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Douglas AP, Smibert OC, Bajel A, Halliday CL, Lavee O, McMullan B, Yong MK, Hal SJ, Chen SC. Consensus guidelines for the diagnosis and management of invasive aspergillosis, 2021. Intern Med J 2021; 51 Suppl 7:143-176. [DOI: 10.1111/imj.15591] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Abby P. Douglas
- Department of Infectious Diseases Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Sir Peter MacCallum Department of Oncology University of Melbourne Melbourne Victoria Australia
- National Centre for Infections in Cancer Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Department of Infectious Diseases Austin Health Melbourne Victoria Australia
| | - Olivia. C. Smibert
- Department of Infectious Diseases Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Sir Peter MacCallum Department of Oncology University of Melbourne Melbourne Victoria Australia
- National Centre for Infections in Cancer Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Department of Infectious Diseases Austin Health Melbourne Victoria Australia
| | - Ashish Bajel
- Sir Peter MacCallum Department of Oncology University of Melbourne Melbourne Victoria Australia
- Department of Clinical Haematology Peter MacCallum Cancer Centre and The Royal Melbourne Hospital Melbourne Victoria Australia
| | - Catriona L. Halliday
- Centre for Infectious Diseases and Microbiology Laboratory Services Institute of Clinical Pathology and Medical Research, New South Wales Health Pathology, Westmead Hospital Sydney New South Wales Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity The University of Sydney Sydney New South Wales Australia
| | - Orly Lavee
- Department of Haematology St Vincent's Hospital Sydney New South Wales Australia
| | - Brendan McMullan
- National Centre for Infections in Cancer Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Department of Immunology and Infectious Diseases Sydney Children's Hospital Sydney New South Wales Australia
- School of Women's and Children's Health University of New South Wales Sydney New South Wales Australia
| | - Michelle K. Yong
- Department of Infectious Diseases Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Sir Peter MacCallum Department of Oncology University of Melbourne Melbourne Victoria Australia
- National Centre for Infections in Cancer Peter MacCallum Cancer Centre Melbourne Victoria Australia
- Victorian Infectious Diseases Service Royal Melbourne Hospital Melbourne Victoria Australia
| | - Sebastiaan J. Hal
- Sydney Medical School University of Sydney Sydney New South Wales Australia
- Department of Microbiology and Infectious Diseases Royal Prince Alfred Hospital Sydney New South Wales Australia
| | - Sharon C.‐A. Chen
- Centre for Infectious Diseases and Microbiology Laboratory Services Institute of Clinical Pathology and Medical Research, New South Wales Health Pathology, Westmead Hospital Sydney New South Wales Australia
- Marie Bashir Institute for Infectious Diseases and Biosecurity The University of Sydney Sydney New South Wales Australia
- Sydney Medical School University of Sydney Sydney New South Wales Australia
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Leroux S, Mechinaud-Heloury F, Jacqz-Aigrain E. Contribution of Population Pharmacokinetics of Glycopeptides and Antifungals to Dosage Adaptation in Paediatric Onco-hematological Malignancies: A Review. Front Pharmacol 2021; 12:635345. [PMID: 33867986 PMCID: PMC8048069 DOI: 10.3389/fphar.2021.635345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 02/08/2021] [Indexed: 11/29/2022] Open
Abstract
The response to medications in children differs not only in comparison to adults but also between children of the different age groups and according to the disease. This is true for anti-infectives that are widely prescribed in children with malignancy. In the absence of pharmacokinetic/pharmacodynamic paediatric studies, dosage is frequently based on protocols adapted to adults. After a short presentation of the drugs, we reviewed the population pharmacokinetic studies available for glycopeptides (vancomycin and teicoplanin, n = 5) and antifungals (voriconazole, posaconazole, and amphotericin B, n = 9) currently administered in children with onco-hematological malignancies. For each of them, we reported the main study characteristics including identified covariates affecting pharmacokinetics and proposed paediatric dosage recommendations. This review highlighted the very limited amount of data available, the lack of consensus regarding PK/PD targets used for dosing optimization and regarding dosage recommendations when available. Additional PK studies are urgently needed in this specific patient population. In addition to pharmacokinetics, efficacy may be altered in immunocompromised patients and prospective clinical evaluation of new dosage regimen should be provided as they are missing in most cases.
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Affiliation(s)
- Stéphanie Leroux
- Department of Paediatrics, CHU Rennes, University of Rennes 1, Rennes, France.,Department of Paediatric Pharmacology and Pharmacogenetics, University Hospital Robert Debré (APHP), Rennes, France
| | | | - Evelyne Jacqz-Aigrain
- Department of Paediatric Pharmacology and Pharmacogenetics, University Hospital Robert Debré (APHP), Rennes, France.,Paris University, Paris, France
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Abstract
Neonates and immunosuppressed/immunocompromised pediatric patients are at high risk of invasive fungal diseases. Appropriate antifungal selection and optimized dosing are imperative to the successful prevention and treatment of these life-threatening infections. Conventional amphotericin B was the mainstay of antifungal therapy for many decades, but dose-limiting nephrotoxicity and infusion-related adverse events impeded its use. Despite the development of several new antifungal classes and agents in the past 20 years, and their now routine use in at-risk pediatric populations, data to guide the optimal dosing of antifungals in children are limited. This paper reviews the spectra of activity for approved antifungal agents and summarizes the current literature specific to pediatric patients regarding pharmacokinetic/pharmacodynamic data, dosing, and therapeutic drug monitoring.
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Affiliation(s)
- Kevin J Downes
- Division of Infectious Diseases, Children's Hospital of Philadelphia, 2716 South Street, Suite 10360, Philadelphia, PA, 19146, USA.
- Center for Pediatric Clinical Effectiveness, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Center for Clinical Pharmacology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Pediatrics, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA.
| | - Brian T Fisher
- Division of Infectious Diseases, Children's Hospital of Philadelphia, 2716 South Street, Suite 10360, Philadelphia, PA, 19146, USA
- Center for Pediatric Clinical Effectiveness, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, Perelman School of Medicine of the University of Pennsylvania, Philadelphia, PA, USA
| | - Nicole R Zane
- Center for Clinical Pharmacology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
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Warris A, Lehrnbecher T, Roilides E, Castagnola E, Brüggemann RJM, Groll AH. ESCMID-ECMM guideline: diagnosis and management of invasive aspergillosis in neonates and children. Clin Microbiol Infect 2019; 25:1096-1113. [PMID: 31158517 DOI: 10.1016/j.cmi.2019.05.019] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 05/19/2019] [Accepted: 05/23/2019] [Indexed: 01/01/2023]
Abstract
SCOPE Presenting symptoms, distributions and patterns of diseases and vulnerability to invasive aspergillosis (IA) are similar between children and adults. However, differences exist in the epidemiology and underlying conditions, the usefulness of newer diagnostic tools, the pharmacology of antifungal agents and in the evidence from interventional phase 3 clinical trials. Therefore, the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) and the European Confederation of Medical Mycology (ECMM) have developed a paediatric-specific guideline for the diagnosis and management of IA in neonates and children. METHODS Review and discussion of the scientific literature and grading of the available quality of evidence was performed by the paediatric subgroup of the ESCMID-ECMM-European Respiratory Society (ERS) Aspergillus disease guideline working group, which was assigned the mandate for the development of neonatal- and paediatric-specific recommendations. QUESTIONS Questions addressed by the guideline included the epidemiology of IA in neonates and children; which paediatric patients may benefit from antifungal prophylaxis; how to diagnose IA in neonates and children; which antifungal agents are available for use in neonates and children; which antifungal agents are suitable for prophylaxis and treatment of IA in neonates and children; what is the role of therapeutic drug monitoring of azole antifungals; and which management strategies are suitable to be used in paediatric patients. This guideline provides recommendations for the diagnosis, prevention and treatment of IA in the paediatric population, including neonates. The aim of this guideline is to facilitate optimal management of neonates and children at risk for or diagnosed with IA.
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Affiliation(s)
- A Warris
- MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology, the Netherlands.
| | - T Lehrnbecher
- Division of Paediatric Haematology and Oncology, Hospital for Children and Adolescents, Johann Wolfgang Goethe-University, Frankfurt, Germany; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology, the Netherlands
| | - E Roilides
- Infectious Diseases Unit, 3rd Department of Paediatrics, Faculty of Medicine, Aristotle University 96 School of Health Sciences, Thessaloniki, Greece; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology, the Netherlands
| | - E Castagnola
- Infectious Diseases Unit, IRCCS Istituto Giannina Gaslini Children's Hospital, Genoa, Italy; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG)
| | - R J M Brüggemann
- Radboud Center for Infectious Diseases, Radboud University Medical Centre, Center of Expertise in Mycology Radboudumc/CWZ, European Confederation of Medical Mycology (ECMM) Excellence Center of Medical Mycology, Nijmegen, the Netherlands; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG)
| | - A H Groll
- Infectious Disease Research Program, Center for Bone Marrow Transplantation and Department of Paediatric Hematology/Oncology, University Children's Hospital Münster, Münster, Germany; European Society of Clinical Microbiology and Infectious Diseases Fungal Infection Study Group (EFISG); European Confederation of Medical Mycology, the Netherlands
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Kip AE, Schellens JHM, Beijnen JH, Dorlo TPC. Clinical Pharmacokinetics of Systemically Administered Antileishmanial Drugs. Clin Pharmacokinet 2019; 57:151-176. [PMID: 28756612 PMCID: PMC5784002 DOI: 10.1007/s40262-017-0570-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review describes the pharmacokinetic properties of the systemically administered antileishmanial drugs pentavalent antimony, paromomycin, pentamidine, miltefosine and amphotericin B (AMB), including their absorption, distribution, metabolism and excretion and potential drug–drug interactions. This overview provides an understanding of their clinical pharmacokinetics, which could assist in rationalising and optimising treatment regimens, especially in combining multiple antileishmanial drugs in an attempt to increase efficacy and shorten treatment duration. Pentavalent antimony pharmacokinetics are characterised by rapid renal excretion of unchanged drug and a long terminal half-life, potentially due to intracellular conversion to trivalent antimony. Pentamidine is the only antileishmanial drug metabolised by cytochrome P450 enzymes. Paromomycin is excreted by the kidneys unchanged and is eliminated fastest of all antileishmanial drugs. Miltefosine pharmacokinetics are characterized by a long terminal half-life and extensive accumulation during treatment. AMB pharmacokinetics differ per drug formulation, with a fast renal and faecal excretion of AMB deoxylate but a much slower clearance of liposomal AMB resulting in an approximately ten-fold higher exposure. AMB and pentamidine pharmacokinetics have never been evaluated in leishmaniasis patients. Studies linking exposure to effect would be required to define target exposure levels in dose optimisation but have only been performed for miltefosine. Limited research has been conducted on exposure at the drug’s site of action, such as skin exposure in cutaneous leishmaniasis patients after systemic administration. Pharmacokinetic data on special patient populations such as HIV co-infected patients are mostly lacking. More research in these areas will help improve clinical outcomes by informed dosing and combination of drugs.
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Affiliation(s)
- Anke E Kip
- Department of Pharmacy and Pharmacology, Antoni van Leeuwenhoek Hospital/MC Slotervaart, Amsterdam, The Netherlands
- Division of Pharmacoepidemiology and Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
| | - Jan H M Schellens
- Division of Pharmacoepidemiology and Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
- Department of Clinical Pharmacology, Antoni van Leeuwenhoek Hospital/The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jos H Beijnen
- Department of Pharmacy and Pharmacology, Antoni van Leeuwenhoek Hospital/MC Slotervaart, Amsterdam, The Netherlands
- Division of Pharmacoepidemiology and Clinical Pharmacology, Faculty of Science, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands
- Department of Clinical Pharmacology, Antoni van Leeuwenhoek Hospital/The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Thomas P C Dorlo
- Department of Pharmacy and Pharmacology, Antoni van Leeuwenhoek Hospital/MC Slotervaart, Amsterdam, The Netherlands.
- Pharmacometrics Research Group, Department of Pharmaceutical Biosciences, Uppsala University, Uppsala, Sweden.
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Goldman JL, Abdel-Rahman SM. Pharmacokinetic considerations in treating invasive pediatric fungal infections. Expert Opin Drug Metab Toxicol 2016; 12:645-55. [PMID: 27111148 DOI: 10.1080/17425255.2016.1181752] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Despite the increased availability of systemic antifungal agents in recent years, the management of invasive fungal disease is still associated with significant morbidity and mortality. Knowledge of a drug's pharmacokinetic behavior is critical for optimizing existing treatment strategies. AREAS COVERED This review examines the pharmacokinetics of the major drug classes used to treat invasive mycoses including the echinocandins, imidazoles, triazoles, nucleoside analogs, and polyenes. It examines the mechanisms behind dose-exposure profiles that differ in children as compared with adults and explores the utility of pharmacogenetic testing and therapeutic drug monitoring. EXPERT OPINION Lifesaving medical advances for oncologic and autoimmune conditions have resulted in a significant increase in the frequency of opportunistic fungal infections. Owing to the high rate of treatment failures observed when managing invasive fungal infections, strategies to optimize antifungal therapy are critical when caring for these complex patients. Opportunities to maximize positive outcomes include dose refinement based on age or genetic status, formulation selection, co-administration of interacting medications, and administration with regard to food. The application of therapeutic drug monitoring for dose individualization is a valuable strategy to achieve pharmacodynamic targets.
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Affiliation(s)
- Jennifer L Goldman
- a Department of Pediatrics , UMKC School of Medicine , Kansas City , MO , USA.,b Drug Safety Service Children's Mercy Hospital , Kansas City , MO , USA.,c Antimicrobial Stewardship Program Children's Mercy Hospital , Kansas City , MO , USA.,d Divisions Pediatric Infectious Diseases & Clinical Pharmacology , Toxicology, and Therapeutic Innovation Children's Mercy Hospital , Kansas City , MO , USA
| | - Susan M Abdel-Rahman
- a Department of Pediatrics , UMKC School of Medicine , Kansas City , MO , USA.,d Divisions Pediatric Infectious Diseases & Clinical Pharmacology , Toxicology, and Therapeutic Innovation Children's Mercy Hospital , Kansas City , MO , USA
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Ramos-Martín V, O’Connor O, Hope W. Clinical pharmacology of antifungal agents in pediatrics: children are not small adults. Curr Opin Pharmacol 2015; 24:128-34. [DOI: 10.1016/j.coph.2015.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/14/2015] [Accepted: 08/25/2015] [Indexed: 10/23/2022]
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Stergiopoulou T, Walsh TJ. Clinical pharmacology of antifungal agents to overcome drug resistance in pediatric patients. Expert Opin Pharmacother 2015; 16:213-26. [PMID: 25579070 DOI: 10.1517/14656566.2015.1000302] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Antifungal resistance is an emerging problem that increases morbidity and mortality in immunosuppressed pediatric patients, who suffer from invasive fungal diseases. Optimal pharmacological management is critical for the successful treatment of invasive fungal infections by resistant strains. AREAS COVERED This paper reviews the mechanisms of resistance of different classes of antifungal agents and the current understanding of pediatric antifungal pharmacology for overcoming antifungal resistance in children based on laboratory and clinical studies in the English literature. The therapeutic choices against fungal pathogens with intrinsic or acquired resistance are further reviewed. EXPERT OPINION There is a paucity of data in the pediatric population regarding the epidemiology of the resistant organisms to different antifungal agents. It is also unknown if there are more prevalent molecular mechanisms that promote antifungal resistance. Selection and dosages of the most effective antifungal agent for overcoming the antifungal resistance is crucial. However, there are limited studies guiding the optimal dosage and duration of treatment for management of emergent antifungal resistance. Further studies are warranted to elucidate the optimal pharmacology of the current antifungal agents against resistant organisms and to advance the development of new antifungal agents.
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Botero-Calderon L, Benjamin DK, Cohen-Wolkowiez M. Advances in the treatment of invasive neonatal candidiasis. Expert Opin Pharmacother 2015; 16:1035-48. [PMID: 25842986 PMCID: PMC4402277 DOI: 10.1517/14656566.2015.1031108] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION Invasive candidiasis is responsible for ∼ 10% of nosocomial sepsis in very-low-birth-weight infants and is associated with substantial morbidity and mortality. Over the last two decades, the antifungal armamentarium against Candida spp. has increased; however, efficacy and safety studies in this population are lacking. AREAS COVERED We reviewed the medical literature and extracted information on clinical and observational studies evaluating the use of antifungal agents in neonates with invasive candidiasis. EXPERT OPINION Efficacy and safety data for antifungals in neonates are lacking, and the majority of studies conducted to date have concentrated on pharmacokinetic/pharmacodynamic evaluations. Unlike other anti-infective agents, efficacy data in the setting of neonatal candidiasis cannot be extrapolated from adult studies due to differences in the pathophysiology of the disease in this population relative to older children and adults. Data for amphotericin B deoxycholate, fluconazole, and micafungin suggest that these are the current agents of choice for this disease in neonates until data for newer antifungal agents become available. For prophylaxis, data from fluconazole randomized controlled trials will be submitted to the regulatory agencies for labeling. Ultimately, the field of therapeutics for neonatal candidiasis will require multidisciplinary collaboration given the numerous challenges associated with conducting clinical trials in neonates.
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Abstract
Since the introduction of amphotericin B as an antifungal agent, the morbidity and mortality of pediatric patients with mycotic infections have increased, primarily because of the increased immunocompromised patients. Despite the fact that deoxycholate amphotericin B was once the primary drug used for mycotic infections, its administration to children older than neonates is currently controversial because of its nephrotoxic effects. Three lipid-associated formulations have been developed and have reportedly shown similar efficacy and fewer nephrotoxic effects in adults than conventional amphotericin B, but the conclusions from comparative studies in children evaluating the nephrotoxicity risks of the 4 agents are controversial. Nevertheless, guidelines favor liposomal or lipid complex amphotericin B when polyene antifungal therapy is recommended in this age group. However, high acquisition costs often preclude their prescription in economically poor regions. Thus, physicians must consider all of these factors when determining the most cost-effective polyene antifungal treatment for their pediatric patients. This is particularly pertinent in developing countries where resources are scarce. Adjuvant sodium supplementation has been reported to be effective in protecting kidney function in extremely low birth weight infants prescribed deoxycholate amphotericin B. Further pharmacokinetic and pharmacodynamic studies of the drug in children could also provide information for rational dosing regimens designed to decrease nephrotoxicity. Conventional amphotericin B, with appropriate kidney protective measures, still plays a role in the treatment of empiric invasive mycotic infections in most pediatric patients. Liposomal and lipid complex amphotericin B should be reserved for those receiving long-term nephrotoxic agents or with altered renal function or disease. Antifungal susceptibility, renal compromise and the clinical status of the patient should determine treatment for culture-proven infections. Under the current cost limitations, undertaking and evaluating low-cost, kidney-sparing, deoxycholate amphotericin B treatments for children should be a primary concern.
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Autmizguine J, Guptill JT, Cohen-Wolkowiez M, Benjamin DK, Capparelli EV. Pharmacokinetics and pharmacodynamics of antifungals in children: clinical implications. Drugs 2014; 74:891-909. [PMID: 24872147 PMCID: PMC4073603 DOI: 10.1007/s40265-014-0227-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Invasive fungal disease (IFD) remains life threatening in premature infants and immunocompromised children despite the recent development of new antifungal agents. Optimal dosing of antifungals is one of the few factors clinicians can control to improve outcomes of IFD. However, dosing in children cannot be extrapolated from adult data because IFD pathophysiology, immune response, and drug disposition differ from adults. We critically examined the literature on pharmacokinetics (PK) and pharmacodynamics (PD) of antifungal agents and highlight recent developments in treating pediatric IFD. To match adult exposure in pediatric patients, dosing adjustment is necessary for almost all antifungals. In young infants, the maturation of renal and metabolic functions occurs rapidly and can significantly influence drug exposure. Fluconazole clearance doubles from birth to 28 days of life and, beyond the neonatal period, agents such as fluconazole, voriconazole, and micafungin require higher dosing than in adults because of faster clearance in children. As a result, dosing recommendations are specific to bracketed ranges of age. PD principles of antifungals mostly rely on in vitro and in vivo models but very few PD studies specifically address IFD in children. The exposure-response relationship may differ in younger children compared with adults, especially in infants with invasive candidiasis who are at higher risk of disseminated disease and meningoencephalitis, and by extension severe neurodevelopmental impairment. Micafungin is the only antifungal agent for which a specific target of exposure was proposed based on a neonatal hematogenous Candida meningoencephalitis animal model. In this review, we found that pediatric data on drug disposition of newer triazoles and echinocandins are lacking, dosing of older antifungals such as fluconazole and amphotericin B products still need optimization in young infants, and that target PK/PD indices need to be clinically validated for almost all antifungals in children. A better understanding of age-specific PK and PD of new antifungals in infants and children will help improve clinical outcomes of IFD by informing dosing and identifying future research areas.
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Affiliation(s)
- Julie Autmizguine
- Duke Clinical Research Institute, 2400 Pratt St, Durham, NC 27705, USA
| | | | | | | | - Edmund V. Capparelli
- Department of Pediatric Pharmacology, University of California, 9500 Gilman Drive, La Jolla, CA 92093-0831, USA
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Lestner JM, Smith PB, Cohen-Wolkowiez M, Benjamin DK, Hope WW. Antifungal agents and therapy for infants and children with invasive fungal infections: a pharmacological perspective. Br J Clin Pharmacol 2014; 75:1381-95. [PMID: 23126319 DOI: 10.1111/bcp.12025] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/31/2012] [Indexed: 12/30/2022] Open
Abstract
Invasive fungal infections, although relatively rare, are life-threatening diseases in premature infants and immunocompromised children. While many advances have been made in antifungal therapeutics in the last two decades, knowledge of the pharmacokinetics and pharmacodynamics of antifungal agents for infants and children remains incomplete. This review summarizes the pharmacology and clinical utility of currently available antifungal agents and discusses the opportunities and challenges for future research.
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Affiliation(s)
- Jodi M Lestner
- Department of Molecular and Clinical Pharmacology, University of Liverpool, Liverpool, UK
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13
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Hope W, Castagnola E, Groll A, Roilides E, Akova M, Arendrup M, Arikan-Akdagli S, Bassetti M, Bille J, Cornely O, Cuenca-Estrella M, Donnelly J, Garbino J, Herbrecht R, Jensen H, Kullberg B, Lass-Flörl C, Lortholary O, Meersseman W, Petrikkos G, Richardson M, Verweij P, Viscoli C, Ullmann A. ESCMID* *This guideline was presented in part at ECCMID 2011. European Society for Clinical Microbiology and Infectious Diseases. guideline for the diagnosis and management of Candida diseases 2012: prevention and management of invasive infections in neonates and children caused by Candida spp. Clin Microbiol Infect 2012; 18 Suppl 7:38-52. [DOI: 10.1111/1469-0691.12040] [Citation(s) in RCA: 216] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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Abstract
Invasive fungal infections in immunocompromised children are common and often fatal. The first antifungal agents such as amphotericin B and fluconazole offered effective treatment, but their use was often limited by toxicity and resistance. Numerous new antifungal agents have since been developed and appear to be as effective. Most dosing and safety trials have been done in adults, and extrapolation of this data to children has proven inadequate. We reviewed the literature regarding the pharmacokinetics/pharmacodynamics (PK/PD) and safety of antifungal agents with an emphasis on the newer azoles and echinocandins. From a small but growing number of PK/PD trials, better dosing guidelines have been developed.
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Affiliation(s)
- Kevin Watt
- Department of Pediatrics, Duke University, Durham, NC, USA
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Pediatric pharmacology of antifungal agents. CURRENT FUNGAL INFECTION REPORTS 2008. [DOI: 10.1007/s12281-008-0008-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Chiou CC, Walsh TJ, Groll AH. Clinical pharmacology of antifungal agents in pediatric patients. Expert Opin Pharmacother 2007; 8:2465-89. [DOI: 10.1517/14656566.8.15.2465] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Hope WW, Warn PA, Sharp A, Reed P, Keevil B, Louie A, Walsh TJ, Denning DW, Drusano GL. Optimization of the dosage of flucytosine in combination with amphotericin B for disseminated candidiasis: a pharmacodynamic rationale for reduced dosing. Antimicrob Agents Chemother 2007; 51:3760-2. [PMID: 17682101 PMCID: PMC2043255 DOI: 10.1128/aac.00488-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Amphotericin B and flucytosine (5FC) have an additive effect when used for disseminated candidiasis. Here, we bridge the results of an experimental pharmacodynamic study to humans and demonstrate that a 5FC dosage of 25 mg/kg of body weight/day in four divided doses in combination with amphotericin B produces near-maximal effect.
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Affiliation(s)
- William W Hope
- Department of Medicine, The University of Manchester, 1.800 Stopford Building, Oxford Road, Manchester, UK.
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Blyth CC, Palasanthiran P, O'Brien TA. Antifungal therapy in children with invasive fungal infections: a systematic review. Pediatrics 2007; 119:772-84. [PMID: 17403849 DOI: 10.1542/peds.2006-2931] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Invasive fungal infections are associated with significant morbidity and mortality. Differences between children and adults are reported, yet few trials of antifungal agents have been performed in pediatric populations. We performed a systematic review of the literature to guide appropriate pediatric treatment recommendations. From available trials that compared antifungal agents in either prolonged febrile neutropenia or invasive candidal or Aspergillus infection, no clear difference in treatment efficacy was demonstrated, although few trials were adequately powered. Differing antifungal pharmacokinetics between children and adults were demonstrated, requiring dose modification. Significant differences in toxicity, particularly nephrotoxicity, were identified between classes of antifungal agents. Therapy needs to be guided by the pathogen or suspected pathogens, the degree of immunosuppression, comorbidities (particularly renal dysfunction), concurrent nephrotoxins, and the expected length of therapy.
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Affiliation(s)
- Christopher C Blyth
- Department of Immunology and Infectious Diseases, Sydney Children's Hospital, High Street, Randwick, New South Wales 2130, Australia
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Nath CE, Shaw PJ, Montgomery K, Earl JW. Population pharmacokinetics of melphalan in paediatric blood or marrow transplant recipients. Br J Clin Pharmacol 2007; 64:151-64. [PMID: 17324241 PMCID: PMC2000639 DOI: 10.1111/j.1365-2125.2007.02862.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To develop a population pharmacokinetic model for melphalan in children with malignant diseases and to evaluate limited sampling strategies for melphalan. METHODS Melphalan concentration data following a single intravenous dose were collected from 59 children with malignant diseases aged between 0.3 and 18 years. The data were split into two sets: the model development dataset (39 children, 571 concentration observations) and the model validation dataset (20 children, 277 concentration observations). Population pharmacokinetic modelling was performed with the NONMEM software. Stepwise multiple linear regression was used to develop a limited sampling model for melphalan. RESULTS A two-compartment model was fitted to the concentration-vs.-time data. The following covariate population pharmacokinetic models were obtained: (i) Clearance (l h(-1)) = 0.34.WT - 3.17.CPT + 0.0377.GFR, where WT = weight (kg), CPT = prior carboplatin therapy (0 = no, 1 = yes), and GFR = glomerular filtration rate (ml min(-1) 1.73 m(-2)); (ii) Volume of distribution (l) = 1.12 + 0.178.WT. Interpatient variability (coefficient of variation) was 27.3% for clearance and 33.8% for volume of distribution. There was insignificant bias and imprecision between observed and model-predicted melphalan concentrations in the validation dataset. A three-sample limited sampling model was developed which adequately predicted the area under the concentration-time curve (AUC) in the development and validation datasets. CONCLUSIONS A population pharmacokinetic model for melphalan has been developed and validated and may now be used in conjunction with pharmacodynamic data to develop safe and effective dosing guidelines in children with malignant diseases.
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Affiliation(s)
- Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, NSW, Australia.
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Nath CE, McLachlan AJ, Shaw PJ, Coakley JC, Earl JW. Amphotericin B dose optimization in children with malignant diseases. Chemotherapy 2007; 53:142-7. [PMID: 17310120 DOI: 10.1159/000100013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Accepted: 01/17/2006] [Indexed: 11/19/2022]
Abstract
In this study, rational dosing guidelines for amphotericin B-deoxycholate (AmB) are proposed for children. AmB steady-state trough concentrations (C(ss,trough)) and plasma creatinine concentrations (C(creat)) were measured in 83 children (age: 10 months to 18 years) receiving prophylactic AmB therapy (1 mg/kg/day). Maximum tolerable AmB C(ss,trough) were identified by determining the probability of large (>24%, 75th percentile) increases in C(creat) after 6 days of AmB for a series of C(ss,trough) ranges. Dose requirements were determined using a concentration-targeting approach. The 0.76-1.05 mg/l C(ss,trough) range provided the maximum concentrations that still had a low probability (p < 0.29) of adverse renal effects. 1 mg/kg/day AmB produces C(ss,trough) within this range for children weighing 25-45 kg. Lighter children (10-25 kg) require higher AmB doses (1.25-1.5 mg/kg/day) to achieve target C(ss,trough), while heavier children (45-55 kg) require lower doses (0.75 mg/kg/day). These starting dose guidelines may require individualization and prospective evaluation.
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Affiliation(s)
- Christa E Nath
- Department of Biochemistry, The Children's Hospital at Westmead, Westmead, Australia.
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22
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Meletiadis J, Chanock S, Walsh TJ. Human pharmacogenomic variations and their implications for antifungal efficacy. Clin Microbiol Rev 2006; 19:763-87. [PMID: 17041143 PMCID: PMC1592689 DOI: 10.1128/cmr.00059-05] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pharmacogenomics is defined as the study of the impacts of heritable traits on pharmacology and toxicology. Candidate genes with potential pharmacogenomic importance include drug transporters involved in absorption and excretion, phase I enzymes (e.g., cytochrome P450-dependent mixed-function oxidases) and phase II enzymes (e.g., glucuronosyltransferases) contributing to metabolism, and those molecules (e.g., albumin, A1-acid glycoprotein, and lipoproteins) involved in the distribution of antifungal compounds. By using the tools of population genetics to define interindividual differences in drug absorption, distribution, metabolism, and excretion, pharmacogenomic models for genetic variations in antifungal pharmacokinetics can be derived. Pharmacogenomic factors may become especially important in the treatment of immunocompromised patients or those with persistent or refractory mycoses that cannot be explained by elevated MICs and where rational dosage optimization of the antifungal agent may be particularly critical. Pharmacogenomics has the potential to shift the paradigm of therapy and to improve the selection of antifungal compounds and adjustment of dosage based upon individual variations in drug absorption, metabolism, and excretion.
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Affiliation(s)
- Joseph Meletiadis
- Pediatric Oncology Branch, National Cancer Institute, CRC, 1-5750 10 Center Drive, Bethesda, MD 20892, USA
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23
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Wong M, Balleine RL, Blair EYL, McLachlan AJ, Ackland SP, Garg MB, Evans S, Farlow D, Collins M, Rivory LP, Hoskins JM, Mann GJ, Clarke CL, Gurney H. Predictors of Vinorelbine Pharmacokinetics and Pharmacodynamics in Patients With Cancer. J Clin Oncol 2006; 24:2448-55. [PMID: 16651648 DOI: 10.1200/jco.2005.02.1295] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purpose Marked interindividual variation in drug disposition and toxicity pose an ongoing challenge to chemotherapy dosage individualization. The aim of this study was to evaluate pretreatment clinical features, genotype and functional indicators of drug clearance as predictors of vinorelbine clearance, and myelotoxicity that could inform dosage optimization. Patients and Methods Forty-one patients with cancer received a 60 mg intravenous dose of vinorelbine. Pretreatment routine body size measurements and blood tests were performed. Midazolam clearance and hepatic technetium labeled sestamibi (99mTc-MIBI) clearance were used to investigate CYP3A and ABCB1 (MDR1, P-glycoprotein) phenotype respectively and selected single nucleotide polymorphisms in CYP3A and ABCB1 were documented. A limited blood sampling strategy was employed and vinorelbine concentrations were determined by high-performance liquid chromatography. Posterior Bayesian estimates of vinorelbine clearance were obtained for each patient using population pharmacokinetic modeling. Myelotoxicity was estimated from the fractional survival of neutrophils post-treatment. Results There was 4.3-fold variation in vinorelbine clearance across the cohort. In a multivariable analysis, pretreatment estimated creatinine clearance (P < .01) and hepatic 99mTc-MIBI clearance (P = .01) were independent predictors of vinorelbine clearance. Fractional survival of neutrophils ranged from 1.3% to 100% and was significantly correlated with vinorelbine clearance (P < .01). Body-surface area was the only pretreatment predictor of fractional survival of neutrophils independent of vinorelbine clearance (P = .02). Conclusion Specific indicators of drug clearance provide predictive information about vinorelbine pharmacokinetics, and body-surface area, probably reflecting normal bone marrow reserve, provides an additional pharmacodynamic indicator. Use of a fixed dose of vinorelbine with modifications guided by pretreatment measures is worthy of prospective evaluation.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adult
- Aged
- Aged, 80 and over
- Antineoplastic Agents, Phytogenic/administration & dosage
- Antineoplastic Agents, Phytogenic/adverse effects
- Antineoplastic Agents, Phytogenic/pharmacokinetics
- Antineoplastic Agents, Phytogenic/pharmacology
- Body Size
- Body Surface Area
- Bone Marrow/drug effects
- Chromatography, High Pressure Liquid
- Cytochrome P-450 CYP3A
- Cytochrome P-450 Enzyme System/metabolism
- Feasibility Studies
- Female
- Genotype
- Humans
- Male
- Midazolam/pharmacokinetics
- Middle Aged
- Multivariate Analysis
- Neoplasms/drug therapy
- Phenotype
- Polymorphism, Single Nucleotide
- Predictive Value of Tests
- Technetium Tc 99m Sestamibi/metabolism
- Vinblastine/administration & dosage
- Vinblastine/adverse effects
- Vinblastine/analogs & derivatives
- Vinblastine/pharmacokinetics
- Vinblastine/pharmacology
- Vinorelbine
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Affiliation(s)
- Mark Wong
- Westmead Institute for Cancer Research Westmead Millennium Institute, Department of Translational Oncology, Westmead, Australia
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Abstract
Antifungal drugs for treating systemic mycoses are flucytosine, amphotéricin B, azoles and caspofungin. Their pharmacokinetics and pharmacodynamics are reviewed in order to determine the optimal modalities of their administration and the best dosing regimen for several populations: neonates, infants, patients with renal or liver disease, patients with hemodialysis or hemofiltration.
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Affiliation(s)
- Michel Tod
- Pharmacie-toxicologie, Hôpital Cochin, Paris, France.
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25
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Tabone MD, Guyader NL, Leverger G. Spécificités pédiatriques de l’utilisation des antifongiques. Therapie 2006; 61:243-8. [DOI: 10.2515/therapie:2006042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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26
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Hong Y, Shaw PJ, Nath CE, Yadav SP, Stephen KR, Earl JW, McLachlan AJ. Population pharmacokinetics of liposomal amphotericin B in pediatric patients with malignant diseases. Antimicrob Agents Chemother 2006; 50:935-42. [PMID: 16495254 PMCID: PMC1426421 DOI: 10.1128/aac.50.3.935-942.2006] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A population pharmacokinetic model of liposomal amphotericin B (L-AmB) in pediatric patients with malignant diseases was developed and evaluated. Blood samples were collected from 39 pediatric oncology patients who received multiple doses of L-AmB with a dose range from 0.8 to 5.9 mg/kg of body weight/day. The patient cohort had an average age of 7 years (range, 0.2 to 17 years) and weighed an average of 28.8 +/- 19.8 kg. Population pharmacokinetic analyses were performed with NONMEM software. Pharmacokinetic parameters, interindividual variability (IIV), between-occasion variability (BOV), and intraindividual variability were estimated. The influence of patient characteristics on the pharmacokinetics of L-AmB was explored. The final population pharmacokinetic model was evaluated by using a bootstrap sampling technique. The L-AmB plasma concentration-time data was described by a two-compartment pharmacokinetic model with zero-order input and first-order elimination. The population mean estimates of clearance (CL) and volume of distribution in the central compartment (V1) were 0.44 liters/h and 3.12 liters, respectively, and exhibited IIV (CL, 10%) and significant BOV (CL, 46% and V1, 56%). The covariate models were CL (liters/h) = 0.44 . e(0.0152.(WT-21)) and V1 (liters) = 3.12.e(0.0241.(WT-21)), where WT is the patient's body weight (kg) centered on the study population cohort median of 21 kg. Model evaluation by the bootstrap procedure indicated that the full pharmacokinetic model was robust and parameter estimates were accurate. In conclusion, the pharmacokinetics of L-AmB in pediatric oncology patients were adequately described by the developed population model. The model has been evaluated and can be used in the design of rational dosing strategies for L-AmB antifungal therapy in this special population.
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Affiliation(s)
- Ying Hong
- Faculty of Pharmacy, Pharmacy Building (A15), Camperdown Campus, University of Sydney, Sydney, NSW 2006, Australia
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27
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Paradisis M, Evans N, Kluckow M, Osborn D, McLachlan AJ. Pilot study of milrinone for low systemic blood flow in very preterm infants. J Pediatr 2006; 148:306-13. [PMID: 16615956 DOI: 10.1016/j.jpeds.2005.11.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 09/29/2005] [Accepted: 11/10/2005] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To examine the hemodynamic effects of milrinone given prophylactically to very preterm infants at high risk of low superior vena cava (SVC) flow and to investigate the preliminary efficacy and safety of an optimal dose. STUDY DESIGN This was a prospective, open-label study in two stages. The first involved dose escalation in two cohorts. Milrinone infusions of 0.25 microg/kg per minute (n = 8) and then 0.5 microg/kg per minute (n = 11) were administered from 3 to 24 hours of age. Population pharmacokinetic modeling was used to develop an optimized dose regimen. Ten infants then were loaded with 0.75 microg/kg per minute for 3 hours, followed by 0.2 microg/kg per minute maintenance until 18 hours of age. Infants were monitored for blood pressure, serial echocardiograms, and blood milrinone levels. The primary outcome was maintenance of SVC flow greater than 45 mL/kg per minute through the first 24 hours. RESULTS Low SVC flow developed in 36% of babies at both 0.25 microg/kg per minute and 0.5 microg/kg per minute of milrinone. Blood levels on these two regimens were slow to reach the target range and accumulated above this range by 24 hours. At 0.75 to 0.2 microg/kg per minute, no infant had SVC flow below 45 mL/kg per minute, compared with 61% in historic control subjects. Four infants needed an additional inotrope to support blood pressure. Blood levels were within the target range in 9 of 10 babies. CONCLUSIONS We used population pharmacokinetic modeling to develop an optimal dosing regimen for milrinone. The efficacy and safety in this novel preventative approach to circulatory support is encouraging but inconclusive. We do not recommend the use of milrinone in preterm infants outside a research setting.
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Affiliation(s)
- Mary Paradisis
- Department of Newborn Care, Royal Prince Alfred Hospital and University of Sydney, Camperdown, New South Wales, Australia
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28
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Foster DJR, Somogyi AA, White JM, Bochner F. Population pharmacokinetics of (R)-, (S)- and rac-methadone in methadone maintenance patients. Br J Clin Pharmacol 2004; 57:742-55. [PMID: 15151520 PMCID: PMC1884530 DOI: 10.1111/j.1365-2125.2004.02079.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
AIM To construct a population pharmacokinetic model for methadone enantiomers in the setting of methadone maintenance treatment for opioid dependence. METHODS A population pharmacokinetic model was developed using P-Pharm software for rac-, (R)- and (S)-methadone using data (8-13 plasma samples per subject) obtained from 59 methadone maintenance patients during one interdosing interval at steady state. The patients were randomly assigned to either a development (n = 38) or a validation dataset (n = 21). The model was refined by inclusion of all subjects to construct a final basic model, which was used to construct a covariate model. RESULTS A population-based two-compartment open model with first-order absorption and lag time was developed and validated for all analytes. The population geometric mean (coefficient of variation) of maximum a posteriori probability Bayesian estimated values for clearance, terminal half-life and volume of distribution at steady-state of the active (R)-enantiomer were 8.7 (42%) l h(-1), 51 (45%) h and 597 (45%) l, respectively. For all analytes, the volume of the central compartment was decreased with increasing plasma alpha(1)-acid glycoprotein concentration and was lower in females, while the delay in absorption was longer at higher doses. No covariates were identified for apparent oral clearance. The apparent oral clearance of (R)-methadone (geometric mean ratio; 95% confidence interval) was 105% (99, 110), that of (S)-methadone (P = 0.19), while (R)-methadone V(c)/F (154%; 151, 157), V(dss) /F (173%; 164, 183), t(1/2beta) (162%; 153, 172) and mean residence time (166%; 156, 176) were significantly greater (P < 0.0001) than for (S)-methadone. The population pharmacokinetic models were able to predict accurately oral clearance values from limited (one or two samples) blood sampling protocols. CONCLUSIONS The substantial stereoselectivity in methadone disposition reinforces the potential for misinterpretation of racemic methadone disposition data. The marked interindividual variability in (R)-methadone clearance, with no covariates identified, highlights the need for alternative methods to determine an individual's metabolic clearance. The ability to predict (R)-methadone clearance from one to two blood samples at steady state may prove clinically useful if a drug-drug interaction or poor adherence are suspected and guide the prescriber in deciding if a client's request for a dose increase is warranted or whether an alternative opioid would be more appropriate.
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Affiliation(s)
- David J R Foster
- Department of Clinical and Experimental Pharmacology, The University of Adelaide, Adelaide 5005, Australia.
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Blair EYL, Rivory LP, Clarke SJ, McLachlan AJ. Population pharmacokinetics of raltitrexed in patients with advanced solid tumours. Br J Clin Pharmacol 2004; 57:416-26. [PMID: 15025739 PMCID: PMC1884470 DOI: 10.1111/j.1365-2125.2003.02050.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
AIMS To investigate the population pharmacokinetics of raltitrexed in patients with advanced solid tumours and to identify patient covariates contributing to the interpatient variability in the pharmacokinetics of raltitrexed. METHODS Patient covariate and concentration-time data were collected from patients receiving 0.1-4.5 mg m(-2) raltitrexed during the early clinical trials of raltitrexed. Data were fitted using nonlinear mixed effects modelling to generate population mean estimates for clearance (CL) and central volume of distribution (V). The relationship between individual estimates of the pharmacokinetic parameters and patient covariates was examined and the influence of significant covariates on the population parameter estimates and their variance was investigated using stepwise multiple linear regression. The performance of the developed model was tested using an independent validation dataset. All patient data were pooled in the total cohort to refine the population pharmacokinetic model for raltitrexed. RESULTS three-compartment pharmacokinetic model was used to fit the concentration-time data of raltitrexed. Estimated creatinine clearance (CL(CR)) was found to influence significantly the CL of raltitrexed and explained 35% of variability in this parameter, whilst body weight (WT) and serum albumin concentrations (ALB) accounted for 56% of the variability in V. Satisfactory prediction (mean prediction error 0.17 micro g l(-1) and root mean square prediction error 4.99 micro g l(-1)) of the observed raltitrexed concentrations was obtained in the model validation step. The final population mean estimates were 2.17 l h(-1)[95% confidence interval (CI) 2.06, 2.28] and 6.36 l (95% CI 6.02, 6.70) for CL and V, respectively. Interpatient variability in the pharmacokinetic parameters was reduced (CL 28%, V 25%) when influential covariates were included in the final model. The following covariate relationships with raltitrexed parameters were described by the final population model: CL (l h(-1)) = 0.54 + 0.02 CL(CR) (ml min(-1)) and V (l) = 6.64 + 0.08 WT (kg) - 0.16 ALB (g l(-1)). CONCLUSIONS A population pharmacokinetic model has been developed for raltitrexed in patients with advanced cancer. Pharmacokinetic parameters of raltitrexed are markedly influenced by the patient's renal function, body weight and serum albumin levels, which may be taken into account in dose individualization. The use of influential covariates to guide anticancer dosage selection may result in less variability in drug exposure and potentially a better clinical outcome.
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Affiliation(s)
- Elaine Y L Blair
- Faculty of Pharmacy, The University of Sydney, NSW 2006, Australia
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30
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Slaviero KA, Clarke SJ, McLachlan AJ, Blair EYL, Rivory LP. Population pharmacokinetics of weekly docetaxel in patients with advanced cancer. Br J Clin Pharmacol 2004; 57:44-53. [PMID: 14678339 PMCID: PMC1884416 DOI: 10.1046/j.1365-2125.2003.01956.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2002] [Accepted: 06/27/2003] [Indexed: 11/20/2022] Open
Abstract
AIMS Previous pharmacokinetic studies of the 3-weekly regimen (100 mg m(-2) every 3 weeks) of docetaxel have shown that docetaxel clearance is affected by liver function, body surface area, age, serum alpha1-acid glycoprotein and cytochrome P450 3A4 (CYP3A4) activity. However, the pharmacokinetics of a weekly docetaxel (40 mg m(-2) week(-1)) schedule are not well characterized. The aims of this study were (a) to investigate the pharmacokinetics of docetaxel (40 mg m(-2) week(-1)) using sparse concentration-time data collected from patients with advanced cancer and (b) to utilize a population pharmacokinetic approach to identify patient covariates that significantly influence the clearance of docetaxel when administered according to this regimen. METHODS A two-compartment pharmacokinetic model was used to describe the docetaxel concentration-time data from 54 patients with advanced cancer. The mean population and individual posterior Bayesian estimates of docetaxel clearance were estimated using P-PHARM. The relationships between docetaxel clearance and 21 covariates were investigated. This included estimates of CYP3A4 function in each patient using the erythromycin breath test (1/tmax). Significant covariates were included into the final population pharmacokinetic model. Pharmacokinetic models were validated using a data splitting approach with a dataset consisting of 16 patients. RESULTS Significant relationships were found between docetaxel clearance and 1/tmax (erythromycin breath test parameter) and several of the liver function enzymes and CL was best described by the equation; CL = 21.51 + 217 (1/tmax) - 0.13 (ALT). This final population pharmacokinetic model provided both precise and unbiased predictions of docetaxel concentrations in a validation group of patients and an estimate of the population mean (95% confidence interval) clearance of docetaxel was 30.13 l h(-1) (12.54, 46.04 l h(-1)) with an intersubject variability 30%. CONCLUSIONS A population pharmacokinetic model has been developed and validated for weekly docetaxel (40 mg m(-2)) in patients with advanced cancer. These results indicate that CYP3A4 activity and hepatic function have an impact on the pharmacokinetics of docetaxel when administered weekly.
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Affiliation(s)
- Kellie A Slaviero
- Department of Pharmacology, University of Sydney, 2006, NSW, Australia
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