scholarly journals 66. Utilizing ceftazidime/avibactam therapeutic drug monitoring in the treatment of neurosurgical meningitis caused by Difficult-to-treat resistant (DTR)-Pseudomonas aeruginosa and KPC-producing Enterobacterales

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S44-S45
Author(s):  
Mohamad Yasmin ◽  
Amir nutman ◽  
Lu Wang ◽  
Steven Marshall ◽  
Dafna Yahav ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Therapeutic Drug Monitoring ◽  
Human Plasma ◽  
Drug Monitoring ◽  
Therapeutic Drug ◽  
Bacterial Identification ◽  
Research Support ◽  
Bacterial Killing ◽  
Dosing Interval ◽  
Cns Infections

Abstract Background Central nervous system (CNS) infections caused by carbapenem-resistant Enterobacterales (CRE) and Difficult-to-treat resistant (DTR)-Pseudomonas aeruginosa (PA) are a therapeutic challenge. Data demonstrating the pharmacokinetic/pharmacodynamic (PK/PD) properties of newer beta-lactamase inhibitors remains scarce. A clinical challenge lies in selecting an antimicrobial regimen that diffuses across the blood brain barrier and maintains concentrations to achieve PD targets associated with bacterial killing. These complexities compelled us to quantify the pharmacological properties of ceftazidime/avibactam (CZA). Utilizing therapeutic drug monitoring (TDM), we evaluated the adequacy of therapy and aimed to guide precise CNS dosing in the treatment of three patients with neurosurgical meningitis. Methods Bacterial identification and susceptibility testing were performed using MicroScan. TDM of CZA was implemented using a dose of 2.5 g infused intravenously over 2-hours, every 8 hours. The concentrations of ceftazidime and avibactam were determined by liquid chromatography/mass spectrometry. For patients 2 and 3, four unique CSF and plasma samples spanning the dosing interval were obtained; including trough values. (See table) Results Bacterial identification and CZA MICs for patients 1, 2, and 3 revealed blaKPCKp (0.25μg/mL), DTR PA (4 μg/mL), and blaKPCE. cloacae (0.25 μg/mL), respectively. Measured plasma and CSF concentrations of avibactam (AVI) and ceftazidime (CAZ) are shown in Table 1. Table 1a. Therapeutic Drug Monitoring of CAZ-AVI depicting dosing, time of samples, and measured concentrations in CSF and Human Plasma (HP) Table 1b. Therapeutic Drug Monitoring of CAZ-AVI concentrations in CSF and Human Plasma (HP) pertaining to patient 2 and 3 Conclusion Measuring CZA concentration levels in CSF was achieved in 3 patients with complicated CNS infections. Post-infusion concentrations indicated that adequate CAZ and AVI exposures were attained in the CSF. Notably, avibactam was shown to achieve concentrations ≥1 µg/ml in the CSF throughout the dosing interval. For avibactam and ceftazidime, the PK/PD target correlated with bacterial killing is ~50% fT >MIC. In 2 out of 3 patients, concentrations were determined to be above the respective MICs throughout the entire dosing interval in the CSF. All patients attained clinical and microbiological cure. A novel CZA TDM method was successfully employed to establish that CZA maintains therapeutic CSF concentrations that exceed the MIC throughout the dosing interval. Disclosures Robert A. Bonomo, MD, entasis (Research Grant or Support)Merck (Grant/Research Support)NIH (Grant/Research Support)VA Merit Award (Grant/Research Support)VenatoRx (Grant/Research Support)

scholarly journals 1111. Therapeutic Drug Monitoring of Colistin in Cerebrospinal Fluid in the Treatment of Neurosurgical Meningitis caused by Pseudomonas aeruginosa and KPC-producing Enterobacterales

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S647-S647
Author(s):  
Mohamad Yasmin ◽  
Amir nutman ◽  
Steven Marshall ◽  
Lu Wang ◽  
Ke Chen ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Drug Monitoring ◽  
External Ventricular Drain ◽  
Plasma Concentrations ◽  
Cns Infection ◽  
Therapeutic Drug ◽  
Pharmacokinetic Data ◽  
Research Support ◽  
Cns Infections

Abstract Background Central nervous system (CNS) infections caused by carbapenem-resistant Enterobacterales (CRE) and Difficult-to-treat resistant (DTR)-P. aeruginosa (PA) present a therapeutic dilemma. Therapies are limited due to antibiotic resistance and inadequate CNS diffusion. Intraventricular polymyxins are utilized in this setting despite a lack in pharmacokinetic data after CNS injection. We describe the utilization of intravenous and intrathecal polymyxin E [colistimethate (CMS)] therapeutic drug monitoring (TDM) in 3 cases of post-neurosurgical meningitis. Methods Bacterial identification and susceptibility testing were performed using MicroScan. TDM was employed by dosing CMS at 125,000 IU (i.e., 4.1 mg CBA or 10 mg) administered via external ventricular drain twice daily and 4.5 MIU (133.2 CBA or 360 mg) CMS administered over 30 minutes IV twice daily. Four pairs of CSF and blood samples were collected for each patient (Table 1). Samples were placed on ice to minimize in-vitro conversion of CMS to Colistin. Colistin binding in plasma and CSF was measured using ultracentrifugation. Concentrations of CMS and Colistin in CSF and human plasma were determined by liquid chromatography/mass spectrometry. Patients A, B and C received 20, 15, and 12 doses of CMS, respectively, prior to TDM. Results Bacterial cultures revealed DTR PA, blaKPCE. cloacae and blaOXA-48K. pneumoniae for patients A, B and C, respectively. Colistin minimum inhibitory concentrations (MIC) were 0.5 µg/ml, 0.125 µg/ml, and 0.125 µg/ml, respectively. The measured CSF and plasma concentrations of CMS, Colistin, and binding are shown in Table 1. Clinical resolution and microbiological cure were attained in all patients. Therapeutic Drug Monitoring of Unchanged CMS and Formed Colistin in CSF samples for patient A, B, and C Therapeutic Drug Monitoring of Unchanged CMS and Formed Colistin in Plasma Samples for patient A, B, and C Conclusion Favorable concentrations of formed Colistin and CMS in CSF were achieved in 3 patients with complicated CNS infection. To the best of our knowledge, this is the first study to report the binding of Colistin in CSF in humans. A TDM method was effectively applied to demonstrate that Colistin achieves and maintains the PK/PD target (fAUC/MIC) [ratio of area under the plasma concentration curve of unbound drug to MIC] that best correlates with killing activity. Overall, our results support intraventricular polymyxins for treating DTR Gram-negative CNS infections. Disclosures Robert A. Bonomo, MD, entasis (Research Grant or Support)Merck (Grant/Research Support)NIH (Grant/Research Support)VA Merit Award (Grant/Research Support)VenatoRx (Grant/Research Support)

scholarly journals Development and validation of a new HPLC method for valproic acid determination in human plasma and its application to a therapeutic drug monitoring study

2020 ◽  
Vol 66 (1) ◽  
Author(s):  
Emrah Dural ◽  
Seniha Çelebi ◽  
Aslı Bolayır ◽  
Burhanettin Çiğdem
Keyword(s):  
Valproic Acid ◽  
Therapeutic Drug Monitoring ◽  
Human Plasma ◽  
Drug Monitoring ◽  
High Performance ◽  
High Standard ◽  
Hplc Method ◽  
Therapeutic Drug ◽  
Recommended Treatment ◽  
Monitoring Study

The aim of this study was to develop a new, simple and reliable high performance liquid chromatography (HPLC) method for analysis of valproic acid (VPA) in human plasma and apply to it to a therapeutic drug monitoring study. Also, the relationship between plasma-VPA concentrations and the amount of VPA used by patients was aimed to be evaluated. Plasma samples (0.25 mL) were precipitated with the same volume of acetonitrile and after centrifugation, aliquots were applied to a C18 column (250 mm x 4.6 mm). Mobile phase was prepared with phosphate buffer and acetonitrile (47.5:52.5, v/v). The flow-rate was 1.2 mL/min. Accuracy was between -2.9 and 3.2% and precision was ≤6.6%. Method was specific and sensitive with a detection limit of 2.2 µg/mL and the average recovery was 94.3%. Calibration curve was linear (r2>0.9968) from 10 to 150 µg/mL. Plasma-VPA levels of the epileptic patient population (n=33) treated with VPA between 0.5 and 1.5 g/day were also determined. Patient plasma-VPA concentrations ranged from 2.9 to 166.4 µg/g/mL (56.3±38.8). High RSD% (68.8%) was observed in dose-rated plasma-VPA results. Moreover, VPA plasma levels were found to be outside the recommended treatment range in 30.3% of the patients examined. The procedure described was found to be relatively simple, precise, and applicable for routine therapeutic drug monitoring (TDM) especially in neurology clinics or in toxicology reference laboratories. The high standard deviation (SD) observed in the dose depended plasma-VPA values of the volunteers proved the importance of TDM during the use of this drug. The results showed that for rational drug use, it is important to identify individual polymorphisms in the CYP2C9, CYP2A6 and CYP2B6 subtypes responsible for VPA metabolism, and to rearrange drug doses taking these enzyme activities into account.

scholarly journals Simultaneous Quantification of Methotrexate and Its Metabolite 7-Hydroxy-Methotrexate in Human Plasma for Therapeutic Drug Monitoring

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Xinxin Ren ◽  
Zhipeng Wang ◽  
Yunlei Yun ◽  
Guangyi Meng ◽  
Xialan Zhang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Therapeutic Drug Monitoring ◽  
Human Plasma ◽  
Drug Monitoring ◽  
Internal Standard ◽  
Gradient Elution ◽  
Therapeutic Drug ◽  
Tandem Mass ◽  
The Matrix ◽  
Analytical Time

Objective. To establish and validate a simple, sensitive, and rapid liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the determination of methotrexate (MTX) and its major metabolite 7-hydroxy-methotrexate (7-OH-MTX) in human plasma. Method. The chromatographic separation was achieved on a Zorbax C18 column (3.5 μm, 2.1 × 100 mm) using a gradient elution with methanol (phase B) and 0.2% formic acid aqueous solution (phase A). The flow rate was 0.3 mL/min with analytical time of 3.5 min. Mass spectrometry detection was performed in a triple-quadruple tandem mass spectrometer under positive ion mode with the following mass transitions: m/z 455.1/308.1 for MTX, 471.0/324.1 for 7-OH-MTX, and 458.2/311.1 for internal standard. The pretreatment procedure was optimized with dilution after one-step protein precipitation. Results. The calibration range of methotrexate and 7-OH-MTX was 5.0-10000.0 ng/mL. The intraday and interday precision and accuracy were less than 15% and within ±15% for both analytes. The recovery for MTX and 7-OH-MTX was more than 90% and the matrix effect ranged from 97.90% to 117.60%. Conclusion. The method was successfully developed and applied to the routine therapeutic drug monitoring of MTX and 7-OH-MTX in human plasma.

A simple and automated online SPE-LC-MS/MS method for simultaneous determination of olanzapine, fluoxetine and norfluoxetine in human plasma and its application in therapeutic drug monitoring

RSC Advances ◽  
2015 ◽  
Vol 5 (43) ◽  
pp. 34342-34352 ◽  
Author(s):  
Yiran Fan ◽  
Guanghu Shen ◽  
Ping Li ◽  
Xiaonan Xi ◽  
Haiting Wu ◽  
...  
Keyword(s):  
Therapeutic Drug Monitoring ◽  
Simultaneous Determination ◽  
Human Plasma ◽  
Drug Monitoring ◽  
Sample Pretreatment ◽  
Therapeutic Drug ◽  
High Quality ◽  
Online Spe

An integration of sample pretreatment automation using online SPE technique could provide an easy to use, efficient, sensitive and high quality methods for TDM.

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