Pharmacokinetics and pharmacodynamics in critically ill patients

The purpose of this review is to highlight the recently published studies in the area of pharmacokinetics and pharmacodynamics in critically ill patients and ascertain the relevance to clinical practice.

The majority of the published studies in this area were related to antibiotics and this will form the main focus of this review. A number of studies have focused on antibiotic concentrations at various target sites of infection or other tissue sites including cerebrospinal fluid, peritoneal fluid and burns tissues. The administration of time-dependent antibiotics using continuous infusion has also been the subject of recently published studies which support the superior achievement of pharmacodynamic targets using continuous infusion compared with bolus dosing. Antibiotic dosing during renal replacement therapies, mainly during extended daily dialysis (EDD) and during other forms of extracorporeal techniques including extracorporeal membrane oxygenation (ECMO), have also been described in a few recent studies and case reports.

Studies have shown that critically ill patients display large variations in pharmacokinetics mainly due to altered pathophysiology. An understanding of the pathophysiological changes that occur in critically ill patients is essential to optimize dosing particularly to achieve the pharmacodynamic targets for antibiotics.