body weight.

CONCLUSIONS

An LD of 10.7 mg per kg TBW was optimal in our study population. Using this LD, 17.9% of simulated vancomycin serum levels were just below the therapeutic range, only 10.7% concentrations exceeded the target range and no concentration was toxic. The use of a LD would lead to reduced median time to reach target concentrations from 17 to 1 h.

Old antimicrobials and Gram-positive cocci through the example of infective endocarditis and bone and joint infections

The management of some serious infections such as infective endocarditis (IE) and bone and joint infections (BJIs) caused by Gram-positive cocci (GPC) is complex and requires great responsiveness and effective antimicrobials with high bioavailability in heart valves or bone tissues. Treatment of these infections requires the use of a higher dosage that may result in increased toxicity or the use of new promising antimicrobials to control the infection. However, use of these new antimicrobials could still bring about new toxicity and resistance. Another approach may be the 'comeback' of old antimicrobials, which is evaluated in this review in the treatment of IE and BJIs caused by GPC.

Optimizing the Clinical Use of Vancomycin

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

Continuous versus intermittent infusion of vancomycin in adult patients: A systematic review and meta-analysis

Continuous infusion of vancomycin (CIV) and intermittent infusion of vancomycin (IIV) are two major administration strategies in clinical settings. However, previous articles comparing the efficacy and safety of CIV versus IIV showed inconsistent results. Therefore, a meta-analysis was conducted to compare the efficacy and safety of CIV and IIV. PubMed, the Cochrane Library and Web of Science up to June 2015 were searched using the keywords 'vancomycin', 'intravenous', 'parenteral', 'continuous', 'intermittent', 'discontinuous', 'infusion', 'administration' and 'dosing'. Eleven studies were included in the meta-analysis. Neither heterogeneity nor publication bias were observed. Patients treated with CIV had a significantly lower incidence of nephrotoxicity compared with patients receiving IIV [risk ratio (RR)=0.61, 95% confidence interval (CI) 0.47-0.80; P<0.001]. No significant difference in treatment failure between the two groups was detected. Mortality between patients receiving CIV and patients receiving IIV was similar (RR=1.15, 95% CI 0.85-1.54; P=0.365). This meta-analysis showed that CIV had superior safety compared with IIV, whilst the clinical efficacy was not significantly different. A further multicentre, randomised controlled trial is required to confirm these results.

Continuous infusion vs intermittent vancomycin in neurosurgical intensive care unit patients

PURPOSE

Target plasma level achievement has remained a challenge in neurosurgical intensive care unit patients receiving intravenous vancomycin. We evaluated continuous infusion (CI) and intermittent vancomycin dosing strategies in these patients.

METHODS

This retrospective cohort compared CI vancomycin (target random levels, 20-30 mg/L) to intermittent vancomycin (target troughs, 15-20 mg/L) in regards to achievement of target plasma levels, nephrotoxicity, pharmacodynamic target attainment, and cost savings in 130 patients.

RESULTS

Continuous infusion resulted in greater achievement of goal plasma concentrations at the first steady-state level (40 vs 21.5%, P = .02), more rapid achievement of goal plasma concentrations (2.04 vs 3.76 days, P < .0001), and increased time within therapeutic range (55% vs 34%, P < .0001) but no significant difference in nephrotoxicity (15.4% vs 21.5%, P = .5). Continuous infusion improved pharmacodynamic target attainment (92.3% vs 30.8%, P < .0001) and also reduced levels drawn (3.8 vs 5.7, P = .0007), dose adjustments (1.4 vs 2.4, P = .0006), days of therapy (10.4 vs 14.1, P = .01), and mean total daily dose requirements (33 vs 35.7 mg/kg, P < .0001) per patient.

CONCLUSIONS

Continuous infusion appears beneficial for improving attainment of target plasma concentrations, pharmacodynamic goals, and financial burden, without increasing risk of acute kidney injury.

Vancomycin-associated nephrotoxicity: A meta-analysis of administration by continuous versus intermittent infusion

Vancomycin is a glycopeptide antibiotic widely used in the management of meticillin-resistant Staphylococcus aureus (MRSA). Guidelines currently recommend vancomycin be administered by intermittent infusion, despite recent research suggesting that continuous infusion (CI) may be associated with lower rates of vancomycin-associated nephrotoxicity. In 2012, Cataldo et al. presented a meta-analysis supporting the use of CI. Here we present an updated meta-analysis, inclusive of a recently published large-scale retrospective study. PubMed, EMBASE and Cochrane Reviews databases were searched using the keywords 'vancomycin' and 'continuous' or 'intermittent' or 'infusion' or 'discontinuous' or 'administration'. Seven studies were included in the final analysis. Using a random-effects model, a non-significant trend of reduced nephrotoxicity in those who received vancomycin by CI (risk ratio=0.799, 95% confidence interval 0.523-1.220; P=0.299) was identified. A large, randomised controlled trial is necessary to confirm these results.

The pharmacokinetic/pharmacodynamic rationale for administering vancomycin via continuous infusion

WHAT IS KNOWN AND OBJECTIVE

Vancomycin is administered via intermittent infusion (II) almost exclusively in the United States, whereas continuous infusion (CI) dosing methods are used regularly in many European countries. The purpose of this literature analysis is to review current evidence regarding the advantages and disadvantages of CI vancomycin in relation to II, based on the pharmacokinetic and pharmacodynamic aspects of dosing and monitoring therapy, and to identify current practices of CI vancomycin dosing.

METHODS

Medline, Cochrane and GoogleScholar databases were searched using vancomycin as a MeSH term, along with continuous and infusion in all fields, which identified 136 citations. A second search added the terms intermittent and survey, producing nine additional articles. All articles that reported an assessment of CI or II vancomycin administration in adult patients, based on clinical, pharmacokinetic, cost or monitoring considerations, were identified. A total of 43 publications were determined to be suitable for final analysis and possible inclusion in the report.

RESULTS AND DISCUSSION

A meta-analysis of six studies concluded that CI vancomycin was associated with a lower relative risk of kidney injury than II therapy, although other studies reported equivocal findings. The results of several clinical studies suggest that CI vancomycin produces clinical outcomes that are comparable to II. Current vancomycin consensus guidelines promote aggressive dosing to achieve trough levels of 10-15 or 15-20 mg/L, but also include recommendations to target a daily area under the curve (AUC24 ) to minimum inhibitory concentration (MIC) ratio of at least 400. Because vancomycin is a non-concentration-dependent antibiotic, it might be more prudent to monitor steady-state serum concentrations (Css ) during a CI rather than trough concentrations during II, due to the questionable correlation between measured trough concentration and AUC. From a pharmacokinetic/pharmacodynamic perspective, vancomycin dosing and monitoring practices associated with CI offer potentially greater reliability than II. A major disadvantage of CI involves the possibility of having to intravenously co-administer another drug that might not be compatible with vancomycin.

WHAT IS NEW AND CONCLUSION

Continuous infusion vancomycin therapy offers the advantage of Css monitoring, thus avoiding the variabilities associated with the timing of trough levels. Current CI practices include a loading dose of 15-20 mg/kg followed by an infusion of 10-40 mg/kg/day based on the patient's renal function, with a target Css of about 20-30 mg/L. An alternative approach to weight-based (mg/kg) CI dosing is to calculate the dose from an estimation of the patient's vancomycin clearance (in L/h), derived from creatinine clearance (CrCl) via the equation (CrCl∙0·041) + 0·22. The daily dose is then determined by multiplying vancomycin clearance (in L/h) by the desired AUC24 . A new CI vancomycin dosing chart includes clearance-based dosing recommendations for Css values ranging from 17·5 to 27·5 mg/L or AUC24 values ranging from 420 to 660 mg h/L. Although sufficient data already exist to support the use of CI vancomycin as a reasonable therapeutic alternative to II, there is still much to learn about administering the drug in this fashion.

Influence of vancomycin infusion methods on endothelial cell toxicity

Peripheral intravenous therapy is frequently used in routine hospital practice and, due to various factors, its most common side effect is phlebitis. The infusion of vancomycin is particularly associated with phlebitis despite its widespread use. French guidelines recommend central intravenous infusion for high concentrations of vancomycin, but peripheral intravenous therapy is often preferred in intensive care units. Methods of vancomycin infusion are either intermittent infusion or continuous infusion. A comparison of these methods under in vitro conditions simulating clinical use could result in better infusion efficacy. Human umbilical vein endothelial cells (HUVECs) were therefore challenged with clinical doses of vancomycin over a 24- to 72-h period using these infusion methods. Cell death was measured with the alamarBlue test. Concentration-dependent and time-dependent vancomycin toxicity on HUVECs was noted with a 50% lethal dose at 5 mg/ml after 24 h, reaching 2.5 mg/ml after 72 h of infusion, simulating long-term infusion. This toxicity does not seem to be induced by acidic pH. In comparing infusion methods, we observed that continuous infusion induced greater cell toxicity than intermittent infusion at doses higher than 1 g/day. The increasing use of vancomycin means that new guidelines are required to avoid phlebitis. If peripheral intravenous therapy is used to reduce infusion time, along with intermittent infusion, vein irritation and localized phlebitis may be reduced. Further studies have to be carried out to explore the causes of vancomycin endothelial toxicity.

Design and prospective validation of a dosing instrument for continuous infusion of vancomycin: a within-population approach

INTRODUCTION

The clinical application of continuous infusion (CoI) of vancomycin has gained interest in recent years. Since no international guidelines on initial dosing of vancomycin CoI exist, there is a need for methods to facilitate the switch from intermittent to continuous vancomycin dosing algorithms in clinically infected populations. Therefore, the aim of this study was to design and validate an a priori dosing schedule for CoI of vancomycin in clinical practice.

METHODS

A dosing table for CoI of vancomycin based on estimated glomerular filtration rate (eGFR) was developed by simulation of continuous infusion of vancomycin using pharmacokinetic (PK) software and a PK population model designed from historical within-population data in intermittently dosed patients. The target range for the first vancomycin serum concentrations drawn approximately 24 h after start of infusion' (C24) was set at 15-20 mg/L corresponding with an area under the curve (AUC) of at least 350 mg·h·L(-1). The performance of the dosing schedule was primarily assessed by describing the percentages of patients attaining the predefined target.

RESULTS

An eGFR-derived dosing schedule for CoI of vancomycin was established and implemented in clinical practice. Prospective assessment in 35 general ward and 45 intensive care unit patients showed that the C24 target was reached in 69 and 63 % and the AUC target was attained in 80 and 72 % of patients, respectively.

CONCLUSIONS

An easy method to design and validate an eGFR-derived dosing algorithm for the continuous infusion of vancomycin to switch from intermittent to continuous dosing of vancomycin was developed.

Does contemporary vancomycin dosing achieve therapeutic targets in a heterogeneous clinical cohort of critically ill patients? Data from the multinational DALI study

Introduction

The objective of this study was to describe the pharmacokinetics of vancomycin in ICU patients and to examine whether contemporary antibiotic dosing results in concentrations that have been associated with favourable response.

Methods

The Defining Antibiotic Levels in Intensive Care (DALI) study was a prospective, multicentre pharmacokinetic point-prevalence study. Antibiotic dosing was as per the treating clinician either by intermittent bolus or continuous infusion. Target trough concentration was defined as ≥15 mg/L and target pharmacodynamic index was defined as an area under the concentration-time curve over a 24-hour period divided by the minimum inhibitory concentration of the suspected bacteria (AUC_0–24/MIC ratio) >400 (assuming MIC ≤1 mg/L).

Results

Data of 42 patients from 26 ICUs were eligible for analysis. A total of 24 patients received vancomycin by continuous infusion (57%). Daily dosage of vancomycin was 27 mg/kg (interquartile range (IQR) 18 to 32), and not different between patients receiving intermittent or continuous infusion. Trough concentrations were highly variable (median 27, IQR 8 to 23 mg/L). Target trough concentrations were achieved in 57% of patients, but more frequently in patients receiving continuous infusion (71% versus 39%; P = 0.038). Also the target AUC_0–24/MIC ratio was reached more frequently in patients receiving continuous infusion (88% versus 50%; P = 0.008). Multivariable logistic regression analysis with adjustment by the propensity score could not confirm continuous infusion as an independent predictor of an AUC_0–24/MIC >400 (odds ratio (OR) 1.65, 95% confidence interval (CI) 0.2 to 12.0) or a C_min ≥15 mg/L (OR 1.8, 95% CI 0.4 to 8.5).

Conclusions

This study demonstrated large interindividual variability in vancomycin pharmacokinetic and pharmacodynamic target attainment in ICU patients. These data suggests that a re-evaluation of current vancomycin dosing recommendations in critically ill patients is needed to more rapidly and consistently achieve sufficient vancomycin exposure.

Intravenous and Inhaled Antimicrobials at Home in Cystic Fibrosis Patients

The primary clinical characteristics of cystic fibrosis (CF) are malnutrition caused by malabsorption secondary to pancreatic insufficiency, chronic pulmonary infections, and male infertility. The major cause of morbidity and mortality are bronchiectasis and obstructive pulmonary disease. Lung disease in CF is manifested by this chronic lung disease progression, with intermittent episodes of acute worsening of symptoms called pulmonary exacerbations. Once the patient has stabilized, and if suitable care can be arranged, these interventions are often transitioned to the home. This review summarizes important points pertinent to the use of intravenous and inhaled antimicrobials that may be encountered by prescribers, nurses, technicians, and case managers in the home health setting. Appropriate dosing, indications, adverse drug reactions, monitoring parameters, and practicality of both intravenous and inhaled antimicrobials are discussed.

Adherence to the 2009 consensus guidelines for vancomycin dosing and monitoring practices: a cross-sectional survey of U.S. hospitals

STUDY OBJECTIVES

To describe the implementation of vancomycin dosing and monitoring practices recommended by the consensus guidelines in a diverse sample of hospitals, and to identify needs for quality improvement and research.

DESIGN

Cross-sectional study using an online survey instrument.

SETTING

Making a Difference in Infectious Diseases Pharmacotherapy (MAD-ID) Research Network.

PARTICIPANTS

A total of 163 respondents from MAD-ID who work in antimicrobial stewardship and represent unique hospitals.

MEASUREMENTS AND MAIN RESULTS

The survey population represented a wide range of patient populations (96% adult, 49% pediatric, and 23% long-term care) and settings (52% not-for-profit nonuniversity, 31% university based, and 11% for profit). Automatic consultation of pharmacy services for all vancomycin dosing was reported in 51% of the institutions. Among the dosing and monitoring practices endorsed by the consensus guidelines, participant institutions commonly followed these recommendations: use of trough concentrations without peak concentrations, maintenance of trough concentration higher than 10 mg/L, and target trough concentrations of 15-20 mg/L for complicated infections. In contrast, there was less consistent application of appropriate timing of trough concentrations, use of loading doses, and use of actual body weight. The remaining challenges and controversies surrounding vancomycin dosing are discussed.

CONCLUSION

Despite the availability of consensus guideline recommendations, practices for dosing and monitoring of vancomycin are not universally applied. The findings of this survey highlight many opportunities for future research and quality improvement strategies.

Evaluation of a pediatric continuous-infusion vancomycin therapy guideline

PURPOSE

An institutional guideline for converting pediatric patients to continuous-infusion vancomycin (CIV) therapy if therapeutic targets are not achieved with intermittent i.v. dosing was evaluated.

METHODS

All patients within a specified age range (>6 months but <19 years) who were converted to CIV therapy for pneumonia or osteomyelitis during the 2 years after guideline implementation were included in the evaluation. The guideline calls for conversion to CIV therapy if goals for trough serum vancomycin concentration (SVC) are not attained with escalating intermittent-infusion vancomycin (IIV) dosing. Primary outcome measures included the rate of attainment of the goal steady-state trough SVC (15-20 mg/L), preferably within 24-48 hours, the adequacy of an empirical dosing strategy, and adverse events. Secondary study outcomes included final vancomycin doses and the time to attainment of therapeutic SVCs.

RESULTS

Within 24-48 hours after conversion to CIV therapy, the mean initial plateau SVC in the evaluated cases (n = 15) was 20.2 mg/L; the mean of all SVCs was 19.1 mg/L. The range of dosages required to achieve a plateau SVC of 15 mg/L was 23.8-65.4 mg/kg/day (median, 41 mg/kg/day). The mean ± S.D. vancomycin dosage at the end of CIV therapy was 44.3 ± 12.8 mg/kg/day. Monitoring of serum creatinine, urine output, and glomerular filtration rate indicated that no patients developed nephrotoxicity during CIV therapy.

CONCLUSION

Conversion from IIV to CIV therapy in selected pediatric patients appeared to be safe and well tolerated, with few adverse effects noted. Using the institutional CIV dosing guideline, goal plateau SVC values were attained in most patients within 24-48 hours.

Continuous versus intermittent infusions of antibiotics for the treatment of severe acute infections

BACKGROUND

Intravenous broad-spectrum antibiotics are indicated for the treatment of severe infections. However, the emergence of infections caused by multi-drug resistant organisms in conjunction with a lack of novel antibiotics has prompted the investigation of alternative dosing strategies to improve clinical efficacy and tolerability. To optimise pharmacokinetic and pharmacodynamic antibiotic parameters, continuous antibiotic infusions have been compared to traditional intermittent antibiotic infusions.

OBJECTIVES

To compare the clinical efficacy and safety of continuous intravenous administration of concentration-dependent and time-dependent antibiotics to traditional intermittent intravenous administration in adults with severe acute bacterial infections.

SEARCH METHODS

The following electronic databases were searched in September 2012: The Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL, ISI Web of Science: Science Citation Index Expanded (SCI-EXPANDED), ISI Web of Science: Conference Proceedings Citation Index-Science (CPCI-S). The reference lists of all relevant material, the Internet and the trials registry www.clinicaltrials.gov for completed and ongoing trials were also searched.

SELECTION CRITERIA

Randomized controlled trials in adults with a bacterial infection requiring intravenous antibiotic therapy comparing continuous versus intermittent infusions of antibiotics were included. Both time-dependent and concentration-dependent antibiotics were considered.

DATA COLLECTION AND ANALYSIS

Three independent authors performed data extraction for the included studies. All data was cross-checked and disagreements resolved by consensus. An intention to treat analysis was conducted using a random-effects model.

MAIN RESULTS

Twenty-nine studies met inclusion criteria with a combined total of over 1,600 patients. The majority of included studies were judged to be at unclear or high risk of bias with regard to randomisation sequence generation, allocation concealment, blinding, management of incomplete outcome data, selective outcome reporting, and other potential threats to validity. No studies were judged to be at low risk of bias for all methodological quality items assessed. There were no differences in all-cause mortality (n=1241, RR 0.89, 95% CI 0.67 - 1.20, p=0.45), infection recurrence (n=398, RR 1.22, 95% CI 0.35 - 4.19, p=0.76), clinical cure (n=975, RR 1.00, 95% CI 0.93 - 1.08, p=0.98), and superinfection post-therapy (n=813, RR 1.08, 95% CI 0.60 - 1.94, p=0.79). There were no differences in safety outcomes including adverse events (n=575, RR 1.02, 95% CI 0.94 - 1.12, p=0.63), serious adverse events (n=871, RR 1.36, 95% CI 0.80 - 2.30, p=0.26), and withdrawal due to adverse events (n=871, RR 2.03, 95% CI 0.52 - 7.95, p=0.31). A difference was observed in the subgroup analyses of clinical cure in septic versus non-septic patients, where intermittent antibiotic infusions were favoured for clinical cure in septic patients. However, this effect was not consistent between random-effects and fixed-effects analyses. No differences were found in sensitivity analyses conducted.

AUTHORS' CONCLUSIONS

There were no differences in mortality, infection recurrence, clinical cure, superinfection post-therapy, and safety outcomes when comparing continuous infusions of intravenous antibiotics to traditional intermittent infusions of antibiotics. However, the wide confidence intervals suggest that beneficial or harmful effects cannot be ruled out for all outcomes. Therefore, the current evidence is insufficient to recommend the widespread adoption of continuous infusion antibiotics in the place of intermittent infusions of antibiotics. Further large prospective randomised trials, with consistent and complete reporting of clinical outcome measures, conducted with concurrent pharmacokinetic and pharmacodynamic studies in special populations are required to determine whether adoption of continuous antibiotic infusions is warranted in specific circumstances.

Review of Continuous-Infusion Vancomycin

OBJECTIVE:

To evaluate the efficacy and safety of administering vancomycin as a continuous infusion.

DATA SOURCES:

Literature was accessed through MEDLINE (1977-September 2012), Embase (1977-September 2012), and Google Scholar, using the terms vancomycin, continuous, discontinuous, infusion, pharmacokinetics, pharmacodynamics, and nephrotoxicity. In addition, reference citations from publications identified were reviewed.

STUDY SELECTION AND DATA EXTRACTION:

All English-language articles identified from the data sources were evaluated. Studies including more than 30 adults were included in the safety and efficacy review.

DATA SYNTHESIS:

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) carry a significant risk of morbidity and mortality. Vancomycin is commonly prescribed for invasive MRSA infections and has been traditionally administered as an intermittent infusion. Administering vancomycin as a continuous infusion is a novel approach to improving its efficacy and safety profile. Fourteen clinical trials were reviewed (2 prospective, 1 meta-analysis, 11 retrospective). The pharmacodynamic profiles between continuous-infusion vancomycin and intermittent-infusion vancomycin were comparable. Continuous-infusion therapy did not significantly improve the efficacy of vancomycin in the treatment of invasive MRSA infections. Conflicting results exist regarding the safety profile of continuous-infusion compared with intermittent-infusion vancomycin. The only published prospective randomized clinical trial comparing continuous infusion with intermittent therapy found no significant difference in the rates of nephrotoxicity. The data from retrospective studies are heterogeneous and show variable rates of nephrotoxicity. In general, compatibility information for administering vancomycin as a continuous infusion is unavailable.

CONCLUSIONS:

Overall, currently available evidence is insufficient to conclude whether an improvement in vancomycin efficacy exists when it is administered as a continuous infusion. The risk of nephrotoxicity associated with continuous-infusion vancomycin requires further investigation in prospective randomized trials. Specific patient populations that would benefit from continuous-infusion vancomycin have yet to be determined.

Correlation of vancomycin dosing to serum concentrations in pediatric patients: a retrospective database review

OBJECTIVES

Appropriate antimicrobial dosing maximizes therapeutic benefit while minimizing development of antimicrobial resistance. Common pediatric references recommend vancomycin dosing of 40 mg/kg/day divided every 6 to 8 hours for non-central nervous system infections, while some clinicians report utilizing higher initial doses to optimize efficacy. This study compares vancomycin serum concentrations following traditional dosing of 10 mg/kg/dose every 6 to 8 hours versus 15 to 20 mg/kg/dose every 6 to 8 hours.

STUDY DESIGN

Retrospective database review of vancomycin serum concentrations in pediatric patients.

RESULTS

Three hundred fifty-seven patients were analyzed. The mean peak concentration of the 10 mg/kg groups every 6 and every 8 hours were below 25 mg/L, whereas the mean peak concentrations of the 15 mg/ kg groups every 6 and 8 hours were within the 25-40 mg/L range (p < 0.001). The mean trough concentration of the 10 mg/kg group every 6 hours was within the 5-15 mg/L range while the 10 mg/kg group dosed every 8 hours was below target. However, the mean trough concentrations of the 15 mg/kg group dosed every 6 and 8 hours were both within the 5-15 mg/L range (p < 0.001).

CONCLUSIONS

Vancomycin doses of 15 mg/kg every 6 to 8 hours produce peak and trough serum concentrations within target range more often than 10 mg/kg every 6 to 8 hours.

Initial vancomycin dosing recommendations for critically ill patients undergoing continuous venovenous hemodialysis

BACKGROUND

Delaying appropriate antimicrobial therapy for critically ill patients increases the risk of death. Currently, there are insufficient data to guide initial vancomycin dosing for patients undergoing continuous venovenous hemodialysis (CVVHD).

OBJECTIVE

To develop practical recommendations for initial dosing of vancomycin, based on the pharmacokinetics of this drug in critically ill patients undergoing CVVHD.

METHODS

A chart review was conducted for 24 critically ill adult patients who had undergone concurrent CVVHD and vancomycin therapy. Mean pharmacokinetic parameters were determined, along with practical recommendations for initial vancomycin dosing that targeted steady-state trough concentrations for patients receiving intermittent infusions and steady-state levels for those receiving continuous infusions between 15 and 20 mg/L. Monte Carlo simulation was used to develop the initial vancomycin dosing recommendations.

RESULTS

The mean (95% confidence interval) pharmacokinetic parameters for vancomycin (elimination rate constant 0.0315 [0.0254-0.0391], half-life 22.0 h [17.72-27.24 h], volume of distribution 0.96 L/kg [0.77-1.20 L/kg], and clearance 2.4 L/h [1.97-2.92 L/h]) indicated that initial intermittent IV dosing of 1.25-1.5 g q24h or 15 mg/kg q24h would be suitable. For continuous infusion, a 1.5-g IV loading dose followed by continuous infusion of 1-1.5 g IV over 24 h (42-62 mg/h) would be recommended. However, Monte Carlo simulation revealed that the probability of achieving desired concentrations between 15 and 20 mg/L with any of these initial regimens is low.

CONCLUSIONS

There was considerable variation in vancomycin pharmacokinetics in this patient population. The observations reported here raise concerns about the reliability of numerous empiric dosing recommendations derived from small pharmacokinetic studies in heterogeneous populations. Follow-up therapeutic drug monitoring is essential to ensure that concentrations remain within the target range.

Comparison of Continuous and Intermittent IV Infusion of Vancomycin: Systematic Review

BACKGROUND

There is some evidence that administration of vancomycin by continuous infusion has pharmacokinetic and pharmacodynamic advantages over traditional intermittent dosing. Whether these advantages translate into clinical efficacy remains controversial.

OBJECTIVE

To review the literature comparing continuous infusion of vancomycin and conventional intermittent IV dosing in terms of efficacy and safety.

METHODS

A literature search was conducted in the PubMed/MEDLINE and Embase databases and the Cochrane Central Register of Controlled Trials, and by means of the Google search engine, and the reference lists of pertinent articles were searched manually. All human studies published in English or French that evaluated vancomycin given by continuous and intermittent IV infusion were reviewed. Articles that did not include a comparator arm and those that assessed continuous and intermittent intraperitoneal infusions were excluded. The level of evidence of each study was categorized according to the US Preventive Services Task Force rating scale.

RESULTS

In total, 9 studies were identified: 1 in a pediatric population and 8 in adult populations. Of the 3 studies with the highest quality of evidence (level I), one demonstrated pharmacodynamic advantages with continuous infusion of vancomycin. Of the 6 studies representing a moderate level of evidence (level II), 3 also favoured continuous infusion in terms of pharmacokinetic and pharmacodynamic outcomes, but the findings in terms of clinical outcomes were mixed.

CONCLUSIONS

Current evidence evaluating the pharmacokinetic and pharmacodynamic advantages and clinical efficacy of continuous versus intermittent vancomycin infusions is inconsistent and does not support the routine use of continuous infusion for the treatment of multidrug-resistant gram-positive infections.