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Wade KC, Greenberg RG, Benjamin DK, Chen LLH, Vo B, Ang BL, Boutzoukas A, Zimmerman K, Clark RH, Cohen-Wolkowiez M, Le J. Postdiscontinuation Antibiotic Exposure in Hospitalized Infants at Risk for Late-onset Sepsis in the Neonatal Intensive Care Unit. Pediatr Infect Dis J 2024; 43:991-996. [PMID: 38900075 PMCID: PMC11408093 DOI: 10.1097/inf.0000000000004426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
BACKGROUND In the neonatal intensive care unit, infants are at risk for late-onset sepsis. When blood cultures are negative, antibiotic stewardship efforts encourage stopping antibiotics, yet the duration of therapeutic exposure after the last dose is unknown. METHODS This retrospective cohort study of simulated antibiotic exposures used published population pharmacokinetic models within drug-specific neonatal intensive care unit cohorts of preterm and term infants, postnatal age 7-60 days and exposed to cefepime, piperacillin-tazobactam or tobramycin. Monte Carlo simulations (NONMEM 7.3) were used to predict steady-state exposures after a 72-hour antibiotic course per Neofax dosing. Exposure was assessed relative to drug-specific minimum inhibitory concentration (MIC) targets between 1 and 16 mcg/mL for Pseudomonas and Enterobacteriaceae species. Postdiscontinuation antibiotic exposure (PDAE) was defined as the time from the last dose to when antibiotic concentration decreased below a specific MIC. RESULTS Piperacillin-tazobactam, cefepime and tobramycin cohorts included infants with median gestation age 29, 32 and 32 weeks and postnatal age 17, 19 and 15 days, respectively. The mean PDAE was 19-68 hours, depending on the specific antibiotic/MIC combination. PDAE was longer for infants <28 days old and preterm (vs. term) infants. Cefepime exhibited the longest mean PDAE of 68 hours for Enterobacteriaceae MIC 1. Piperacillin mean PDAE was 25 hours for Enterobacteriaceae MIC 8. Tobramycin had a short mean PDAE of 19 hours. CONCLUSIONS Piperacillin and cefepime exposures remained therapeutic long after the expected 8- to 12-hour dosing interval. PDAE is an important consideration for antibiotic stewardship among hospitalized infants, particularly premature infants and those within 1 month postbirth.
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Affiliation(s)
- Kelly C Wade
- From the Department of Pediatrics, University of Pennsylvania School of Medicine
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Rachel G Greenberg
- Department of Pediatrics, Duke University Medical Center
- Duke Clinical Research Institute, Durham, North Carolina
| | - Daniel K Benjamin
- Department of Pediatrics, Duke University Medical Center
- Duke Clinical Research Institute, Durham, North Carolina
| | - Lydia Li-Hui Chen
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, California
| | - Brandon Vo
- University of California Riverside, Riverside, California
| | - Berwyn Liselle Ang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, California
| | - Angelique Boutzoukas
- Department of Pediatrics, Duke University Medical Center
- Duke Clinical Research Institute, Durham, North Carolina
| | - Kanecia Zimmerman
- Department of Pediatrics, Duke University Medical Center
- Duke Clinical Research Institute, Durham, North Carolina
| | - Reese H Clark
- MEDNAX Center for Research, Education, Quality, and Safety, Sunrise, Florida
| | - Michael Cohen-Wolkowiez
- Department of Pediatrics, Duke University Medical Center
- Duke Clinical Research Institute, Durham, North Carolina
| | - Jennifer Le
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, La Jolla, California
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2
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Therapeutic drug monitoring of antimicrobial drugs in neonates. An opinion paper. Ther Drug Monit 2021; 44:65-74. [PMID: 34369442 PMCID: PMC8994040 DOI: 10.1097/ftd.0000000000000919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 06/29/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE Neonatal infections are associated with high morbidity and mortality rates. Optimal treatment of these infections requires knowledge of neonatal pharmacology and integration of neonatal developmental pharmacokinetics of antimicrobial drugs in the design of dosing regimens for use with different gestational and postnatal ages. Population pharmacokinetic (PK) and pharmacodynamic (PD) models are used to personalize the use of these drugs in these fragile patients. The final step to further minimize variability in an individual patient is therapeutic drug monitoring (TDM), where the same population PK/PD models are used in concert with optimally drawn blood samples to further fine-tune therapy. The purpose of this manuscript is to describe the present status and future role of model-based precision dosing and TDM of antimicrobial drugs in neonates. METHODS PubMed was searched for clinical trials or clinical studies of TDM in neonates. RESULTS A total of 447 papers were retrieved, of which 19 were concerned with antimicrobial drugs. Two papers (one aminoglycoside and one vancomycin) addressed the effects of TDM in neonates. We found that, in addition to aminoglycosides and vancomycin, TDM also plays a role in beta-lactam antibiotics and antifungal drugs. CONCLUSION There is a growing awareness that, in addition to aminoglycosides and vancomycin, the use of beta-lactam antibiotics, such as amoxicillin and meropenem, and other classes of antimicrobial drugs, such as antifungal drugs, may benefit from TDM. However, the added value must be shown. New analytical techniques and software development may greatly support these novel developments.
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Assessing Predictive Performance of Published Population Pharmacokinetic Models of Intravenous Tobramycin in Pediatric Patients. Antimicrob Agents Chemother 2016; 60:3407-14. [PMID: 27001806 DOI: 10.1128/aac.02654-15] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/11/2016] [Indexed: 11/20/2022] Open
Abstract
Several population pharmacokinetic models describe the dose-exposure relationship of tobramycin in pediatric patients. Before the implementation of these models in clinical practice for dosage adjustment, their predictive performance should be externally evaluated. This study tested the predictive performance of all published population pharmacokinetic models of tobramycin developed for pediatric patients with an independent patient cohort. A literature search was conducted to identify suitable models for testing. Demographic and pharmacokinetic data were collected retrospectively from the medical records of pediatric patients who had received intravenous tobramycin. Tobramycin exposure was predicted from each model. Predictive performance was assessed by visual comparison of predictions to observations, by calculation of bias and imprecision, and through the use of simulation-based diagnostics. Eight population pharmacokinetic models were identified. A total of 269 concentration-time points from 41 pediatric patients with cystic fibrosis were collected for external evaluation. Three models consistently performed best in all evaluations and had mean errors ranging from -0.4 to 1.8 mg/liter, relative mean errors ranging from 4.9 to 29.4%, and root mean square errors ranging from 47.8 to 66.9%. Simulation-based diagnostics supported these findings. Models that allowed a two-compartment disposition generally had better predictive performance than those that used a one-compartment disposition model. Several published models of the pharmacokinetics of tobramycin showed reasonable low levels of bias, although all models seemed to have some problems with imprecision. This suggests that knowledge of typical pharmacokinetic behavior and patient covariate values alone without feedback concentration measurements from individual patients is not sufficient to make precise predictions.
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Wilbaux M, Fuchs A, Samardzic J, Rodieux F, Csajka C, Allegaert K, van den Anker JN, Pfister M. Pharmacometric Approaches to Personalize Use of Primarily Renally Eliminated Antibiotics in Preterm and Term Neonates. J Clin Pharmacol 2016; 56:909-35. [PMID: 26766774 DOI: 10.1002/jcph.705] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/05/2016] [Accepted: 01/06/2016] [Indexed: 12/13/2022]
Abstract
Sepsis remains a major cause of mortality and morbidity in neonates, and, as a consequence, antibiotics are the most frequently prescribed drugs in this vulnerable patient population. Growth and dynamic maturation processes during the first weeks of life result in large inter- and intrasubject variability in the pharmacokinetics (PK) and pharmacodynamics (PD) of antibiotics. In this review we (1) summarize the available population PK data and models for primarily renally eliminated antibiotics, (2) discuss quantitative approaches to account for effects of growth and maturation processes on drug exposure and response, (3) evaluate current dose recommendations, and (4) identify opportunities to further optimize and personalize dosing strategies of these antibiotics in preterm and term neonates. Although population PK models have been developed for several of these drugs, exposure-response relationships of primarily renally eliminated antibiotics in these fragile infants are not well understood, monitoring strategies remain inconsistent, and consensus on optimal, personalized dosing of these drugs in these patients is absent. Tailored PK/PD studies and models are useful to better understand relationships between drug exposures and microbiological or clinical outcomes. Pharmacometric modeling and simulation approaches facilitate quantitative evaluation and optimization of treatment strategies. National and international collaborations and platforms are essential to standardize and harmonize not only studies and models but also monitoring and dosing strategies. Simple bedside decision tools assist clinical pharmacologists and neonatologists in their efforts to fine-tune and personalize the use of primarily renally eliminated antibiotics in term and preterm neonates.
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Affiliation(s)
- Mélanie Wilbaux
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland
| | - Aline Fuchs
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland
| | - Janko Samardzic
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland.,Institute of Pharmacology, Clinical Pharmacology and Toxicology, Medical Faculty, University of Belgrade, Belgrade, Serbia
| | - Frédérique Rodieux
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland
| | - Chantal Csajka
- Division of Clinical Pharmacology, Service of Biomedicine, Department of Laboratory, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.,Department of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
| | - Karel Allegaert
- Department of Development and Regeneration, KU Leuven, Belgium.,Intensive Care and Department of Surgery, Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Johannes N van den Anker
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland.,Intensive Care and Department of Surgery, Erasmus Medical Center-Sophia Children's Hospital, Rotterdam, The Netherlands.,Division of Clinical Pharmacology, Children's National Health System, Washington, DC, USA
| | - Marc Pfister
- Division of Paediatric Pharmacology and Pharmacometrics, University of Basel Children's Hospital, Basel, Switzerland.,Quantitative Solutions LP, Menlo Park, CA, USA
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Marsot A, Boulamery A, Bruguerolle B, Simon N. Population pharmacokinetic analysis during the first 2 years of life: an overview. Clin Pharmacokinet 2013. [PMID: 23179579 DOI: 10.1007/s40262-012-0015-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Three decades after its introduction, pharmacokinetic population approaches have become a reference method for drug modelling, particularly in paediatrics. The main practical limitation in this specific population is the collected blood volume. Pharmacokinetic population approaches using sparse sampling may resolve this issue. The pharmacokinetics of many drugs have been studied during the last 25 years using such methods. This review summarizes all of the published studies concerning population pharmacokinetic approaches in paediatric subjects from neonate to 2 years old. A literature search was conducted using the PubMed database, from 1985 to December 2010, using the following terms: pharmacokinetic(s), population, paediatric/pediatric and neonate(s). Articles were excluded if they were not pertinent according to our criteria. References of all relevant articles were also evaluated. Ninety-eight studies were included in this review. The following information was extracted from the articles: drug name, therapeutic class, population size, age of patients, number of samples per patient, covariates used for clearance and volume of distribution estimates, software used for modelling and validation methods. An increasing rate of publications over the years was observed; 44 different drugs were studied using a pharmacokinetic population approach. Antibacterials were the most studied class of drugs, including a large number of studies devoted to vancomycin and gentamicin. It must be underlined that few studies have been performed on anticonvulsant drugs and anaesthetics used in clinical daily practice conditions.
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Affiliation(s)
- Amélie Marsot
- Service de Pharmacologie Médicale et Clinique, Aix Marseille Université, France.
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Newman JC, Prange T, Jennings S, Barlow BM, Davis JL. Pharmacokinetics of tobramycin following intravenous, intramuscular, and intra-articular administration in healthy horses. J Vet Pharmacol Ther 2013; 36:532-41. [DOI: 10.1111/jvp.12048] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 02/25/2013] [Indexed: 11/30/2022]
Affiliation(s)
- J. C. Newman
- Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC USA
| | - T. Prange
- Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC USA
| | - S. Jennings
- Department of Population Health and Pathobiology; College of Veterinary Medicine; North Carolina State University; Raleigh NC USA
| | - B. M. Barlow
- Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC USA
| | - J. L. Davis
- Department of Clinical Sciences; College of Veterinary Medicine; North Carolina State University; Raleigh NC USA
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Touw DJ, Westerman EM, Sprij AJ. Therapeutic drug monitoring of aminoglycosides in neonates. Clin Pharmacokinet 2009; 48:71-88. [PMID: 19271781 DOI: 10.2165/00003088-200948020-00001] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The efficacy and toxicity of aminoglycosides show a strong direct positive relationship with blood drug concentrations, therefore, therapy with aminoglycosides in adults is usually guided by therapeutic drug monitoring. Dosing regimens in adults have evolved from multiple daily dosing to extended-interval dosing. This evolution has also taken place in neonates. Neonates, however, display large interindividual differences in the pharmacokinetics of aminoglycosides due to developmental differences early in life. The volume of distribution of aminoglycosides shows a strong relationship with bodyweight, which tends to be larger (corrected for bodyweight) in more premature infants and those with sepsis. Renal clearance of aminoglycosides increases with gestational age and accelerates immediately after birth. Because of these developmental influences, there is great inter- and intraindividual variability in the volume of distribution and clearance of these drugs, and investigators have established aminoglycoside dosing regimens based on bodyweight and/or gestational age. Widely practised dosing regimens comprise 4-5 mg/kg bodyweight of gentamicin every 24-48 hours as a first dose, followed by dose adjustment based on therapeutic drug monitoring. Although formal toxicity studies are scarce, there is no evidence that aminoglycoside toxicity in neonates differs from that in adults. Monitoring of blood drug concentrations and intelligent reconstruction of individual pharmacokinetic behaviour using a population pharmacokinetic model, optimally chosen blood sampling times and appropriate pharmacokinetic software, help clinicians to quickly optimize aminoglycoside dosing regimens to maximize the clinical effect and minimize the toxicity of these drugs.
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Würthwein G, Groll AH, Hempel G, Adler-Shohet FC, Lieberman JM, Walsh TJ. Population pharmacokinetics of amphotericin B lipid complex in neonates. Antimicrob Agents Chemother 2006; 49:5092-8. [PMID: 16304177 PMCID: PMC1315949 DOI: 10.1128/aac.49.12.5092-5098.2005] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The pharmacokinetics of amphotericin B lipid complex (ABLC) were investigated in neonates with invasive candidiasis enrolled in a phase II multicenter trial. Sparse blood (153 samples; 1 to 9 per patient, 1 to 254 h after the dose) and random urine and cerebrospinal fluid (CSF) samples of 28 neonates (median weight [WT], 1.06 kg; range, 0.48 to 4.9 kg; median gestational age, 27 weeks; range, 24 to 41 weeks) were analyzed. Patients received intravenous ABLC at 2.5 (n = 15) or 5 (n = 13) mg/kg of body weight once a day over 1 or 2 h, respectively, for a median of 21 days (range, 4 to 47 days). Concentrations of amphotericin B were quantified as total drug by high-performance liquid chromatography. Blood data for time after dose (TAD) of <24 h fitted best to a one-compartment model with an additive-error model for residual variability, WT0.75 (where 0.75 is an exponent) as a covariate of clearance (CL), and WT as a covariate of volume of distribution (V). Prior amphotericin B, postnatal age, and gestational age did not further improve the model. The final model equations were CL (liters/h) = 0.399 x WT(0.75) (interindividual variability, 35%) and V (liters) = 10.5 x WT (interindividual variability, 43%). Noncompartmental analysis of pooled data with a TAD of >24 h revealed a terminal half-life of 395 h. Mean concentrations in the urine after 1, 2, and 3 weeks ranged from 0.082 to 0.430 microg/ml, and those in CSF ranged from undetectable to 0.074 microg/ml. The disposition of ABLC in neonates was similar to that observed in other age groups: weight was the only factor that influenced clearance. Based on these results and previously published safety and efficacy data, we recommend a daily dosage between 2.5 and 5.0 mg/kg for treatment of invasive Candida infections in neonates.
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Affiliation(s)
- Gudrun Würthwein
- Infectious Disease Research Program, Center for Bone Marrow Transplantation and Department of Pediatric Hematology/Oncology, Children's University Hospital, Muenster, Federal Republic of Germany
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Inclan G, Suarez E, Calvo R, Aguirre C, Macheras P, Gazouli M, Lukas JC. Bicompartmental kinetics of tobramycin analysed with a wide range of covariates. Int J Antimicrob Agents 2005; 26:304-11. [PMID: 16168626 DOI: 10.1016/j.ijantimicag.2005.05.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2005] [Accepted: 05/10/2005] [Indexed: 11/29/2022]
Abstract
The pharmacokinetics of tobramycin was studied in adult patients (N = 151) admitted either for initial suspicion of Gram-negative infection or for prophylaxis. In addition to age, weight, height and creatinine clearance (CrCL), a range of other covariates were also analysed, including type of pathology, co-medication, fever, sex and ethnicity (Basque or not). All patients received 100mg tobramycin every 8 h and samples were collected at three time points after the first dose and at two time points after the fourth dose and assayed with a fluorescence polarisation immunoassay. The population mixed effects bicompartmental parameters were obtained from 725 concentration measurements using NONMEM, FOCE method, and were: systemic clearance, CL = 6.03 L/h (between-subject coefficient of variation (CV) %, 29.4%); volume of distribution, V = 15.04 L (7.3%); and intercompartmental constants, k(12) = 0.192 h(-1) (56%) and k(21) = 0.55 h(-1) (no CV% determined). Covariate modelling was performed within NONMEM. Two alternative significant covariate models (Models 1 and 2) are proposed, with functions of CrCL and/or sex (Model 2). However, for clinical purposes, differentiation by sex is insignificant. Model 1 is for CL = 3.1 + 0.05.CrCLL/h (17.3%); V = 14.6 L (12%); k(12) = 0.224 h(-1) (63%) and k(21) = 0.468 h(-1). Stochastic simulation was used to predict the expected concentration 95th percentiles after the recommended 7 mg/kg dose and for minimum inhibitory concentration (MIC) = 1 mg/L, as well as alternative once-daily dosing regimens for MIC = 2 mg/L. It is seen that once-daily high-dose tobramycin is an appropriate strategy with respect to pharmacodynamic indices, C(peak)/MIC or AUC/MIC (where C(peak) is the peak plasma concentration and AUC is the area under the concentration-time curve).
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Affiliation(s)
- Gabriel Inclan
- Galdakao Hospital, Internal Medicine Service, Vizcaya, Spain
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Kimura T, Sunakawa K, Matsuura N, Kubo H, Shimada S, Yago K. Population pharmacokinetics of arbekacin, vancomycin, and panipenem in neonates. Antimicrob Agents Chemother 2004; 48:1159-67. [PMID: 15047516 PMCID: PMC375245 DOI: 10.1128/aac.48.4.1159-1167.2004] [Citation(s) in RCA: 59] [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
Immature renal function in neonates requires antibiotic dosage adjustment. Population pharmacokinetic studies were performed to determine the optimal dosage regimens for three types of antibiotics: an aminoglycoside, arbekacin; a glycopeptide, vancomycin; and a carbapenem, panipenem. Eighty-three neonates received arbekacin (n = 41), vancomycin (n = 19), or panipenem (n = 23). The postconceptional ages (PCAs) were 24.1 to 48.4 weeks, and the body weights (BWs) ranged from 458 to 5,200 g. A one-compartment open model with first-order elimination was applied and evaluated with a nonlinear mixed-effect model for population pharmacokinetic analysis. In the fitting process, the fixed effects significantly related to clearance (CL) were PCA, postnatal age, gestational age, BW, and serum creatinine level; and the fixed effect significantly related to the volume of distribution (V) was BW. The final formulas for the population pharmacokinetic parameters are as follows: CL(arbekacin) = 0.0238 x BW/serum creatinine level for PCAs of <33 weeks and CL(arbekacin) = 0.0367 x BW/serum creatinine level for PCAs of > or = 33 weeks, V(arbekacin) = 0.54 liters/kg, CL(vancomycin) = 0.0250 x BW/serum creatinine level for PCAs of <34 weeks and CL(vancomycin) = 0.0323 x BW/serum creatinine level for PCAs of > or = 34 weeks, V(vancomycin) = 0.66 liters/kg, CL(panipenem) = 0.0832 for PCAs of <33 weeks and CL(panipenem) = 0.179 x BW for PCAs of > or = 33 weeks, and V(panipenem) = 0.53 liters/kg. When the CL of each drug was evaluated by the nonlinear mixed-effect model, we found that the mean CL for subjects with PCAs of <33 to 34 weeks was significantly smaller than those with PCAs of > or = 33 to 34 weeks, and CL showed an exponential increase with PCA. Many antibiotics are excreted by glomerular filtration, and maturation of glomerular filtration is the most important factor for estimation of antibiotic clearance. Clinicians should consider PCA, serum creatinine level, BW, and chemical features when determining the initial antibiotic dosing regimen for neonates.
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Affiliation(s)
- Toshimi Kimura
- Department of Pharmacy, Kitasato University Hospital, 1-15-1 Kitasato, Sagamihara-shi, Kanagawa 228-8555, Japan.
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