The impact of ibuprofen or indomethacin on renal drug clearance in neonates

Physiologically Based Pharmacokinetic Modeling of Vancomycin in Critically Ill Neonates: Assessing the Impact of Pathophysiological Changes

Dosing vancomycin for critically ill neonates is challenging owing to substantial alterations in pharmacokinetics (PKs) caused by variability in physiology, disease, and clinical interventions. Therefore, an adequate PK model is needed to characterize these pathophysiological changes. The intent of this study was to develop a physiologically based pharmacokinetic (PBPK) model that reflects vancomycin PK and pathophysiological changes in neonates under intensive care. PK-sim software was used for PBPK modeling. An adult model (model 0) was established and verified using PK profiles from previous studies. A neonatal model (model 1) was then extrapolated from model 0 by scaling age-dependent parameters. Another neonatal model (model 2) was developed based not only on scaled age-dependent parameters but also on quantitative information on pathophysiological changes obtained via a comprehensive literature search. The predictive performances of models 1 and 2 were evaluated using a retrospectively collected dataset from neonates under intensive care (chictr.org.cn, ChiCTR1900027919), comprising 65 neonates and 92 vancomycin serum concentrations. Integrating literature-based parameter changes related to hypoalbuminemia, small-for-gestational-age, and co-medication, model 2 offered more optimized precision than model 1, as shown by a decrease in the overall mean absolute percentage error (50.6% for model 1; 37.8% for model 2). In conclusion, incorporating literature-based pathophysiological changes effectively improved PBPK modeling for critically ill neonates. Furthermore, this model allows for dosing optimization before serum concentration measurements can be obtained in clinical practice.

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.

Ibuprofen treatment after the first days of life in preterm neonates with patent ductus arteriosus

AIM

Patent ductus arteriosus (PDA) is treated with ibuprofen and it is known that the clearance of ibuprofen increases with postnatal age. We aimed to study whether postnatal age-adjusted ibuprofen dosages improve the effectiveness of treatment compared to standard ibuprofen dosages after the first days of life.

METHODS

A historical cohort of 207 preterm neonates treated with standard ibuprofen dosages (Group A; 2011-2015) was compared to a prospective cohort of 66 preterm neonates treated with postnatal age-adjusted ibuprofen dosages (Group B; 2015-2016).

RESULTS

Both groups had comparable background characteristics. Treatment was started after median 6 (25-75th percentile: 4-11) and 5 (25-75th percentile: 4-11) days and effectiveness was 33.2 and 44.7% (p = .17) in groups A and B, respectively. No hemodynamically significant PDA was found in 23/49 (46.9%) of the patients born before 28 weeks after adjusted ibuprofen dosages compared to 48/162 (29.6%) after standard ibuprofen dosages (p = .04). There were significantly more reversible side effects with the postnatal age-adjusted ibuprofen dosages (p = .04).

CONCLUSIONS

There seems to be a trend to higher effectiveness with the adjusted ibuprofen dosages in preterm neonates before 28 weeks, but it is associated with more reversible side effects.

Risk of nonsteroidal anti-inflammatory drug-associated renal dysfunction among neonates diagnosed with patent ductus arteriosus and treated with gentamicin

OBJECTIVE

To evaluate the risk of nonsteroidal anti-inflammatory drug (NSAID) therapy-associated acute kidney injury (AKI) among neonates diagnosed with patent ductus arteriosus (PDA) who are treated with gentamicin.

STUDY DESIGN

Multicenter retrospective observational study of patients ⩽44 postmenstrual weeks of age diagnosed with PDA who received gentamicin during hospitalization between January 2006 and December 2014. Patients with and without NSAID exposure were matched on covariates associated with AKI and NSAID therapy. The primary end point, AKI, was defined according to Kidney Disease Improving Global Outcomes neonatal criteria.

RESULTS

The rate of AKI for the entire cohort (n=594) was 12% (n=71). Among neonates receiving NSAIDS, 14.8% (n=44) experienced an AKI as compared to 9.1% (n=27) for those who were not exposed (relative risk, 1.6; 95% confidence interval, 1.0 to 2.6). Therefore, the attributable risk of NSAID use was 5.7% (95% confidence interval, 0.5 to 11.0).

CONCLUSION

Among neonates with PDA and receiving gentamicin, NSAID therapy increases the risk of AKI by about 6%.

Dosing antibiotics in neonates: review of the pharmacokinetic data

Antibiotics are often used in neonates despite the absence of relevant dosing information in drug labels. For neonatal dosing, clinicians must extrapolate data from studies for adults and older children, who have strikingly different physiologies. As a result, dosing extrapolation can lead to increased toxicity or efficacy failures in neonates. Driven by these differences and recent legislation mandating the study of drugs in children and neonates, an increasing number of pharmacokinetic studies of antibiotics are being performed in neonates. These studies have led to new dosing recommendations with particular consideration for neonate body size and maturation. Herein, we highlight the available pharmacokinetic data for commonly used systemic antibiotics in neonates.

Pharmacometric Approaches to Personalize Use of Primarily Renally Eliminated Antibiotics in Preterm and Term Neonates

Sepsis remains a major cause of mortality and morbidity in neonates, and, as a consequence, antibiotics are the most frequently prescribed drugs in this vulnerable patient population. Growth and dynamic maturation processes during the first weeks of life result in large inter- and intrasubject variability in the pharmacokinetics (PK) and pharmacodynamics (PD) of antibiotics. In this review we (1) summarize the available population PK data and models for primarily renally eliminated antibiotics, (2) discuss quantitative approaches to account for effects of growth and maturation processes on drug exposure and response, (3) evaluate current dose recommendations, and (4) identify opportunities to further optimize and personalize dosing strategies of these antibiotics in preterm and term neonates. Although population PK models have been developed for several of these drugs, exposure-response relationships of primarily renally eliminated antibiotics in these fragile infants are not well understood, monitoring strategies remain inconsistent, and consensus on optimal, personalized dosing of these drugs in these patients is absent. Tailored PK/PD studies and models are useful to better understand relationships between drug exposures and microbiological or clinical outcomes. Pharmacometric modeling and simulation approaches facilitate quantitative evaluation and optimization of treatment strategies. National and international collaborations and platforms are essential to standardize and harmonize not only studies and models but also monitoring and dosing strategies. Simple bedside decision tools assist clinical pharmacologists and neonatologists in their efforts to fine-tune and personalize the use of primarily renally eliminated antibiotics in term and preterm neonates.

Drug-induced renal damage in preterm neonates: state of the art and methods for early detection

Only a small fraction of drugs widely used in neonatal intensive care units (NICU) are specifically authorized for this population. Even if unlicensed or off-label use is necessary, it is associated with increased adverse drug reactions, which must be carefully weighed against expected benefits. In particular, renal damage is frequent among preterm babies, and is considered a predisposing factor for the development of chronic kidney disease in adulthood. Apart from specific conditions affecting premature neonates (e.g. respiratory distress syndrome, perinatal asphyxia), drugs play an important role in impairing renal function because of well-known nephrotoxicity and/or interaction with renal developmental factors. From a review of the available studies on drug use in NICU patients, we identified and described the most commonly administered drugs that are correlated to renal damage. Early detection of kidney injury is becoming an essential aspects for clinicians because of the limited number of biomarkers applicable in the neonatal population. Postnatal changes of biochemical processes that influence pharmacokinetic and pharmacodynamic aspects need to be further investigated in order to better understand the mechanisms of drug toxicity in this population. The most promising strategies for dose adjustment and therapeutic schemes are discussed. The purpose of this review was to describe current knowledge on drug use among premature babies and their implication in kidney injury development, as well as to highlight available strategies for early detection of renal damage.

Effect of Kidney Function on Drug Kinetics and Dosing in Neonates, Infants, and Children

Neonates, infants, and children differ from adults in many aspects, not just in age, weight, and body composition. Growth, maturation and environmental factors affect drug kinetics, response and dosing in pediatric patients. Almost 80% of drugs have not been studied in children, and dosing of these drugs is derived from adult doses by adjusting for body weight/size. As developmental and maturational changes are complex processes, such simplified methods may result in subtherapeutic effects or adverse events. Kidney function is impaired during the first 2 years of life as a result of normal growth and development. Reduced kidney function during childhood has an impact not only on renal clearance but also on absorption, distribution, metabolism and nonrenal clearance of drugs. 'Omics'-based technologies, such as proteomics and metabolomics, can be leveraged to uncover novel markers for kidney function during normal development, acute kidney injury, and chronic diseases. Pharmacometric modeling and simulation can be applied to simplify the design of pediatric investigations, characterize the effects of kidney function on drug exposure and response, and fine-tune dosing in pediatric patients, especially in those with impaired kidney function. One case study of amikacin dosing in neonates with reduced kidney function is presented. Collaborative efforts between clinicians and scientists in academia, industry, and regulatory agencies are required to evaluate new renal biomarkers, collect and share prospective pharmacokinetic, genetic and clinical data, build integrated pharmacometric models for key drugs, optimize and standardize dosing strategies, develop bedside decision tools, and enhance labels of drugs utilized in neonates, infants, and children.

The interplay between drugs and the kidney in premature neonates

The kidney plays a central role in the clearance of drugs. However, renal drug handling entails more than glomerular filtration and includes tubular excretion and reabsorption, and intracellular metabolization by cellular enzyme systems, such as the Cytochrome P450 isoenzymes. All these processes show maturation from birth onwards, which is one of the reasons why drug dosing in children is not simply similar to dosing in small adults. As kidney development normally finishes around the 36th week of gestation, being born prematurely will result in even more immature renal drug handling. Environmental effects, such as extra-uterine growth restriction, sepsis, asphyxia, or drug treatments like caffeine, aminoglycosides, or non-steroidal anti-inflammatory drugs, may further hamper drug handling in the kidney. Dosing in preterm neonates is therefore dependent on many factors that need to be taken into account. Drug treatment may significantly hamper postnatal kidney development in preterm neonates, just like renal immaturity has an impact on drug handling. The restricted kidney development results in a lower number of nephrons that may have several long-term sequelae, such as hypertension, albuminuria, and renal failure. This review focuses on the interplay between drugs and the kidney in premature neonates.

Transition to postnatal renal function

In-utero the placenta is the primary organ responsible for neonatal homeostasis of fluid and electrolyte balance. With birth, this responsibility now transitions to the neonatal kidney. For successful transition to extrauterine renal physiology to occur maturation of neonatal glomerular filtration must occur, which is dependent on the development of renal blood flow. While these functions are decreased at birth, the term infant's kidneys are still able to manage homeostasis and are sufficient for growth and development. However, stressors can limit the adaptive properties of the neonatal kidney. This is especially important for those infants born before 34 weeks' gestation, when nephrogenesis is not yet complete. Knowledge of the changes in renal physiology is essential in caring for the neonate during transition. This article describes those changes.

Laboratory blood tests useful in monitoring renal function in neonates

It is important to monitor renal function in the neonate, especially in premature infants where nephrogenesis is still in process upon birth. The kidneys are responsible for maintaining homeostasis in the extracellular environment by preventing overaccumulation of waste products and electrolytes. This review describes developmental physiology of the renal system as well as laboratory testing to monitor renal function and glomerular filtration in neonates. Drugs that may affect renal function in infants are also discussed.

Clinical pharmacology of indomethacin in preterm infants: implications in patent ductus arteriosus closure

Indomethacin is a non-steroidal anti-inflammatory drug that is a potent inhibitor of prostaglandin E(2) synthesis. After birth, the ductus arteriosus closes spontaneously within 2-4 days in term infants. The major factor closing the ductus arteriosus is the tension of oxygen, which increases significantly after birth. Prostaglandin E(2) has the opposite effect to that of oxygen; it relaxes smooth muscle and tends to inhibit the closure of the ductus arteriosus. In preterm infants with respiratory distress syndrome, the ductus arteriosus fails to close (patent ductus arteriosus [PDA]) because the concentration of prostaglandin E2 is relatively high. PDA occurs in more than 70 % of neonates weighing less than 1,500 g at birth. The aim of this article was to review the published data on the clinical pharmacology of indomethacin in preterm infants in order to provide a critical analysis of the literature and a useful tool for physicians. The bibliographic search was performed electronically using the PubMed and EMBASE databases as search engines and February 2012 was the cutoff point. A remarkable interindividual variability was observed for the half-life (t(½)), clearance (CL), and volume of distribution (V(d)) of indomethacin. Prophylactic indomethacin consists of a continuous infusion of low levels of indomethacin and may be useful in preterm infants. Extremely preterm infants are less likely to respond to indomethacin. Infants with a postnatal age of 2 months do not respond to treatment with indomethacin. Indomethacin has several adverse effects, the most common of which is renal failure. An increase in serum creatinine of ≥0.5 % mg/dL after indomethacin was observed in about 10-15 % of the patients and creatinine returns to a normal level about 1 week after cessation of therapy. Indomethacin should be administered intravenously by syringe pump for at least 30 min to minimize adverse effects on cerebral, gastrointestinal, and renal blood flow velocities. A prolonged course of indomethacin appears to reduce the risk of severe intracranial hemorrhage and renal impairment in patients with PDA. In conclusion, indomethacin is a useful drug to treat PDA.

A neonatal amikacin covariate model can be used to predict ontogeny of other drugs eliminated through glomerular filtration in neonates

PURPOSE

Recently, a covariate model characterizing developmental changes in clearance of amikacin in neonates has been developed using birth bodyweight and postnatal age. The aim of this study was to evaluate whether this covariate model can be used to predict maturation in clearance of other renally excreted drugs.

METHODS

Five different neonatal datasets were available on netilmicin, vancomycin, tobramycin and gentamicin. The extensively validated covariate model for amikacin clearance was used to predict clearance of these drugs. In addition, independent reference models were developed based on a systematic covariate analysis.

RESULTS

The descriptive and predictive properties of the models developed using the amikacin covariate model were good, and fairly similar to the independent reference models (goodness-of-fit plots, NPDE). Moreover, similar clearance values were obtained for both approaches. Finally, the same covariates as in the covariate model of amikacin, i.e. birth bodyweight and postnatal age, were identified on clearance in the independent reference models.

CONCLUSIONS

This study shows that pediatric covariate models may contain physiological information since information derived from one drug can be used to describe other drugs. This semi-physiological approach may be used to optimize sparse data analysis and to derive individualized dosing algorithms for drugs in children.

Treatment of patent ductus arteriosus (PDA) using ibuprofen: renal side-effects in VLBW and ELBW newborns

OBJECTIVES

This study aims to determine whether or not treatment of preterm neonates with PDA using IV ibuprofen can impair renal function and in what range of birth weights and gestational ages the risk of major renal side-effects due to ibuprofen is highest.

METHODS

134 preterm newborns with PDA were enrolled and randomized to receive either placebo or a 3-day-course (10, 5 and 5 mg/kg) of IV ibuprofen. 67 newborns (mGA: 27(+3) w and mBW: 989 g) with PDA received ibuprofen.

RESULTS

Subdividing the infants according to BW and to GA, the values of creatinine and BUN were only significantly higher than initial values at the end of the therapy in newborns with a BW ≤1000 g and/or GA ≤26 weeks. Renal impairment is greater the lower the weight and gestational age of the infant at birth.

CONCLUSIONS

Ibuprofen significantly impairs renal function in preterm infants with a GA ≤26 weeks and/or in ELBW neonates, while it may be considered safe for infants with a BW >1000 g and/or GA >26 weeks. Thus, before starting therapy with IV ibuprofen, it is essential to take into account the BW and GA of newborns and the effective need for treatment from the point of view of the ratio of risks to benefits, due to its substantial renal side-effects.

Clinical pharmacokinetics of vancomycin in the neonate: a review

Neonatal sepsis is common and is a major cause of morbidity and mortality. Vancomycin is the preferred treatment of several neonatal staphylococcal infections. The aim of this study was to review published data on vancomycin pharmacokinetics in neonates and to provide a critical analysis of the literature. A bibliographic search was performed using PubMed and Embase, and articles with a publication date of August 2011 or earlier were included in the analysis. Vancomycin pharmacokinetic estimates, which are different in neonates compared with adults, also exhibit extensive inter-neonatal variability. In neonates, several vancomycin dosing schedules have been proposed, mainly based on age (i.e., postmenstrual and postnatal), body weight or serum creatinine level. Other covariates [e.g., extracorporeal membrane oxygenation (ECMO), indomethacin or ibuprofen, and growth restriction] of vancomycin pharmacokinetics have been reported in neonates. Finally, vancomycin penetrates cerebrospinal fluid (range = 7-42%). Renal function drives vancomycin pharmacokinetics. Because either age or weight is the most relevant covariate of renal maturation, these covariates should be considered first in neonatal vancomycin dosing guidelines and further adjusted by renal dysfunction indicators (e.g., ECMO and ibuprofen/indomethacin). In addition to the prospective validation of available dosing guidelines, future studies should focus on the relevance of therapeutic drug monitoring and on the value of continuous vancomycin administration in neonates.

Effects of ibuprofen treatment on the developing preterm baboon kidney

Preterm neonates are commonly exposed postnatally to pharmacological treatments for a patent ductus arteriosus. Exposure of the developing kidney to nephrotoxic medications may adversely impact renal development. This study aimed to determine the effect of early postnatal ibuprofen treatment, both alone and in combination with a nitric oxide synthase inhibitor (NOSi), on renal development and morphology. Baboon neonates were delivered prematurely at 125-day (125d) gestation (term = 185d) and were euthanized at birth or postnatal day 6. Neonates were divided into four groups: 125d gestational controls (n = 8), Untreated (n = 8), Ibuprofen (n = 6), and ibuprofen (Ibu)+NOSi (n = 4). Animals in the Ibuprofen and Ibu+NOSi groups received five doses of ibuprofen, with the Ibuprofen+NOSi animals additionally administered a NOS inhibitor (N(G)-monomethyl-l-arginine). There was no difference among groups in body weight, kidney weight, or glomerular generation number. Nephrogenic zone width was significantly reduced in the Ibuprofen group (123.5 ± 7.4 μm) compared with the 125d gestational control (176.1 ± 6.9 μm) and Untreated animals (169.7 ± 78.8 μm). In the Ibu+NOSi group, nephrogenic zone width averaged 152.7 ± 3.9 μm, which was not significantly different from any other group. Morphologically abnormal glomeruli were present at a range of 0.0-22.9% in the Untreated group, 0.0-6.1% in the Ibuprofen group, and 0.0-1.4% in the Ibu+NOSi group. In conclusion, early postnatal ibuprofen exposure is associated with a reduced nephrogenic zone width, which may suggest the early cessation of nephrogenesis following treatment. Ultimately, this may impact the number of nephrons formed in the preterm kidney.

Effects of ibuprofen treatment on the developing preterm baboon kidney

Preterm neonates are commonly exposed postnatally to pharmacological treatments for a patent ductus arteriosus. Exposure of the developing kidney to nephrotoxic medications may adversely impact renal development. This study aimed to determine the effect of early postnatal ibuprofen treatment, both alone and in combination with a nitric oxide synthase inhibitor (NOSi), on renal development and morphology. Baboon neonates were delivered prematurely at 125-day (125d) gestation (term = 185d) and were euthanized at birth or postnatal day 6. Neonates were divided into four groups: 125d gestational controls (n = 8), Untreated (n = 8), Ibuprofen (n = 6), and ibuprofen (Ibu)+NOSi (n = 4). Animals in the Ibuprofen and Ibu+NOSi groups received five doses of ibuprofen, with the Ibuprofen+NOSi animals additionally administered a NOS inhibitor (N(G)-monomethyl-l-arginine). There was no difference among groups in body weight, kidney weight, or glomerular generation number. Nephrogenic zone width was significantly reduced in the Ibuprofen group (123.5 ± 7.4 μm) compared with the 125d gestational control (176.1 ± 6.9 μm) and Untreated animals (169.7 ± 78.8 μm). In the Ibu+NOSi group, nephrogenic zone width averaged 152.7 ± 3.9 μm, which was not significantly different from any other group. Morphologically abnormal glomeruli were present at a range of 0.0-22.9% in the Untreated group, 0.0-6.1% in the Ibuprofen group, and 0.0-1.4% in the Ibu+NOSi group. In conclusion, early postnatal ibuprofen exposure is associated with a reduced nephrogenic zone width, which may suggest the early cessation of nephrogenesis following treatment. Ultimately, this may impact the number of nephrons formed in the preterm kidney.

Creatinine reference values in ELBW infants: impact of quantification by Jaffe or enzymatic method

OBJECTIVE

Serum creatinine (Scr) reflects to a certain extent glomerular filtration rate in neonates, but postnatal observations also depends on the technique used to quantify Scr (Jaffe colorimetry or enzymatic quantification).

METHODS

In an attempt to quantify differences between these techniques, we compared postnatal Scr trends in two consecutive cohorts of extremely low birth-weight (ELBW) neonates before and following a switch from uncompensated Jaffe to enzymatic Scr quantification. Postnatal Scr (Days 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 21, 28, and 42) in 151 ELBW neonates (uncompensated Jaffe) was compared to 116 more recently admitted ELBW neonates (enzymatic).

RESULTS

Although clinical characteristics were similar between both cohorts, median postnatal Jaffe Scr values were significantly higher compared to enzymatic quantification (all days, at least p < 0.001) throughout postnatal life. While both cohorts displayed a similar trend with an initial increase with a Scr peak on Days 3 and 4 and a subsequent decrease, the difference in within-day median values fluctuated between 11 and 24 mmol.L(-1). There is neither fixed nor relative difference in Scr between both techniques.

CONCLUSIONS

When using Scr to estimate renal function in ELBW neonates, clinicians should in addition to the postnatal changes and other covariates of renal function, also consider the technique applied. We provide reference values and comparison between both techniques.

Current evidence on the safety profile of NSAIDs for the treatment of PDA

Patent ductus arteriosus (PDA) complicates the clinical course of preterm infants. Nonsteroidal anti-inflammatory drugs, especially Indomethacin and Ibuprofen, have been widely used for both prevention and treatment of PDA. Short-term efficacy of Indomethacin or Ibuprofen is equivalent, while Ibuprofen results show a higher safety profile. Ibuprofen is associated with fewer clinical gastrointestinal and renal side effects with respect to Indomethacin even if subclinical potential effects are reported. When administered as prophylaxis, Ibuprofen has no effects on prevention of intraventricular haemorrhage unlike Indomethacin. Considering the potential adverse effects of both these drugs, a careful monitoring during and after the treatment period is highly recommended.

Renal Side Effects of Non-Steroidal Anti-Inflammatory Drugs in Neonates

Non-steroidal anti-inflammatory drugs like ibuprofen or indomethacin are commonly prescribed drugs to induce pharmacologic closure of a patent ductus arteriosus in preterm neonates. Based on a recently published Cochrane meta-analysis, both drugs are equally effective to induce closure. Drug choice can therefore be based on differences in side effects or pharmaco-economic arguments. The current review quantifies the negative impact of either ibuprofen or indomethacin on renal function, including diuresis, glomerular filtration rate and renal tubular function. Both ibuprofen and indomethacin have a quantifiable impact on renal function. However, compared to ibuprofen, the negative impact of indomethacin is more pronounced.