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Background: To determine whether intermittent intravenous (IV) paracetamol as primary analgesic would significantly reduce morphine consumption in children aged 0-3 years after cardiac surgery with cardiopulmonary bypass., Methods: Multi-center, randomized, double-blinded, controlled trial in four level-3 Pediatric Intensive Care Units (PICU) in the Netherlands and Belgium. Inclusion period; March 2016-July 2020. Children aged 0-3 years, undergoing cardiac surgery with cardiopulmonary bypass were eligible. Patients were randomized to continuous morphine or intermittent IV paracetamol as primary analgesic after a loading dose of 100 mcg/kg morphine was administered at the end of surgery. Rescue morphine was given if numeric rating scale (NRS) pain scores exceeded predetermined cutoff values. Primary outcome was median weight-adjusted cumulative morphine dose in mcg/kg in the first 48 h postoperative. For the comparison of the primary outcome between groups, the nonparametric Van Elteren test with stratification by center was used. For comparison of the proportion of patients with one or more NRS pain scores of 4 and higher between the two groups, a non-inferiority analysis was performed using a non-inferiority margin of 20%., Results: In total, 828 were screened and finally 208 patients were included; parents of 315 patients did not give consent and 305 were excluded for various reasons. Fourteen of the enrolled 208 children were withdrawn from the study before start of study medication leaving 194 patients for final analysis. One hundred and two patients received intermittent IV paracetamol, 106 received continuous morphine. The median weight-adjusted cumulative morphine consumption in the first 48 h postoperative in the IV paracetamol group was 5 times lower (79%) than that in the morphine group (median, 145.0 (IQR, 115.0-432.5) mcg/kg vs 692.6 (IQR, 532.7-856.1) mcg/kg; P < 0.001). The rescue morphine consumption was similar between the groups (p = 0.38). Non-inferiority of IV paracetamol administration in terms of NRS pain scores was proven; difference in proportion - 3.1% (95% CI - 16.6-10.3%)., Conclusions: In children aged 0-3 years undergoing cardiac surgery, use of intermittent IV paracetamol reduces the median weight-adjusted cumulative morphine consumption in the first 48 h after surgery by 79% with equal pain relief showing equipoise for IV paracetamol as primary analgesic. Trial Registration Clinicaltrials.gov, Identifier: NCT05853263; EudraCT Number: 2015-001835-20., (© 2024. The Author(s).)

Aims: To investigate the pharmacokinetics and safety of prolonged paracetamol use (>72 h) for neonatal pain., Methods: Neonates were included if they received paracetamol orally or intravenously for pain treatment. A total of 126 samples were collected. Alanine aminotransferase and bilirubin were measured as surrogate liver safety markers. Paracetamol and metabolites were measured in plasma. Pharmacokinetic parameters for the parent compound were estimated with a nonlinear mixed-effects model., Results: Forty-eight neonates were enrolled (38 received paracetamol for >72 h). Median gestational age was 38 weeks (range 25-42), and bodyweight at inclusion was 2954 g (range 713-4750). Neonates received 16 doses (range 4-55) over 4.1 days (range 1-13.8). The median (range) dose was 10.1 mg/kg (2.9-20.3). The median oxidative metabolite concentration was 14.6 μmol/L (range 0.12-113.5) and measurable >30 h after dose. There was no significant difference (P > .05) between alanine aminotransferase and bilirubin measures at <72 h or >72 h of paracetamol treatment or the start and end of the study. Volume of distribution and paracetamol clearance for a 2.81-kg neonate were 2.99 L (% residual standard error = 8, 95% confidence interval 2.44-3.55) and 0.497 L/h (% residual standard error = 7, 95% confidence interval 0.425-0.570), respectively. Median steady-state concentration from the parent model was 50.3 μmol/L (range 30.6-92.5), and the half-life was 3.55 h (range 2.41-5.65)., Conclusion: Our study did not provide evidence of paracetamol-induced liver injury nor changes in metabolism in prolonged paracetamol administration in neonates., (© 2023 The Authors. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Importance: Continuous morphine infusion as standard postoperative analgesic therapy in young infants is associated with unwanted adverse effects such as respiratory depression., Objective: To determine whether intravenous paracetamol (acetaminophen) would significantly (>30%) reduce morphine requirements in neonates and infants after major surgery., Design, Setting, and Patients: Single-center, randomized, double-blind study conducted in a level 3 pediatric intensive care unit in Rotterdam, The Netherlands. Patients were 71 neonates or infants younger than 1 year undergoing major thoracic (noncardiac) or abdominal surgery between March 2008 and July 2010, with follow-up of 48 hours., Interventions: All patients received a loading dose of morphine 30 minutes before the end of surgery, followed by continuous morphine or intermittent intravenous paracetamol up to 48 hours postsurgery. Infants in both study groups received morphine (boluses and/or continuous infusion) as rescue medication on the guidance of the validated pain assessment instruments., Main Outcome Measures: Primary outcome was cumulative morphine dose (study and rescue dose). Secondary outcomes were pain scores and morphine-related adverse effects., Results: The cumulative median morphine dose in the first 48 hours postoperatively was 121 (interquartile range, 99-264) μg/kg in the paracetamol group (n = 33) and 357 (interquartile range, 220-605) μg/kg in the morphine group (n = 38), P < .001, with a between-group difference that was 66% (95% CI, 34%-109%) lower in the paracetamol group. Pain scores and adverse effects were not significantly different between groups., Conclusion and Relevance: Among infants undergoing major surgery, postoperative use of intermittent intravenous paracetamol compared with continuous morphine resulted in a lower cumulative morphine dose over 48 hours., Trial Registration: trialregister.nl Identifier: NTR1438.

Introduction: Pharmacologic pain management in newborns and infants is often based on limited scientific data. To close the knowledge gap, drug-related research in this population is increasingly supported by the authorities, but remains very challenging. This review summarizes the challenges of analgesic studies in newborns and infants on morphine and paracetamol (acetaminophen). Areas covered: Aspects such as the definition and multimodal character of pain are reflected to newborn infants. Specific problems addressed include defining pharmacodynamic endpoints, performing clinical trials in this population and assessing developmental changes in both pharmacokinetics and pharmacodynamics. Expert commentary: Neonatal and infant pain management research faces two major challenges: lack of clear biomarkers and very heterogeneous pharmacokinetics and pharmacodynamics of analgesics. There is a clear call for integral research addressing the multimodality of pain in this population and further developing population pharmacokinetic models towards physiology-based models. [ABSTRACT FROM AUTHOR]

Purpose: Based on recovered metabolite ratios in urine, it has been concluded that paracetamol glucuronidation may be up-regulated upon multiple dosing. This study investigates paracetamol clearance in neonates and infants after single and multiple dosing using a population modelling approach. Methods: A population pharmacokinetic model was developed in NONMEM VI, based on paracetamol plasma concentrations from 54 preterm and term neonates and infants, and on paracetamol, paracetamol-glucuronide and paracetamol-sulphate amounts in urine from 22 of these patients. Patients received either a single intravenous propacetamol dose or up to 12 repeated doses. Results: Paracetamol and metabolite disposition was best described with one-compartment models. The formation clearance of paracetamol-sulphate was 1.46 mL/min/kg, which was about 5.5 times higher than the formation clearance of the glucuronide of 0.266 mL/min/kg. The renal excretion rate constants of both metabolites was estimated to be 11.4 times higher than the excretion rate constant of unchanged paracetamol, yielding values of 0.580 mL/min/kg. Developmental changes were best described by bodyweight in linear relationships on the distribution volumes, the formation of paracetamol-glucuronide and the unchanged excretion of paracetamol, and in an exponential relationship on the formation of paracetamol-sulphate. There was no evidence for up-regulation or other time-varying changes in any of the model parameters. Simulations with this model illustrate how paracetamol-glucuronide recovery in urine increases over time due to the slower formation of this metabolite and in the absence of up-regulation. Conclusions: Developmental changes, described by bodyweight-based functions, rather than up-regulation, explain developmental changes in paracetamol disposition in neonates and infants. [ABSTRACT FROM AUTHOR]

Pain is a predictable consequence following operations, but the management of postoperative pain is another challenge for anesthesiologists and inappropriately controlled pain may lead to unwanted outcomes in the postoperative period. Opioids are indeed still at the mainstream of postoperative pain control, but solely using only opioids for postoperative pain management may be connected with risks of complications and adverse effects. As a consequence, the concept of multimodal analgesia has been proposed and is recommended whenever possible. Acetaminophen is one of the most commonly used analgesic and antipyretic drug for its good tolerance and high safety profiles. The introduction of intravenous form of acetaminophen has led to a wider flexibility of its use during peri- and postoperative periods, allowing the early initiation of multimodal analgesia. Many studies have revealed the efficacy, safety and opioid sparing effects of intravenous acetaminophen. Intravenous ibuprofen has also shown to be well tolerated and demonstrated to have significant opioid sparing effects during the postoperative period. However, the number of randomized controlled trials confirming the efficacy and safety is small and should be used in caution in certain group of patients. Intravenous acetaminophen and ibuprofen are important options for multimodal postoperative analgesia, improving pain and patient satisfaction. [ABSTRACT FROM AUTHOR]

Background: Pediatric drug development is hampered by practical, ethical, and scientific challenges. Microdosing is a promising new method to obtain pharmacokinetic data in children with minimal burden and minimal risk. The use of a labeled oral microdose offers the added benefit to study intestinal and hepatic drug disposition in children already receiving an intravenous therapeutic drug dose for clinical reasons. Objective: The objective of this study was to present pilot data of an oral [C]paracetamol [acetaminophen (AAP)] microdosing study as proof of concept to study developmental pharmacokinetics in children. Methods: In an open-label microdose pharmacokinetic pilot study, infants (0-6 years of age) received a single oral [C]AAP microdose (3.3 ng/kg, 60 Bq/kg) in addition to intravenous therapeutic doses of AAP (15 mg/kg intravenous every 6 h). Blood samples were taken from an indwelling catheter. AAP blood concentrations were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and [C]AAP and metabolites ([C]AAP-Glu and [C]AAP-4Sul) were measured by accelerator mass spectrometry. Results: Ten infants (aged 0.1-83.1 months) were included; one was excluded as he vomited shortly after administration. In nine patients, [C]AAP and metabolites in blood samples were detectable at expected concentrations: median (range) maximum concentration ( C) [C]AAP 1.68 (0.75-4.76) ng/L, [C]AAP-Glu 0.88 (0.34-1.55) ng/L, and [C]AAP-4Sul 0.81 (0.29-2.10) ng/L. Dose-normalized oral [C]AAP C approached median intravenous average concentrations ( C): 8.41 mg/L (3.75-23.78 mg/L) and 8.87 mg/L (3.45-12.9 mg/L), respectively. Conclusions: We demonstrate the feasibility of using a [C]labeled microdose to study AAP pharmacokinetics, including metabolite disposition, in young children. [ABSTRACT FROM AUTHOR]

Paracetamol (acetaminophen) is one of the most popular and widely used drugs for the treatment of pain and fever in children. This drug has multiple mechanisms of action, but its pharmacodynamic is still not well known. The central nervous system is the main site of action and it mirrors the paracetamol effect compartment. The recommended dosages and routes of administration should be different whether paracetamol is used for the treatment of pain or fever. For example, the rectal route, while being efficacious for the treatment of fever, should be avoided in pain management. Paracetamol is a safe drug, but some clinical conditions and concomitant drugs, which are frequent in clinical practice, may increase the risk of paracetamol toxicity. Therefore, it is important to optimize its administration to avoid overdoses and maximize its effect. The principal mediator of the paracetamol toxicity is the N-acetyl- p-benzo-quinone imine (NAPQI), a toxic product of the paracetamol metabolism, which could bind cysteine groups on proteins forming paracetamol-protein adduct in the liver. Conclusion: Although frequently prescribed, the concept of 'effect compartment concentration' and the possible co-factors that could cause toxicity at recommended doses are not familiar to all pediatricians and general practitioners. We reviewed the literature concerning paracetamol mechanisms of action, we highlighted some relevant pharmacodynamic concepts for clinical practice, and we summarized the possible risk factors for toxicity at therapeutic dosages. [ABSTRACT FROM AUTHOR]

An abstract of the report "Concurrent Use of Diuretics, Angiotensin Converting Enzyme Inhibitors, and Angiotensin Receptor Blockers With Non-Steroidal Anti-Inflammatory Drugs and Risk of Acute Kidney Injury: Nested Case-Control Study" by F. Lapi, L. Azoulay, H. Yin, S. J. Nessim, and S. Suissa in the January 8, 2013 online edition of the "British Medical Journal" is presented.

Background: Morphine is worldwide the analgesic of first choice after cardiac surgery in children. Morphine has unwanted hemodynamic and respiratory side effects. Therefore, post-cardiac surgery patients may potentially benefit from a non-opioid drug for pain relief. A previous study has shown that intravenous (IV) paracetamol is effective and opioid-sparing in children after major non-cardiac surgery. The aim of the study is to test the hypothesis that intermittent IV paracetamol administration in children after cardiac surgery will result in a reduction of at least 30% of the cumulative morphine requirement.Methods: This is a prospective, multi-center, randomized controlled trial at four level-3 pediatric intensive care units (ICUs) in the Netherlands and Belgium. Children who are 0-36 months old will be randomly assigned to receive either intermittent IV paracetamol or continuous IV morphine up to 48 h post-operatively. Morphine will be available as rescue medication for both groups. Validated pain and sedation assessment tools will be used to monitor patients. The sample size (n = 208, 104 per arm) was calculated in order to detect a 30% reduction in morphine dose; two-sided significance level was 5% and power was 95%.Discussion: This study will focus on the reduction, or replacement, of morphine by IV paracetamol in children (0-36 months old) after cardiac surgery. The results of this study will form the basis of a new pain management algorithm and will be implemented at the participating ICUs, resulting in an evidence-based guideline on post-operative pain after cardiac surgery in infants who are 0-36 months old.Trial Registration: Dutch Trial Registry ( www.trialregister.nl ): NTR5448 on September 1, 2015. Institutional review board approval (MEC2015-646), current protocol version: July 3, 2017. [ABSTRACT FROM AUTHOR]