Lack of vancomycin-associated nephrotoxicity in newborn infants: a case-control study

Incidence and risk factors of drug-induced kidney injury in children: a systematic review and meta-analysis

PURPOSE

To comprehensively summarize the incidence and risk factors of drug-induced kidney injury (DIKI) in children.

METHODS

We systematically searched seven databases from inception to November 2022. Two independent reviewers selected studies, extracted data, and assessed the risk of bias. Meta-analyses were conducted to quantify the incidence and risk factors of DIKI in children.

RESULTS

A total of 69 studies comprising 195,894 pediatric patients were included. Overall, the incidence of DIKI in children was 18.2% (95%CI: 16.4%-20.1%). The incidence of DIKI in critically ill children (19.6%, 95%CI: 15.9%-23.3%) was higher than that in non-critically ill children (16.1%, 95%CI: 12.9%-19.4%). Moreover, the risk factors for DIKI in children were intensive care unit (ICU) admission (OR = 1.59, 95% CI: 1.42-1.78, P = 0.000), treatment days (OR = 1.04, 95% CI: 1.03-1.05, P = 0.000), surgical intervention (OR = 1.43, 95% CI: 1.00-2.02, P = 0.048), infection (OR = 2.30, 95% CI: 1.44-3.66, P = 0.000), patent ductus arteriosus (OR = 4.78, 95% CI: 1.82-12.57, P = 0.002), chronic kidney disease (OR = 2.78, 95% CI: 1.92-4.02, P = 0.000), combination with antibacterial agents (OR = 1.98, 95% CI: 1.54-2.55, P = 0.000), diuretics (OR = 1.97, 95% CI: 1.51-2.56, P = 0.000), combination with antiviral agents (OR = 1.50, 95% CI: 1.11-2.04, P = 0.008), combination with non-steroidal anti-inflammatory drugs (OR = 1.79, 95% CI: 1.40-2.28, P = 0.000), and combination with immunosuppressive agents (OR = 2.84, 95% CI: 1.47-5.47, P = 0.002).

CONCLUSION

The incidence of DIKI in children is high, especially in critically ill children. Identifying high-risk groups and determining safer treatments is critical to reducing the incidence of DIKI in children. In clinical practice, clinicians should adjust medication regimens for high-risk pediatric groups, such as ICU admission, some underlying diseases, combination with nephrotoxic drugs, etc., and regularly evaluate kidney function throughout treatment.

Factors associated with acute kidney injury among preterm infants administered vancomycin: a retrospective cohort study

BACKGROUND

Vancomycin (VCM) is a widely used antibiotic for the treatment of gram-positive microorganisms, with some nephrotoxic effects. Recent studies have suggested that piperacillin-tazobactam (TZP) aggravates VCM-induced nephrotoxicity in adults and adolescents. However, there is a lack of research investigating these effects in the newborn population. Therefore, this study investigates whether the concomitant use of TZP with VCM use increases the risk of acute kidney injury (AKI) and to explore the factors associated with AKI in preterm infants treated with VCM.

METHODS

This retrospective study included preterm infants with birth weight < 1,500 g in a single tertiary center who were born between 2018 and 2021 and received VCM for a minimum of 3 days. AKI was defined as an increase in serum creatinine (SCr) of at least 0.3 mg/dL and an increase in SCr of at least 1.5 times baseline during and up to 1 week after discontinuation of VCM. The study population was categorized as those with or without concomitant use of TZP. Data on perinatal and postnatal factors associated with AKI were collected and analyzed.

RESULTS

Of the 70 infants, 17 died before 7 postnatal days or antecedent AKI and were excluded, while among the remaining participants, 25 received VCM with TZP (VCM + TZP) and 28 VCM without TZP (VCM-TZP). Gestational age (GA) at birth (26.4 ± 2.8 weeks vs. 26.5 ± 2.6 weeks, p = 0.859) and birthweight (750.4 ± 232.2 g vs. 838.1 ± 268.7 g, p = 0.212) were comparable between the two groups. There were no significant differences in the incidence of AKI between groups. Multivariate analysis showed that GA (adjusted OR: 0.58, 95% CI: 0.35-0.98, p = 0.042), patent ductus arteriosus (PDA) (adjusted OR: 5.23, 95% CI: 0.67-41.05, p = 0.115), and necrotizing enterocolitis (NEC) (adjusted OR: 37.65, 95% CI: 3.08-459.96, p = 0.005) were associated with AKI in the study population.

CONCLUSIONS

In very low birthweight infants, concomitant use of TZP did not increase the risk of AKI during VCM administration. Instead, a lower GA, and NEC were associated with AKI in this population.

Implementation of a Vancomycin Dose-Optimization Protocol in Neonates: Impact on Vancomycin Exposure, Biological Parameters, and Clinical Outcomes

Vancomycin dosing used in neonates results frequently in insufficient concentrations. A vancomycin dose-optimization protocol consisting of an individualization of loading and maintenance doses (administered during continuous infusion) through a previously validated pharmacokinetic model was implemented in our center. This monocenter retrospective study aimed to compare vancomycin average concentration (Cavg) in the therapeutic range (15 to 25 mg/L) and biological and clinical parameters before and after implementation of this protocol. A total of 60 and 59 courses of vancomycin treatment in 45 and 49 patients were analyzed in groups before and after implementation, respectively. Initial vancomycin Cavg were more frequently in the therapeutic range in the group after implementation (74.6% versus 28.3%, P < 0.001), with 1.6-fold higher Cavg (20.3 [17.0-22.2] mg/L versus 12.9 [11.3-17.0] mg/L, P < 0.001). Considering all Cavg during longitudinal therapeutic drug monitoring (TDM), the frequency of therapeutic Cavg was higher in the group after implementation (74.8% [n = 103] versus 31% [n = 116], P < 0.001). The dose optimization protocol was also associated with a reduced time to obtain a negative blood culture (P < 0.001) and fewer antibiotic switches (P = 0.025), without increasing the frequency of nephrotoxicity. Clinical outcomes also appeared to be improved, with less periventricular leukomalacia (P = 0.021), trended toward less respiratory instability (P = 0.15) and a shorter duration of vasoactive drug use (P = 0.18) for neonates receiving personalized doses of vancomycin. This personalized vancomycin dose protocol improves vancomycin exposure in neonates, with good safety, and suggests an improvement in biological and clinical outcomes.

Association between Nephrotoxic Drug Combinations and Acute Kidney Injury in the Neonatal Intensive Care Unit

OBJECTIVE

To determine the incidence of acute kidney injury (AKI) in infants exposed to nephrotoxic drug combinations admitted to 268 neonatal intensive care units managed by the Pediatrix Medical Group.

STUDY DESIGN

We included infants born at 22-36 weeks gestational age, ≤120 days postnatal age, exposed to nephrotoxic drug combinations, with serum creatinine measurements available, and discharged between 2007 and 2016. To identify risk factors associated with a serum creatinine definition of AKI based on the Kidney Disease: Improving Global Outcomes criteria, we performed multivariable logistic and Cox regression adjusting for gestational age, sex, birth weight, postnatal age, race/ethnicity, sepsis, respiratory distress syndrome, baseline serum creatinine, and duration of combination drug exposure. The adjusted odds of AKI were determined relative to gentamicin + indomethacin for the following nephrotoxic drug combinations: chlorothiazide + ibuprofen; chlorothiazide + indomethacin; furosemide + gentamicin; furosemide + ibuprofen; furosemide + tobramycin; ibuprofen + spironolactone; and vancomycin + piperacillin-tazobactam.

RESULTS

Among 8286 included infants, 1384 (17%) experienced AKI. On multivariable analysis, sepsis, lower baseline creatinine, and duration of combination therapy were associated with increased odds of AKI. Furosemide + tobramycin and vancomycin + piperacillin-tazobactam were associated with a decreased risk of AKI relative to gentamicin + indomethacin in both the multivariable and Cox regression models.

CONCLUSIONS

In this cohort, infants receiving longer durations of nephrotoxic combination therapy had an increased odds of developing AKI.

Model-Informed Precision Dosing of Antibiotics in Pediatric Patients: A Narrative Review

Optimal pharmacotherapy in pediatric patients with suspected infections requires understanding and integration of relevant data on the antibiotic, bacterial pathogen, and patient characteristics. Because of age-related physiological maturation and non-maturational covariates (e.g., disease state, inflammation, organ failure, co-morbidity, co-medication and extracorporeal systems), antibiotic pharmacokinetics is highly variable in pediatric patients and difficult to predict without using population pharmacokinetics models. The intra- and inter-individual variability can result in under- or overexposure in a significant proportion of patients. Therapeutic drug monitoring typically covers assessment of pharmacokinetics and pharmacodynamics, and concurrent dose adaptation after initial standard dosing and drug concentration analysis. Model-informed precision dosing (MIPD) captures drug, disease, and patient characteristics in modeling approaches and can be used to perform Bayesian forecasting and dose optimization. Incorporating MIPD in the electronic patient record system brings pharmacometrics to the bedside of the patient, with the aim of a consisted and optimal drug exposure. In this narrative review, we evaluated studies assessing optimization of antibiotic pharmacotherapy using MIPD in pediatric populations. Four eligible studies involving amikacin and vancomycin were identified from 418 records. Key articles, independent of year of publication, were also selected to highlight important attributes of MIPD. Although very little research has been conducted until this moment, the available data on vancomycin indicate that MIPD is superior compared to conventional dosing strategies with respect to target attainment. The utility of MIPD in pediatrics needs to be further confirmed in frequently used antibiotic classes, particularly aminoglycosides and beta-lactams.

A propensity-matched cohort study of vancomycin-associated nephrotoxicity in neonates

BACKGROUND

The incidence of nephrotoxicity among vancomycin-treated neonates has been reported to range from 2% to 20%. These widely varying estimates have led to confusion and controversy regarding the safety of vancomycin among neonates.

OBJECTIVE

Evaluate the incidence of nephrotoxicity among neonates receiving vancomycin concomitantly with gentamicin.

DESIGN

Retrospective observational cohort study using propensity score matching to provide covariate balance between neonates who did or did not receive vancomycin based on factors known to be related to the development of renal dysfunction.

SETTING

Hospitals (n=22) throughout the Intermountain West, including a quaternary care children's hospital.

PATIENTS

Neonates ≤44 postmenstrual weeks (median gestational age: 31 (IQR 28-36) weeks) receiving intravenous gentamicin with or without exposure to vancomycin from January 2006 to December 2012.

MAIN OUTCOME MEASURES

Nephrotoxicity based on the modified Acute Kidney Injury Network criteria for acute kidney injury (AKI) or serum creatinine concentration ≥1.5 mg/dL persisting for ≥48 h.

RESULTS

The final cohort was comprised of 1066 neonates (533 receiving vancomycin and gentamicin vs 533 receiving gentamicin). In a propensity score-matched cohort that was well balanced across 16 covariates, AKI was not associated with vancomycin use (16 neonates receiving vancomycin vs 7 controls experienced AKI; OR 1.5; 95% CI 0.6 to 4.0). However, the presence of a patent ductus arteriosus, concomitant non-steroidal anti-inflammatory drug use, ≥1 positive blood cultures, low birth weight and higher severity of illness and risk of mortality scores were associated with an increased risk of nephrotoxicity.

CONCLUSIONS

These results corroborate several earlier reports and much anecdotal evidence describing the infrequent occurrence of nephrotoxicity in neonates receiving concomitant vancomycin and gentamicin.

Drug-induced acute kidney injury in neonates

PURPOSE OF REVIEW

Acute kidney injury (AKI) is an independent risk factor for morbidity and mortality in critically ill neonates. Nephrotoxic medication exposure is common in neonates. Nephrotoxicity represents the most potentially avoidable cause of AKI in this population.

RECENT FINDINGS

Recent studies in critically ill children revealed the importance of recognizing AKI and potentially modifiable risk factors for the development of AKI such as nephrotoxic medication exposures. Data from critically ill children who have AKI suggest that survivors are at risk for the development of chronic kidney disease. Premature infants are born with incomplete nephrogenesis and are at risk for chronic kidney disease. The use of nephrotoxic medications in the neonatal intensive care unit is very common; yet the effects of medication nephrotoxicity on the short and long-term outcomes remains highly understudied.

SUMMARY

The neonatal kidney is predisposed to nephrotoxic AKI. Our ability to improve outcomes for this vulnerable group depends on a heightened awareness of this issue. It is important for clinicians to develop methods to minimize and prevent nephrotoxic AKI in neonates through a multidisciplinary approach aiming at earlier recognition and close monitoring of nephrotoxin-induced AKI.

Clinical Utility and Safety of a Model-Based Patient-Tailored Dose of Vancomycin in Neonates

Pharmacokinetic modeling has often been applied to evaluate vancomycin pharmacokinetics in neonates. However, clinical application of the model-based personalized vancomycin therapy is still limited. The objective of the present study was to evaluate the clinical utility and safety of a model-based patient-tailored dose of vancomycin in neonates. A model-based vancomycin dosing calculator, developed from a population pharmacokinetic study, has been integrated into the routine clinical care in 3 neonatal intensive care units (Robert Debré, Cochin Port Royal, and Clocheville hospitals) between 2012 and 2014. The target attainment rate, defined as the percentage of patients with a first therapeutic drug monitoring serum vancomycin concentration achieving the target window of 15 to 25 mg/liter, was selected as an endpoint for evaluating the clinical utility. The safety evaluation was focused on nephrotoxicity. The clinical application of the model-based patient-tailored dose of vancomycin has been demonstrated in 190 neonates. The mean (standard deviation) gestational and postnatal ages of the study population were 31.1 (4.9) weeks and 16.7 (21.7) days, respectively. The target attainment rate increased from 41% to 72% without any case of vancomycin-related nephrotoxicity. This proof-of-concept study provides evidence for integrating model-based antimicrobial therapy in neonatal routine care.

Duration of vancomycin treatment for coagulase-negative Staphylococcus sepsis in very low birth weight infants

AIM

Vancomycin is widely used to treat late onset coagulase-negative Staphylococcus (CoNS) sepsis in very low birth weight (VLBW) infants. Although vancomycin is associated with a risk of toxicity and bacterial resistance, the appropriate duration of use has not been established. This study sought to investigate the association between the duration of vancomycin therapy and clinical outcome in VLBW infants with CoNS sepsis.

METHODS

The files of all VLBW infants treated for CoNS sepsis at a tertiary paediatric medical centre from 1995-2003 were reviewed for clinical data, laboratory variables and outcome. Only patients with two positive diagnostic blood cultures were included. The findings were analyzed by duration of vancomycin treatment after the last positive blood culture.

RESULTS

The study cohort included 126 infants, 48 treated for 5 days, 32 for 6-7 days, 31 for 8-10 days and 15 for >10 days. There were no differences among the groups in perinatal characteristics, central catheter dwell time, laboratory data including haematologic, renal and liver function tests, or rate of complications of prematurity. Five infants were diagnosed with infective endocarditis or aortic thrombi and were treated for >10 days. CoNS sepsis recurred in two infants (1.6%). No toxicity of vancomycin treatment was observed.

CONCLUSIONS

In VLBW infants with uncomplicated CoNS sepsis, treatment with vancomycin for 5 days after the last positive blood culture appears to be associated with a satisfactory outcome and no adverse effects. A well-controlled prospective multicentre study is needed to confirm these findings.

Evaluation of the vancomycin dosage regimen based on serum creatinine used in the neonatal intensive care unit

BACKGROUND

Vancomycin is frequently used for the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections; however, determining the optimal dosage for neonates is difficult because of their immature renal function.

METHODS

Serum creatinine-based dosing was introduced in Kumamoto City Hospital Neonatal Medical Center. Serum trough concentration and therapeutic efficacy of vancomycin were evaluated before and after the introduction of the creatinine-based dosing.

RESULTS

When the therapeutic range of serum trough concentration of vancomycin at steady state was set to 5-15 µg/mL, 20 trough concentrations (48.8%) were within the therapeutic range and 21 trough concentrations were outside the therapeutic range before the introduction of the serum creatinine-based dosing. After the introduction of serum creatinine-based dosing, 18 trough concentrations (81.8%) were within the therapeutic range and 4 trough concentrations were not, and there was an increase in the number of patients with trough concentrations in the therapeutic range (P= 0.01; Fisher's exact test).

CONCLUSIONS

The serum creatinine-based dosing of vancomycin is useful in maintaining the appropriate serum level of vancomycin in neonates.

Cochrane meta-analysis: teicoplanin versus vancomycin for proven or suspected infection

ABSTRACT Objective: To compare efficacy and safety of vancomycin versus teicoplanin in patients with proven or suspected infection. Methods: Data Sources: Cochrane Renal Group's Specialized Register, CENTRAL, MEDLINE, EMBASE, nephrology textbooks and review articles. Inclusion criteria: Randomized controlled trials in any language comparing teicoplanin to vancomycin for patients with proven or suspected infection. Data extraction: Two authors independently evaluated methodological quality and extracted data. Study investigators were contacted for unpublished information. A random effect model was used to estimate the pooled risk ratio (RR) with 95% confidence interval (CI). Results: A total of 24 studies (2,610 patients) were included. The drugs had similar rates of clinical cure (RR: 1.03; 95%CI: 0.98-1.08), microbiological cure (RR: 0.98; 95%CI: 0.93-1.03) and mortality (RR: 1.02; 95%CI: 0.79-1.30). Teicoplanin had lower rates of skin rash (RR: 0.57; 95%CI: 0.35-0.92), red man syndrome (RR: 0.21; 95%CI: 0.08-0.59) and total adverse events (RR: 0.73; 95%CI: 0.53-1.00). Teicoplanin reduced the risk of nephrotoxicity (RR: 0.66; 95%CI: 0.48-0.90). This effect was consistent for patients receiving aminoglycosides (RR: 0.51; 95%CI: 0.30-0.88) or having vancomycin doses corrected by serum levels (RR: 0.22; 95%CI: 0.10-0.52). There were no cases of acute kidney injury needing dialysis. Limitations: Studies lacked a standardized definition for nephrotoxicity. Conclusions: Teicoplanin and vancomycin are equally effective; however the incidence of nephrotoxicity and other adverse events was lower with teicoplanin. It may be reasonable to consider teicoplanin for patients at higher risk for acute kidney injury.

Teicoplanin versus vancomycin for proven or suspected infection

BACKGROUND

Vancomycin and teicoplanin are commonly used to treat gram-positive infections, particularly those caused by methicillin-resistant Staphylococcus aureus (MRSA). There is uncertainty regarding the effects of teicoplanin compared to vancomycin on kidney function with some previous studies suggesting teicoplanin is less nephrotoxic than vancomycin.

OBJECTIVES

To investigate the efficacy and safety of vancomycin versus teicoplanin in patients with proven or suspected infection.

SEARCH STRATEGY

We searched the Cochrane Renal Group's Specialised Register, CENTRAL, MEDLINE, EMBASE, reference lists of nephrology textbooks, review articles with relevant studies and sent letters seeking information about unpublished or incomplete studies to investigators involved in previous studies.

SELECTION CRITERIA

We searched for randomised controlled trials (RCTs) in any language comparing teicoplanin to vancomycin for patients with proven or suspected infection.

DATA COLLECTION AND ANALYSIS

Two authors independently evaluated methodological quality and extracted data using standardised data extraction forms. Study investigators were contacted for information not available in the original manuscripts. Random effects model was used to estimate the pooled risk ratio (RR) with 95% confidence interval (CI).

MAIN RESULTS

We included 24 studies (2,610 patients) in this review. Teicoplanin reduced the risk of nephrotoxicity compared to vancomycin (RR 0.66, 95% CI 0.48 to 0.90).The effects of teicoplanin or vancomycin were similar for clinical cure (RR 1.03, 95% CI 0.98 to 1.08), microbiological cure (RR 0.98, 95% CI 0.93 to 1.03) and mortality (RR 1.02, 95% CI 0.79 to1.30). Six studies reported no cases of acute kidney injury (AKI) needing dialysis. Adverse events were less frequent with teicoplanin including cutaneous rash (RR 0.57, 95% CI 0.35 to 0.92), red man syndrome (RR 0.21, 95% CI 0.08 to 0.59) and total adverse events (RR 0.73, 95% CI 0.53 to 1.00). A lower risk of nephrotoxicity with teicoplanin was observed in patients either with (RR 0.51, 95% CI 0.30 to 0.88) or without aminoglycosides (RR 0.31, 95% 0.07 to 1.50), and also when vancomycin dosing was guided by serum levels (RR 0.22, 95% CI 0.10 to 0.52).

AUTHORS' CONCLUSIONS

Teicoplanin and vancomycin are both effective in treating those with proven or suspected infection; however the incidence of adverse effects including nephrotoxicity was lower with teicoplanin. There were no cases of AKI needing dialysis. It remains unclear whether the differential effect on kidney function should influence which antibiotic be prescribed, although it may be reasonable to consider teicoplanin for patients at higher risk for AKI needing dialysis.

Drug-Associated Renal Dysfunction

Acute renal failure (ARF) in patients in the ICU is associated with a high mortality. Drug-induced renal dysfunction is an important, yet often overlooked, cause of ARF in this patient population. A drug use evaluation at the authors' institution, to assess the prescribing patterns of potential nephrotoxins in the adult and pediatric ICUs, found that antibiotics (aminoglycosides, amphotericin B, penicillins, cephalosporins, acyclovir), nonsteroidal anti-inflammatory drugs, contrast dye, and various other nephrotoxic medications are used widely in all of the ICUs. By focusing on several commonly prescribed classes of nephrotoxic medications in the ICU, this article reviews the general mechanisms of drug-associated renal dysfunction.

Population pharmacokinetics of vancomycin in patients receiving extracorporeal membrane oxygenation

AIMS

Extracorporeal membrane oxygenation (ECMO) is a life support system used during severe respiratory or cardiorespiratory failure. The objective of this study was to characterize the population pharmacokinetics of vancomycin during ECMO.

METHODS

A population model was developed using WinNonMix (Version 2.0.1) from a total of 366 plasma observations in 45 patients, including term neonates, older children and adults. The study utilized both rich prospective and sparse retrospective data. Prospective samples were drawn at baseline and then 30, 60,90, 120, 180, 240, 300, 360 and 420 min postinfusion. Steady state concentrations were obtained retrospectively from an assay database, cross-referencing with the patients' medical records.

RESULTS

Data were examined using a two-compartment model with an additive and proportional residual error. Model fit improved substantially when clearance, CL (l kg(-1) h(-1)) was modelled as a nonlinear function of serum creatinine (Cr) micromol l(-1). There was a linear relationship between CL and age up to 1000 days: CL (Age < 1000 days) = [2.4 + 0.0018 x Age (days)]/Cr; CL (Age > 1000 days) = 4.3/Cr. Age also influenced central volume (V1) when included in the model as a dichotomous variable: V1 (Age < 4000 days) = 0.45 l kg(-1); V1 (Age > 4000 days) = 0.36 l kg(-1). Intercompartmental clearance and tissue volume were estimated to be 0.09 l kg(-1) h(-1) and 0.25 l kg(-1), respectively. Model validation in a separate group of 20 patients revealed a bias of -7.7% and a precision of 26.7%.

CONCLUSIONS

The clearance of vancomycin was decreased and its volume of distribution increased in patients receiving ECMO, suggesting altered drug disposition during this treatment.

New dosing strategies for antibacterial agents in the neonate

Dosing of antibiotics in neonates requires finding a delicate balance between maximal efficacy and minimal toxicity. There is a lack of data on efficacy of currently used antibiotics in neonates, and rational dosing therefore needs to be based on gestational- and postnatal-age-dependent pharmacokinetics in combination with surrogate markers. These surrogate markers are: (i) the area-under-the serum concentration time curve to minimum inhibitory concentration ratio (AUC/MIC); (ii) peak concentration to MIC ratio (Cmax/MIC); and (iii) the time the concentration remains above the MIC (T>MIC). Whereas the efficacy of beta-lactam antibiotics (including carbapenems) depends on T>MIC, the efficacy of most other antimicrobials (including aminoglycosides and fluoroquinolones) is related to AUC/MIC and Cmax/MIC. Most modern dosing regimens are adequate when these concentration effect relationships are taken into account. Dosing adjustments in neonates are suggested, based on these relationships. Several antimicrobial combinations for treatment of meningitis and necrotizing enterocolitis exist. Empiric treatment should be based on efficacy, concerns about resistance as well as information from institutional microbiological surveillance.

Vancomycin

This review describes the use of vancomycin in neonates over the last three decades. Given the relation of late-onset neonatal septicaemia to outcome and the increase in coagulase-negative staphylococcal infection as causative organism, vancomycin remains an important antibacterial in the neonatal intensive care unit. The pharmacokinetic behaviour of vancomycin in neonates can be adequately described by a one- or two-compartment model and is mainly determined by postconceptional age and renal function. In neonates, a patent ductus arteriosus as well as treatment with indomethacin or extracorporeal membrane oxygenation (ECMO) leads to an increase in volume of distribution and a decrease in clearance. Microbiological studies in vitro have shown that an increase in vancomycin concentrations above the minimum inhibitory concentration does not result in more effective killing. The microbiological and clinical efficacy of vancomycin in neonates has only been studied explicitly in a restricted number of patients. There are no definitive data relating serum concentrations to effect in this patient group. Vancomycin-related nephrotoxicity and ototoxicity in neonates is rare, and no clear relation to serum concentrations has been demonstrated. Based on the pharmacokinetic profile of vancomycin in neonates, several administration regimens have been constructed. Recent guidelines have suggested that dosage can be independent of gestational age or postconceptional age in neonates without renal failure. In patients with renal failure, therapy can be adequately tailored by using a regimen based on serum creatinine. The usefulness of routine monitoring of peak serum concentrations is doubtful based on the current literature. Recent research demonstrates a shift towards taking only routine trough serum concentrations in order to optimise efficacy. Patients with renal failure and other special subpopulations, such as patients exposed to ECMO or indomethacin, need to be monitored more closely.

Renal transport of antibiotics and nephrotoxicity: a review

The renal excretion of a drug can essentially be divided schematically into three functional processes: glomerular filtration, tubular reabsorption and tubular secretion. When assessing nephrotoxicity, the tubular secretion system, which allows transport of the drug from the blood to the urine via the tubular cells, is particularly important. Historically, two distinct tubular secretion mechanisms have been described for drugs: one via organic cations and the other via organic anions. More recently, a third tubular secretion mechanism has been identified, mediated by P-glycoprotein. In the present review, a number of examples will be given relating to antibiotic-induced kidney damage determined via the tubular reabsorption mechanism (aminoglycosides, amphotericin B) and via the tubular secretion mechanism (cephalosporins, vancomycin), respectively. Drug transport within the tubular cells is the first fundamental stage in the onset of the nephrotoxic process. Knowledge of these concepts is important for the prevention of iatrogenic kidney damage, particularly in patients with underlying disease receiving concomitant treatment with several potentially nephrotoxic molecules.

Vancomycin for prophylaxis against sepsis in preterm neonates

BACKGROUND

Nosocomial, late onset sepsis occurs in up to 50% of infants of less than 1000gm at birth. The commonest organism isolated is coagulase negative staphylococcus (CoNS). A number of studies have evaluated the efficacy or prophylactic low dose vancomycin given either as a continuous infusion added to the infant's hyperalimentation fluid or by intermittent intravenous administration and these studies in very low birth weight infants are the subject of this review.

OBJECTIVES

To evaluate the safety and efficacy of vancomycin prophylaxis for the prevention of late-onset sepsis, coagulase negative staphylococcal sepsis, mortality, and effects on length of stay, total vancomycin exposure, evidence of vancomycin toxicity, and the development of vancomycin resistant organisms in the preterm neonate.

SEARCH STRATEGY

Searches were made of Medline, (MeSH terms: Vancomycin and Sepsis; limits: age groups, newborn infants), HealthStar and EMBase, electronic abstracts, personal files and conference proceedings.

SELECTION CRITERIA

Randomized controlled trials which compared the incidence of sepsis and mortality in preterm neonates receiving vancomycin prophylaxis versus a control group receiving no prophylaxis.

DATA COLLECTION AND ANALYSIS

Data regarding clinical outcomes including the overall incidence of sepsis, the incidence of coagulase negative staphylococcal sepsis, mortality, length of stay, total vancomycin exposure, evidence of vancomycin toxicity, and the development of vancomycin resistant organisms were excerpted from previous clinical trials. Data analysis was done in accordance with the standards of the Cochrane Neonatal Review Group.

MAIN RESULTS

The administration of prophylactic vancomycin reduced the incidence of both total neonatal nosocomial sepsis and coagulase negative staphylococcal sepsis in eligible preterm infants. Mortality, length of stay, and evidence of vancomycin toxicity were not significantly different between the two groups. There was insufficient evidence to ascertain the risks of development of vancomycin resistant organisms in the nurseries involved in these trials.

REVIEWER'S CONCLUSIONS

The use of prophylactic vancomycin in low doses reduces the incidence of nosocomial sepsis in the neonate. The methodologies of these studies may have contributed to the low rate of sepsis in the treated groups, as the blood cultures drawn from central lines may have failed to grow due to the low levels of vancomycin in the infusate. Although there is a theoretical concern regarding the development of resistant organisms with the administration of prophylactic antibiotic, there is insufficient evidence to ascertain the risks of development of vancomycin resistant organisms. Few clinically important benefits have been demonstrated for very low birth weight infants treated with prophylactic vancomycin. It therefore appears that routine prophylaxis with vancomycin should not be undertaken at present.