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Himebauch AS, Sankar WN, Flynn JM, Sisko MT, Moorthy GS, Gerber JS, Zuppa AF, Fox E, Dormans JP, Kilbaugh TJ. Skeletal muscle and plasma concentrations of cefazolin during complex paediatric spinal surgery. Br J Anaesth 2018; 117:87-94. [PMID: 27317707 DOI: 10.1093/bja/aew032] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2015] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Surgical site infections (SSIs) can have devastating consequences for children who undergo spinal instrumentation. Prospective evaluations of prophylactic cefazolin in this population are limited. The purpose of this study was to describe the pharmacokinetics and skeletal muscle disposition of prophylactic cefazolin in a paediatric population undergoing complex spinal surgery. METHODS This prospective pharmacokinetic study included 17 children with adolescent idiopathic scoliosis undergoing posterior spinal fusion, with a median age of 13.8 [interquartile range (IQR) 13.4-15.4] yr and a median weight of 60.6 (IQR 50.8-66.0) kg. A dosing strategy consistent with published guidelines was used. Serial plasma and skeletal muscle microdialysis samples were obtained during the operative procedure and unbound cefazolin concentrations measured. Non-compartmental pharmacokinetic analyses were performed. The amount of time that the concentration of unbound cefazolin exceeded the minimal inhibitory concentration for bacterial growth for selected SSI pathogens was calculated. RESULTS Skeletal muscle concentrations peaked at a median of 37.6 (IQR 26.8-40.0) µg ml(-1) within 30-60 min after the first cefazolin 30 mg kg(-1) dose. For patients who received a second 30 mg kg(-1) dose, the peak concentrations reached a median of 40.5 (IQR 30.8-45.7) µg ml(-1) within 30-60 min. The target cefazolin concentrations for SSI prophylaxis for meticillin-sensitive Staphylococcus aureus (MSSA) and Gram-negative pathogens were exceeded in skeletal muscle 98.9 and 58.3% of the intraoperative time, respectively. CONCLUSIONS For children with adolescent idiopathic scoliosis undergoing posterior spinal fusion, the cefazolin dosing strategy used in this study resulted in skeletal muscle concentrations that were likely not to be effective for intraoperative SSI prophylaxis against Gram-negative pathogens.
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Affiliation(s)
- A S Himebauch
- Department of Anesthesiology and Critical Care Medicine Center for Clinical Pharmacology
| | - W N Sankar
- Department of Surgery, Division of Orthopedic Surgery
| | - J M Flynn
- Department of Surgery, Division of Orthopedic Surgery
| | - M T Sisko
- Department of Anesthesiology and Critical Care Medicine
| | | | - J S Gerber
- Department of Pediatrics, Division of Infectious Diseases
| | - A F Zuppa
- Department of Anesthesiology and Critical Care Medicine Center for Clinical Pharmacology
| | - E Fox
- Center for Clinical Pharmacology Department of Pediatrics, Division of Oncology, Perelman School of Medicine, University of Pennsylvania and The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - J P Dormans
- Division of Orthopedic Surgery, Texas Children's Hospital, Houston, TX 77030, USA
| | - T J Kilbaugh
- Department of Anesthesiology and Critical Care Medicine
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Koenig HC, Mounzer K, Daughtridge GW, Sloan CE, Lalley-Chareczko L, Moorthy GS, Conyngham SC, Zuppa AF, Montaner LJ, Tebas P. Urine assay for tenofovir to monitor adherence in real time to tenofovir disoproxil fumarate/emtricitabine as pre-exposure prophylaxis. HIV Med 2017; 18:412-418. [PMID: 28444867 DOI: 10.1111/hiv.12518] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is approved for pre-exposure prophylaxis (PrEP) against HIV infection. Adherence is critical for the success of PrEP, but current adherence measurements are inadequate for real-time adherence monitoring. We developed and validated a urine assay to measure tenofovir (TFV) to objectively monitor adherence to PrEP. METHODS We developed a urine assay using high-performance liquid chromatography coupled to tandem mass spectrometry with high sensitivity/specificity for TFV that allowed us to determine TFV concentrations in log10 categories between 0 and 10 000 ng/mL. We validated the assay in three cohorts: (1) HIV-positive subjects with undetectable viral loads on a TDF/FTC-based regimen, (2) healthy HIV-negative subjects who received a single dose of TDF/FTC, and (3) HIV-negative subjects receiving daily TDF/FTC as PrEP for 24 weeks. RESULTS The urine assay detected TFV with greater sensitivity than plasma-based measures and with a window of measurements within 7 days of the last TDF/FTC dose. Based on the urine log-linear clearance after the last dose and its concordance with all detectable plasma levels, a urine TFV concentration > 1000 ng/mL was identified as highly predictive of the presence of TFV in plasma at > 10 ng/mL. The urine assay was able to distinguish high and low adherence patterns within the last 48 h (> 1000 ng/mL versus 10-1000 ng/mL), as well as nonadherence (< 10 ng/mL) extended over at least 1 week prior to measurement. CONCLUSIONS We provide proof of concept that a semiquantitative urine assay measuring levels of TFV could be further developed into a point-of-care test and be a useful tool to monitor adherence to PrEP.
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Affiliation(s)
- H C Koenig
- Philadelphia FIGHT, Philadelphia, PA, USA.,Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - K Mounzer
- Philadelphia FIGHT, Philadelphia, PA, USA.,Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - G W Daughtridge
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - C E Sloan
- Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | | | - G S Moorthy
- Center for Clinical Pharmacology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - A F Zuppa
- Center for Clinical Pharmacology, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - P Tebas
- Division of Infectious Diseases, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Darwich AS, Ogungbenro K, Vinks AA, Powell JR, Reny JL, Marsousi N, Daali Y, Fairman D, Cook J, Lesko LJ, McCune JS, Knibbe CAJ, de Wildt SN, Leeder JS, Neely M, Zuppa AF, Vicini P, Aarons L, Johnson TN, Boiani J, Rostami-Hodjegan A. Why Has Model-Informed Precision Dosing Not Yet Become Common Clinical Reality? Lessons From the Past and a Roadmap for the Future. Clin Pharmacol Ther 2017; 101:646-656. [DOI: 10.1002/cpt.659] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 12/17/2022]
Affiliation(s)
- A S Darwich
- Centre for Applied Pharmacokinetic Research, Division of Pharmacy and Optometry; University of Manchester; Manchester UK
| | - K Ogungbenro
- Centre for Applied Pharmacokinetic Research, Division of Pharmacy and Optometry; University of Manchester; Manchester UK
| | - A A Vinks
- Cincinnati Children's Hospital Medical Center; Cincinnati Ohio USA
- Department of Pediatrics; University of Cincinnati School of medicine; Cincinnati Ohio USA
| | - J R Powell
- Eshelman School of Pharmacy; University of North Carolina; Chapel Hill North Carolina USA
| | - J-L Reny
- Geneva Platelet Group, School of Medicine; University of Geneva; Geneva Switzerland
- Department of Internal Medicine, Rehabilitation and Geriatrics; Geneva University Hospitals; Geneva Switzerland
| | - N Marsousi
- Clinical Pharmacology and Toxicology; Geneva University Hospitals; Geneva Switzerland
| | - Y Daali
- Geneva Platelet Group, School of Medicine; University of Geneva; Geneva Switzerland
- Clinical Pharmacology and Toxicology; Geneva University Hospitals; Geneva Switzerland
| | - D Fairman
- Clinical Pharmacology Modeling and Simulation, GSK Stevenage; UK
| | - J Cook
- Clinical Pharmacology, Pfizer Inc; Groton Connecticut USA
| | - L J Lesko
- Department of Pharmaceutics, Center for Pharmacometrics and Systems Pharmacology; University of Florida at Lake Nona (Orlando); Orlando Florida USA
| | - J S McCune
- University of Washington Department of Pharmaceutics and Fred Hitchinson Cancer Research Center Clinical Research Division; Seattle Washington USA
| | - C A J Knibbe
- Department of Clinical Pharmacy, St. Antonius Hospital, Nieuwegein, the Netherlands and Division of Pharmacology, Leiden Academic Centre for Drug Research; Leiden University; the Netherlands
| | - S N de Wildt
- Department of Pharmacology and Toxicology; Radboud University; Nijmegen the Netherlands
- Intensive Care and Department of Pediatric Surgery, Erasmus MC Sophia Children's Hospital; Rotterdam the Netherlands
| | - J S Leeder
- Division of Pediatric Pharmacology and Medical Toxicology, Department of Pediatrics, Children's Mercy Hospitals and Clinics; Kansas City Missouri USA
- Department of Pharmacology; University of Missouri-Kansas City; Kansas City Missouri USA
| | - M Neely
- University of Southern California and the Children's Hospital of Los Angeles; Los Angeles California USA
| | - A F Zuppa
- Children's Hospital of Philadelphia; Philadelphia Pennsylvania USA
| | - P Vicini
- Clinical Pharmacology, Pharmacometrics and DMPK, MedImmune; Cambridge UK
| | - L Aarons
- Centre for Applied Pharmacokinetic Research, Division of Pharmacy and Optometry; University of Manchester; Manchester UK
| | - T N Johnson
- Certara, Blades Enterprise Centre; Sheffield UK
| | - J Boiani
- Epstein Becker & Green; Washington DC USA
| | - A Rostami-Hodjegan
- Centre for Applied Pharmacokinetic Research, Division of Pharmacy and Optometry; University of Manchester; Manchester UK
- Epstein Becker & Green; Washington DC USA
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Stricker PA, Gastonguay MR, Singh D, Fiadjoe JE, Sussman EM, Pruitt EY, Goebel TK, Zuppa AF. Population pharmacokinetics of ϵ-aminocaproic acid in adolescents undergoing posterior spinal fusion surgery. Br J Anaesth 2015; 114:689-99. [PMID: 25586726 DOI: 10.1093/bja/aeu459] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Despite demonstrated efficacy of ϵ-aminocaproic acid (EACA) in reducing blood loss in adolescents undergoing spinal fusion, there are no population-specific pharmacokinetic data to guide dosing. The aim of this study was to determine the pharmacokinetics of EACA in adolescents undergoing spinal fusion surgery and make dosing recommendations. METHODS Twenty children ages 12-17 years were enrolled, with 10 children in each of two groups based on diagnosis (idiopathic scoliosis or non-idiopathic scoliosis). Previously reported data from infants undergoing craniofacial surgery were included in the model to enable dosing recommendations over a wide range of weights, ages, and diagnoses. A population non-linear mixed effects modelling approach was used to characterize EACA pharmacokinetics. RESULTS Population pharmacokinetic parameters were estimated using a two-compartment disposition model with allometrically scaled weight and an age effect on clearance. Pharmacokinetic parameters for the typical patient were a plasma clearance of 153 ml min(-1) 70 kg(-1) (6.32 ml min(-1) kg(-0.75)), intercompartmental clearance of 200 ml min(-1) 70 kg(-1) (8.26 ml min(-1) kg(-0.75)), central volume of distribution of 8.78 litre 70 kg(-1) (0.13 litre kg(-1)), and peripheral volume of distribution of 15.8 litre 70 kg(-1) (0.23 litre kg(-1)). Scoliosis aetiology did not have a clinically significant effect on drug pharmacokinetics. CONCLUSIONS The following dosing schemes are recommended according to patient weight: weight <25 kg, 100 mg kg(-1) loading dose and 40 mg kg(-1) h(-1) infusion; weight ≤25 kg-<50 kg, 100 mg kg(-1) loading dose and 35 mg kg(-1) h(-1) infusion; and weight ≥50 kg, 100 mg kg(-1) loading dose and 30 mg kg(-1) h(-1) infusion. An efficacy trial employing this dosing strategy is warranted. CLINICAL TRIAL REGISTRATION NCT01408823.
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Affiliation(s)
- P A Stricker
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | | | - D Singh
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - J E Fiadjoe
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - E M Sussman
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - E Y Pruitt
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - T K Goebel
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - A F Zuppa
- Department of Anesthesiology and Critical Care Medicine, Division of Critical Care Medicine, Department of Pediatrics, Division of Clinical Pharmacology and Therapeutics, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Stricker PA, Zuppa AF, Fiadjoe JE, Maxwell LG, Sussman EM, Pruitt EY, Goebel TK, Gastonguay MR, Taylor JA, Bartlett SP, Schreiner MS. Population pharmacokinetics of epsilon-aminocaproic acid in infants undergoing craniofacial reconstruction surgery. Br J Anaesth 2013; 110:788-99. [PMID: 23353035 DOI: 10.1093/bja/aes507] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Understanding the clinical pharmacology of the antifibrinolytic epsilon-aminocaproic acid (EACA) is necessary for rational drug administration in children. The aim of this study is to determine the pharmacokinetics (PKs) of EACA in infants aged 6-24 months undergoing craniofacial reconstruction surgery. METHODS Cohorts of six infants were enrolled sequentially to one of the three escalating loading dose-continuous i.v. infusion (CIVI) regimens: 25 mg kg(-1), 10 mg kg(-1) h(-1); 50 mg kg(-1), 20 mg kg(-1) h(-1); 100 mg kg(-1), 40 mg kg(-1) h(-1). Plasma EACA concentrations were determined using a validated high-performance liquid chromatography-tandem mass spectrometry assay. A population non-linear mixed effects modelling approach was used to characterize EACA PKs. RESULTS Population PK parameters of EACA were estimated using a two-compartment disposition model with weight expressed as an allometric covariate and an age effect. The typical patient in this study had an age of 38.71 weeks and a weight of 8.82 kg. PK parameters for this typical patient were: pre-/postoperative plasma drug clearance of 32 ml min(-1) (3.6 ml kg(-1) min(-1)), inter-compartmental clearance of 42.4 ml min(-1) (4.8 ml min(-1) kg(-1)), central volume of distribution of 1.27 litre (0.14 litre kg(-1)), and peripheral volume of distribution of 2.53 litre (0.29 litre kg(-1)). Intra-operative clearance and central volume of distribution were 89% and 80% of the pre-/postoperative value, respectively. CONCLUSIONS EACA clearance increased with weight and age. The dependence of clearance on body weight supports weight-based dosing. Based on this study, a loading dose of 100 mg kg(-1) followed by a CIVI of 40 mg kg(-1) h(-1) is appropriate to maintain target plasma EACA concentrations in children aged 6-24 months undergoing these procedures.
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Affiliation(s)
- P A Stricker
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4399, USA
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