Pharmacokinetics and pharmacodynamics of beta-lactam antibiotics in critically ill patients

Optimal antibiotic therapy for critically ill patients can be complicated by the altered physiology associated with critical illness. Antibiotic pharmacokinetics and exposures can be altered driven by the underlying critical illness and medical interventions that critically ill patients receive in the intensive care unit. Furthermore, pathogens that are usually isolated in the intensive care unit are commonly less susceptible and "resistant" to common antibiotics. Indeed, antibiotic dosing that does not consider these unique differences will likely fail leading to poor clinical outcomes and the emergence of antibiotic resistance in the intensive care unit. The aims of this narrative review were to describe the pharmacokinetics of beta-lactam antibiotics in critically ill patients, to highlight pharmacokinetic/pharmacodynamic targets for both non- critically ill and critically ill patients, and to discuss important strategies that can be undertaken to optimize beta-lactam antibiotic dosing for critically ill patients in the intensive care unit.