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Maglalang PD, Wen J, Hornik CP, Gonzalez D. Sources of pharmacokinetic and pharmacodynamic variability and clinical pharmacology studies of antiseizure medications in the pediatric population. Clin Transl Sci 2024; 17:e13793. [PMID: 38618871 PMCID: PMC11017206 DOI: 10.1111/cts.13793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 03/08/2024] [Accepted: 03/25/2024] [Indexed: 04/16/2024] Open
Abstract
Multiple treatment options exist for children with epilepsy, including surgery, dietary therapies, neurostimulation, and antiseizure medications (ASMs). ASMs are the first line of therapy, and more than 30 ASMs have U.S. Food and Drug Administration (FDA) approval for the treatment of various epilepsy and seizure types in children. Given the extensive FDA approval of ASMs in children, it is crucial to consider how the physiological and developmental changes throughout childhood may impact drug disposition. Various sources of pharmacokinetic (PK) variability from different extrinsic and intrinsic factors such as patients' size, age, drug-drug interactions, and drug formulation could result in suboptimal dosing of ASMs. Barriers exist to conducting clinical pharmacological studies in neonates, infants, and children due to ethical and practical reasons, limiting available data to fully characterize these drugs' disposition and better elucidate sources of PK variability. Modeling and simulation offer ways to circumvent traditional and intensive clinical pharmacology methods to address gaps in epilepsy and seizure management in children. This review discusses various physiological and developmental changes that influence the PK and pharmacodynamic (PD) variability of ASMs in children, and several key ASMs will be discussed in detail. We will also review novel trial designs in younger pediatric populations, highlight the role of extrapolation of efficacy in epilepsy, and the use of physiologically based PK modeling as a tool to investigate sources of PK/PD variability in children. Finally, we will conclude with current challenges and future directions for optimizing the efficacy and safety of these drugs across the pediatric age spectrum.
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Affiliation(s)
- Patricia D. Maglalang
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of PharmacyThe University of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
| | - Jiali Wen
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of PharmacyThe University of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
| | - Christoph P. Hornik
- Duke Clinical Research InstituteDurhamNorth CarolinaUSA
- Department of PediatricsDuke University School of MedicineDurhamNorth CarolinaUSA
| | - Daniel Gonzalez
- Duke Clinical Research InstituteDurhamNorth CarolinaUSA
- Division of Clinical Pharmacology, Department of MedicineDuke University School of MedicineDurhamNorth CarolinaUSA
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2
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Ziobro JM, Eschbach K, Shellhaas RA. Novel Therapeutics for Neonatal Seizures. Neurotherapeutics 2021; 18:1564-1581. [PMID: 34386906 PMCID: PMC8608938 DOI: 10.1007/s13311-021-01085-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2021] [Indexed: 02/04/2023] Open
Abstract
Neonatal seizures are a common neurologic emergency for which therapies have not significantly changed in decades. Improvements in diagnosis and pathophysiologic understanding of the distinct features of acute symptomatic seizures and neonatal-onset epilepsies present exceptional opportunities for development of precision therapies with potential to improve outcomes. Herein, we discuss the pathophysiology of neonatal seizures and review the evidence for currently available treatment. We present emerging therapies in clinical and preclinical development for the treatment of acute symptomatic neonatal seizures. Lastly, we discuss the role of precision therapies for genetic neonatal-onset epilepsies and address barriers and goals for developing new therapies for clinical care.
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Affiliation(s)
- Julie M Ziobro
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA.
| | - Krista Eschbach
- Department of Pediatrics, Section of Neurology, Denver Anschutz School of Medicine, Children's Hospital Colorado, University of Colorado, Aurora, CO, 80045, USA
| | - Renée A Shellhaas
- Department of Pediatrics, Michigan Medicine, C.S. Mott Children's Hospital, University of Michigan, 1540 E. Hospital Dr, Ann Arbor, MI, USA
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3
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van den Anker J, Reed MD, Allegaert K, Kearns GL. Developmental Changes in Pharmacokinetics and Pharmacodynamics. J Clin Pharmacol 2018; 58 Suppl 10:S10-S25. [DOI: 10.1002/jcph.1284] [Citation(s) in RCA: 121] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 06/21/2018] [Indexed: 12/22/2022]
Affiliation(s)
- John van den Anker
- Division of Clinical Pharmacology; Children's National Health System; Washington DC USA
- Division of Paediatric Pharmacology and Pharmacometrics; University of Basel Children's Hospital; Basel Switzerland
- Intensive Care and Department of Pediatric Surgery; Erasmus Medical Center-Sophia Children's Hospital; Rotterdam the Netherlands
| | - Michael D. Reed
- Emeritus Professor of Pediatrics; School of Medicine; Case Western Reserve University; Cleveland OH USA
| | - Karel Allegaert
- Intensive Care and Department of Pediatric Surgery; Erasmus Medical Center-Sophia Children's Hospital; Rotterdam the Netherlands
- Department of Pediatrics; Division of Neonatology; Erasmus Medical Center-Sophia Children's Hospital; Rotterdam the Netherlands
- Department of Development and Regeneration; KU Leuven; Leuven Belgium
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Yozawitz E, Stacey A, Pressler RM. Pharmacotherapy for Seizures in Neonates with Hypoxic Ischemic Encephalopathy. Paediatr Drugs 2017; 19:553-567. [PMID: 28770451 DOI: 10.1007/s40272-017-0250-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Seizures are common in neonates with moderate and severe hypoxic ischemic encephalopathy (HIE) and are associated with worse outcomes, independent of HIE severity. In contrast to adults and older children, no new drugs have been licensed for treatment of neonatal seizures over the last 50 years, because of a lack of controlled clinical trials. Hence, many antiseizure medications licensed in older children and adults are used off-label for neonatal seizure, which is associated with potential risks of adverse effects during a period when the brain is particularly vulnerable. Phenobarbital is worldwide the first-line drug and is considered standard of care, although there is a limited evidence base for its efficacy. Second-line agents include phenytoin, benzodiazepines, levetiracetam, and lidocaine. These drugs are discussed in more detail along with two emerging drugs (bumetanide and topiramate). More safety, pharmacokinetic, and efficacy data are needed from well-designed clinical trials to develop safe and effective antiseizure regimes for the treatment of neonatal seizures in HIE.
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Affiliation(s)
- Elissa Yozawitz
- Department of Neurology and Pediatrics, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Arthur Stacey
- UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Ronit M Pressler
- Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, Great Ormond Street, London, WC1N 3JH, UK. .,Clinical Neurosciences, UCL- Great Ormond Street Institute of Child Health, 30 Guilford Street, London, WC1N 1EH, UK.
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Nicolas JM, Bouzom F, Hugues C, Ungell AL. Oral drug absorption in pediatrics: the intestinal wall, its developmental changes and current tools for predictions. Biopharm Drug Dispos 2017; 38:209-230. [PMID: 27976409 PMCID: PMC5516238 DOI: 10.1002/bdd.2052] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 11/21/2016] [Accepted: 11/30/2016] [Indexed: 12/14/2022]
Abstract
The dissolution, intestinal absorption and presystemic metabolism of a drug depend on its physicochemical characteristics but also on numerous physiological (e.g. gastrointestinal pH, volume, transit time, morphology) and biochemical factors (e.g. luminal enzymes and flora, intestinal wall enzymes and transporters). Over the past decade, evidence has accumulated indicating that these factors may differ in children and adults resulting in age-related changes in drug exposure and drug response. Thus, drug dosage may require adjustment for the pediatric population to ensure the desired therapeutic outcome and to avoid side-effects. Although tremendous progress has been made in understanding the effects of age on intestinal physiology and function, significant knowledge gaps remain. Studying and predicting pharmacokinetics in pediatric patients remains challenging due to ethical concerns associated with clinical trials in this vulnerable population, and because of the paucity of predictive in vitro and in vivo animal assays. This review details the current knowledge related to developmental changes determining intestinal drug absorption and pre-systemic metabolism. Supporting experimental approaches as well as physiologically based pharmacokinetic modeling are also discussed together with their limitations and challenges. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jean-Marie Nicolas
- Non-Clinical Development Department, UCB Biopharma sprl, Braine-l'Alleud, Belgium
| | - François Bouzom
- Non-Clinical Development Department, UCB Biopharma sprl, Braine-l'Alleud, Belgium
| | - Chanteux Hugues
- Non-Clinical Development Department, UCB Biopharma sprl, Braine-l'Alleud, Belgium
| | - Anna-Lena Ungell
- Non-Clinical Development Department, UCB Biopharma sprl, Braine-l'Alleud, Belgium
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7
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Donovan MD, Boylan GB, Murray DM, Cryan JF, Griffin BT. Treating disorders of the neonatal central nervous system: pharmacokinetic and pharmacodynamic considerations with a focus on antiepileptics. Br J Clin Pharmacol 2015; 81:62-77. [PMID: 26302437 DOI: 10.1111/bcp.12753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 08/05/2015] [Accepted: 08/13/2015] [Indexed: 12/31/2022] Open
Abstract
A major consideration in the treatment of neonatal disorders is that the selected drug, dose and dosage frequency is safe, effective and appropriate for the intended patient population. Thus, a thorough knowledge of the pharmacokinetics and pharmacodynamics of the chosen drug within the patient population is essential. In paediatric and neonatal populations two additional challenges can often complicate drug treatment - the inherently greater physiological variability, and a lack of robust clinical evidence of therapeutic range. There has traditionally been an overreliance in paediatric medicine on extrapolating doses from adult values by adjusting for bodyweight or body surface area, but many other sources of variability exist which complicate the choice of dose in neonates. The lack of reliable drug dosage data in neonates has been highlighted by regulatory authorities, as only ~50% of the most commonly used paediatric medicines have been examined in a paediatric population. Moreover, there is a paucity of information on the pharmacokinetic parameters which affect drug concentrations in different body tissues, and pharmacodynamic responses to drugs in the neonate. Thus, in the present review, we draw attention to the main pharmacokinetic factors that influence the unbound brain concentration of neuroactive drugs. Moreover, the pharmacodynamic differences between neonates and adults that affect the activity of centrally-acting therapeutic agents are briefly examined, with a particular emphasis on antiepileptic drugs.
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Affiliation(s)
- Maria D Donovan
- Pharmacodelivery Group, School of Pharmacy, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Geraldine B Boylan
- Department of Paediatrics and Child Health, University College Cork, Cork, Ireland.,Irish Centre for Fetal and Neonatal Translational Research, University College Cork and Cork University Maternity Hospital, Cork, Ireland
| | - Deirdre M Murray
- Department of Paediatrics and Child Health, University College Cork, Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Alimentary Pharmabiotic Centre, University College Cork, Cork, Ireland
| | - Brendan T Griffin
- Pharmacodelivery Group, School of Pharmacy, University College Cork, Cork, Ireland
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Hennig S, Norris R, Tu Q, van Breda K, Riney K, Foster K, Lister B, Charles B. Population pharmacokinetics of phenytoin in critically ill children. J Clin Pharmacol 2014; 55:355-64. [PMID: 25331445 DOI: 10.1002/jcph.417] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 10/16/2014] [Indexed: 11/06/2022]
Abstract
The objective was to study the population pharmacokinetics of bound and unbound phenytoin in critically ill children, including influences on the protein binding profile. A population pharmacokinetic approach was used to analyze paired protein-unbound and total phenytoin plasma concentrations (n = 146 each) from 32 critically ill children (0.08-17 years of age) who were admitted to a pediatric hospital, primarily intensive care unit. The pharmacokinetics of unbound and bound phenytoin and the influence of possible influential covariates were modeled and evaluated using visual predictive checks and bootstrapping. The pharmacokinetics of protein-unbound phenytoin was described satisfactorily by a 1-compartment model with first-order absorption in conjunction with a linear partition coefficient parameter to describe the binding of phenytoin to albumin. The partitioning coefficient describing protein binding and distribution to bound phenytoin was estimated to be 8.22. Nonlinear elimination of unbound phenytoin was not supported in this patient group. Weight, allometrically scaled for clearance and volume of distribution for the unbound and bound compartments, and albumin concentration significantly influenced the partition coefficient for protein binding of phenytoin. The population model can be applied to estimate the fraction of unbound phenytoin in critically ill children given an individual's albumin concentration.
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Affiliation(s)
- Stefanie Hennig
- School of Pharmacy, Pharmacy Australia Centre of Excellence (PACE), The University of Queensland, Brisbane, Queensland, Australia
| | - Ross Norris
- School of Pharmacy, Pharmacy Australia Centre of Excellence (PACE), The University of Queensland, Brisbane, Queensland, Australia.,Australian Centre for Paediatric Pharmacokinetics, Mater Pathology Services and Mater Research Institute, Brisbane, Queensland, Australia.,School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia
| | - Quyen Tu
- Mater Pharmacy Services, Mater Health Services, Brisbane, Queensland, Australia
| | - Karin van Breda
- Australian Centre for Paediatric Pharmacokinetics, Mater Pathology Services and Mater Research Institute, Brisbane, Queensland, Australia
| | - Kate Riney
- Neurosciences Unit, Mater Children's Hospital, Brisbane, Queensland, Australia.,Mater Medical Research Institute, University of Queensland, Brisbane, Queensland, Australia
| | - Kelly Foster
- Acute Care Stream, West Moreton Hospital and Health Service, Ipswich, Queensland, Australia
| | - Bruce Lister
- Paediatric Intensive Care Unit, Mater Children's Hospital, Brisbane, Queensland, Australia.,Medical School, Griffith University, Gold Coast, Queensland, Australia
| | - Bruce Charles
- School of Pharmacy, Pharmacy Australia Centre of Excellence (PACE), The University of Queensland, Brisbane, Queensland, Australia
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Marsot A, Boulamery A, Bruguerolle B, Simon N. Population pharmacokinetic analysis during the first 2 years of life: an overview. Clin Pharmacokinet 2013. [PMID: 23179579 DOI: 10.1007/s40262-012-0015-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Three decades after its introduction, pharmacokinetic population approaches have become a reference method for drug modelling, particularly in paediatrics. The main practical limitation in this specific population is the collected blood volume. Pharmacokinetic population approaches using sparse sampling may resolve this issue. The pharmacokinetics of many drugs have been studied during the last 25 years using such methods. This review summarizes all of the published studies concerning population pharmacokinetic approaches in paediatric subjects from neonate to 2 years old. A literature search was conducted using the PubMed database, from 1985 to December 2010, using the following terms: pharmacokinetic(s), population, paediatric/pediatric and neonate(s). Articles were excluded if they were not pertinent according to our criteria. References of all relevant articles were also evaluated. Ninety-eight studies were included in this review. The following information was extracted from the articles: drug name, therapeutic class, population size, age of patients, number of samples per patient, covariates used for clearance and volume of distribution estimates, software used for modelling and validation methods. An increasing rate of publications over the years was observed; 44 different drugs were studied using a pharmacokinetic population approach. Antibacterials were the most studied class of drugs, including a large number of studies devoted to vancomycin and gentamicin. It must be underlined that few studies have been performed on anticonvulsant drugs and anaesthetics used in clinical daily practice conditions.
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Affiliation(s)
- Amélie Marsot
- Service de Pharmacologie Médicale et Clinique, Aix Marseille Université, France.
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Abstract
Physiological differences between children and adults result in age-related differences in pharmacokinetics and drug effect. In neonates and infants, decreased weight-adjusted doses are required because of decreased protein binding, renal excretion, and/or metabolism. For children older than 1 year of age, significantly higher weight-corrected doses compared with adults are needed for drugs eliminated by the cytochrome P450 (CYP) isozymes CYP1A2, CYP2C9, and CYP3A4. In contrast, weight-corrected doses for drugs eliminated by renal excretion or metabolism by CYP2C19, CYP2D6, N-Acetyl-transferase, and UDP glucuronosyltransferase in children are similar to those in adults. Ideally, pharmacokinetic and pharmacodynamic data should be available for all drugs used in children. Because many drugs are not approved for pediatric use, data are often limited, especially for older drugs. Understanding the effects of age on pharmacokinetics can help to determine appropriate pediatric dosing in situations in which there is limited information.
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Affiliation(s)
- Gail D Anderson
- Department of Pharmacy, University of Washington, Seattle, WA98195, USA.
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Anderson GD, Lynn AM. Optimizing pediatric dosing: a developmental pharmacologic approach. Pharmacotherapy 2009; 29:680-90. [PMID: 19476420 DOI: 10.1592/phco.29.6.680] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Many physiologic differences between children and adults can result in age-related differences in pharmacokinetics. Understanding the effects of age on bioavailability, volume of distribution, protein binding, hepatic metabolic isoenzymes, and renal elimination can provide insight into optimizing doses for pediatric patients. We performed a search of English-language literature using the MEDLINE database regarding age and pharmacokinetics (1979-July 2008). We then evaluated the literature with an emphasis on drugs with one primary elimination pathway, such as renal clearance or a pathway involving a single metabolic isoenzyme. Our mechanistic-based analysis revealed that children need weight-corrected doses that are substantially higher than adult doses for drugs that are metabolically eliminated solely by the specific cytochrome P450 (CYP) isoenzymes CYP1A2, CYP2C9, and CYP3A4. In contrast, weight-corrected doses for drugs eliminated by renal excretion or metabolism involving CYP2C19, CYP2D6, N-acetyltransferase 2, or uridine diphosphate glucuronosyltransferases are similar in children and adults. In children, bioavailability of drugs with high first-pass metabolism is decreased for drugs metabolized by CYP1A2, CYP2C9, and CYP3A4. Limited data suggest that by age 5 years, bioavailability of drugs affected by efflux transporters should be equivalent to that of adults. Using a pharmacokinetics-based approach, rational predictions can be made for the effects of age on drugs that undergo similar pathways of elimination, even when specific pharmacokinetic data are limited or unavailable.
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Affiliation(s)
- Gail D Anderson
- Department of Pharmacy, University of Washington, Seattle, Washington 98195, USA.
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