67 research outputs found
Vancomycin Clearance in Obese Adults is not Predictive of Clearance in Obese Adolescents
Contradictory pharmacokinetic (PK) results have been observed between obese adults and obese adolescents, with absolute clearance (CL) reported to be either unaltered, lower, or higher in obese adolescents compared to obese adults. This study investigates the PK of vancomycin in adolescents and adults who are overweight or obese. Data from 125 overweight and obese adolescents (aged 10â18 years, weight 28.3â188 kg) and 81 overweight and obese adults (aged 29â88 years, weight 66.7â143 kg) were analysed using population PK modelling. In addition to age, sex, renal function estimates, and regular weight descriptors, we evaluated standard weight (WTstandard, defined as weight for length, age, and sex in adolescents and weight for length in adults) and excess weight (WTexcess, defined as total body weight (TBW) minus WTstandard) as covariates in order to distinguish between weight resulting from length versus weight resulting from obesity. Analyzing adolescents and adults together, vancomycin CL was found to increase with TBW and decrease with increasing age (p \u3c 0.001). A covariate analysis investigating adolescents and adults separately found that vancomycin CL increased with WTstandard in adolescents and adults, albeit with different functions, with adolescents having a higher CL per WTstandard than adults. Moreover, in this separate model, adolescent males had 21% higher CL than adolescent females of the same WTstandard, while in adults, CL decreased with increasing age (p \u3c 0.001). There are apparent differences in vancomycin CL in overweight and obese adults versus overweight and obese adolescents, implying that dosing of vancomycin cannot be directly extrapolated between these populations
Impact of Bariatric Surgery in the Short and Long Term: A Need for Time-Dependent Dosing of Drugs
Sparse information is available on pharmacokinetic changes of drugs over time after bariatric surgery. By reviewing the literature on the short- and long-term pharmacokinetic changes of drugs, several patterns were identified for 39 drugs. No relevant pharmacokinetic changes were identified for roughly a third of the drugs. Of the remaining drugs, levels were variable and partly unpredictable shortly after the surgery. In the long term, most of the drug levels remain altered, but in some cases they returned to preoperative values. Based on the changes and the efficacy-safety balance of each drug, clinicians may need to perform additional clinical monitoring for specific drugs, including measuring drug levels. This review provides suggestions for clinicians and pharmacists for specific time-dependent drug dosing advice
Pre- and Postnatal Maturation are Important for Fentanyl Exposure in Preterm and Term Newborns : A Pooled Population Pharmacokinetic Study
Publisher Copyright: © 2021, The Author(s).Background and Objective Fentanyl is an opioid commonly used to prevent and treat severe pain in neonates; however, its use is off label and mostly based on bodyweight. Given the limited pharmacokinetic information across the entire neonatal age range, we characterized the pharmacokinetics of fentanyl across preterm and term neonates to individualize dosing. Methods We pooled data from two previous studies on 164 newborns with a median gestational age of 29.0 weeks (range 23.9-42.3), birthweight of 1055 g (range 390-4245), and postnatal age (PNA) of 1 day (range 0-68). In total, 673 plasma samples upon bolus dosing (69 patients; median dose 2.1 mu g/kg, median 2 boluses per patient) or continuous infusions (95 patients; median dose 1.1 mu g/kg/h for 30 h) with and without boluses were used for population pharmacokinetic modeling in NONMEM(R) 7.4. Results Clearance in neonates with birthweight of 2000 and 3000 g was 2.8- and 5.0-fold the clearance in a neonate with birthweight of 1000 g, respectively. Fentanyl clearance at PNA of 7, 14, and 21 days was 2.7-fold, 3.8-fold, and 4.6-fold the clearance at 1 day, respectively. Bodyweight-based dosing resulted in large differences in fentanyl concentrations. Depending on PNA and birthweight, fentanyl concentrations increased slowly after the start of therapy for both intermittent boluses and continuous infusion and reached a maximum concentration at 12-48 h. Conclusions As both prenatal and postnatal maturation are important for fentanyl exposure, we propose a birthweight- and PNA-based dosage regimen. To provide rapid analgesia in the first 24 h of treatment, additional loading doses need to be considered.Peer reviewe
Anaesthesia and postoperative analgesia in surgical neonates with or without Downs syndrome: Is it really different?
BackgroundReports conflict on optimal postoperative analgesic treatment in children with intellectual disability. We retrospectively compared postoperative analgesics consumption between neonates with and without Downs syndrome in relation to anaesthesia requirements and pain scores. MethodsWe analysed hypnotic and analgesic drug administration, pain scores [COMFORT-Behaviour (COMFORT-B) scale], and duration of mechanical ventilation during the first 48 h after surgical repair of congenital duodenal obstruction in neonates, between 1999 and 2011. Data of 15 children with Downs syndrome were compared with data of 30 children without Downs syndrome. ResultsGeneral anaesthesia requirements did not differ. The median (inter-quartile range) maintenance dose of morphine during the first 24 h after operation was 9.5 (7.810.1) g kg -1 h -1 in the Downs syndrome group vs 7.7 (5.010.0) g kg -1 h -1 in the control group (P0.46). Morphine doses at postoperative day 2 and COMFORT-B scores at day 1 did not significantly differ between the two groups. COMFORT-B scores at day two were lower in children with Downs syndrome (P0.04). The duration of postoperative mechanical ventilation did not statistically differ between the two groups (P0.89). ConclusionsIn this study, neonates with and without Downs syndrome received adequate postoperative analgesia, as judged from comparable analgesic consumption and pain scores. We recommend prospective studies in children of different age groups with Downs syndrome and in other groups of intellectually disabled children to provide further investigation of the hypothesis that intellectual disability predisposes to different analgesic requirements
Maturation of Paracetamol Elimination Routes in Preterm Neonates Born Below 32Â Weeks of Gestation
Purpose: Despite being off-label, intravenous paracetamol (PCM) is increasingly used to control mild-to-moderate pain in preterm neonates. Here we aim to quantify the maturation of paracetamol elimination pathways in preterm neonates born below 32Â weeks of gestation. Methods: Datasets after single dose (rich data) or multiple doses (sparse data) of intravenous PCM dose (median (range)) 9 (3â25) mg/kg were pooled, containing 534 plasma and 44 urine samples of PCM and metabolites (PCMâglucuronide, PCMâsulfate, PCMâcysteine, and PCMâmercapturate) from 143 preterm neonates (gestational age 27.7 (24.0â31.9) weeks, birthweight 985 (462â1,925) g, postnatal age (PNA) 5 (0â30) days, current weight 1,012 (462â1,959) g. Population pharmacokinetic analysis was performed using NONMEMÂź 7.4. Results: For a typical preterm neonate (birthweight 985Â g; PNA 5Â days), PCM clearance was 0.137 L/h, with glucuronidation, sulfation, oxidation and unchanged renal clearance accounting for 5.3%, 73.7%, 16.3% and 4.6%, respectively. Maturational changes in total PCM clearance and its elimination pathways were best described by birthweight and PNA. Between 500â1,500Â g birthweight, total PCM clearance increases by 169%, with glucuronidation, sulfation and oxidation clearance increasing by 347%, 164% and 164%. From 1â30Â days PNA for 985 g birthweight neonate, total PCM clearance increases by 167%, with clearance via glucuronidation and oxidation increasing by 551%, and sulfation by 69%. Conclusion: Birthweight and PNA are the most important predictors for maturational changes in paracetamol clearance and its glucuronidation, sulfation and oxidation. As a result, dosing based on bodyweight alone will not lead to consistent paracetamol concentrations among preterm neonates.</p
Immune Reconstitution Kinetics as an Early Predictor for Mortality using Various Hematopoietic Stem Cell Sources in Children
AbstractThe severity of complications of allogeneic hematopoietic stem cell transplantation (HSCT) is governed mainly by the status of immune reconstitution. In this study, we investigated differences in immune reconstitution with different cell sources and the association between the kinetics of immune reconstitution and mortality. Immunophenotyping was performed every 2 weeks in children who had undergone HSCTÂ between 2004 and 2008 at University Medical Center Utrecht. Lymphocyte reconstitution in the first 90Â days after HSCT was studied in relation to mortality in 3 HSCT groups: matched sibling bone marrow (BM) recipients (35 patients), unrelated BM recipients (32 patients), and unrelated cord blood recipients (36Â patients). The median age of recipients was 5.9 years (range, 0.1-21 years). The nature and speed of T cell, B cell, and natural killer (NK) cell reconstitution were highly dependent on the cell source. In the first 90 days after HSCT, faster B cell and NK cell reconstitution and delayed T cell reconstitution were shown in unrelated cord blood recipients compared with matched sibling BM and unrelated BM recipients. Of the lymphocyte subsets investigated, a large number of NK cells and a more rapid CD4+ immune reconstitution over time, resulting in sustained higher CD4+ counts, were the only predictors of a lower mortality risk in all cell sources. The final model showed that during the first 90 days, patients with an area under the CD4+ cell receiver- operating curve of >4,300 cells/day and no peak in CD4+ cell counts had the highest likelihood of survival (hazard ratio for mortality, 0.2; 95% confidence interval, 0.06-0.5). Our data indicate that CD4+ kinetics may be used to identify patients at greatest risk for mortality early after HSCT
Quantifying the Pharmacodynamics of Morphine in the Treatment of Postoperative Pain in Preverbal Children
While the pharmacokinetics of morphine in children have been studied extensively, little is known about the pharmacodynamics of morphine in this population. Here, we quantified the concentrationâeffect relationship of morphine for postoperative pain in preverbal children between 0 and 3 years of age. For this, we applied item response theory modeling in the pharmacokinetic/pharmacodynamic analysis of COMFORTâBehavior (COMFORTâB) scale data from 2 previous clinical studies. In the model, we identified a sigmoid maximal efficacy model for the effect of morphine and found that in 26% of children, increasing morphine concentrations were not associated with lower pain scores (nonresponders to morphine upâtitration). In responders to morphine upâtitration, the COMFORTâB score slowly decreases with increasing morphine concentrations at morphine concentrations >20 ng/mL. In nonresponding children, no decrease in COMFORTâB score is expected. In general, lower baseline COMFORTâB scores (2.1 points on average) in younger children (postnatal age 10 days. These findings support a dosing regimen previously suggested by Krekels et al, which would put >95% of patients within this morphine target concentration range at steady state. Our modeling approach provides a promising platform for pharmacodynamic research of analgesics and sedatives in children
When will the Glomerular Filtration Rate in Former Preterm Neonates Catch up with Their Term Peers?
Aims: Whether and when glomerular filtration rate (GFR) in preterms catches up with term peers is unknown. This study aims to develop a GFR maturation model for (pre)term-born individuals from birth to 18Â years of age. Secondarily, the function is applied to data of different renally excreted drugs. Methods: We combined published inulin clearance values and serum creatinine (Scr) concentrations in (pre)term born individuals throughout childhood. Inulin clearance was assumed to be equal to GFR, and Scr to reflect creatinine synthesis rate/GFR. We developed a GFR function consisting of GFR birth (GFR at birth), and an Emax model dependent on PNA (with GFR max, PNA 50 (PNA at which half of GFR max is reached) and Hill coefficient). The final GFR model was applied to predict gentamicin, tobramycin and vancomycin concentrations. Result: In the GFR model, GFR birth varied with birthweight linearly while in the PNA-based Emax equation, GA was the best covariate for PNA 50, and current weight for GFR max. The final model showed that for a child born at 26Â weeks GA, absolute GFR is 18%, 63%, 80%, 92% and 96% of the GFR of a child born at 40Â weeks GA at 1Â month, 6Â months, 1Â year, 3Â years and 12Â years, respectively. PopPK models with the GFR maturation equations predicted concentrations of renally cleared antibiotics across (pre)term-born neonates until 18Â years well. Conclusions: GFR of preterm individuals catches up with term peers at around three years of age, implying reduced dosages of renally cleared drugs should be considered below this age.</p
Exploring the Relationship Between Morphine Concentration and Oversedation in Children After Cardiac Surgery
Titrating analgesic and sedative drugs in pediatric intensive care remains a challenge for caregivers due to the lack of pharmacodynamic knowledge in this population. The aim of the current study is to explore the concentration-effect relationship for morphine-associated oversedation after c
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) 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
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