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Krzyzanski W, Stockard B, Gaedigk A, Scott A, Nolte W, Gibson K, Leeder JS, Lewis T. Developmental pharmacokinetics of indomethacin in preterm neonates: Severely decreased drug clearance in the first week of life. CPT Pharmacometrics Syst Pharmacol 2022; 12:110-121. [PMID: 36309972 PMCID: PMC9835126 DOI: 10.1002/psp4.12881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 09/28/2022] [Accepted: 10/16/2022] [Indexed: 11/07/2022] Open
Abstract
Indomethacin is used commonly in preterm neonates for the prevention of intracranial hemorrhage and closure of an abnormally open cardiac vessel. Due to biomedical advances, the infants who receive this drug in the neonatal intensive care unit setting have become younger, smaller, and less mature (more preterm) at the time of treatment. To develop a pharmacokinetics (PK) model to aid future dosing, we designed a prospective cohort study to characterize indomethacin PK in a dynamically changing patient population. A population PK base model was created using NONMEM, and a covariate model was developed in a primary development cohort and subsequently was tested for accuracy in a validation cohort. Postnatal age was a significant covariate for hepatic clearance (CLH ) and renal clearance (CLR ). The typical value of the total clearance (CL, the sum of CLR and CLH ) was 3.09 ml/h and expressed as CL/WTmedian = 3.96 ml/h/kg, where WTmedian is the median body weight. The intersubject variability of CLR and CLH were 61% and 207%, respectively. The typical value of the volume of distribution Vp = 366 ml (Vp /WTmedian = 470 ml/kg), and its intersubject variability was 38.8%. Half-life was 82.1 h. Compared with more mature and older preterm populations studied previously, indomethacin CL is considerably lower in this contemporary population. Model-informed precision dosing incorporating important covariates other than weight alone offers an opportunity to individualize dosing in a susceptible patient undergoing rapid change.
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Affiliation(s)
- Wojciech Krzyzanski
- Department of Pharmaceutical SciencesThe State University of New York at BuffaloBuffaloNew YorkUSA
| | - Bradley Stockard
- Department of PediatricsUniversity of Missouri Kansas City School of MedicineKansas CityMissouriUSA
| | - Andrea Gaedigk
- Department of PediatricsUniversity of Missouri Kansas City School of MedicineKansas CityMissouriUSA,Division of Clinical PharmacologyToxicology and Therapeutic Innovation, Children's Mercy HospitalKansas CityMissouriUSA
| | - Allison Scott
- Division of NeonatologyChildren's Mercy HospitalKansas CityMissouriUSA
| | - Whitney Nolte
- Division of Clinical PharmacologyToxicology and Therapeutic Innovation, Children's Mercy HospitalKansas CityMissouriUSA
| | - Kim Gibson
- Division of Clinical PharmacologyToxicology and Therapeutic Innovation, Children's Mercy HospitalKansas CityMissouriUSA
| | - J. Steven Leeder
- Department of PediatricsUniversity of Missouri Kansas City School of MedicineKansas CityMissouriUSA,Division of Clinical PharmacologyToxicology and Therapeutic Innovation, Children's Mercy HospitalKansas CityMissouriUSA
| | - Tamorah Lewis
- Department of PediatricsUniversity of Missouri Kansas City School of MedicineKansas CityMissouriUSA,Division of Clinical PharmacologyToxicology and Therapeutic Innovation, Children's Mercy HospitalKansas CityMissouriUSA,Division of NeonatologyChildren's Mercy HospitalKansas CityMissouriUSA
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Dontukurthy S, Tobias JD. Update on Local Anesthetic Toxicity, Prevention and Treatment During Regional Anesthesia in Infants and Children. J Pediatr Pharmacol Ther 2021; 26:445-454. [PMID: 34239395 DOI: 10.5863/1551-6776-26.5.445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/17/2020] [Indexed: 01/29/2023]
Abstract
Local anesthetic agents play a key role in the treatment and prevention of pain in children. Although generally safe and effective, as with any pharmacologic agent, adverse effects may occur with the administration of these medications. Systemic absorption or inadvertent systemic injection during bolus dosing or continuous infusion can result in local anesthetic systemic toxicity with life-threatening neurological and cardiac complications. The following article reviews the pharmacology of local anesthetic agents, outlines previous reports of systemic toxicity during regional anesthesia, and discusses prevention and treatment algorithms.
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3
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Zhou W, Fu Y, Zhang M, Buabeid MA, Ijaz M, Murtaza G. Nanoparticle-mediated therapy of neuronal damage in the neonatal brain. J Drug Deliv Sci Technol 2021. [DOI: 10.1016/j.jddst.2020.102208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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4
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Birnbaum AK, Meador KJ, Karanam A, Brown C, May RC, Gerard EE, Gedzelman ER, Penovich PE, Kalayjian LA, Cavitt J, Pack AM, Miller JW, Stowe ZN, Pennell PB. Antiepileptic Drug Exposure in Infants of Breastfeeding Mothers With Epilepsy. JAMA Neurol 2020; 77:441-450. [PMID: 31886825 DOI: 10.1001/jamaneurol.2019.4443] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Importance There is limited information on infant drug exposure via breastfeeding by mothers who are receiving antiepileptic drug therapy. Objective To provide direct, objective information on antiepileptic drug exposure through breast milk. Design, Setting, and Participants This prospective cohort study was conducted between December 2012 to October 2016, with follow-up in children until 6 years of age at 20 sites across the United States. Data were collected via an observational multicenter investigation (Maternal Outcomes and Neurodevelopmental Effects of Antiepileptic Drugs [MONEAD]) of outcomes in pregnant mothers with epilepsy and their children. Pregnant women with epilepsy who were aged 14 to 45 years, had pregnancies that had progressed to less than 20 weeks' gestational age, and had measured IQ scores of more than 70 points were enrolled and followed up through pregnancy and 9 postpartum months. Their infants were enrolled at birth. Data were analyzed from May 2014 to August 2019. Exposures Antiepileptic drug exposure in infants who were breastfed. Main Outcomes and Measures The percentage of infant-to-mother concentration of antiepileptic drugs. Antiepileptic drug concentrations were quantified from blood samples collected from infants and mothers at the same visit, 5 to 20 weeks after birth. Concentrations of antiepileptic drugs in infants at less than the lower limit of quantification were assessed as half of the lower limit. Additional measures collected were the total duration of all daily breastfeeding sessions and/or the volume of pumped breast milk ingested from a bottle. Results A total of 351 women (of 865 screened and 503 eligible individuals) were enrolled, along with their 345 infants (179 female children [51.9%]; median [range] age, 13 [5-20] weeks). Of the 345 infants, 222 (64.3%) were breastfed; the data collection yielded 164 matching infant-mother concentration pairs from 138 infants. Approximately 49% of all antiepileptic drug concentrations in nursing infants were less than the lower limit of quantification. The median percentage of infant-to-mother concentration for all 7 antiepileptic drugs and 1 metabolite (carbamazepine, carbamazepine-10,11-epoxide, levetiracetam, lamotrigine, oxcarbazepine, topiramate, valproate, and zonisamide) ranged from 0.3% (range, 0.2%-0.9%) to 44.2% (range, 35.2%-125.3%). In multiple linear regression models, maternal concentration was a significant factor associated with lamotrigine concentration in infants (Pearson correlation coefficient, 0.58; P < .001) but not levetiracetam concentration in infants. Conclusions and Relevance Overall, antiepileptic drug concentrations in blood samples of infants who were breastfed were substantially lower than maternal blood concentrations. Given the well-known benefits of breastfeeding and the prior studies demonstrating no ill effects when the mother was receiving antiepileptic drugs, these findings support the breastfeeding of infants by mothers with epilepsy who are taking antiepileptic drug therapy.
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Affiliation(s)
- Angela K Birnbaum
- Experimental & Clinical Pharmacology, University of Minnesota, Minneapolis
| | - Kimford J Meador
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, California
| | - Ashwin Karanam
- Experimental & Clinical Pharmacology, University of Minnesota, Minneapolis
| | | | - Ryan C May
- The Emmes Corporation, Rockville, Maryland
| | | | | | | | - Laura A Kalayjian
- Department of Neurology, University of Southern California, Los Angeles
| | | | | | - John W Miller
- Department of Neurology, University of Washington, Seattle.,Department of Neurological Surgery, University of Washington, Seattle
| | - Zachary N Stowe
- Department of Psychiatry, University of Wisconsin at Madison, Madison
| | - Page B Pennell
- Department of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
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Bergenwall M, Walker SAN, Elligsen M, Iaboni DC, Findlater C, Seto W, Ng E. Optimizing gentamicin conventional and extended interval dosing in neonates using Monte Carlo simulation - a retrospective study. BMC Pediatr 2019; 19:318. [PMID: 31492162 PMCID: PMC6729057 DOI: 10.1186/s12887-019-1676-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 08/19/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Although aminoglycosides are routinely used in neonates, controversy exists regarding empiric dosing regimens. The objectives were to determine gentamicin pharmacokinetics in neonates, and develop initial mg/kg dosing recommendations that optimized target peak and trough concentration attainment for conventional and extended-interval dosing (EID) regimens. METHODS Patient demographics and steady-state gentamicin concentration data were retrospectively collected for 60 neonates with no renal impairment admitted to a level III neonatal intensive care unit. Mean pharmacokinetics were calculated and multiple linear regression was performed to determine significant covariates of clearance (L/h) and volume of distribution (L). Classification and regression tree (CART) analysis identified breakpoints for significant covariates. Monte Carlo Simulation (MCS) was used to determine optimal dosing recommendations for each CART-identified sub-group. RESULTS Gentamicin clearance and volume of distribution were significantly associated with weight at gentamicin initiation. CART-identified breakpoints for weight at gentamicin initiation were: ≤ 850 g, 851-1200 g, and > 1200 g. MCS identified that a conventional dose of gentamicin 3.5 mg/kg given every 48 h or an EID of 8-9 mg/kg administered every 72 h in neonates weighing ≤ 850 g, and every 24 and 48 h, respectively, in neonates weighing 851-1200 g, provided the best probability of attaining conventional (peak: 5-10 mg/L and trough: ≤ 2 mg/L) and EID targets (peak:12-20 mg/L, trough:≤ 0.5 mg/L). Insufficient sample size in the > 1200 g neonatal group precluded further investigation of this weight category. CONCLUSIONS This study provides initial gentamicin dosing recommendations that optimize target attainment for conventional and EID regimens in neonates weighing ≤ 1200 g. Prospective validation and empiric dose optimization for neonates > 1200 g is needed.
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Affiliation(s)
- Monique Bergenwall
- Department of Pharmacy, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, E-302, Toronto, ON M4N 3M5 Canada
- Present Address: Grandview Medical Centre Family Health Team, 167 Hespeler Rd, Cambridge, ON N1R 3H7 Canada
| | - Sandra A. N. Walker
- Department of Pharmacy, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, E-302, Toronto, ON M4N 3M5 Canada
- Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, ON Canada
- Division of Infectious Diseases, Sunnybrook Health Sciences Centre, Toronto, ON Canada
- Sunnybrook Health Sciences Centre Research Institute, Toronto, ON Canada
| | - Marion Elligsen
- Department of Pharmacy, Sunnybrook Health Sciences Centre, 2075 Bayview Avenue, E-302, Toronto, ON M4N 3M5 Canada
| | - Dolores C. Iaboni
- Women and Babies Program, Sunnybrook Health Sciences Centre, Toronto, ON Canada
| | - Carla Findlater
- Women and Babies Program, Sunnybrook Health Sciences Centre, Toronto, ON Canada
| | - Winnie Seto
- Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, ON Canada
- Department of Pharmacy, Hospital for Sick Children, Toronto, ON Canada
| | - Eugene Ng
- Women and Babies Program, Sunnybrook Health Sciences Centre, Toronto, ON Canada
- Department of Paediatrics, University of Toronto, Toronto, ON Canada
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Arteaga Cabeza O, Mikrogeorgiou A, Kannan S, Ferriero DM. Advanced nanotherapies to promote neuroregeneration in the injured newborn brain. Adv Drug Deliv Rev 2019; 148:19-37. [PMID: 31678359 DOI: 10.1016/j.addr.2019.10.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 09/19/2019] [Accepted: 10/23/2019] [Indexed: 12/16/2022]
Abstract
Neonatal brain injury affects thousands of babies each year and may lead to long-term and permanent physical and neurological problems. Currently, therapeutic hypothermia is standard clinical care for term newborns with moderate to severe neonatal encephalopathy. Nevertheless, it is not completely protective, and additional strategies to restore and promote regeneration are urgently needed. One way to ensure recovery following injury to the immature brain is to augment endogenous regenerative pathways. However, novel strategies such as stem cell therapy, gene therapies and nanotechnology have not been adequately explored in this unique age group. In this perspective review, we describe current efforts that promote neuroprotection and potential targets that are unique to the developing brain, which can be leveraged to facilitate neuroregeneration.
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Llanos-Paez CC, Hennig S, Staatz CE. Population pharmacokinetic modelling, Monte Carlo simulation and semi-mechanistic pharmacodynamic modelling as tools to personalize gentamicin therapy. J Antimicrob Chemother 2017; 72:639-667. [PMID: 28062683 DOI: 10.1093/jac/dkw461] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Population pharmacokinetic modelling, Monte Carlo simulation and semi-mechanistic pharmacodynamic modelling are all tools that can be applied to personalize gentamicin therapy. This review summarizes and evaluates literature knowledge on the population pharmacokinetics and pharmacodynamics of gentamicin and identifies areas where further research is required to successfully individualize gentamicin therapy using modelling and simulation techniques. Thirty-five studies have developed a population pharmacokinetic model of gentamicin and 15 studies have made dosing recommendations based on Monte Carlo simulation. Variability in gentamicin clearance was most commonly related to renal function in adults and body weight and age in paediatrics. Nine studies have related aminoglycoside exposure indices to clinical outcomes. Most commonly, efficacy has been linked to a Cmax/MIC ≥7-10 and a AUC24/MIC ≥70-100. No study to date has shown a relationship between predicted achievement of exposure targets and actual clinical success. Five studies have developed a semi-mechanistic pharmacokinetic/pharmacodynamic model to predict bacteria killing and regrowth following gentamicin exposure and one study has developed a deterministic model of aminoglycoside nephrotoxicity. More complex semi-mechanistic models are required that consider the immune response, use of multiple antibiotics, the severity of illness, and both efficacy and toxicity. As our understanding grows, dosing of gentamicin based on sound pharmacokinetic/pharmacodynamic principles should be applied more commonly in clinical practice.
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Wells TG. Underserved Therapeutic Classes: Examples Which Should Not be Ignored in Infants and Children. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/009286159603000437] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Thomas G. Wells
- Department of Pediatrics, Divisions of Clinical Pharmacology and Nephrology, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock, Arkansas
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Almas S, Vance J, Baker T, Hale T. Management of Multiple Sclerosis in the Breastfeeding Mother. Mult Scler Int 2016; 2016:6527458. [PMID: 26966579 PMCID: PMC4757692 DOI: 10.1155/2016/6527458] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/30/2015] [Accepted: 12/31/2015] [Indexed: 12/12/2022] Open
Abstract
Multiple Sclerosis (MS) is an autoimmune neurological disease characterized by inflammation of the brain and spinal cord. Relapsing-Remitting MS is characterized by acute attacks followed by remission. Treatment is aimed at halting these attacks; therapy may last for months to years. Because MS disproportionately affects females and commonly begins during the childbearing years, clinicians treat pregnant or nursing MS patients. The intent of this review is to perform an in-depth analysis into the safety of drugs used in breastfeeding women with MS. This paper is composed of several drugs used in the treatment of MS and current research regarding their safety in breastfeeding including immunomodulators, immunosuppressants, monoclonal antibodies, corticosteroids, and drugs used for symptomatic treatment. Typically, some medications are large polar molecules which often do not pass into the milk in clinically relevant amounts. For this reason, interferon beta is likely safe for the infant when given to a breastfeeding mother. However, other drugs with particularly dangerous side effects may not be recommended. While treatment options are available and some data from clinical studies does exist, there continues to be a need for investigation and ongoing review of the medications used in breastfeeding mothers.
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Affiliation(s)
- Saneea Almas
- Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, 1400 Wallace Boulevard, Amarillo, TX 79106, USA
| | - Jesse Vance
- Infant Risk Center, Texas Tech University Health Sciences Center, 1400 Wallace Boulevard, Amarillo, TX 79106, USA
| | - Teresa Baker
- Department of Obstetrics & Gynecology, School of Medicine, Texas Tech University Health Sciences Center, 1400 Coulter Street, Amarillo, TX 79106, USA
| | - Thomas Hale
- Department of Pediatrics, School of Medicine, Texas Tech University Health Sciences Center, 1400 Wallace Boulevard, Amarillo, TX 79106, USA
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Grimsrud KN, Sherwin CMT, Constance JE, Tak C, Zuppa AF, Spigarelli MG, Mihalopoulos NL. Special population considerations and regulatory affairs for clinical research. CLINICAL RESEARCH AND REGULATORY AFFAIRS 2015; 32:47-56. [PMID: 26401094 PMCID: PMC4577021 DOI: 10.3109/10601333.2015.1001900] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Special populations, including women (non-pregnant and pregnant), pediatrics, and the elderly, require additional consideration with regard to clinical research. There are very specific regulatory laws, which protect these special populations, that need to be understood and adhered to in order to perform clinical research. This review provides a broad overview of some of the physiological differences in special populations and discusses how these differences may affect study design and regulatory considerations. These various special populations, with respect to regulatory affairs, are clearly defined within the Code of Federal Regulations. The definition of "special population" exists to provide enhanced awareness of their vulnerabilities, thereby allowing the creation of regulatory guidance aimed to decrease injury or outright harm. Currently, progress is being made to be more inclusive of special populations in clinical trials. This reflects changing attitudes towards drug information, with it being more representative of those patients that will ultimately be prescribed or exposed to the therapy. However, all research undertaken in these populations should be performed in a manner that ensures all protections of each participant are upheld.
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Affiliation(s)
- Kristin N. Grimsrud
- Department of Surgery, School of Medicine, University of California, Davis, Sacramento, CA, USA
| | - Catherine M. T. Sherwin
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jonathan E. Constance
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Casey Tak
- Department of Pharmacotherapy, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
| | - Athena F. Zuppa
- Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, PA, USA
| | - Michael G. Spigarelli
- Division of Clinical Pharmacology, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
- Department of Pharmacology and Toxicology, College of Pharmacy, University of Utah, Salt Lake City, UT, USA
- Division of Adolescent Medicine, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Nicole L. Mihalopoulos
- Division of Adolescent Medicine, Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT, USA
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Fuchs A, Guidi M, Giannoni E, Werner D, Buclin T, Widmer N, Csajka C. Population pharmacokinetic study of gentamicin in a large cohort of premature and term neonates. Br J Clin Pharmacol 2015; 78:1090-101. [PMID: 24938850 DOI: 10.1111/bcp.12444] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 06/09/2014] [Indexed: 12/01/2022] Open
Abstract
AIM This study aims to investigate the clinical and demographic factors influencing gentamicin pharmacokinetics in a large cohort of unselected premature and term newborns and to evaluate optimal regimens in this population. METHODS All gentamicin concentration data, along with clinical and demographic characteristics, were retrieved from medical charts in a Neonatal Intensive Care Unit over 5 years within the frame of a routine therapeutic drug monitoring programme. Data were described using non-linear mixed-effects regression analysis ( nonmem®). RESULTS A total of 3039 gentamicin concentrations collected in 994 preterm and 455 term newborns were included in the analysis. A two compartment model best characterized gentamicin disposition. The average parameter estimates, for a median body weight of 2170 g, were clearance (CL) 0.089 l h(-1) (CV 28%), central volume of distribution (Vc ) 0.908 l (CV 18%), intercompartmental clearance (Q) 0.157 l h(-1) and peripheral volume of distribution (Vp ) 0.560 l. Body weight, gestational age and post-natal age positively influenced CL. Dopamine co-administration had a significant negative effect on CL, whereas the influence of indomethacin and furosemide was not significant. Both body weight and gestational age significantly influenced Vc . Model-based simulations confirmed that, compared with term neonates, preterm infants need higher doses, superior to 4 mg kg(-1) , at extended intervals to achieve adequate concentrations. CONCLUSIONS This observational study conducted in a large cohort of newborns confirms the importance of body weight and gestational age for dosage adjustment. The model will serve to set up dosing recommendations and elaborate a Bayesian tool for dosage individualization based on concentration monitoring.
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Affiliation(s)
- Aline Fuchs
- Division of Clinical Pharmacology, Service of Biomedicine, Department of Laboratory, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland
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12
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Pharmacokinetics of ε-Aminocaproic Acid in Neonates Undergoing Cardiac Surgery with Cardiopulmonary Bypass. Anesthesiology 2015; 122:1002-9. [PMID: 25723765 DOI: 10.1097/aln.0000000000000616] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Antifibrinolytic medications such as ε-aminocaproic acid (EACA) are used in pediatric heart surgery to decrease surgical bleeding and transfusion. Dosing schemes for neonates are often based on adult regimens, or are simply empiric, in part due to the lack of neonatal pharmacokinetic information. The authors sought to determine the pharmacokinetics of EACA in neonates undergoing cardiac surgery and to devise a dosing regimen for this population. METHODS Ten neonates undergoing cardiac surgery with cardiopulmonary bypass were given EACA according to standard practice, and blood was drawn at 10 time points to determine drug concentrations. Time-concentration profiles were analyzed using nonlinear mixed effects models. Parameter estimates (standardized to a 70-kg person) were used to develop a dosing regimen intended to maintain a target concentration shown to inhibit fibrinolysis in neonatal plasma (50 mg/l). RESULTS Pharmacokinetics were described using a two-compartment model plus an additional compartment for the cardiopulmonary bypass pump. First-order elimination was described with a clearance of 5.07 l/h × (WT/70). Simulation showed a dosing regimen with a loading dose of 40 mg/kg and an infusion of 30 mg · kg · h, with a pump prime concentration of 100 mg/l maintained plasma concentrations above 50 mg/l in 90% of neonates during cardiopulmonary bypass surgery. CONCLUSIONS EACA clearance, expressed using allometry, is reduced in neonates compared with older children and adults. Loading dose and infusion dose are approximately half those required in children and adults.
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Abstract
Introduction Ethanol has been used for years in neonatal and infant liquid medications, yet the pharmacokinetics, pharmacodynamics, and safety of ethanol in this vulnerable population have not been well characterized. The purpose of this review is to raise awareness of ethanol use as an excipient in neonatal and infant medications and to provide insight, based on the available evidence, into clearance rates of ethanol in babies. We also discuss ethanol pharmacokinetics in adults, theoretical pharmacokinetic changes in neonates and infants as it may apply to ethanol disposition, and case reports involving ethanol exposure in neonates and infants. Materials and methods This study was a narrative review in which relevant papers were selected using databases and scientific search engines such as PubMed with the key words ethanol, infant, and newborninfant. Results It remains unclear what ethanol exposure is safe for neonates and infants. The Food and Drug Administration and American Academy of Pediatrics have both taken action, by either setting limits of ethanol content in over-the-counter medications or by recommending restricted exposure to ethanol-containing pediatric formulations. Conclusions Until the short- and long-term health effects of chronic ethanol administration can be further characterized, ethanol-containing medications should be used with caution.
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Affiliation(s)
- Elizabeth Marek
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Walter K Kraft
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania
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Wetmore BA, Allen B, Clewell HJ, Parker T, Wambaugh JF, Almond LM, Sochaski MA, Thomas RS. Incorporating population variability and susceptible subpopulations into dosimetry for high-throughput toxicity testing. Toxicol Sci 2014; 142:210-24. [PMID: 25145659 DOI: 10.1093/toxsci/kfu169] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Momentum is growing worldwide to use in vitro high-throughput screening (HTS) to evaluate human health effects of chemicals. However, the integration of dosimetry into HTS assays and incorporation of population variability will be essential before its application in a risk assessment context. Previously, we employed in vitro hepatic metabolic clearance and plasma protein binding data with in vitro in vivo extrapolation (IVIVE) modeling to estimate oral equivalent doses, or daily oral chemical doses required to achieve steady-state blood concentrations (Css) equivalent to media concentrations having a defined effect in an in vitro HTS assay. In this study, hepatic clearance rates of selected ToxCast chemicals were measured in vitro for 13 cytochrome P450 and five uridine 5'-diphospho-glucuronysyltransferase isozymes using recombinantly expressed enzymes. The isozyme-specific clearance rates were then incorporated into an IVIVE model that captures known differences in isozyme expression across several life stages and ethnic populations. Comparison of the median Css for a healthy population against the median or the upper 95th percentile for more sensitive populations revealed differences of 1.3- to 4.3-fold or 3.1- to 13.1-fold, respectively. Such values may be used to derive chemical-specific human toxicokinetic adjustment factors. The IVIVE model was also used to estimate subpopulation-specific oral equivalent doses that were directly compared with subpopulation-specific exposure estimates. This study successfully combines isozyme and physiologic differences to quantitate subpopulation pharmacokinetic variability. Incorporation of these values with dosimetry and in vitro bioactivities provides a viable approach that could be employed within a high-throughput risk assessment framework.
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Affiliation(s)
- Barbara A Wetmore
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Brittany Allen
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Harvey J Clewell
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Timothy Parker
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - John F Wambaugh
- United States Environmental Protection Agency, Office of Research and Development, National Center for Computational Toxicology, Research Triangle Park, North Carolina 27711
| | - Lisa M Almond
- Simcyp Limited (a Certara company), Blades Enterprise Centre, John Street, Sheffield S2 4SU, UK
| | - Mark A Sochaski
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
| | - Russell S Thomas
- The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709-2137
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Abstract
Neonatal surgical antibioprophylaxis must take into account the specificities of this life period, as immunological immaturity, microbiotal implantation and antibiotic treatment pharmacokinetics properties. Very few data are available, but it seems that coagulase negative Staphylococcus (CNS) is the most reported bacteria, in intestinal tract at the time of surgery as well as in surgical site infections. Usual vertical transmission bacteria as S. agalactiae or E. coli K1 are rarely documented. The antibioprophylaxis treatment must consider the age and the environmental context of the newborn; first or second generation cephalosporins sometimes in association with vancomycin seem appropriate in this context. It is now urgent to conduct clinical trials in order to validate theses propositions.
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Lacey R, Aldous D, Peterson G, Cooper G. Gentamicin dosing in neonates: evaluation of a dosing protocol. INTERNATIONAL JOURNAL OF PHARMACY PRACTICE 2011. [DOI: 10.1111/j.2042-7174.1995.tb00828.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract
A study was carried out to examine the dosing of gentamicin and to investigate some of the determinants of serum gentamicin concentrations in neonates at the Royal Hobart hospital, Tasmania, Australia, and to examine the appropriateness of the current dosing protocol (that of the Royal Children's hospital, Melbourne). Clinical and demographic data were retrospectively collected from the records of 39 neonates who had received therapy with gentamicin for suspected or proven septicaemia during the period May to September, 1993. Peak and trough serum concentrations of gentamicin were measured, at least 36 hours after starting therapy. The mean gestational age (± SD) of the sample was 32.3 ± 4.9 weeks, and 30 patients were male. The mean dosage of gentamicin was 4.0 ± 1.3mg/kg/day and the median duration of therapy was 4 days (range 2 to 22 days). Trough serum concentrations of gentamicin ranged from 0.6 to 6.0mg/L (mean 1.9 ± 1.0mg/L), with 35.9 per cent being 2.0mg/L or higher. Peak serum concentrations ranged from 4.3 to 12.9 mg/L (mean 6.1 ± 1.5 mg/L), with 89.7 per cent being between 5.0 and 8.0mg/L. The peak and trough serum concentrations were significantly related, while the total daily dosage of gentamicin and the resulting peak and trough serum concentrations were not significantly related. The trough serum concentration of gentamicin was significantly related to the serum creatinine concentration. Patients who had been dosed correctly according to the protocol were less likely to have a potentially toxic trough serum concentration of gentamicin. Those administered gentamicin every 12 hours tended to have higher serum trough concentrations of the drug than those who received it either 18- or 24-hourly.
This study has confirmed that excessive serum concentrations of gentamicin occur frequently in neonates, a situation which may be improved by greater usage of an 18-hourly dosing regimen and prompt adjustment of dosage according to renal function.
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Affiliation(s)
- Ruth Lacey
- Tasmanian School of Pharmacy, Faculty of Medicine and Pharmacy, University of Tasmania at Hobart, GPO Box 252C, Hobart, Tas 7001, Australia
| | - Diane Aldous
- Pharmacy Department, Royal Hobart Hospital, Tasmania
| | - Gregory Peterson
- Tasmanian School of Pharmacy, Faculty of Medicine and Pharmacy, University of Tasmania at Hobart, GPO Box 252C, Hobart, Tas 7001, Australia
| | - Gabrielle Cooper
- Tasmanian School of Pharmacy, Faculty of Medicine and Pharmacy, University of Tasmania at Hobart, GPO Box 252C, Hobart, Tas 7001, Australia
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18
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Sherwin CMT, Svahn S, Van Der Linden A, Broadbent RS, Medlicott NJ, Reith DM. Individualised dosing of amikacin in neonates: a pharmacokinetic/pharmacodynamic analysis. Eur J Clin Pharmacol 2009; 65:705-13. [DOI: 10.1007/s00228-009-0637-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 02/11/2009] [Indexed: 10/21/2022]
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19
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Dasandi B, Shah S, Shivprakash. Development and validation of a high throughput and robust LC–MS/MS with electrospray ionization method for simultaneous quantitation of diltiazem and its two metabolites in human plasma: Application to a bioequivalence study. J Chromatogr B Analyt Technol Biomed Life Sci 2009; 877:791-8. [DOI: 10.1016/j.jchromb.2009.02.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 01/29/2009] [Accepted: 02/05/2009] [Indexed: 11/26/2022]
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20
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DeWoskin RS, Thompson CM. Renal clearance parameters for PBPK model analysis of early lifestage differences in the disposition of environmental toxicants. Regul Toxicol Pharmacol 2008; 51:66-86. [DOI: 10.1016/j.yrtph.2008.02.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2006] [Revised: 02/12/2008] [Accepted: 02/15/2008] [Indexed: 10/22/2022]
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21
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Dorne JLCM. Human variability in hepatic and renal elimination: implications for risk assessment. J Appl Toxicol 2007; 27:411-20. [PMID: 17497760 DOI: 10.1002/jat.1255] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Hepatic metabolism and renal excretion constitute the main routes of xenobiotic elimination in humans. Improving human risk assessment for threshold contaminants requires the incorporation of quantitative data related to their elimination (toxicokinetics) and potential toxic effects (toxicodynamics). This type of data provides a scientific basis to replace the standard uncertainty factor (UF = 10) allowing for the consideration of human variability in toxicokinetics and toxicodynamics. This review focuses on recent research efforts aiming to incorporate human variability in hepatic and renal elimination (toxicokinetics) into the risk assessment process. A therapeutic drug database was developed to quantify pathway-related variability in human phase I and phase II hepatic metabolism as well as renal excretion in subgroups of the population (healthy adults, neonates and the elderly), using data on compounds cleared primarily through each route (> 60% dose). For each subgroup of the population and elimination route, pathway-related UFs were then derived to cover 95-99% of each subgroup. Overall, the default toxicokinetic UFs would not cover neonates, the elderly for most elimination routes and any subgroup of the population for compounds metabolized via polymorphic isozymes (such as CYP2C19 and CYP2D6). These pathway-related UFs allow the incorporation of in vivo metabolism and toxicokinetic data in the risk assessment process and provide a flexible intermediate option between the default UF and chemical-specific adjustment factors (CSAFs) derived from physiologically based pharmacokinetic models. Implications of human variability in hepatic metabolism and renal excretion for chemical risk assessment are discussed.
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Affiliation(s)
- J L C M Dorne
- Division of Developmental Origins of Health and Disease, Institute of Human Nutrition, Clinical Pharmacology Group, School of Medicine, University of Southampton, Southampton, UK.
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22
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Affiliation(s)
- Thomas W Hale
- Division of Clinical Pharmacology, Texas Tech University School of Medicine, 1400 Wallace Blvd., Amarillo, TX 79106, USA
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23
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Abstract
In addition to differences in the pharmacodynamic response in the infant, the dose and the pharmacokinetic processes acting upon that dose principally determine the efficacy and/or safety of a therapeutic or inadvertent exposure. At a given dose, significant differences in therapeutic efficacy and toxicant susceptibility exist between the newborn and adult. Immature pharmacokinetic processes in the newborn predominantly explain such differences. With infant development, the physiological and biochemical processes that govern absorption, distribution, metabolism, and excretion undergo significant growth and maturational changes. Therefore, any assessment of the safety associated with an exposure must consider the impact of these maturational changes on drug pharmacokinetics and response in the developing infant. This paper reviews the current data concerning the growth and maturation of the physiological and biochemical factors governing absorption, distribution, metabolism, and excretion. The review also provides some insight into how these developmental changes alter the efficiency of pharmacokinetics in the infant. Such information may help clarify why dynamic changes in therapeutic efficacy and toxicant susceptibility occur through infancy.
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Affiliation(s)
- Jane Alcorn
- College of Pharmacy and Nutrition, University of Saskatchewan, 110 Science Place, SK, S7N 5C9, Saskatoon, Canada.
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24
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Abstract
Dramatic developmental changes in the physiological and biochemical processes that govern drug pharmacokinetics and pharmacodynamics occur during the first year of life. These changes may have significant consequences for the way infants respond to and deal with drugs. The ontogenesis of systemic clearance mechanisms is probably the most critical determinant of a pharmacological response in the developing infant. In recent years, advances in molecular techniques and an increased availability of fetal and infant tissues have afforded enhanced insight into the ontogeny of clearance mechanisms. Information from these studies is reviewed to highlight the dynamic and complex nature of developmental changes in clearance mechanisms in infants during the first year of life. Hepatic and renal elimination mechanisms constitute the two principal clearance pathways of the developing infant. Drug metabolising enzyme activity is primarily responsible for the hepatic clearance of many drugs. In general, when compared with adult activity levels normalised to amount of hepatic microsomal protein, hepatic cytochrome P450-mediated metabolism and the phase II reactions of glucuronidation, glutathione conjugation and acetylation are deficient in the neonate, but sulfate conjugation is an efficient pathway at birth. Parturition triggers the dramatic development of drug metabolising enzymes, and each enzyme demonstrates an independent rate and pattern of maturation. Marked interindividual variability is associated with their developmental expression, making the ontogenesis of hepatic metabolism a highly variable process. By the first year of life, most enzymes have matured to adult activity levels. When compared with adult values, renal clearance mechanisms are compromised at birth. Dramatic increases in renal function occur in the ensuing postpartum period, and by 6 months of age glomerular filtration rate normalised to bodyweight has approached adult values. Maturation of renal tubular functions exhibits a more protracted time course of development, resulting in a glomerulotubular imbalance. This imbalance exists until adult renal tubule function values are approached by 1 year of age. The ontogeny of hepatic biliary and renal tubular transport processes and their impact on the elimination of drugs remain largely unknown. The summary of the current understanding of the ontogeny of individual pathways of hepatic and renal elimination presented in this review should serve as a basis for the continued accruement of age-specific information concerning the ontogeny of clearance mechanisms in infants. Such information can only help to improve the pharmacotherapeutic management of paediatric patients.
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Affiliation(s)
- Jane Alcorn
- Division of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536-0082, USA
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25
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Oberlander TF, Eckstein Grunau R, Fitzgerald C, Ellwood AL, Misri S, Rurak D, Riggs KW. Prolonged prenatal psychotropic medication exposure alters neonatal acute pain response. Pediatr Res 2002; 51:443-53. [PMID: 11919328 DOI: 10.1203/00006450-200204000-00008] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Selective serotonin reuptake inhibitors (SSRIs) and benzodiazepines are frequently used to treat maternal depression during pregnancy, however the effect of increased serotonin (5HT) and gamma-amino-butyric acid (GABA) agonists in the fetal human brain remains unknown. 5HT and GABA are active during fetal neurologic growth and play early roles in pain modulation, therefore, if prolonged prenatal exposure alters neurodevelopment this may become evident in altered neonatal pain responses. To examine biologic and behavioral effects of prenatal exposure, neonatal responses to acute pain (phenylketonuria heel lance) in infants with prolonged prenatal exposure were examined. Facial action (Neonatal Facial Coding System) and cardiac autonomic reactivity derived from the relationship between respiratory activity and short term variations of heart rate (HRV) were compared between 22 infants with SSRI exposure (SE) [fluoxetine (n = 7), paroxetine (n = 11), sertraline (n = 4)]; 16 infants exposed to SSRIs and clonazepam (SE+) [paroxetine (n = 14), fluoxetine (n = 2)]; and 23 nonexposed infants during baseline, lance, and recovery periods of a heel lance. Length of maternal SSRI use did not vary significantly between exposure groups-[mean (range)] SE:SE+ 183 (31-281):141 (54-282) d (p > 0.05). Infants exposed to SE and SE+ displayed significantly less facial activity to heel lance than control infants. Mean HR increased with lance, but was significantly lower in SE infants during recovery. Using measures of HRV and the transfer relationship between heart rate and respiration, SSRI infants had a greater return of parasympathetic cardiac modulation in the recovery period, whereas a sustained sympathetic response continued in the control group. Prolonged prenatal SSRI exposure appears to be associated with reduced behavioral pain responses and increased parasympathetic cardiac modulation in recovery following an acute neonatal noxious event. Possible 5HT-mediated pain inhibition, pharmacologic factors and the developmental course remain to be studied.
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Affiliation(s)
- Tim F Oberlander
- Department of Pediatrics, University of British Columbia, Vancouver, BC, Canada.
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26
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Pons G, Tréluyer JM, Dimet J, Merlé Y. Potential benefit of Bayesian forecasting for therapeutic drug monitoring in neonates. Ther Drug Monit 2002; 24:9-14. [PMID: 11805715 DOI: 10.1097/00007691-200202000-00002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Therapeutic drug monitoring in neonate has been hampered by invasiveness of blood samplings raising ethical problems. A methodologic approach has been developped in adults and in children that is still unsufficiently developped in neonates, the Bayesian forecasting of drug plasma concentration. This method is particularly attractive in neonates using a few blood samples from an individual patient and more informations from a prior patient sample representative of the population the individual patient belongs to. The present article aims at reviewing the different procedures and methods to minimize invasiveness during therapeutic drug monitoring in neonate and at reviewing the methods for improving the quality of different dose adjustments using a Bayesian approach.
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Affiliation(s)
- Gérard Pons
- Perinatal and Pediatric Pharmacology, Saint-Vincent de Paul Hospital, René Descartes University, Paris, France.
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27
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Abstract
Breastfeeding provides important benefits to mothers and infants and should be encouraged strongly as the optimal feeding choice for most infants. In assessing the effects of maternal medication on breastfeeding, clinicians must weigh the many benefits of breastfeeding for mothers and infants against the risk for exposing infants to a drug as it is present in breast milk. With regard to most medications, continued breastfeeding despite drug exposure is advantageous to mothers and infants.
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Affiliation(s)
- C R Howard
- Division of General Pediatrics, Departments of Pediatrics, Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
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28
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Abstract
BACKGROUND Because determining the pharmacokinetics of drugs used in pediatric patients allows for appropriate dosing and optimal clinical response, we have reviewed the pharmacokinetic data on the use of cefepime in the pediatric population. METHODS Three studies encompassing 88 patients ages 2 months to 16 years examined the pharmacokinetics of cefepime given as a single iv dose, as multiple iv doses and by im administration. In all studies serial blood and urine or cerebrospinal fluid (CSF) samples were collected after a single dose and/or at steady state, defined as after at least 2 days of dosing. Pharmacokinetic parameters were generated from concentration-vs.-time curves and were analyzed using noncompartmental methods. RESULTS In all studies cefepime exhibited a linear pharmacokinetic profile and concentrations declined proportionally over time. Minimal accumulation was observed after multiple dosing. Pharmacokinetic parameters were similar in all studies and appeared to be dose-independent. Mean (range) parameters observed in this review were: t 1/2 = 1.7 h (1.26 to 1.93); volume of distribution at steady state, 0.37 liter/kg (0.33 to 0.40); total body clearance, 3.1 ml/min/kg (1.43 to 4.01); renal total body clearance, 2.3 ml/min/kg (1.86 to 3.05); absolute bioavailability of cefepime after the im dose, 82.3%; and urinary recovery, 72% (57 to 85%). Penetration into CSF appeared to be good, with CSF concentrations averaging 3.3 to 5.7 microg/ml 0.5 and 8 h after administration of the dose, respectively. CONCLUSION Cefepime displayed a linear pharmacokinetic profile, was well-absorbed via im injection and had adequate penetration into the CSF of patients with bacterial meningitis, compared with other beta-lactams.
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Affiliation(s)
- J L Blumer
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
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29
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Rocha MJ, Almeida AM, Afonso E, Martins V, Santos J, Leitão F, Falcão AC. The kinetic profile of gentamicin in premature neonates. J Pharm Pharmacol 2000; 52:1091-7. [PMID: 11045889 DOI: 10.1211/0022357001775010] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The kinetic profile of gentamicin in premature infants has been studied to enable the development of optimized dosage schedules for neonatal intensive-care units and to stress the relationship between the pharmacokinetic parameters and several demographic, developmental and clinical factors which might be associated with changes in gentamicin disposition. Sixty-eight newborn patients of 24- to 34-weeks gestational age and 600-3,100 g current weight in their first week of life, undergoing routine therapeutic drug monitoring of their gentamicin serum levels, were included in this retrospective analysis. Gentamicin pharmacokinetic parameters were determined through non-linear regression by using a single-compartment open model. By regression analysis the current weight (g) was shown to be the strongest co-variate, and both gentamicin clearance (L h(-1)) and volume of distribution (L) had to be normalized. Additionally, gentamicin clearance depended on gestational age with a cut-off at 30 weeks, which allowed the division of the overall population into two subsets (< 30 weeks and between 30-34 weeks of gestational age). The younger neonates (<30 weeks of gestational age) showed a lower gentamicin clearance (0.0288 vs 0.0340 L h(-1) kg(-1)), a slightly higher volume of distribution (0.464 vs 0.435 L kg(-1)), and a longer half-life (11.17 vs 8.88 h) compared with the older subgroup (30-34 weeks of gestational age). On the basis of the pharmacokinetic parameters obtained, we suggest loading doses of 3.7 and 3.5 mg kg(-1) for the two subgroups of neonates (<30 weeks and 30-34 weeks of gestational age), respectively. The appropriate maintenance doses in accordance with the characteristics of the patients should be 2.8 mgkg(-1)/24h and 2.6 mg kg(-1)/18 h for neonates < 30 weeks and between 30-34 weeks of gestational age, respectively. Finally, when compared with previous studies, the information obtained on the pharmacokinetics and determinants of the pharmacokinetic variability of gentamicin in neonates was shown to be consistent.
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Affiliation(s)
- M J Rocha
- Pharmacy Department, Coimbra University Hospital, Portugal
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30
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Yeung MY, Smyth JP. Targeting Gentamicin Concentrations in Babies: The Younger the Baby, the Larger the Loading Dose and the Longer the Dose Interval. ACTA ACUST UNITED AC 2000. [DOI: 10.1002/jppr200030398] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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31
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Abstract
Although opiates can provide patients with relief from pain and the discomfort of cough, the routine prescription of these drugs for infants demands caution and concern. Infants, particularly neonates, are not merely small adults requiring smaller dosages, but rather uniquely different patients. Neonates present with an immature physiology and biochemistry with respect to drug metabolism. We report a case of codeine intoxication in the neonate, in which the drug was prescribed for cough control during an emergency department visit.
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Affiliation(s)
- B Magnani
- Department of Pathology and Laboratory Medicine, Boston Medical Center, Boston University School of Medicine, MA 02118, USA.
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32
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de Wildt SN, Kearns GL, Leeder JS, van den Anker JN. Cytochrome P450 3A: ontogeny and drug disposition. Clin Pharmacokinet 1999; 37:485-505. [PMID: 10628899 DOI: 10.2165/00003088-199937060-00004] [Citation(s) in RCA: 392] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The maturation of organ systems during fetal life and childhood exerts a profound effect on drug disposition. The maturation of drug-metabolising enzymes is probably the predominant factor accounting for age-associated changes in non-renal drug clearance. The group of drug-metabolising enzymes most studied are the cytochrome P450 (CYP) superfamily. The CYP3A subfamily is the most abundant group of CYP enzymes in the liver and consists of at least 3 isoforms: CYP3A4, 3A5 and 3A7. Many drugs are mainly metabolised by the CYP3A subfamily. Therefore, maturational changes in CYP3A ontogeny may impact on the clinical pharmacokinetics of these drugs. CYP3A4 is the most abundantly expressed CYP and accounts for approximately 30 to 40% of the total CYPcontent in human adult liver and small intestine. CYP3A5 is 83% homologous to CYP3A4, is expressed at a much lower level than CYP3A4 in the liver, but is the main CYP3A isoform in the kidney. CYP3A7 is the major CYP isoform detected in human embryonic, fetal and newborn liver, but is also detected in adult liver, although at a much lower level than CYP3A4. Substrate specificity for the individual isoforms has not been fully elucidated. Because of large interindividual differences in CYP3A4 and 3A5 expression and activity, genetic polymorphisms have been suggested. However, although some gene mutations have been identified, the impact of these mutations on the pharmacokinetics of CYP3A substrates has to be established. Ontogeny of CYP3A activity has been studied in vitro and in vivo. CYP3A7 activity is high during embryonic and fetal life and decreases rapidly during the first week of life. Conversely, CYP3A4 is very low before birth but increases rapidly thereafter, reaching 50% of adult levels between 6 and 12 months of age. During infancy, CYP3A4 activity appears to be slightly higher than that of adults. Large interindividual variations in CYP3A5 expression and activity were observed during all stages of development, but no apparent developmental pattern of CYP3A5 activity has been identified to date. Profound changes occur in the activity of CYP3A isoforms during all stages of development. These changes have, in many instances, proven to be of clinical significance when treatment involves drugs that are substrates, inhibitors or inducers of CYP3A. Investigators and clinicians should consider the impact of ontogeny on CYP3A in both pharmacokinetic study design and data interpretation, as well as when prescribing drugs to children.
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Affiliation(s)
- S N de Wildt
- Department of Pediatrics, Sophia Children's Hospital, Rotterdam, The Netherlands.
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33
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Burin GJ, Saunders DR. Addressing human variability in risk assessment--the robustness of the intraspecies uncertainty factor. Regul Toxicol Pharmacol 1999; 30:209-16. [PMID: 10620470 DOI: 10.1006/rtph.1999.1351] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Addressing human variability and sensitive subpopulations is one of the challenges of risk assessment and is an important aspect of the Food Quality Protection Act, the law passed in 1996 that regulates food use pesticides in the United States. The intraspecies uncertainty factor is intended to address differences in susceptibility within the human population. This paper examines the history and scientific basis for the intraspecies uncertainty factor. Our best source of knowledge about human variability in the response to chemicals comes from clinical trials of pharmaceuticals. This large body of data allows both qualitative and quantitative characterization of variability in pharmacokinetic and pharmacodynamic parameters in the general population and in subgroups such as children. The preponderance of evidence in the areas of pharmacodynamics and pharmacokinetics supports the routine use of an intraspecies uncertainty factor in the range of 1-10 as being protective of greater than 99% of the human population. The intraspecies uncertainty factor is highly protective of various subpopulations, including infants and children.
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Affiliation(s)
- G J Burin
- Technology Sciences Group, Inc., 1101 17th Street NW, Suite 500, Washington, DC 20036, USA
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34
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Abstract
The bacteria most commonly responsible for early-onset (materno-fetal) infections in neonates are group B streptococci, enterococci, Enterobacteriaceae and Listeria monocytogenes. Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, are the main pathogens in late-onset (nosocomial) infections, especially in high-risk patients such as those with very low birthweight, umbilical or central venous catheters or undergoing prolonged ventilation. The primary objective of the paediatrician is to identity all potential cases of bacterial disease quickly and begin antibacterial treatment immediately after the appropriate cultures have been obtained. Combination therapy is recommended for initial empirical treatment in the neonate. In early-onset infections, an effective first-line empirical therapy is ampicillin plus an aminoglycoside (duration of treatment 10 days). An alternative is ampicillin plus a third-generation cephalosporin such as cefotaxime, a combination particularly useful in neonatal meningitis (mean duration of treatment 14 to 21 days), in patients at risk of nephrotoxicity and/or when therapeutic monitoring of aminoglycosides is not possible. Another potential substitute for the aminoglycoside is aztreonam. Triple combination therapy (such as amoxicillin plus cefotaxime and an aminoglycoside) could also be used for the first 2 to 3 days of life, followed by dual therapy after the microbiological results. In late-onset infections the combination oxacillin plus an aminoglycoside is widely recommended. However, vancomycin plus ceftazidime (+/- an aminoglycoside for the first 2 to 3 days) may be a better choice. Teicoplanin may be a substitute for vancomycin. However, the initial approach should always be modified by knowledge of the local bacterial epidemiology. After the microbiological results, treatment should be switched to narrower spectrum agents if a specific organism has been identified, and should be discontinued if cultures are negative and the neonate is in good clinical condition. Penicillins and third-generation cephalosporins are generally well tolerated in neonates. There is controversy regarding whether therapeutic drug monitoring of aminoglycosides will decrease toxicity (particularly renal damage) in neonates, and on the efficacy and safety of a single daily dose versus multiple daily doses of these drugs. Toxic effects caused by vancomycin are uncommon, but debate still exists over the need for therapeutic drug monitoring of this agent. When antibacterials are used in neonates, accurate determination of dosage is required, particularly for compounds with a low therapeutic index and in patients with renal failure. Very low birthweight infants are also particularly prone to antibacterial-induced toxicity.
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Affiliation(s)
- V Fanos
- Paediatric Department, University of Verona, Italy.
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35
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Abstract
Very few studies have been carried out looking at how the effects of drugs and their toxicity in humans change during their lifespan (developing and ageing). The purpose of this study is to review the literature on the changes in probe-drug metabolism, classified by cytochrome P450 (P450 or CYP) at five stages in life: neonates < 4 weeks, infants < 12 months, children < 19 years, young/mature adults 20-64 years, and elderly adults > 65 years. The main probe drugs include caffeine and theophylline, whose metabolism is catalysed by CYP1A2, tolbutamide, phenytoin and ibuprofen, catalysed by CYP2C9, amitriptyline and nortriptyline, catalysed by CYP2C19, acetaminophen, catalysed by CYP2E1 and lidocaine, midazolam and terfenadine, catalysed by 3A3/4. From the published in vivo studies two different patterns of drug metabolism can be identified: (i) activity is low immediately after birth, increases, then peaks at the young/mature adult level and, finally, decreases in old age (drugs catalysed by CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A3/4) and (ii) activity increases rapidly after birth to reach a level equivalent to that in the young/mature adult, then gradually decreases and finally decreasing faster in old age (drugs catalysed by CYP2E1). Further study of the changes in P450 with age is warranted to help prevent adverse reactions and to guide us in tailoring therapy better for the individual patient.
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Affiliation(s)
- E Tanaka
- Institute of Community Medicine, University of Tsukuba, Ibaraki-ken, Japan.
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36
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Renwick AG. Toxicokinetics in infants and children in relation to the ADI and TDI. FOOD ADDITIVES AND CONTAMINANTS 1998; 15 Suppl:17-35. [PMID: 9602909 DOI: 10.1080/02652039809374612] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Age-dependent developmental changes in toxicokinetics occur in both rats and humans, particularly in relation to renal function and hepatic xenobiotic metabolism. These processes are immature in humans at birth, especially in the pre-term neonate, but mature rapidly over the first months of life. In consequence the duration of immaturity primarily corresponds to the period of suckling. Similar developmental changes occur in the neonatal rat over the first weeks of life. Rat pups start to consume some of the adult diet in the third week of life, prior to weaning, so that there is a potential for consumption of the adult diet during the period of immaturity. There is an extensive database on the pharmacokinetics of therapeutic drugs in infants and children. The elimination/clearance of many drugs is higher in children than in adults and this difference would apply to other xenobiotics. In consequence, children frequently will have lower body burdens than adults for the same daily intake of a chemical when this is expressed on a body weight basis, as used to describe the ADI (Acceptable Daily Intake) or TDI (Tolerable Daily Intake) (e.g. mg/kg body weight/day). Therefore, an increased safety or uncertainty factor for post-suckling infants and children is not required in relation to age-related differences in toxicokinetics. Indeed, the higher clearance of many xenobiotics (toxicokinetics) by children compared with adults may compensate, at least in part, for increased organ sensitivity (toxicodynamics) during development.
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Affiliation(s)
- A G Renwick
- Clinical Pharmacology Group, University of Southampton, UK
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37
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Ramamoorthy C, Anderson GD, Williams GD, Lynn AM. Pharmacokinetics and side effects of milrinone in infants and children after open heart surgery. Anesth Analg 1998; 86:283-9. [PMID: 9459233 DOI: 10.1097/00000539-199802000-00011] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
UNLABELLED We investigated the pharmacokinetics and side effects of milrinone in infants and children (< or = 13 yr) after open heart surgery in this prospective, open-label study. Milrinone binding to cardiopulmonary bypass (CPB) circuitry was also examined in out two groups. Children in the small dose group (n = 11) received two 25-microg/kg boluses with a final infusion rate of 0.5 microg kg(-1) x min(-1); those in the large dose group (n = 8) received a 50-microg/kg bolus and a 25-microg/kg bolus with a final infusion rate of 0.75 microg x kg(-1) x min(-1). Blood samples for milrinone concentration were drawn 30 min after each bolus, at steady state, and after discontinuing the milrinone infusion. Pharmacokinetics were evaluated using traditional and nonlinear mixed effects modeling analysis. Milrinone kinetics best fit a two-compartment model. Steady-state plasma levels in the small and large dose groups were within the adult therapeutic range (113 +/- 39 and 206 +/- 74 ng/mL, respectively). The volumes of distribution (Vbeta) in infants (0.9 L/kg) and children (0.7 L/kg) were not different, but infants had significantly lower milrinone clearance (3.8 vs 5.9 mL x kg(-1) x min(-1)). Thrombocytopenia (defined as platelet count < or = 100,000 mm(-3)) occurred in 58%, and the risk increased significantly with duration of infusion. Tachyarrythmias were noted in two patients. Milrinone did not bind to CPB circuitry. We conclude that milrinone is cleared more rapidly in children than in adults. The major complication was thrombocytopenia. IMPLICATIONS Most pediatric dosing is based on data published for adults. Infants and children have kinetics that differ from adults. We studied the distribution of I.V. milrinone in infants and children after open heart surgery. Milrinone had a larger volume of distribution and a faster clearance in infants and children than in adults, and dosing should be adjusted accordingly.
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Affiliation(s)
- C Ramamoorthy
- Department of Anesthesiology, University of Washington School of Medicine, Seattle, USA.
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Ramamoorthy C, Anderson GD, Williams GD, Lynn AM. Pharmacokinetics and Side Effects of Milrinone in Infants and Children After Open Heart Surgery. Anesth Analg 1998. [DOI: 10.1213/00000539-199802000-00011] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Sturgill MG, Lambert GH. Xenobiotic-induced hepatotoxicity: mechanisms of liver injury and methods of monitoring hepatic function. Clin Chem 1997. [DOI: 10.1093/clinchem/43.8.1512] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
AbstractXenobiotic-induced liver injury is a clinically important etiology of hepatic disease that, if not recognized, can lead to hepatic failure. In this article we discuss the mechanisms of xenobiotic-induced liver injury, various factors that can alter the risk and severity of injury, the clinical and laboratory manifestations of injury, and the methods used to detect the presence of injury and (or) functioning liver mass.
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Affiliation(s)
- Marc G Sturgill
- Department of Pharmacy Practice and Administration, Rutgers University College of Pharmacy, PO Box 789 William Levine Hall, Piscataway, NJ 08855-0789
- Division of Pediatric Pharmacology and Toxicology, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School, 681 Frelinghuysen Rd., PO Box 1179, Piscataway, NJ 08855-1179
| | - George H Lambert
- Division of Pediatric Pharmacology and Toxicology, University of Medicine and Dentistry of New Jersey–Robert Wood Johnson Medical School, 681 Frelinghuysen Rd., PO Box 1179, Piscataway, NJ 08855-1179
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Ito K, Niida Y, Sato J, Owada E, Ito K, Umetsu M. Pharmacokinetics of mefenamic acid in preterm infants with patent ductus arteriosus. ACTA PAEDIATRICA JAPONICA : OVERSEAS EDITION 1994; 36:387-91. [PMID: 7942001 DOI: 10.1111/j.1442-200x.1994.tb03207.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The pharmacokinetics of mefenamic acid (MA), 2 mg/kg, were studied in 17 preterm infants with symptomatic patent ductus arteriosus. They were given this dosage orally at 24 h intervals. There were marked inter-individual differences in some of the pharmacokinetic parameters after the first dose; peak plasma concentration (Cmax) varied from 1.2 to 6.1 micrograms/mL with a mean of 3.8 micrograms/mL, time to reach Cmax (tmax) varied from 2 to 18 h with a mean of 7.7 h and plasma half-life (t1/2) varied from 3.8 to 43.6 h with a mean of 18.7 h. The group of infants (10/17) who had ductus closure after the first dose had significantly lower clearance (P < 0.01), longer t1/2 (P < 0.01) and higher 24 h plasma concentration (P < 0.001) compared to the group of infants (7/17) who had no ductus closure after the first dose. It appeared that the plasma concentration of MA had to be above 2.0 micrograms/mL and maintained at this concentration for at least 12 h for MA associated with ductus closure in preterm infants to take effect. In view of the inter-individual variation of plasma MA concentration and the effective plasma concentration, we suggest that measurement of the plasma concentration should be done 24 h after the first dose. This might be useful for safe and effective therapy for infants with ductus closure failure after the first dose.
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Affiliation(s)
- K Ito
- Department of Pediatrics, Hokkaido Children's Hospital and Medical Center, Japan
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Ascalone V, Locatelli M, Malavasi B. Determination of diltiazem and its main metabolites in human plasma by automated solid-phase extraction and high-performance liquid chromatography: a new method overcoming instability of the compounds and interference problems. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1994; 657:133-40. [PMID: 7952059 DOI: 10.1016/0378-4347(94)80079-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
An automated sample preparation method, based on solid-phase extraction (SPE) was developed on an ASPEC-Gilson device and combined with HPLC for the determination of diltiazem and three of its metabolites in human plasma (N-desacetylmonodesmethyldiltiazem, N-monodesmethyldiltiazem, O-desacetyldiltiazem). A 1-ml volume of plasma is diluted with 0.5 ml of 0.1 M ammonium dihydrogen phosphate and the sample is automatically loaded onto a SPE silica (C18) column (100 mg); the column is flushed with two different solvents, then eluted with 0.5 ml of a 0.1 M ammonium dihydrogen phosphate-acetonitrile mixture (20:80, v/v) containing 0.06% of triethylamine. The eluate is evaporated to dryness and the residue reconstituted with a suitable solvent and injected onto a C8 silica column connected to a UV detector (lambda = 238 nm). This method overcomes problems caused by the partial instability of diltiazem and metabolites in human plasma during analysis. There is no chromatographic interference from endogenous compounds. The limits of quantitation (LOQ) are 2.5 and 2 ng ml-1 for diltiazem and the metabolites in human plasma, respectively. Linearity between concentrations and detector response for diltiazem and metabolites ranged from 10-200 and 5-100 ng ml-1 in human plasma, respectively. The method has been validated.
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Affiliation(s)
- V Ascalone
- Synthélabo Recherche, Department of Chemical and Pharmaceutical Development, Clinical Pharmacokinetics Group of Milan, Limito (MI), Italy
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Dionne R, McManus C. Pediatric Critical Care Pharmacodynamics. Crit Care Nurs Clin North Am 1993. [DOI: 10.1016/s0899-5885(18)30575-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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McNamara PJ, Burgio D, Yoo SD. Pharmacokinetics of acetaminophen, antipyrine, and salicylic acid in the lactating and nursing rabbit, with model predictions of milk to serum concentration ratios and neonatal dose. Toxicol Appl Pharmacol 1991; 109:149-60. [PMID: 2038745 DOI: 10.1016/0041-008x(91)90198-n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The rabbit was utilized for examining the pharmacokinetics of three compounds (acetaminophen, AC; antipyrine, AN; and salicylic acid, SA) in nursing adults and their suckling offspring and for assessing the ability of a diffusional model to predict milk to serum drug concentration ratios (M/S) from in vitro experiments. AC, AN, and SA serum concentration time profiles declined monoexponentially for both adults and their pups. The mean systemic clearance (Cls) for AC in the adults and pups was 16.1 and 13.7 ml/min/kg, respectively. The mean half-lives of AC (t1/2) were 25.5 and 33.3 min in the adult and pup groups, respectively. AN declined in parallel for adult rabbits and an older group of suckling pups (23-25 days old). In a younger group of pups (18-21 days old) it declined with a longer t1/2 (97.5, 95.1, and 347.6 min in the adults, older pups, and younger pups, respectively). The mean AN Cls in the adults, the older pups, and the younger pups was 5.34, 6.30, and 1.91 ml/min/kg, respectively. The time course of SA was prolonged in the suckling pups (t1/2 of 633 min in the pups vs 78.7 min in the adult). The mean Cls values in the adults and the pups were 1.05 and 0.27 ml/min/kg, respectively. The mean systemic clearance of unbound drug (Clu) for SA was 11.2 ml/min/kg in the adults and 0.92 ml/min/kg in the pups. The serum protein binding of AC and AN was limited, whereas the mean free fraction for SA was 9.7% in adult serum and 32.5% in pup serum. AC and AN in milk paralleled serum drug profiles; a time lag was noted for milk SA. M/S ratios were determined in vivo (M/Sobs; AN = 0.885, AC = 0.580, and SA = 0.125) using area under the milk and serum concentration time profiles. Predicted M/S values (M/Spred; AN = 0.779, AC = 0.578, and SA = 0.085) were calculated from in vitro measurements of the unbound fractions of drug in skim milk and serum, the skim to whole milk drug concentration ratio, milk and serum pH, and the pKa of the model compound. Mean values for M/Sobs were highly correlated with M/Spred values (r2 = 0.976) when the present data were combined with previous data for propranolol, phenobarbital, phenytoin, and diazepam (Fleishaker, J.C., and McNamara, P.J., J. Pharmacol. Exp. Ther. 244, 919, 1988). These results support the usefulness of the diffusional model for predicting M/S in vivo, provided that the distributional process is governed by passive diffusion.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- P J McNamara
- Division of Pharmacology and Experimental Therapeutics, College of Pharmacy, University of Kentucky, Lexington 40536
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