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Rodieux F, Vutskits L, Posfay-Barbe KM, Habre W, Piguet V, Desmeules JA, Samer CF. When the Safe Alternative Is Not That Safe: Tramadol Prescribing in Children. Front Pharmacol 2018; 9:148. [PMID: 29556194 PMCID: PMC5844975 DOI: 10.3389/fphar.2018.00148] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 02/13/2018] [Indexed: 01/10/2023] Open
Abstract
Children represent a vulnerable population in which management of nociceptive pain is complex. Drug responses in children differ from adults due to age-related differences. Moreover, therapeutic choices are limited by the lack of indication for a number of analgesic drugs due to the challenge of conducting clinical trials in children. Furthermore the assessment of efficacy as well as tolerance may be complicated by children's inability to communicate properly. According to the World Health Organization, weak opioids such as tramadol and codeine, may be used in addition to paracetamol and ibuprofen for moderate nociceptive pain in both children and adults. However, codeine prescription has been restricted for the last 5 years in children because of the risk of fatal overdoses linked to the variable activity of cytochrome P450 (CYP) 2D6 which bioactivates codeine. Even though tramadol has been considered a safe alternative to codeine, it is well established that tramadol pharmacodynamic opioid effects, efficacy and safety, are also largely influenced by CYP2D6 activity. For this reason, the US Food and Drug Administration recently released a boxed warning regarding the use of tramadol in children. To provide safe and effective tramadol prescription in children, a personalized approach, with dose adaptation according to CYP2D6 activity, would certainly be the safest method. We therefore recommend this approach in children requiring chronic or recurrent nociceptive pain treatment with tramadol. In case of acute inpatients nociceptive pain management, prescribing tramadol at the minimal effective dose, in a child appropriate dosage form and after clear instructions are given to the parents, remains reasonable based on current data. In all other situations, morphine should be preferred for moderate to severe nociceptive pain conditions.
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Affiliation(s)
- Frédérique Rodieux
- Division of Clinical Pharmacology and Toxicology, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland
| | - Laszlo Vutskits
- Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland.,Department of Basic Neuroscience, Faculty of Medicine, University of GenevaGeneva, Switzerland.,Division of Anesthesiology, Unit for Pediatric Anesthesia, Children's Hospitals of Geneva, Geneva University Hospitals, University of GenevaGeneva, Switzerland
| | - Klara M Posfay-Barbe
- Pediatric Infectious Diseases Unit, Department of Pediatrics, Children's Hospital of Geneva, Geneva University Hospitals, University of GenevaGeneva, Switzerland
| | - Walid Habre
- Division of Anesthesiology, Unit for Pediatric Anesthesia, Children's Hospitals of Geneva, Geneva University Hospitals, University of GenevaGeneva, Switzerland.,Anesthesiological Investigations Unit, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland
| | - Valérie Piguet
- Division of Clinical Pharmacology and Toxicology, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland
| | - Jules A Desmeules
- Division of Clinical Pharmacology and Toxicology, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland.,School of Pharmaceutical Sciences, University of Geneva, University of LausanneGeneva, Switzerland
| | - Caroline F Samer
- Division of Clinical Pharmacology and Toxicology, Department of Anesthesiology, Pharmacology and Intensive Care, Geneva University Hospitals, University of GenevaGeneva, Switzerland
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Cook SF, Stockmann C, Samiee-Zafarghandy S, King AD, Deutsch N, Williams EF, Wilkins DG, Sherwin CM, van den Anker JN. Neonatal Maturation of Paracetamol (Acetaminophen) Glucuronidation, Sulfation, and Oxidation Based on a Parent-Metabolite Population Pharmacokinetic Model. Clin Pharmacokinet 2016; 55:1395-411. [PMID: 27209292 DOI: 10.1007/s40262-016-0408-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVES This study aimed to model the population pharmacokinetics of intravenous paracetamol and its major metabolites in neonates and to identify influential patient characteristics, especially those affecting the formation clearance (CLformation) of oxidative pathway metabolites. METHODS Neonates with a clinical indication for intravenous analgesia received five 15-mg/kg doses of paracetamol at 12-h intervals (<28 weeks' gestation) or seven 15-mg/kg doses at 8-h intervals (≥28 weeks' gestation). Plasma and urine were sampled throughout the 72-h study period. Concentration-time data for paracetamol, paracetamol-glucuronide, paracetamol-sulfate, and the combined oxidative pathway metabolites (paracetamol-cysteine and paracetamol-N-acetylcysteine) were simultaneously modeled in NONMEM 7.2. RESULTS The model incorporated 259 plasma and 350 urine samples from 35 neonates with a mean gestational age of 33.6 weeks (standard deviation 6.6). CLformation for all metabolites increased with weight; CLformation for glucuronidation and oxidation also increased with postnatal age. At the mean weight (2.3 kg) and postnatal age (7.5 days), CLformation estimates (bootstrap 95% confidence interval; between-subject variability) were 0.049 L/h (0.038-0.062; 62 %) for glucuronidation, 0.21 L/h (0.17-0.24; 33 %) for sulfation, and 0.058 L/h (0.044-0.078; 72 %) for oxidation. Expression of individual oxidation CLformation as a fraction of total individual paracetamol clearance showed that, on average, fractional oxidation CLformation increased <15 % when plotted against weight or postnatal age. CONCLUSIONS The parent-metabolite model successfully characterized the pharmacokinetics of intravenous paracetamol and its metabolites in neonates. Maturational changes in the fraction of paracetamol undergoing oxidation were small relative to between-subject variability.
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Krekels EHJ, van Ham S, Allegaert K, de Hoon J, Tibboel D, Danhof M, Knibbe CAJ. Developmental changes rather than repeated administration drive paracetamol glucuronidation in neonates and infants. Eur J Clin Pharmacol 2015; 71:1075-82. [PMID: 26139379 PMCID: PMC4532713 DOI: 10.1007/s00228-015-1887-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/09/2015] [Indexed: 01/02/2023]
Abstract
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/kg1.4, 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. Electronic supplementary material The online version of this article (doi:10.1007/s00228-015-1887-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elke H J Krekels
- Division of Pharmacology, Leiden Academic Center for Drug Research, Leiden, The Netherlands
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Abstract
Information on drug absorption and disposition in infants and children has increased considerably over the past 2 decades. However, the impact of specific age-related effects on pharmacokinetics, pharmacodynamics, and dose requirements remains poorly understood. Absorption can be affected by the differences in gastric pH and stomach emptying time that have been observed in the pediatric population. Low plasma protein concentrations and a higher body water composition can change drug distribution. Metabolic processes are often immature at birth, which can lead to a reduced clearance and a prolonged half-life for those drugs for which metabolism is a significant mechanism for elimination. Renal excretion is also reduced in neonates due to immature glomerular filtration, tubular secretion, and reabsorption. Limited data are available on the pharmacodynamic behavior of drugs in the pediatric population. Understanding these age effects provide a mechanistic way to identify initial doses for the pediatric population. The various factors that impact pharmacokinetics and pharmacodynamics mature towards adult values at different rates, thus requiring continual modification of drug dose regimens in neonates, infants, and children. In this paper, the age-related changes in drug absorption, distribution, metabolism, and elimination in infants and children are reviewed, and the age-related dosing regimens for this population are discussed.
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Affiliation(s)
- Hong Lu
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island
| | - Sara Rosenbaum
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island
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