Vancomycin dosing assessment in intensive care unit patients based on a population pharmacokinetic/pharmacodynamic simulation |
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Authors: | Natalia Revilla Ana Mart��n-Su��rez Marta Paz P��rez F��lix Mart��n Gonz��lez Mar��a del Mar Fern��ndez de Gatta |
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Affiliation: | 1Service of Pharmacy, University Hospital of Salamanca, Salamanca, Spain;2Department of Pharmacy and Pharmaceutical Technology, University of Salamanca, Salamanca, Spain;3Intensive Care Unit, University Hospital of Salamanca, Salamanca, Spain |
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Abstract: | AIMTo estimate the vancomycin pharmacokinetic profile in adult ICU patients and to assess vancomycin dosages for increasing the likelihood of optimal exposure.METHODSFive hundred and sixty-nine concentration–time data from 191 patients were analysed using a population pharmacokinetic approach (NONMEN™). External model evaluation was made in 46 additional patients. The 24 h area under the concentration–time curve (AUC(0,24 h)) was derived from the final model. Minimum inhibitory concentration (MIC) values for S. aureus were obtained from the EUCAST database. AUC(0,24 h) : MIC ≥ 400 was considered as PK/PD efficacy index. The probability of different dosages attaining the target considering different strains of S. aureus and patient subgroups was estimated with Monte Carlo simulation.RESULTSVancomycin CL showed a significant dependence on patient age and renal function whereas CrSe > 1 mg dl−1 increased V more than twofold. For our representative ICU patient, 61 years, 73 kg, CrSe= 1.4 mg dl−1, measured CLCr= 74.7 ml min−1, the estimated values were CL = 1.06 ml min−1 kg−1 and V= 2.04 l kg−1. The cumulative fraction of response for a standard vancomycin dose (2 g day−1) was less than 25% for VISA strains, and 33% to 95% for susceptible S. aureus, depending on patient characteristics.CONCLUSIONSSimulations provide useful information regarding the initial assessment of vancomycin dosing, the conventional dosing regimen probably being suboptimal in adult ICU patients. A graphic approach provides the recommended dose for any selected probability of attaining the PK/PD efficacy target or to evaluate the cumulative fraction of response for any dosing regimen in this population. |
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Keywords: | AUC(0,24 h) : MIC dosage individualization intensive care unit population pharmacokinetics pharmacokinetics/pharmacodynamics or PK/PD vancomycin |
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