Long-Term Effects of Inhaled Budesonide for Bronchopulmonary Dysplasia.

BACKGROUND: The long-term effects on neurodevelopment of the use of inhaled glucocorticoids in extremely preterm infants for the prevention or treatment of bronchopulmonary dysplasia are uncertain. METHODS: We randomly assigned 863 infants (gestational age, 23 weeks 0 days to 27 weeks 6 days) to receive early (within 24 hours after birth) inhaled budesonide or placebo. The prespecified secondary long-term outcome was neurodevelopmental disability among survivors, defined as a composite of cerebral palsy, cognitive delay (a Mental Development Index score of <85 [1 SD below the mean of 100] on the Bayley Scales of Infant Development, Second Edition, with higher scores on the scale indicating better performance), deafness, or blindness at a corrected age of 18 to 22 months. RESULTS: Adequate data on the prespecified composite long-term outcome were available for 629 infants. Of these infants, 148 (48.1%) of 308 infants assigned to budesonide had neurodevelopmental disability, as compared with 165 (51.4%) of 321 infants assigned to placebo (relative risk, adjusted for gestational age, 0.93; 95% confidence interval [CI], 0.80 to 1.09; P=0.40). There was no significant difference in any of the individual components of the prespecified outcome. There were more deaths in the budesonide group than in the placebo group (82 [19.9%] of 413 infants vs. 58 [14.5%] of 400 infants for whom vital status was available; relative risk, 1.37; 95% CI, 1.01 to 1.86; P=0.04). CONCLUSIONS: Among surviving extremely preterm infants, the rate of neurodevelopmental disability at 2 years did not differ significantly between infants who received early inhaled budesonide for the prevention of bronchopulmonary dysplasia and those who received placebo, but the mortality rate was higher among those who received budesonide. (Funded by the European Union and Chiesi Farmaceutici; ClinicalTrials.gov number, NCT01035190 .).

Drug-drug and drug-food interactions in an infant with early-onset SCN2A epilepsy treated with carbamazepine, phenytoin and a ketogenic diet.

Sodium channel 2 subunit α (SCN2A) mutations cause difficult-to-treat early-onset epilepsy. Effective treatment includes high-dose phenytoin or carbamazepine ± ketogenic diet (KD). We describe an infant with early-onset SCN2A-epilepsy with subtherapeutic carbamazepine concentration during transition from phenytoin treatment to avoid long-term neurotoxicity. The transition from high-dose phenytoin (20 mg kg-1 d-1 , concentration: ≥20 mg/L) with KD, to carbamazepine (50-75 mg kg-1 d-1 , concentration: 9-12 mg/L) lasted 85 days, which we suspected was due to significant drug-drug and/or drug-food interactions. Model-based analysis of carbamazepine pharmacokinetics quantified significant time- and dose-dependent phenytoin-mediated CYP3A4 induction and carbamazepine concentration-dependent auto-induction (apparent clearance increased up to 2.5/3-fold). Lower carbamazepine concentrations under KD were modelled as decreased relative bioavailability (44%), potentially related to decreased fraction absorbed (unexpected for this lipophilic drug), increased intestinal/hepatic metabolism and/or decreased protein-binding with KD. This suggests importance of carbamazepine-concentration monitoring during KD-introduction/removal and necessity of high carbamazepine doses to achieve therapeutic concentrations, especially in infants treated with high-dose phenytoin.

Pharmacokinetics and safety of pegylated recombinant human granulocyte colony-stimulating factor in children with acute leukaemia.

AIMS: This open-label, phase I study evaluated the pharmacokinetics and safety of pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) for the treatment of chemotherapy-induced neutropenia in children with acute leukaemia. METHODS: PEG-rhG-CSF was administered as a single 100 mcg/kg (3 mg maximum dose) subcutaneous injection at the end of each chemotherapy period when neutropenia occurred. Blood samples were obtained from patients treated with PEG-rhG-CSF. PEG-rhG-CSF serum concentrations were determined by an enzyme-linked immunosorbent assay. Population pharmacokinetic (PPK) analysis was implemented using the nonlinear mixed-effects model. Short-term safety was evaluated through adverse events collection (registered at clinicaltrials.gov identifier: 03844360). RESULTS: A total of 16 acute leukaemia patients (1.8-13.6 years) were included, of whom two (12.5%) had grade 3 neutropenia, six (37.5%) had grade 4 neutropenia, and eight (50.0%) had severe neutropenia. For PPK modelling, 64 PEG-rhG-CSF serum concentrations were obtainable. A one-compartment model with first-order elimination was used for pharmacokinetic data modelling. The current weight was a significant covariate. The median (range) of clearance (CL) and area under the serum concentration-time curve (AUC) were 5.65 (1.49-14.45) mL/h/kg and 16514.75 (6632.45-54423.30) ng·h/mL, respectively. Bone pain, pyrexia, anaphylaxis and nephrotoxicity were not observed. One patient died 13 days after administration, and the objective assessment of causality was that an association with PEG-rhG-CSF was "possible". CONCLUSIONS: The AUC of PEG-rhG-CSF (100 mcg/kg, 3 mg maximum dose) in paediatric patients with acute leukaemia were similar to those of PEG-rhG-CSF (100 mcg/kg) in children with sarcoma. PEG-rhG-CSF is safe, representing an important therapeutic option for chemotherapy-induced neutropenia in paediatric patients with acute leukaemia.

Monitoring the recovery time of children after tonsillectomy using commercial activity trackers.

An observational prospective feasibility study in which children received a tracker 2 weeks before a tonsillectomy and were required to wear it until four weeks postoperatively. The parents used a diary to log the estimated steps of their child. As primary endpoint, the compliance of complete datasets was compared between the tracker and the diary. As secondary endpoints, the agreement of steps between tracker and diary, and the recovery time after tonsillectomy were analyzed.Twenty-four patients (50% male) with a median age of 6 years were recruited. The tracker had a complete dataset compliance of 91.7% in the pre-operative and 58.3% in postoperative period, whereas the diary's compliance was 62.5% in the pre-operative and 12.5% in the postoperative period. The difference of 29.2% and 45.8% in the pre-operative and postoperative periods between the tracker and the diary was significant (p < 0.005). The tracker and diary had a mean agreement difference of 1063 steps per day. Mean recovery time was 21 days after tonsillectomy.Conclusion: The results of this pilot study support the use of a tracker in terms of compliance and practicability. Consumer-level activity trackers are a viable alternative to conventional manual logging for clinical use in pediatric research.Trial registration: ClinicalTrials.gov Identifier: NCT03174496 What is known: • Consumer-level activity trackers are already used in clinical research to monitor steps and physical activity. • The use of consumer-level activity trackers in clinical studies has mostly been validated in the adult population. What is new: • This study proves the feasibility of using physical activity trackers in a pediatric population before and after a surgical intervention. • Recovery of a patient could be assessed with an activity tracker.

Population pharmacokinetic meta-analysis of individual data to design the first randomized efficacy trial of vancomycin in neonates and young infants.

OBJECTIVES: In the absence of consensus, the present meta-analysis was performed to determine an optimal dosing regimen of vancomycin for neonates. METHODS: A 'meta-model' with 4894 concentrations from 1631 neonates was built using NONMEM, and Monte Carlo simulations were performed to design an optimal intermittent infusion, aiming to reach a target AUC0-24 of 400 mg·h/L at steady-state in at least 80% of neonates. RESULTS: A two-compartment model best fitted the data. Current weight, postmenstrual age (PMA) and serum creatinine were the significant covariates for CL. After model validation, simulations showed that a loading dose (25 mg/kg) and a maintenance dose (15 mg/kg q12h if <35 weeks PMA and 15 mg/kg q8h if ≥35 weeks PMA) achieved the AUC0-24 target earlier than a standard 'Blue Book' dosage regimen in >89% of the treated patients. CONCLUSIONS: The results of a population meta-analysis of vancomycin data have been used to develop a new dosing regimen for neonatal use and to assist in the design of the model-based, multinational European trial, NeoVanc.

Dose evaluation of intravenous metamizole (dipyrone) in infants and children: a prospective population pharmacokinetic study.

PURPOSE: The prodrug metamizole is prescribed intravenously for postoperative pain in children, including off-label use in infants < 1 year. We aimed to assess the pharmacokinetics of the main metabolites of metamizole in children aged 3-72 months. METHODS: A single dose of 10 mg/kg metamizole was administered intravenously for postoperative analgesia. Pharmacokinetic samples were drawn at predefined time points. Pharmacokinetics of the main active metabolite 4-methylaminoantipyrine and three other metabolites was characterized by both non-compartmental and population pharmacokinetic analysis. AUC0-inf of 4-methylaminoantipyrine was calculated by non-compartmental analysis for two age cohorts (3-23 months, 2-6 years) and compared with the 80-125% range of adult dose-adjusted reference exposure (AUCref). Population pharmacokinetic analysis investigated age and weight dependency of the pharmacokinetics and optimal dosing strategies to achieve equivalent adult exposure. RESULTS: A total of 25 children aged 5 months-5.8 years (7.8-24.8 kg) with at least one concentration sample were included; 19 children had ≥ 5 predefined samples up to 10 h after metamizole dose administration. AUC0-inf of 4-methylaminoantipyrine in children 2-6 years was 29.9 mg/L/h (95% CI 23.4-38.2), significantly lower than AUCref (80-125% range 39.2-61.2 mg/L/h). AUC0-inf of 4-methylaminoantipyrine in infants < 2 years was 43.6 mg/L/h (95% CI 15.8-119.0), comparable with AUCref, while infants < 12 months showed increased exposure. Observed variability could be partially explained by covariates weight and age. CONCLUSIONS: Age-related changes in pharmacokinetics of 4-methylaminoantipyrine requires reduced weight-based IV dosing in infants < 1 year compared with infants and children up to 6 years (5 versus 10-20 mg/kg) to achieve equivalent adult exposure. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02660177 .

Early Inhaled Budesonide for the Prevention of Bronchopulmonary Dysplasia.

BACKGROUND: Systemic glucocorticoids reduce the incidence of bronchopulmonary dysplasia among extremely preterm infants, but they may compromise brain development. The effects of inhaled glucocorticoids on outcomes in these infants are unclear. METHODS: We randomly assigned 863 infants (gestational age, 23 weeks 0 days to 27 weeks 6 days) to early (within 24 hours after birth) inhaled budesonide or placebo until they no longer required oxygen and positive-pressure support or until they reached a postmenstrual age of 32 weeks 0 days. The primary outcome was death or bronchopulmonary dysplasia, confirmed by means of standardized oxygen-saturation monitoring, at a postmenstrual age of 36 weeks. RESULTS: A total of 175 of 437 infants assigned to budesonide for whom adequate data were available (40.0%), as compared with 194 of 419 infants assigned to placebo for whom adequate data were available (46.3%), died or had bronchopulmonary dysplasia (relative risk, stratified according to gestational age, 0.86; 95% confidence interval [CI], 0.75 to 1.00; P=0.05). The incidence of bronchopulmonary dysplasia was 27.8% in the budesonide group versus 38.0% in the placebo group (relative risk, stratified according to gestational age, 0.74; 95% CI, 0.60 to 0.91; P=0.004); death occurred in 16.9% and 13.6% of the patients, respectively (relative risk, stratified according to gestational age, 1.24; 95% CI, 0.91 to 1.69; P=0.17). The proportion of infants who required surgical closure of a patent ductus arteriosus was lower in the budesonide group than in the placebo group (relative risk, stratified according to gestational age, 0.55; 95% CI, 0.36 to 0.83; P=0.004), as was the proportion of infants who required reintubation (relative risk, stratified according to gestational age, 0.58; 95% CI, 0.35 to 0.96; P=0.03). Rates of other neonatal illnesses and adverse events were similar in the two groups. CONCLUSIONS: Among extremely preterm infants, the incidence of bronchopulmonary dysplasia was lower among those who received early inhaled budesonide than among those who received placebo, but the advantage may have been gained at the expense of increased mortality. (Funded by the European Union and Chiesi Farmaceutici; ClinicalTrials.gov number, NCT01035190.).

Predicting CYP3A-mediated midazolam metabolism in critically ill neonates, infants, children and adults with inflammation and organ failure.

AIMS: Inflammation and organ failure have been reported to have an impact on cytochrome P450 (CYP) 3A-mediated clearance of midazolam in critically ill children. Our aim was to evaluate a previously developed population pharmacokinetic model both in critically ill children and other populations, in order to allow the model to be used to guide dosing in clinical practice. METHODS: The model was evaluated externally in 136 individuals, including (pre)term neonates, infants, children and adults (body weight 0.77-90 kg, C-reactive protein level 0.1-341 mg l-1 and 0-4 failing organs) using graphical and numerical diagnostics. RESULTS: The pharmacokinetic model predicted midazolam clearance and plasma concentrations without bias in postoperative or critically ill paediatric patients and term neonates [median prediction error (MPE) <30%]. Using the model for extrapolation resulted in well-predicted clearance values in critically ill and healthy adults (MPE <30%), while clearance in preterm neonates was over predicted (MPE >180%). CONCLUSION: The recently published pharmacokinetic model for midazolam, quantifying the influence of maturation, inflammation and organ failure in children, yields unbiased clearance predictions and can therefore be used for dosing instructions in term neonates, children and adults with varying levels of critical illness, including healthy adults, but not for extrapolation to preterm neonates.

Management of anaphylaxis and allergies in patients with long QT syndrome: A review of the current evidence.

OBJECTIVE: To develop a treatment algorithm for patients with long QT syndrome (LQTS) in case they need antiallergic medications for allergic reactions, including asthma and anaphylaxis. DATA SOURCES: A literature review was performed to assess safety and to develop antiallergic treatment strategies for patients with LQTS. STUDY SELECTIONS: LQTS is a heterogeneous group of myocardial repolarization disorders characterized by prolongation of the QT interval that potentially results in life-threatening torsades de pointes tachycardia. Data on pharmacologic treatment in case of anaphylaxis in LQTS are sparse. For this narrative review, all currently available articles on the use of antiallergic drugs for allergic reactions, anaphylaxis, and asthma in patients with LQTS were used. RESULTS: Local allergic symptoms can be safely treated primarily with fexofenadine, levocetirizine, desloratadine, or cetirizine and, if needed, a short course of corticosteroids. In case of systemic symptoms, epinephrine should be administered. It may be less effective in patients with LQTS treated with ß-blockers, necessitating the use of glucagon as add-on treatment. In case of lower airway obstruction, ipratropium bromide should be used, but if not effective, inhaled ß2-adrenergic agents may be used. Continuous cardiac monitoring is indicated with the use of epinephrine and inhaled ß2-adrenergic agents. The use of the latter also warrants intense monitoring of serum potassium levels. Clemastine and dimetindene should be avoided in patients with LQTS. CONCLUSION: Patients with LQTS have a higher risk of life-threatening complications during the treatment of their allergic reactions because of the underlying disease and concomitant treatment with ß-blockers. Treatment algorithms will certainly decrease these complications.

Exposure to acetaminophen and all its metabolites upon 10, 15, and 20 mg/kg intravenous acetaminophen in very-preterm infants.

BackgroundExposure to acetaminophen and its metabolites in very-preterm infants is partly unknown. We investigated the exposure to acetaminophen and its metabolites upon 10, 15, or 20 mg/kg intravenous acetaminophen in preterm infants.MethodsIn a randomized trial, 59 preterm infants (24-32 weeks' gestational age, postnatal age <1 week) received 10, 15, or 20 mg/kg acetaminophen intravenously. Plasma concentrations of acetaminophen and its metabolites (glucuronide, sulfate, cysteine, mercapturate, and glutathione) were determined in 293 blood samples. Area under the plasma concentration-time curves (AUC0-500 min) was related to dose and gestational age.ResultsBetween 10 and 20 mg/kg dose, median AUCs of acetaminophen, glucuronide, sulfate, and cysteine increased significantly resulting in unchanged ratios of AUC of metabolite to acetaminophen. The AUC ratio of glucuronide to acetaminophen increased with gestational age, that of sulfate decreased, and the ratio of cysteine and mercapturate remained unchanged.ConclusionWe found a gestational-age-dependent increase in glucuronidation but no evidence for saturation of a specific pathway as there was a proportional increase in exposure of acetaminophen and all metabolites. Compared with adults, very low exposure to glucuronide but higher exposure to sulfate, cysteine, and mercapturate metabolites was found, of which the relevance is not yet known.

Towards Rational Dosing Algorithms for Vancomycin in Neonates and Infants Based on Population Pharmacokinetic Modeling.

Because of the recent awareness that vancomycin doses should aim to meet a target area under the concentration-time curve (AUC) instead of trough concentrations, more aggressive dosing regimens are warranted also in the pediatric population. In this study, both neonatal and pediatric pharmacokinetic models for vancomycin were externally evaluated and subsequently used to derive model-based dosing algorithms for neonates, infants, and children. For the external validation, predictions from previously published pharmacokinetic models were compared to new data. Simulations were performed in order to evaluate current dosing regimens and to propose a model-based dosing algorithm. The AUC/MIC over 24 h (AUC24/MIC) was evaluated for all investigated dosing schedules (target of >400), without any concentration exceeding 40 mg/liter. Both the neonatal and pediatric models of vancomycin performed well in the external data sets, resulting in concentrations that were predicted correctly and without bias. For neonates, a dosing algorithm based on body weight at birth and postnatal age is proposed, with daily doses divided over three to four doses. For infants aged <1 year, doses between 32 and 60 mg/kg/day over four doses are proposed, while above 1 year of age, 60 mg/kg/day seems appropriate. As the time to reach steady-state concentrations varies from 155 h in preterm infants to 36 h in children aged >1 year, an initial loading dose is proposed. Based on the externally validated neonatal and pediatric vancomycin models, novel dosing algorithms are proposed for neonates and children aged <1 year. For children aged 1 year and older, the currently advised maintenance dose of 60 mg/kg/day seems appropriate.

Characterizing and Forecasting Individual Weight Changes in Term Neonates.

OBJECTIVES: To develop a mathematical, semimechanistic model characterizing physiological weight changes in term neonates, identify and quantify key maternal and neonatal factors influencing weight changes, and provide an online tool to forecast individual weight changes during the first week of life. STUDY DESIGN: Longitudinal weight data from 1335 healthy term neonates exclusively breastfed up to 1 week of life were available. A semimechanistic model was developed to characterize weight changes applying nonlinear mixed-effects modeling. Covariate testing was performed by applying a standard stepwise forward selection-backward deletion approach. The developed model was externally evaluated on 300 additional neonates collected in the same center. RESULTS: Weight changes during first week of life were described as a function of a changing net balance between time-dependent rates of weight gain and weight loss. Males had higher birth weights (WT0) than females. Gestational age had a positive effect on WT0 and weight gain rate, whereas mother's age had a positive effect on WT0 and a negative effect on weight gain rate. The developed model showed good predictive performance when externally validated (bias = 0.011%, precision = 0.52%) and was able to accurately forecast individual weight changes up to 1 week with only 3 initial weight measurements (bias = -0.74%, precision = 1.54%). CONCLUSIONS: This semimechanistic model characterizes weight changes in healthy breastfed neonates during first week of life. We provide a user-friendly online tool allowing caregivers to forecast and monitor individual weight changes. We plan to validate this model with data from other centers and expand it with data from preterm neonates.

Adverse drug reactions in neonates and infants: a population-tailored approach is needed.

Drug therapy is a powerful tool to improve outcome, but there is an urgent need to improve pharmacotherapy in neonates through tailored prevention and management of adverse drug reactions (ADRs). At present, infants commonly receive off-label drugs, at dosages extrapolated from those in children or adults. Besides the lack of labelling, inappropriate formulations, (poly)pharmacy, immature organ function and multiple illnesses further raise the risk for ADRs in neonates and infants. Pharmacovigilance to improve the prevention and management of ADRs needs to be tailored to neonates and infants. We illustrate this using prevention strategies for drug prescription and administration errors (e.g. formulation, bedside manipulation, access), detection through laboratory signalling or clinical outlier data (e.g. reference laboratory values, overall high morbidity), assessment through algorithm scoring (e.g. Naranjo or population specific), as well as understanding of the developmental toxicology (e.g. covariates, developmental pharmacology) to avoid re-occurrence and for development of guidelines. Such tailored strategies need collaborative initiatives to combine the knowledge and expertise of different disciplines, but hold promise to become a very effective tool to improve pharmacotherapy and reduce ADRs in infants.

Population pharmacokinetics of midazolam and its metabolites in overweight and obese adolescents.

AIM: In view of the increasing prevalence of obesity in adolescents, the aim of this study was to determine the pharmacokinetics of the CYP3A substrate midazolam and its metabolites in overweight and obese adolescents. METHODS: Overweight (BMI for age ≥ 85(th) percentile) and obese (BMI for age ≥ 95(th) percentile) adolescents undergoing surgery received 2 or 3 mg intravenous midazolam as a sedative drug pre-operatively. Blood samples were collected until 6 or 8 h post-dose. Population pharmacokinetic modelling and systematic covariate analysis were performed using nonmem 7.2. RESULTS: Nineteen overweight and obese patients with a mean body weight of 102.7 kg (62-149.8 kg), a mean BMI of 36.1 kg m(-2) (24.8-55 kg m(-2)), and a mean age of 15.9 years (range 12.5-18.9 years) were included. In the model for midazolam and metabolites, total body weight was not of influence on clearance (0.66 l min(-1) (RSE 8.3%)), while peripheral volume of distribution of midazolam (154 l (11.2%)), increased substantially with total body weight (P < 0.001). The increase in peripheral volume could be explained by excess body weight (WTexcess ) instead of body weight related to growth (WTfor age and length ). CONCLUSIONS: The pharmacokinetics of midazolam and its metabolites in overweight and obese adolescents show a marked increase in peripheral volume of distribution and a lack of influence on clearance. The findings may imply a need for a higher initial infusion rate upon initiation of a continuous infusion in obese adolescents.

Population pharmacokinetics of ciprofloxacin in neonates and young infants less than three months of age.

Ciprofloxacin is used in neonates with suspected or documented Gram-negative serious infections. Currently, its use is off-label partly because of lack of pharmacokinetic studies. Within the FP7 EU project TINN (Treat Infection in NeoNates), our aim was to evaluate the population pharmacokinetics of ciprofloxacin in neonates and young infants <3 months of age and define the appropriate dose in order to optimize ciprofloxacin treatment in this vulnerable population. Blood samples were collected from neonates treated with ciprofloxacin and concentrations were quantified by high-pressure liquid chromatography-mass spectrometry. Population pharmacokinetic analysis was performed using NONMEM software. The data from 60 newborn infants (postmenstrual age [PMA] range, 24.9 to 47.9 weeks) were available for population pharmacokinetic analysis. A two-compartment model with first-order elimination showed the best fit with the data. A covariate analysis identified that gestational age, postnatal age, current weight, serum creatinine concentration, and use of inotropes had a significant impact on ciprofloxacin pharmacokinetics. Monte Carlo simulation demonstrated that 90% of hypothetical newborns with a PMA of <34 weeks treated with 7.5 mg/kg twice daily and 84% of newborns with a PMA ≥34 weeks and young infants receiving 12.5 mg/kg twice daily would reach the AUC/MIC target of 125, using the standard EUCAST MIC susceptibility breakpoint of 0.5 mg/liter. The associated risks of overdose for the proposed dosing regimen were <8%. The population pharmacokinetics of ciprofloxacin was evaluated in neonates and young infants <3 months old, and a dosing regimen was established based on simulation.

Trends in pregnancy labeling and data quality for US-approved pharmaceuticals.

OBJECTIVE: Over the past decades, there have been significant efforts in the United States to improve pharmaceutical labeling pertaining to pregnancy. The goal of this study was to describe trends in pregnancy labeling at the time of drug approval and over time. STUDY DESIGN: The labeling data of 213 new pharmaceutical approvals between January 2003 and December 2012 were systematically reviewed. Initial approval data and subsequent labeling revisions were evaluated for pregnancy category, source of pregnancy and breast-feeding data, data in labor and delivery, presence of a registry, black-box warnings, and utilization of the new labeling format. RESULTS: The most commonly approved pregnancy category was C (51.6%). Most pharmaceuticals (92.9%) had pregnancy data based on animal studies and 5.2% had human pregnancy data. For breast-feeding, there were no data in 47.9% of labels, animal data in 42.7%, and human data in 4.7%. There were no labor and delivery data in 85.9% of labels. Only 2.8% of medications had human data, with the remainder having animal data. The majority of medications (85%) did not have a pregnancy registry. Of those that had a registry, 68.7% were by therapeutic category, not agent specific. Seven medications had black-box warnings related to teratogenicity. Since the new labeling recommendations, 4.7% of medications incorporated the new format into the labeling, primarily approvals that occurred in 2012. CONCLUSION: Despite significant efforts to improve drug labeling for pregnancy and lactation, there remains a paucity of human data in this understudied population.

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.

Simultaneous pharmacokinetic modeling of gentamicin, tobramycin and vancomycin clearance from neonates to adults: towards a semi-physiological function for maturation in glomerular filtration.

PURPOSE: Since glomerular filtration rate (GFR) is responsible for the elimination of a large number of water-soluble drugs, the aim of this study was to develop a semi-physiological function for GFR maturation from neonates to adults. METHODS: In the pharmacokinetic analysis (NONMEM VI) based on data of gentamicin, tobramycin and vancomycin collected in 1,760 patients (age 1 day-18 years, bodyweight 415 g-85 kg), a distinction was made between drug-specific and system-specific information. Since the maturational model for clearance is considered to contain system-specific information on the developmental changes in GFR, one GFR maturational function was derived for all three drugs. RESULTS: Simultaneous analysis of these three drugs showed that maturation of GFR mediated clearance from preterm neonates to adults was best described by a bodyweight-dependent exponent (BDE) function with an exponent varying from 1.4 in neonates to 1.0 in adults (ClGFR = Cldrug*(BW/4 kg)(BDE) with BDE = 2.23*BW(-0.065)). Population clearance values (Cldrug) for gentamicin, tobramycin and vancomycin were 0.21, 0.28 and 0.39 L/h for a full term neonate of 4 kg, respectively. DISCUSSION: Based on an integrated analysis of gentamicin, tobramycin and vancomycin, a semi-physiological function for GFR mediated clearance was derived that can potentially be used to establish evidence based dosing regimens of renally excreted drugs in children.