There are guidelines on lactation following maternal analgo-sedative exposure, but these do not consider the effect of maternal fasting, nor fluid abstention on human milk macronutrient composition. We therefore performed a structured search (PubMed) on ‘human milk composition’ and screened title, abstract and full paper on ‘fasting’ or ‘abstention’ and ‘macronutrient composition’ (lactose, protein, fat, solids, triglycerides, cholesterol). This resulted in 6 papers and one abstract related to religious fasting (n=129 women) and observational studies in lactating women (n=23, healthy volunteers, fasting). These data reflect two different ‘fasting’ patterns: an acute (18-25h) model in 71 (healthy volunteers, Yom Kippur/Ninth of Av) women and a chronic fasting (Ramadan) model in 81 women. Changes were most related to electrolytes and were moderate, with almost no changes in macronutrients during acute fasting. We therefor conclude that neither short term fasting nor fluid abstention (18-25h) affect human milk macronutrient composition, so that women can be reassured when this topic were raised during consulting. Besides the nutritional relevance, this also matters as clinical research samples – especially to estimate analgo-sedative exposure by lactation - are commonly collected after maternal procedural sedation, associated with maternal fasting and physiology-based pharmacokinetic (PBPK) models assume stable human milk composition.

Background: Disentangling adverse drug reactions from confounders remains a major challenge to assess causality and severity in neonates. Vancomycin and amikacin are perceived as nephrotoxic and often prescribed in neonates. We selected these compounds to assess their impact on creatinine dynamics as sensitive tool to detect a renal impairment signal. Methods: A recently developed dynamical model that characterized serum creatinine concentrations of 217 ELBW neonates (4036 serum creatinine observations) was enhanced with data on individual administration of vancomycin and/or amikacin to identify a potential effect of antibiotic exposure by nonlinear mixed-effects modelling analysis. Results: Of our ELBW patients, 77% were exposed to either vancomycin or amikacin. Antibiotic exposure resulted in transient lower overall creatinine clearance and a modest increase in serum creatinine. Dependency on gestational age was observed in the difference in serum creatinine when exposed to antibiotics during the third week after birth (difference in creatinine for a neonate at 24 weeks gestation decreased with 56% for a 32-week-old neonate). Conclusions: A previously described model on creatinine dynamics was used to explore and quantify the impact amikacin or vancomycin exposure on creatinine dynamics. Such tools can be used to explore minor changes, or compare minor differences between treatment modalities.

Many neonates undergoing whole body hypothermia (WBH) following moderate to severe perinatal asphyxia suffer from renal impairment. While recent data suggest a WBH-related reno-protection, the differences in serum creatinine (Scr) patterns to reference patterns were not yet reported. We therefore aimed to document Scr trends and patterns in asphyxiated neonates undergoing WBH, and compared these to centiles reference Scr dataset of non-asphyia neonates. Using a systematic review strategy, reports on Scr trends (mean ± SD, or median and range) were collected (day 1-7) in WBH cohorts, and compared to centiles of an earlier reported reference cohort of non-asphyxia cases. Based on 13 papers on asphyxia+WBH cases, a pattern on postnatal Scr trends in asphyxia+WBH cases was constructed. Compared to the reference cohort, mean or median Scr values at birth (>90th centile) and the first two days of WBH (>75th centile) remained clinical relevantly higher in asphyxia+WBH cases, with a subsequent decline to reach at best high or high normal creatinine values (all >50th centile, but mainly >75th centile) from day 4 onwards. Such patterns are valuable to anticipate average changes in renal clearance capacity relevant for pharmacotherapy, but do not yet cover the relevant inter-patient variability observed in WBH cases.

QTc interval measurement is a widely used screening tool to assess the risk of cardiac diseases, arrhythmias, and is a useful biomarker for pharmacovigilance. However, interpretation of QTc is difficult in neonates due to hemodynamic maturational changes and uncertainties on reference values. To describe trends in QTc values throughout infancy (1 year of life), and to explore the impact of (non)-maturational changes and medicines exposure, a structured systematic review (PROSPERO CRD42022302296) was performed. In term neonates, a decrease was observed over the first week of life, whereafter values increased until two months of age, followed by a progressive decrease until six months. A similar pattern, with longer QTc values was observed in preterms. QTc is influenced by cord clamping, hemodynamic changes, therapeutic hypothermia, illnesses and sleep, not by sex. Cisapride, domperidone and doxapram result in QTc prolongation in neo-nates. Further research in this age category is needed to improve primary screening practices, earlier detection of risk factors and precision pharmacovigilance.

Background: There are anecdotal reports on reversible QTc prolongation during therapeutic hypothermia (TH) for moderate to severe neonatal encephalopathy after asphyxia. As the QTc interval is a relevant biomarker to assess safety during medication development, a structured search and review on published neonatal QTc values to generate reference values is warranted to facilate medication development in this specific population. Methods: A structured search and literature assessment (PubMed, Embase, Google Scholar) with ‘Newborn/Infant, QT and hypothermia’ was conducted (October 2021). Retrieved individual values were converted to QTc (Bazett) over postnatal age (day 1-7). Results: We retrieved 94 QTc intervals [during TH (n=50, until day 3) or subsequent normothermia (n=44, day 4-7)] in 33 neonates from 6 publications. The median (range) of QTc intervals during TH was 508 (430-678), and 410 (317-540) ms afterwards (difference 98 ms, or +28 ms/°C decrease). Four additional cohorts (without individual QTc intervals) confirmed the pattern and magnitude of the effect of body temperature on the QTc interval. Conclusions: We added a relevant non-maturational covariate (TH, °C dependent) and generated reference values for the QTc interval in this specific neonatal subpopulation. This knowledge on QTc during TH should be considered and integrated in neonatal medication development.

Neonatal drug information (DI) is essential for safe and effective pharmacotherapy in (pre)term neonates. Such information is usually absent from drug labels, making formularies a crucial part of the neonatal clinician’s toolbox. Several formularies exist worldwide, but they have never been fully mapped nor compared for content, structure and workflow. The objective of this review was to identify neonatal formularies, explore (dis)similarities, and raise awareness of their existence.Neonatal formularies were identified through self-acquaintance, experts and structured search. A questionnaire was sent to all identified formularies to provide details on formulary function. An original extraction tool was employed to collect DI from the formularies on the 10 most commonly used drugs in pre(term) neonates.Eight different neonatal formularies were identified worldwide (Europe, USA, Australia-New Zealand, Middle East). Six responded to the questionnaire and were compared for structure and content. Each formulary has its own workflow, monograph template and style, and update routine. Focus on certain aspects of DI also varies, as well as the type of initiative and funding.Clinicians should be aware of the various formularies available and their differences in characteristics and content to use them properly for the benefit of their patients.