TY  - GEN
A1  - Wicha, Sebastian G.
A1  - Kees, Martin G.
A1  - Solms, Alexander Maximilian
A1  - Minichmayr, Iris K.
A1  - Kratzer, Alexander
A1  - Kloft, Charlotte
T1  - TDMx: A novel web-based open-access support tool for optimising antimicrobial dosing regimens in clinical routine
T2  - International journal of antimicrobial agents
Y1  - 2015
U6  - https://doi.org/10.1016/j.ijantimicag.2014.12.010
SN  - 0924-8579
SN  - 1872-7913
VL  - 45
IS  - 4
SP  - 442
EP  - 444
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Minichmayr, Iris K.
A1  - Roberts, Jason A.
A1  - Frey, Otto R.
A1  - Roehr, Anka C.
A1  - Kloft, Charlotte
A1  - Brinkmann, Alexander
T1  - Development of a dosing nomogram for continuous-infusion meropenem in critically ill patients based on a validated population pharmacokinetic model
JF  - Journal of Antimicrobial Chemotherapy
N2  - Background: Optimal antibiotic exposure is a vital but challenging prerequisite for achieving clinical success in ICU patients. Objectives: To develop and externally validate a population pharmacokinetic model for continuous-infusion meropenem in critically ill patients and to establish a nomogram based on a routinely available marker of renal function. Methods: A population pharmacokinetic model was developed in NONMEM (R) 7.3 based on steady-state meropenem concentrations (C-ss) collected during therapeutic drug monitoring. Different serum creatinine-based markers of renal function were compared for their influence on meropenem clearance (the Cockcroft-Gault creatinine clearance CLCRcG, the CLCR bedside estimate according to Jelliffe, the Chronic Kidney Disease Epidemiology Collaboration equation and the four-variable Modification of Diet in Renal Disease equation). After validation of the pharmacokinetic model with independent data, a dosing nomogram was developed, relating renal function to the daily doses required to achieve selected target concentrations (4/8/16 mg/L) in 90% of the patients. Probability of target attainment was determined for efficacy (C-ss >= 8 mg/L) and potentially increased likelihood of adverse drug reactions (C-ss >32 mg/L). Results: In total, 433 plasma concentrations (3.20-48.0 mg/L) from 195 patients (median/P-0.05 - P-0.95 at baseline: weight 77.0/55.0-114 kg, CLCRCG 63.0/19.6-168 mL/min) were used for model building. We found that CLCRCG best described meropenem clearance (CL = 7.71 L/h, CLCRCG = 80 mL/min). The developed model was successfully validated with external data (n = 171, 73 patients). According to the nomogram, daily doses of 910/1480/2050/2800/ 3940 mg were required to reach a target C-ss = 8 mg/L in 90% of patients with CLCRCG = 20/50/80/120/180 mL/min, respectively. A low probability of adverse drug reactions (<0.5%) was associated with these doses. Conclusions: A dosing nomogram was developed for continuous-infusion meropenem based on renal function in a critically ill population.
Y1  - 2018
U6  - https://doi.org/10.1093/jac/dkx526
SN  - 0305-7453
SN  - 1460-2091
VL  - 73
IS  - 5
SP  - 1330
EP  - 1339
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - GEN
A1  - Ehmann, Lisa
A1  - Zoller, Michael
A1  - Minichmayr, Iris K.
A1  - Schmitt, Maximilian V.
A1  - Hartung, Niklas
A1  - Huisinga, Wilhelm
A1  - Zander, Johannes
A1  - Kloft, Charlotte
T1  - Development of a tool to identify intensive care patients at risk of meropenem therapy failure
T2  - International Journal of Clinical Pharmacy
Y1  - 2018
SN  - 2210-7703
SN  - 2210-7711
VL  - 40
IS  - 1
SP  - 317
EP  - 317
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Ehmann, Lisa
A1  - Zoller, Michael
A1  - Minichmayr, Iris K.
A1  - Scharf, Christina
A1  - Huisinga, Wilhelm
A1  - Zander, Johannes
A1  - Kloft, Charlotte
T1  - Development of a dosing algorithm for meropenem in critically ill patients based on a population pharmacokinetic/pharmacodynamic analysis
JF  - International journal of antimicrobial agents
N2  - Effective antibiotic dosing is vital for therapeutic success in critically ill patients. This work aimed to develop an algorithm to identify appropriate meropenem dosing in critically ill patients. Population pharma-cokinetic (PK) modelling was performed in NONMEM (R) 7.3 based on densely sampled meropenem serum samples (n(patients) = 48; n(samples) =1376) and included a systematic analysis of 27 pre-selected covariates to identify factors influencing meropenem exposure. Using Monte Carlo simulations newly considering the uncertainty of PK parameter estimates, standard meropenem dosing was evaluated with respect to attainment of the pharmacokinetic/pharmacodynamic (PK/PD) target and was compared with alternative infusion regimens (short-term, prolonged, continuous; daily dose, 2000-6000 mg). Subsequently, a dosing algorithm was developed to identify appropriate dosing regimens. The two-compartment population PK model included three factors influencing meropenem pharmacokinetics: the Cockcroft-Gault creatinine clearance (CLCRCG ) on meropenem clearance; and body weight and albumin on the central and peripheral volume of distribution, respectively; of these, only CLCRCG was identified as a vital influencing factor on PK/PD target attainment. A three-level dosing algorithm was developed (considering PK parameter uncertainty), suggesting dosing regimens depending on renal function and the level (L) of knowledge about the infecting pathogen (L1, pathogen unknown; L2, pathogen known; L3((-MIC)), pathogen and susceptibility known; L3((+MIC)), MIC known). Whereas patients with higher CLCRCG and lower pathogen susceptibility required mainly intensified dosing regimens, lower than standard doses appeared sufficient for highly susceptible pathogens. In conclusion, a versatile meropenem dosing algorithm for critically ill patients is proposed, indicating appropriate dosing regimens based on patient- and pathogen-specific information. (C) 2019 Published by Elsevier B.V.
KW  - beta-Lactams
KW  - Intensive care
KW  - Pharmacokinetics/pharmacodynamics
KW  - Renal function
KW  - Dosing algorithm
Y1  - 2019
U6  - https://doi.org/10.1016/j.ijantimicag.2019.06.016
SN  - 0924-8579
SN  - 1872-7913
VL  - 54
IS  - 3
SP  - 309
EP  - 317
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Ehmann, Lisa
A1  - Zoller, Michael
A1  - Minichmayr, Iris K.
A1  - Scharf, Christina
A1  - Maier, Barbara
A1  - Schmitt, Maximilian V.
A1  - Hartung, Niklas
A1  - Huisinga, Wilhelm
A1  - Vogeser, Michael
A1  - Frey, Lorenz
A1  - Zander, Johannes
A1  - Kloft, Charlotte
T1  - Role of renal function in risk assessment of target non-attainment after standard dosing of meropenem in critically ill patients
BT  - a prospective observational study
JF  - Critical care
N2  - Background: Severe bacterial infections remain a major challenge in intensive care units because of their high prevalence and mortality. Adequate antibiotic exposure has been associated with clinical success in critically ill patients. The objective of this study was to investigate the target attainment of standard meropenem dosing in a heterogeneous critically ill population, to quantify the impact of the full renal function spectrum on meropenem exposure and target attainment, and ultimately to translate the findings into a tool for practical application. Methods: A prospective observational single-centre study was performed with critically ill patients with severe infections receiving standard dosing of meropenem. Serial blood samples were drawn over 4 study days to determine meropenem serum concentrations. Renal function was assessed by creatinine clearance according to the Cockcroft and Gault equation (CLCRCG). Variability in meropenem serum concentrations was quantified at the middle and end of each monitored dosing interval. The attainment of two pharmacokinetic/pharmacodynamic targets (100% T->MIC, 50% T->4xMIC) was evaluated for minimum inhibitory concentration (MIC) values of 2 mg/L and 8 mg/L and standard meropenem dosing (1000 mg, 30-minute infusion, every 8 h). Furthermore, we assessed the impact of CLCRCG on meropenem concentrations and target attainment and developed a tool for risk assessment of target non-attainment. Results: Large inter-and intra-patient variability in meropenem concentrations was observed in the critically ill population (n = 48). Attainment of the target 100% T->MIC was merely 48.4% and 20.6%, given MIC values of 2 mg/L and 8 mg/L, respectively, and similar for the target 50% T->4xMIC. A hyperbolic relationship between CLCRCG (25-255 ml/minute) and meropenem serum concentrations at the end of the dosing interval (C-8h) was derived. For infections with pathogens of MIC 2 mg/L, mild renal impairment up to augmented renal function was identified as a risk factor for target non-attainment (for MIC 8 mg/L, additionally, moderate renal impairment). Conclusions: The investigated standard meropenem dosing regimen appeared to result in insufficient meropenem exposure in a considerable fraction of critically ill patients. An easy-and free-to-use tool (the MeroRisk Calculator) for assessing the risk of target non-attainment for a given renal function and MIC value was developed.
KW  - beta-Lactam
KW  - Intensive care
KW  - Pharmacokinetics/Pharmacodynamics
KW  - Target attainment
KW  - Renal function
KW  - Risk assessment tool
KW  - Continuous renal replacement therapy
Y1  - 2017
U6  - https://doi.org/10.1186/s13054-017-1829-4
SN  - 1466-609X
SN  - 1364-8535
VL  - 21
PB  - BioMed Central
CY  - London
ER  -