[Drugs dosing in intensive care unit during continuous renal replacement therapy]

Drug dosing in the intensive care unit can be challenging. Acute kidney injury (AKI) is a common complication of sepsis and a part of multiple organ dysfunction syndrome. Continuous renal replacement therapy (CRRT) is increasingly used as dialysis therapy in this critically ill population. Available data demonstrate that sepsis, AKI and different modalities of CRRT can profoundly change drugs pharmacokinetic. The severity of these changes depends on molecules characteristics (volume of distribution, plasma protein binding, molecular weight, plasma half-life, plasma clearance), patient itself (volemia, residual renal function, tissue perfusion, hepatic dysfunction) and modality of CRRT (diffusion, convection, adsorption). There are no available recommendations to adapt drug dosing in a given critically ill patient with a given modality of CRRT. It is necessary to fully understand the different methods of CRRT and drug pharmacokinetic to prescribe the appropriate dose and to avoid under or potentially toxic overdosing. Monitoring the plasma level of drug - when available - can establish a relation between the blood concentration and its effect; thus, facilitating drug dosing.

Higher renal replacement therapy dose delivery influences on drug therapy

Higher doses of renal replacement therapy have profound effects on pharmacotherapy, yet little research has been conducted in this area. High-volume renal replacement therapies influence both the pharmacokinetic and the pharmacodynamic profiles of all drugs administered to these critically ill patients. Intermittent high-dose "hybrid" hemodialysis therapies remove drugs to a much different degree than standard thrice-weekly hemodialysis, yet pharmacokinetic studies have not been performed in patients receiving these therapies. High-volume continuous renal replacement therapies offer dosing challenges not seen with standard low-dose therapies. This article describes the pharmacokinetic and pharmacodynamic issues presented by high-volume renal replacement therapies. Given the importance that pharmacotherapy has on optimal patient outcomes, a better understanding of the influence that high-volume renal replacement therapy has on drugs is essential if these high volume therapies are to be used successfully in the intensive care unit.