The effect of pathophysiology on pharmacokinetics in the critically ill patient--concepts appraised by the example of antimicrobial agents

Versatile electrophoresis-based self-test platform

Lab on a Chip technology offers the possibility to extract chemical information from a complex sample in a simple, automated way without the need for a laboratory setting. In the health care sector, this chemical information could be used as a diagnostic tool for example to inform dosing. In this issue, the research underpinning a family of electrophoresis-based point-of-care devices for self-testing of ionic analytes in various sample matrices is described [Electrophoresis 2015, 36, 712-721.]. Hardware, software, and methodological chances made to improve the overall analytical performance in terms of accuracy, precision, detection limit, and reliability are discussed. In addition to the main focus of lithium monitoring, new applications including the use of the platform for veterinary purposes, sodium, and for creatinine measurements are included.

Clinical pharmacological approach for balancing the use of daptomycin and linezolid in comparison with that of vancomycin in the treatment of MRSA-related infections

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most challenging bacterial pathogens responsible for severe infections among hospitalized patients. In recent years there is increasing evidence that the clinical efficacy of vancomycin is progressively decreasing. Although daptomycin and linezolid are valuable alternatives to vancomycin for the treatment of MRSA-related bloodstream infections and pneumonia, respectively, a great deal of debate exists about their role in daily clinical practice due to cost-effectiveness issues. In this article we put into perspective the importance of pharmacokinetic/pharmacodynamic (PK/PD) considerations based on recent experimental and clinical data to argue whether they could be helpful in identifying clinical conditions in which these agents could be advantageous as compared to vancomycin.

In vivo pharmacokinetic/pharmacodynamic profiles of valnemulin in an experimental intratracheal Mycoplasma gallisepticum infection model

Valnemulin, a semisynthetic pleuromutilin antibiotic derivative, is greatly active against Mycoplasma. The objective of our study was to evaluate the effectiveness of valnemulin against Mycoplasma gallisepticum in a neutropenic intratracheal model in chickens using a pharmacokinetic/pharmacodynamic (PK-PD) method. The PK of valnemulin after intramuscular (i.m.) administration at doses of 1, 10, and 20 mg/kg of body weight in M. gallisepticum-infected neutropenic chickens was evaluated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Real-time PCR (RT-PCR) was used for quantitative detection of M. gallisepticum. The ratio of the 24-h area under the concentration-time curve divided by the MIC (AUC24/MIC) correlated well with the in vivo antibacterial effectiveness of valnemulin (R(2) = 0.9669). The AUC24/MIC ratios for mycoplasmastasis (a reduction of 0 log10 color-changing unit [CCU] equivalents/ml), a reduction of 1 log10 CCU equivalents/ml, and a reduction of 2.5 log10 CCU equivalents/ml are 28,820, 38,030, and 56,256, respectively. In addition, we demonstrated that valnemulin at a dose of 6.5 mg/kg resulted in a reduction of 2.5 log10 CCU equivalents/ml. These investigations provide a solid foundation for the usage of valnemulin in poultry with M. gallisepticum infections.

Applications of the pharmacokinetic/pharmacodynamic (PK/PD) analysis of antimicrobial agents

The alarming increase of resistance against multiple currently available antibiotics is leading to a rapid lose of treatment options against infectious diseases. Since the antibiotic resistance is partially due to a misuse or abuse of the antibiotics, this situation can be reverted when improving their use. One strategy is the optimization of the antimicrobial dosing regimens. In fact, inappropriate drug choice and suboptimal dosing are two major factors that should be considered because they lead to the emergence of drug resistance and consequently, poorer clinical outcomes. Pharmacokinetic/pharmacodynamic (PK/PD) analysis in combination with Monte Carlo simulation allows to optimize dosing regimens of the antibiotic agents in order to conserve their therapeutic value. Therefore, the aim of this review is to explain the basis of the PK/PD analysis and associated techniques, and provide a brief revision of the applications of PK/PD analysis from a therapeutic point-of-view. The establishment and reevaluation of clinical breakpoints is the sticking point in antibiotic therapy as the clinical use of the antibiotics depends on them. Two methodologies are described to establish the PK/PD breakpoints, which are a big part of the clinical breakpoint setting machine. Furthermore, the main subpopulations of patients with altered characteristics that can condition the PK/PD behavior (such as critically ill, elderly, pediatric or obese patients) and therefore, the outcome of the antibiotic therapy, are reviewed. Finally, some recommendations are provided from a PK/PD point of view to enhance the efficacy of prophylaxis protocols used in surgery.