Using Real-World Data to Externally Evaluate Population Pharmacokinetic Models of Dexmedetomidine in Children and Infants

Dexmedetomidine is a sedative used in both adults and off-label in children with considerable reported pharmacokinetic (PK) interindividual variability affecting drug exposure across populations. Several published models describe the population PKs of dexmedetomidine in neonates, infants, children, and adolescents, though very few have been externally evaluated. A prospective PK dataset of dexmedetomidine plasma concentrations in children and young adults aged 0.01-19.9 years was collected as part of a multicenter opportunistic PK study. A PubMed search of studies reporting dexmedetomidine PK identified five population PK models developed with data from demographically similar children that were selected for external validation. A total of 168 plasma concentrations from 102 children were compared with both population (PRED) and individualized (IPRED) predicted values from each of the five published models by quantitative and visual analyses using NONMEM (v7.3) and R (v4.1.3). Mean percent prediction errors from observed values ranged from -1% to 120% for PRED, and -24% to 60% for IPRED. The model by James et al, which was developed using similar "real-world" data, nearly met the generalizability criteria from IPRED predictions. Other models developed using clinical trial data may have been limited by inclusion/exclusion criteria and a less racially diverse population than this study's opportunistic dataset. The James model may represent a useful, but limited tool for model-informed dosing of hospitalized children.

Prolonged Beta-lactam Infusions in Children: A Systematic Review and Meta-analysis

OBJECTIVE

To assess whether beta-lactam extended or continuous beta-lactam infusions (EI/CI) improve clinical outcomes in children with proven or suspected bacterial infections.

STUDY DESIGN

We included observational and interventional studies that compared beta-lactam EI or CI with standard infusions in children less than 18 years old, and reported on mortality, hospital or intensive care unit LOS, microbiological cure and/or clinical cure. Data sources included PubMed, Medline, EBM Reviews, EMBASE, and CINAHL and were searched from January 1, 1980, to November 3, 2023. Thirteen studies (2,945 patients) were included: 5 randomized control trials (RCTs), and 8 observational studies. Indications for antimicrobial therapies and clinical severity varied, ranging from cystic fibrosis exacerbation to critically ill children with bacteriemia.

RESULTS

EI and CI were not associated with a reduction in mortality in RCTs (n = 1,464; RR 0.93, 95% CI 0.71, 1.21), but were in observational studies (n = 833; RR 0.43, 95% CI 0.19, 0.96). We found no difference in hospital length of stay. Results for clinical and microbiological cures were heterogeneous and reported as narrative review. The included studies were highly heterogeneous, limiting the strength of our findings. The lack of shared definitions for clinical and microbiological cure outcomes precluded analysis.

CONCLUSIONS

EI and CI were not consistently associated with reduced mortality or LOS in children. Results were conflicting regarding clinical and microbiological cures. More well-designed studies targeting high-risk populations are necessary to determine the efficacy of these alternative dosing strategies.

Optimization of Ganciclovir and Valganciclovir Starting Dose in Children by Machine Learning

BACKGROUND AND OBJECTIVES

Ganciclovir (GCV) and valganciclovir (VGCV) show large interindividual pharmacokinetic variability, particularly in children. The objectives of this study were (1) to develop machine learning (ML) algorithms trained on simulated pharmacokinetics profiles obtained by Monte Carlo simulations to estimate the best ganciclovir or valganciclovir starting dose in children and (2) to compare its performances on real-world profiles to previously published equation derived from literature population pharmacokinetic (POPPK) models achieving about 20% of profiles within the target.

MATERIALS AND METHODS

The pharmacokinetic parameters of four literature POPPK models in addition to the World Health Organization (WHO) growth curve for children were used in the mrgsolve R package to simulate 10,800 pharmacokinetic profiles. ML algorithms were developed and benchmarked to predict the probability to reach the steady-state, area-under-the-curve target (AUC0-24 within 40-60 mg × h/L) based on demographic characteristics only. The best ML algorithm was then used to calculate the starting dose maximizing the target attainment. Performances were evaluated for ML and literature formula in a test set and in an external set of 32 and 31 actual patients (GCV and VGCV, respectively).

RESULTS

A combination of Xgboost, neural network, and random forest algorithms yielded the best performances and highest target attainment in the test set (36.8% for GCV and 35.3% for the VGCV). In actual patients, the best GCV ML starting dose yielded the highest target attainment rate (25.8%) and performed equally for VGCV with the Franck model formula (35.3% for both).

CONCLUSION

The ML algorithms exhibit good performances in comparison with previously validated models and should be evaluated prospectively.

Maternal Ezetimibe Concentrations Measured in Breast Milk and Its Use in Breastfeeding Infant Exposure Predictions

BACKGROUND

Lactating mothers taking ezetimibe, an antihyperlipidemic agent, may be hesitant to breastfeed despite the known benefit of breastfeeding to both mother and infant. Currently, no data exist on the presence or concentration of ezetimibe and its main active metabolite, ezetimibe-glucuronide (EZE-glucuronide), in human breast milk.

METHODS

Voluntary breast milk samples containing ezetimibe and EZE-glucuronide were attained from lactating mothers taking ezetimibe as part of their treatment. An assay was developed and validated to measure ezetimibe and EZE-glucuronide concentrations in breast milk. A workflow that utilized a developed and evaluated pediatric physiologically based pharmacokinetic (PBPK) model, the measured concentrations in milk, and weight-normalized breast milk intake volumes was applied to predict infant exposures and determine the upper area under the curve ratio (UAR).

RESULTS

Fifteen breast milk samples from two maternal-infant pairs were collected. The developed liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay showed an analytical range of 0.039-5.0 ng/mL and 0.39-50.0 ng/mL for ezetimibe and EZE-glucuronide, respectively. The measured concentrations in the breast milk samples were 0.17-1.02 ng/mL and 0.42-2.65 ng/mL of ezetimibe and EZE-glucuronide, respectively. The evaluated pediatric PBPK model demonstrated minimal exposure overlap in adult therapeutic dose and breastfed infant simulated area under the concentration-time curve from time zero to 24 h (AUC24). Calculated UAR across infant age groups ranged from 0.0015 to 0.0026.

CONCLUSIONS

PBPK model-predicted ezetimibe and EZE-glucuronide exposures and UAR suggest that breastfeeding infants would receive non-therapeutic exposures. Future work should involve a 'mother-infant pair study' to ascertain breastfed infant plasma ezetimibe and EZE-glucuronide concentrations to confirm the findings of this work.

Treatment of Congenital Cytomegalovirus and Ganciclovir Therapeutic Drug Monitoring in Twin Preterm Infants

Congenitally acquired cytomegalovirus (CMV) infection is the most prevalent congenital infection worldwide and the most frequent cause of acquired sensorineural hearing loss. The burden of the disease is even more important in premature and very low birth weight infants. However, few data exist on the treatment with intravenous ganciclovir and oral valganciclovir in this vulnerable population. We report the case of twins congenitally infected with CMV and born prematurely at 27 weeks' gestation. Treatment regimens were initially individualized for their prematurity and renal function, and then adjusted with therapeutic drug monitoring (TDM) to adapt to their continuously evolving physiologic maturation. As infants were aging, the plasmatic half-life of ganciclovir slowly decreased to term infant values around 10 weeks of chronological age, or 37 weeks of postmenstrual age. Results for blood polymerase chain reaction tests became negative and long-term follow-ups were satisfactory in both twins. The limited data for infants born before 32 weeks of gestation or at less than 1200 g and evolution of ganciclovir pharmacokinetic parameters justify the use of TDM in these settings.

88 Association between area level material deprivation and incidence of hospitalization among children with SARS-CoV-2 in Montreal

Background

Although sociodemographic factors have been linked with SARS-CoV-2 infection and hospitalizations in adults, there are little data on the association between sociodemographic characteristics and SARS-CoV-2-related hospitalization in children.

Objectives

The objective of this study was to determine the association between area-level material deprivation and incidence of hospitalization with SARS-CoV-2 among children.

Design/Methods

We conducted a retrospective cohort study of all children (0-17 years of age) with a PCR-confirmed SARS-CoV-2 infection between March 1, 2020, and May 31, 2021, at a tertiary care pediatric hospital. Data were collected through chart review and included age, sex, and postal code. Postal codes were then assigned a dissemination area-level material deprivation score, measured via the Pampalon Material Deprivation Index (PMDI) quintiles. The Pampalon Material Deprivation Index (PMDI) uses postal codes to describe factors related to material deprivation obtained from the Canadian census, which are proxies for individual data in a geographic area. Specifically, the PMDI integrates data regarding (i) the proportion of persons without a high school diploma; (ii) the employment-to-population ratio; (iii) average personal income which is aggregated at the dissemination area level. We examined the association between PMDI quintiles and hospitalization using Poisson regression.

Results

During the study period, 964 children had a positive PCR-confirmed SARS-CoV-2 test and 124 were hospitalized due to SARS-CoV-2 infection. Children from the most deprived PMDI quintile represented 31.6% of positive cases and 40.7% of hospitalizations (Figure 1 and 2). Both in bivariate and multivariable regression analyses, there was evidence of greater proportion of positive test results in the most deprived PMDI quintile (Quintile 5) compared to the least deprived quintile (Quintile 1) (rate ratio 1.77, 95%CI: 1.36; 2.62) (Table 1). The incidence of hospitalization due to SARS-CoV-2 infection was 2.42 times greater in the most deprived quintile compared to the least deprived quintile (95%CI: 1.33; 4.41) (table 1). In a post-hoc analysis, the risk for severe disease appeared higher for children living in Q5 areas relative to other areas but the difference did not reach statistical significance.

Conclusion

In conclusion, in this study we found evidence that Canadian children living in neighbourhoods with high material deprivation had a higher incidence of infection and hospitalizations related to SARS-Cov-2 compared to children living in neighbourhoods with less material deprivation. Public health authorities should take these disparities into account when devising public health policy and interventions especially at this crucial point in the pandemic. Special efforts should be deployed to protect children from these more disadvantaged areas, especially as vaccination is not yet available to a majority of children.

Association between area-level material deprivation and incidence of hospitalization among children with SARS-CoV-2 in Montreal

Background

Although sociodemographic factors have been linked with SARS-CoV-2 infection and hospitalizations in adults, there are little data on the association between sociodemographic characteristics and SARS-CoV-2-related hospitalization in children. The objective of this study was to determine the association between area-level material deprivation and incidence of hospitalization with SARS-CoV-2 among children.

Methods

We conducted a retrospective cohort study of all children (0 to 17 years of age) with a PCR-confirmed SARS-CoV-2 infection March 1, 2020 through May 31, 2021 at a tertiary-care paediatric hospital, in Montreal, Canada. Data were collected through chart review and included age, sex, and postal code, allowing linkage to dissemination area-level material deprivation, measured with the Pampalon Material Deprivation Index (PMDI) quintiles. We examined the association between PMDI quintiles and hospitalization using Poisson regression.

Results

During the study period, 964 children had a positive PCR-confirmed SARS-CoV-2 test and 124 were hospitalized. Children living in the most deprived quintile of PMDI represented 40.7% of hospitalizations. Incidence rate ratio of hospitalization for this group compared to the most privileged quintile was 2.42 (95%CI: 1.33; 4.41).

Conclusion

Children living in the most materially deprived areas had more than twice the rate of hospitalizations for COVID-19 than children living in most privileged areas. Special efforts should be deployed to protect children who live in disadvantaged areas, especially pending vaccination of younger children.

L’association entre la défavorisation matérielle par quartier et l’incidence d’hospitalisation chez les enfants infectés par le SRAS-CoV-2 à Montréal

Historique

Même si les facteurs sociodémographiques sont liés à l’infection par le SRAS-CoV-2 et aux hospitalisations chez les adultes, peu de données portent sur l’association entre ces caractéristiques et les hospitalisations attribuables au SRAS-CoV-2 chez les enfants. La présente étude visait à déterminer l’association entre la défavorisation matérielle par quartier et l’incidence d’hospitalisations à cause du SRAS-CoV-2 chez les enfants.

Méthodologie

Les chercheurs ont réalisé une étude de cohorte rétrospective de tous les enfants (de 0 à 17 ans) atteints d’une infection par le SRAS-CoV-2 confirmée par un test d’amplification en chaîne par polymérase après transcription inverse (PCR) entre le 1^er mars et le 31 mai 2021 dans un hôpital pédiatrique de soins tertiaires de Montréal, au Canada. Ils ont colligé les données par examen des dossiers et ont inclus l’âge, le sexe et les codes postaux, afin de pouvoir lier la défavorisation matérielle à l’échelle de l’aire de diffusion, mesurée au moyen des quintiles de l’indice de défavorisation matérielle de Pampalon. Ils ont examiné l’association entre les quintiles de cet indice et les hospitalisations à l’aide de la régression de Poisson.

Résultats

Pendant la période de l’étude, 964 enfants ont reçu un résultat positif au SRAS-CoV-2 confirmé par un test PCR, et 124 d’entre eux ont été hospitalisés. Au total, 40,7 % des enfants hospitalisés habitaient dans le quintile le plus défavorisé d’après l’indice de défavorisation matérielle de Pampalon. Le rapport du taux d’incidence des hospitalisations dans ce groupe était de 2,42 (intervalle de confiance à 95 % : 1,33; 4,41) par rapport au quintile le plus privilégié.

Conclusion

Plus du double des enfants qui habitaient dans les quartiers les plus défavorisés sur le plan matériel étaient hospitalisés à cause de la COVID-19 par rapport à ceux qui habitaient dans les quartiers les plus privilégiés. Il faudrait déployer des efforts particuliers pour protéger les enfants qui habitent dans des quartiers défavorisés, particulièrement dans l’attente de la vaccination des plus jeunes.

Outpatient management of moderate cellulitis in children using high-dose oral cephalexin

Objectives

To evaluate the effectiveness of a high-dose (HD) oral cephalexin treatment guideline for children with moderate cellulitis treated as outpatients.

Methods

In this retrospective cohort study, we included children who presented to the emergency department (ED) with moderate cellulitis and treated according to the institution’s HD oral cephalexin guideline over a 2-year period. All children had standardized follow-up at a medical day hospital (MDH). Treatment was considered effective in the absence of treatment failure, defined as admission, switch to IV treatment or ED visit within 2 weeks of discharge from the MDH. Safety was ascertained by recording adverse events and severe complications at follow-up.

Results

A total of 123 children were treated as outlined in the guideline, including 117 treated with HD oral cephalexin. The success rate was 89.7% (105/117). Among 12 (10.3%) children who had treatment failure, 10 (8.5%) required admission, 1 (0.9%) received IV antibiotics at the MDH and 1 (0.9%) had a return visit to the ED without admission. No severe complications were reported; four abscesses required drainage and one patient had a rash. The mean number of visits per child at the MDH was 1.6 (SD 1.0).

Conclusions

With a success rate of 89.7%, HD oral cephalexin seems effective and safe for the treatment of children with moderate cellulitis. Its use potentially reduces hospitalization rates for this condition and decreases the need for IV insertion.

Practice Summary of Antimicrobial Therapy for Commonly Encountered Conditions in the Neonatal Intensive Care Unit: A Canadian Perspective

Neonates are highly susceptible to infections owing to their immature cellular and humoral immune functions, as well the need for invasive devices. There is a wide practice variation in the choice and duration of antimicrobial treatment, even for relatively common conditions in the NICU, attributed to the lack of evidence-based guidelines. Early decisive treatment with broad-spectrum antimicrobials is the preferred clinical choice for treating sick infants with possible bacterial infection. Prolonged antimicrobial exposure among infants without clear indications has been associated with adverse neonatal outcomes and increased drug resistance. Herein, we review and summarize the best practices from the existing literature regarding antimicrobial use in commonly encountered conditions in neonates.

Pharmacokinetics, Pharmacodynamics, and Therapeutic Drug Monitoring of Valganciclovir and Ganciclovir in Transplantation

Ganciclovir and valganciclovir are first choice drugs for the prevention and treatment of cytomegalovirus infection and disease in solid organ and stem cell transplant recipients. Only a few studies on the pharmacokinetics and exposure/efficacy or exposure/safety relationships of ganciclovir and valganciclovir in transplant recipients have been published so far, and there are still controversies about the exposure parameter to use for therapeutic drug monitoring (TDM). We performed an extensive literature review of the clinical pharmacokinetics data, the exposure/effect relationships in terms of efficacy and safety, and the available tools for valganciclovir and ganciclovir TDM in adults and pediatrics transplant recipients. The pharmacokinetics of ganciclovir and valganciclovir is well described in adults and children, and a high interindividual variability is commonly observed. In contrast, the drug pharmacodynamics has been poorly described in adults and barely in children. The average 24-hour area under the concentration-time curve (AUC_0-24h ) seems to be the best predictor of efficacy and toxicity. The benefit of TDM remains controversial in adult patients but should be considered in children due to higher interindividual variability and lower probability of target attainment. Several bayesian estimators based on limited sampling strategies have been developed with this aim and may be used in clinical practice for the AUC-based individual dose adjustment of ganciclovir and valganciclovir.

Pharmacokinetics of Ceftazidime in Children and Adolescents with Obesity

PURPOSE

The aim of this study was to evaluate ceftazidime pharmacokinetics (PK) in a cohort that includes a predominate number of children and adolescents with obesity and assess the efficacy of competing dosing strategies.

METHODS

A population PK model was developed using opportunistically collected plasma samples. For each dosing strategy, model-based probability of target attainment (PTA) estimates were computed for study participants using empirical Bayes estimates. In addition, the effects of body size and renal function on PTA were evaluated using stochastic model simulations with virtually generated subjects.

RESULTS

Twenty-nine participants, 24 of whom were obese, contributed data towards the analysis. The median (range) age, body weight, and body mass index of participants were 12.2 years (2.3-20.6), 59.2 kg (8.4-121), and 25.2 kg/m2 (13.8-42.9), respectively. Administration of 50 mg/kg intravenously (IV) every 8 hours (q8h; max 6 g/day) or 40 mg/kg IV q6h (max 6 g/day) resulted in PTA values of ≥ 90% (minimum inhibitory concentration 8 mg/L) for the subset of obese participants with estimated glomerular filtration rates (GFR) ≥ ~ 80 mL/min/1.73 m2. However, for both regimens, stochastic model simulations denoted lower PTA values (< 90%) with increasing body weight for virtual subjects with GFR ≥ 120 mL/min/1.73 m2. Alternatively, permitting for a maximum daily dose of 8 g/day using a 40 mg/kg IV q6h regimen provided PTA values that were near or above target (90%) for virtual subjects between 10 to 120 kg with GFR ≥ 80 mL/min/1.73 m2.

CONCLUSION

Our analysis suggests administration of 40 mg/kg IV q6h (max 8 g/day) maximizes PTA in children and adolescents with obesity and GFR ≥ 80 mL/min/1.73 m2.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT01431326.

Correction to: Incorporating Breastfeeding-Related Variability with Physiologically Based Pharmacokinetic Modeling to Predict Infant Exposure to Maternal Medication Through Breast Milk: a Workflow Applied to Lamotrigine

A Correction to this paper has been published: 10.1208/s12248-021-00615-8

External Evaluation of Two Pediatric Population Pharmacokinetics Models of Oral Trimethoprim and Sulfamethoxazole

The antibiotic combination trimethoprim (TMP)-sulfamethoxazole (SMX) has a broad spectrum of activity and is used for the treatment of numerous infections, but pediatric pharmacokinetic (PK) data are limited. We previously published population PK (popPK) models of oral TMP-SMX in pediatric patients based on sparse opportunistically collected data (POPS study) (J. Autmizguine, C. Melloni, C. P. Hornik, S. Dallefeld, et al., Antimicrob Agents Chemother 62:e01813-17, 2017, https://doi.org/10.1128/AAC.01813-17). We performed a separate PK study of oral TMP-SMX in infants and children with more-traditional PK sample collection and independently developed new popPK models of TMP-SMX using this external data set. The POPS data set and the external data set were each used to evaluate both popPK models. The external TMP model had a model and error structure identical to those of the POPS TMP model, with typical values for PK parameters within 20%. The external SMX model did not identify the covariates in the POPS SMX model as significant. The external popPK models predicted higher exposures to TMP (median overprediction of 0.13 mg/liter for the POPS data set and 0.061 mg/liter for the external data set) and SMX (median overprediction of 1.7 mg/liter and 0.90 mg/liter) than the POPS TMP (median underprediction of 0.016 mg/liter and 0.39 mg/liter) and SMX (median underprediction of 1.2 mg/liter and 14 mg/liter) models. Nonetheless, both models supported TMP-SMX dose increases in infants and young children for resistant pathogens with a MIC of 1 mg/liter, although the required dose increase based on the external model was lower. (The POPS and external studies have been registered at ClinicalTrials.gov under registration no. NCT01431326 and NCT02475876, respectively.).

Correction to: Incorporating Breastfeeding-Related Variability with Physiologically Based Pharmacokinetic Modeling to Predict Infant Exposure to Maternal Medication Through Breast Milk: a Workflow Applied to Lamotrigine

A Correction to this paper has been published: https://doi.org/10.1208/s12248-021-00614-9.

Antibiotic Safety and Effectiveness in Premature Infants With Complicated Intraabdominal Infections

BACKGROUND

In premature infants, complicated intraabdominal infections (cIAIs) are a leading cause of morbidity and mortality. Although universally prescribed, the safety and effectiveness of commonly used antibiotic regimens have not been established in this population.

METHODS

Infants ≤33 weeks gestational age and <121 days postnatal age with cIAI were randomized to ≤10 days of ampicillin, gentamicin, and metronidazole (group 1); ampicillin, gentamicin, and clindamycin (group 2); or piperacillin-tazobactam and gentamicin (group 3) at doses stratified by postmenstrual age. Due to slow enrollment, a protocol amendment allowed eligible infants already receiving study regimens to enroll without randomization. The primary outcome was mortality within 30 days of study drug completion. Secondary outcomes included adverse events, outcomes of special interest, and therapeutic success (absence of death, negative cultures, and clinical cure score >4) 30 days after study drug completion.

RESULTS

One hundred eighty infants [128 randomized (R), 52 nonrandomized (NR)] were enrolled: 63 in group 1 (45 R, 18 NR), 47 in group 2 (41 R, 6 NR), and 70 in group 3 (42 R, 28 NR). Thirty-day mortality was 8%, 7%, and 9% in groups 1, 2, and 3, respectively. There were no differences in safety outcomes between antibiotic regimens. After adjusting for treatment group and gestational age, mortality rates through end of follow-up were 4.22 [95% confidence interval (CI): 1.39-12.13], 4.53 (95% CI: 1.21-15.50), and 4.07 (95% CI: 1.22-12.70) for groups 1, 2, and 3, respectively.

CONCLUSIONS

Each of the antibiotic regimens are safe in premature infants with cIAI.

CLINICAL TRIAL REGISTRATION

NCT0199499.

Incorporating Breastfeeding-Related Variability with Physiologically Based Pharmacokinetic Modeling to Predict Infant Exposure to Maternal Medication Through Breast Milk: a Workflow Applied to Lamotrigine

Current methods to assess risk in infants exposed to maternal medication through breast milk do not specifically account for infants most vulnerable to high drug exposure. A workflow applied to lamotrigine incorporated variability in infant anatomy and physiology, milk intake volume, and milk concentration to predict infant exposure. An adult physiologically based pharmacokinetic model of lamotrigine was developed and evaluated. The model was scaled to account for growth and maturation of a virtual infant population (n=100). Daily infant doses were simulated using milk intake volume and concentration models described by a nonlinear equation of weight-normalized intake across infant age and a linear function on the relationship of observed milk concentrations and maternal doses, respectively. Average infant plasma concentration at steady state was obtained through simulation. Models were evaluated by comparing observed to simulated infant plasma concentrations from breastfeeding infants based on a 90% prediction interval (PI). Upper AUC ratio (UAR) was defined as a novel risk metric. Twenty-five paired (milk concentrations measured) and 18 unpaired (milk concentrations unknown) infant plasma samples were retrieved from the literature. Forty-four percent and 11% of the paired and unpaired infant plasma concentrations were outside of the 90% PI, respectively. Over all ages (0-7 months), unpaired predictions captured more observed infant plasma concentrations within 90% PI than paired. UAR was 0.18-0.44 when mothers received 200 mg lamotrigine, suggesting that infants can receive 18-44% of the exposure per dose as compared to adults. UARs determined for further medications could reveal trends to better classify at-risk mother-infant pairs.

Evaluation of cabergoline for lactation inhibition in women living with HIV

We wished to evaluate the efficacy, safety, and acceptability of cabergoline for lactation inhibition in women who live with HIV. In this multicenter prospective observational study, cabergoline was offered as a single oral dose of 1 mg within the first 48 h postpartum. Women were recruited if they delivered a live infant after 35 weeks of gestational age. Participants filled out a questionnaire regarding symptoms of lactation and cabergoline adverse effects on day 2 and day 14 postpartum. On day 14, they also completed a questionnaire about their satisfaction with cabergoline treatment. Prolactin serum level was measured on both visits. Among 68 participants, all but one received cabergoline. The overall effectiveness defined by partial or complete success at day 14 was 98.3% (confidence intervals: 89.5-99.9). At day 14, 67.4% of women who received cabergoline had prolactin serum levels <25 mcg/L (threshold necessary for galactopoiesis). Mild nonspecific adverse effects were experienced by 24 (29.9%) women on day 2 and 24 (41.4%) on day 14, and lasted 48 h or less. Overall, 96% of women were satisfied with cabergoline's ability to prevent postpartum lactation symptoms. In conclusion, cabergoline is an effective, well-accepted, and well-tolerated medication for lactation inhibition in WLWH.

Population pharmacokinetics of olanzapine in children

AIMS

The aim of this study was to evaluate the population pharmacokinetics (PopPK) of olanzapine in children and devise a model-informed paediatric dosing scheme.

METHODS

The PopPK of olanzapine was characterized using opportunistically collected plasma samples from children receiving olanzapine per standard of care for any indication. A nonlinear mixed effect modelling approach was employed for model development using the software NONMEM (v7.4). Simulations from the developed PopPK model were used to devise a paediatric dosing scheme that targeted comparable plasma exposures to adolescents and adults.

RESULTS

Forty-five participants contributed 83 plasma samples towards the analysis. The median (range) postnatal age and body weight of participants were 3.8 years (0.2-19.2) and 14.1 kg (4.2-111.7), respectively. The analysis was restricted to pharmacokinetic (PK) samples collected following enteral administration (oral and feeding tube). A one-compartment model with linear elimination provided an appropriate fit to the data. The final model included the covariates body weight and postmenstrual age (PMA) on apparent olanzapine clearance (CL/F). Typical CL/F and apparent volume of distribution (scaled to 70 kg) were 16.8 L/h (21% RSE) and 663 L (13% RSE), respectively. Developed dosing schemes used weight-normalized doses for children ≤6 months postnatal age or <15 kg and fixed doses for children ≥15 kg.

CONCLUSION

We developed a paediatric PopPK model for enterally-administered olanzapine. To our knowledge, this analysis is the first study to characterize the PK of olanzapine in participants ranging from infants to adolescents. Body weight and PMA were identified as influential covariates for characterizing developmental changes in olanzapine apparent clearance.

Population pharmacokinetics of ganciclovir and valganciclovir in paediatric solid organ and stem cell transplant recipients

AIMS

Ganciclovir (GCV) and its prodrug valganciclovir (VGCV) are first-line agents to prevent and treat cytomegalovirus in transplant recipients. There is high pharmacokinetic (PK) interindividual variability and PK data are scarce, especially in paediatric stem cell transplant (SCT) recipients. We sought to determine the optimal GCV and VGCV dosing in transplanted children.

METHODS

We conducted a single-centre retrospective population PK (POPPK) study of IV GCV and enteral VGCV in paediatric solid organ transplant (SOT) and SCT recipients. We included children who were transplanted and had available plasma GCV concentrations, done per standard of care. POPPK analysis was performed using a nonlinear mixed effects modelling approach with NONMEM. Optimal dosing was determined based on the achievement of the surrogate efficacy target: GCV 24 h area under the concentration-time curve (AUC_0-24h ) of 40-60 mg.h.L^-1 .

RESULTS

Fifty children with a median [range] age of 7.5 years [0.5-17.4] contributed 580 PK samples. A two-compartment model with first-order absorption with a lag time and first-order elimination fit the data well. Creatinine clearance and body weight (WT) were significant covariates for GCV clearance (CL); and WT for the volumes of distribution. IV GCV 15-20 mg.kg^-1 .day^-1 divided every 12 hours achieved the highest probability of target achievement (PTA) (33.0-33.8%). Enteral VGCV 30 and 40 mg.kg^-1 .day^-1 divided every 12 hours in children 0-<6 years, and 6-18 years, respectively, achieved the highest PTA (29.1-33.0%).

CONCLUSION

This is the first POPPK model developed in children with either SOT or SCT. Concentration target achievement was low, suggesting a potential benefit for therapeutic drug monitoring to ensure optimal exposure.

Inhaled Antibiotics for the Prevention of Respiratory Tract Infections in Children With a Tracheostomy

Objective: To describe the use of prophylactic inhaled antibiotics in children with a tracheostomy and assess if its use is associated with a reduction in exposition to broad-spectrum antibiotics and a lower risk of acquired respiratory tract infections. Methods: A case series study was performed in a tertiary care university affiliated hospital. All consecutive children (<18 years old) with a tracheostomy, hospitalized between January 2004 and November 2016, and treated with prophylactic inhaled antibiotics were identified. We analyzed the 3 month- period before and after initiation of prophylactic inhaled antibiotics and described exposure to broad spectrum antibiotics, the number of respiratory tract infections and the associated adverse events. Results: Six children (median age: 11 months, range: 8-100) were included. One received colimycin, 3 received tobramycin and 2 were treated with both antibiotics in alternance. The median duration of treatment was 74 days (22-173) with one patient still being treated at the end of the study. Patients were exposed to systemic antibiotics for 18 days (2-49) in the 3 months preceding the treatment vs. 2 days (0-15) in the 3 months following the treatment initiation (p = 0.115). The number of respiratory tract infections went from median of 2 (0-3) to 1 (0-1) during the same periods (p = 0.07). Adverse events most commonly reported were cough (n = 2) and increased respiratory secretions post-inhalation (n = 4). Only one new bacterial resistance was observed. Conclusions: This series of consecutive cases underlines the need for future studies evaluating the potential benefit of prophylactic inhaled antibiotics in children with a tracheostomy.

Development of a national neonatal intensive care unit-specific antimicrobial stewardship programme in Canada: protocol for a cohort study

INTRODUCTION

Early empiric treatment with broad-spectrum antimicrobials is common in neonatal intensive care units (NICU) due to the non-specific clinical presentation of infection. However, excessive and inappropriate antimicrobial use can lead to the emergence of drug-resistant organisms and adverse neonatal outcomes. This study aims to develop and implement a nationwide NICU-specific antimicrobial stewardship programme (ASP) to promote judicious antimicrobial use and control the emergence of multidrug-resistant organisms (MDROs) in Canada.

METHODS AND ANALYSIS

Our study population will include all very low-birth-weight neonates admitted to participating tertiary NICU in Canada. Based on the existing limited literature, we will develop consensus on NICU antimicrobial stewardship interventions to enhance best practices. Using an expanded Canadian Neonatal Network (CNN) platform, we will collect data on antimicrobial use and the susceptibility of organisms identified in clinical samples from blood and cerebrospinal fluid over a period of 2 years. These data will be used to provide all NICU stakeholders with benchmarked centre-adjusted antimicrobial use and MDRO prevalence reports. An ASP plan will be developed at both individual unit and national levels in the subsequent years. Knowledge translation strategies will be implemented through the well-established Evidence-based Practice for Improving Quality methodology.

ETHICS AND DISSEMINATION

Ethics for the study has been granted by the University of British Columbia Children's & Women's Research Ethics Board (H19-02490) and supported by CNN Executive Committee. The study results will be disseminated through national organisations and open access peer-reviewed publications.

TRIAL REGISTRATION NUMBER

NCT04388293.

Clinical Characteristics and Disease Severity Among Infants With SARS-CoV-2 Infection in Montreal, Quebec, Canada

This case series describes clinical characteristics and disease severity in infants who had SARS-CoV-2 infection in Montreal, Quebec, Canada.

Providing Suitable Pediatric Formulations for Canadian Children: A Call for Action

Background: Many medications given to children have no commercially available, age-appropriate formulations. This leads to manipulation of dosage forms designed for adults (compounding), which can result in an increased risk of dosing errors and adverse events, lack of medication adherence because of taste issues, and suboptimal dosing with therapeutic failure.Objectives: To determine which drugs required compounding for oral administration to children in a Canadian hospital and, for each compounded drug, to determine whether it was available as licensed oral pediatric formulations in the United States or the European Union.Methods: Drugs requiring compounded liquid formulations for oral administration, dispensed from January 1 to December 31, 2015, at a Canadian university-affiliated tertiary pediatric hospital, and prepared in a quantity exceeding 0.5 L per year, were retrospectively identified. The online drug databases of Health Canada, the US Food and Drug Administration, the European Medicines Agency (EMA), and the UK Medicines and Healthcare Products Regulatory Agency were searched to determine the availability of child-friendly oral formulations for these drugs. The regulatory status in each jurisdiction was also compared. For licensed formulations with potential concerns about excipient safety, EMA guidelines for sorbitol, propylene glycol, ethanol, and sodium benzoate were used to determine pediatric suitability.Results: Of the 56 compounded drugs investigated, 27 (48%) had a suitable commercialized child-friendly formulation available outside Canada. Overall, these drugs had been on the Canadian market for a median of 35 years, and almost half (27 [48%]) had a pediatric indication in Canada.Conclusions: Canada is lagging behind the United States and the European Union in ensuring availability of and access to suitable pediatric formulations. Potential explanations for this gap include small market size, regulatory uncertainties, and reimbursement shortcomings. Steps must be taken to implement pediatric-sensitive regulations and incentives, as well as reimbursement policies, to address these unmet needs.Keywords: compounding, child-friendly medicines, pediatric oral medicinesRÉSUMÉContexte : Plusieurs médicaments administrés aux enfants ne sont pas disponibles commercialement sous une forme pharmaceutique adaptée à leur âge. Ceci entraîne une manipulation des formes destinées aux adultes (préparation magistrale) et peut conduire à une augmentation du risque d’erreurs de dosage et d’effets indésirables, un manque d’observance médicamenteuse secondairement à des problèmes de goût, et un dosage sous-optimal associé à des échecs thérapeutiques.Objectifs : Définir les médicaments qui exigent une préparation magistrale pour être administrés par voie orale aux enfants dans un hôpital canadien et, pour chaque médicament faisant l’objet d’une préparation magistrale, déterminer s’il est disponible sous une forme pharmaceutique orale autorisée pour les enfants aux États-Unis ou dans l’Union européene.Méthodes : Les médicaments nécessitant des préparations magistrales liquides pour administration orale, distribués entre le 1er janvier et le 31 décembre 2015 dans un hôpital de soins pédiatriques tertiaires affilié à une université canadienne et dont la quantité préparée était supérieure à 0.5 L par an, ont été déterminés rétrospectivement. Les bases de données en ligne de médicaments de Santé Canada, de la Food and Drug Administration américaine, de l’Agence européenne des médicaments (AEM) et de la Medicines and Healthcare Products Regulatory Agency (Royaume-Uni) ont été interrogées pour déterminer la disponibilité de formes pharmaceutiques orales adaptées aux enfants pour ces médicaments. Le statut réglementaire de chaque pays a également fait l’objet d’une comparaison. Pour les formes pharmaceutiques autorisées présentant des problèmes potentiels d’innocuité des excipients, les directives de l’AEM concernant le sorbitol, le propylène glycol, l’éthanol et le benzoate de sodium ont servi à déterminer si un usage pédiatrique était acceptable.Résultats : Des 56 médicaments étudiés faisant l’objet d’une préparation magistrale, 27 (48 %) avaient une forme pharmaceutique commercialisée adaptée aux enfants en dehors du Canada. Au total, ces médicaments sont sur le marché canadien depuis une médiane de 35 ans et près de la moitié (27 [48 %]) ont une indication pédiatrique au Canada.Conclusions : Le Canada accuse un retard par rapport aux États-Unis et à l’Union européenne quant à la disponibilité et à l’accès à des formes pharmaceutiques adéquates pour les enfants. La petite taille du marché, les incertitudes en matière réglementaire et les lacunes concernant le remboursement pourraient notamment expliquer cet écart. Il est nécessaire de prendre des mesures pour mettre en place des réglementations et des incitatifs ainsi que des politiques de remboursement axés sur les enfants pour répondre à ces besoins criants.Mots-clés : préparation magistrale, médicaments adaptés aux enfants, médicaments pédiatriques pour administration orale