Pharmacokinetic and pharmacodynamic considerations in antimicrobial therapy for sepsis

Introduction: Antimicrobial dose optimization for the treatment of sepsis remains challenging because of dynamic pharmacokinetic alterations and physiological/pathological responses of the host. Subtherapeutic plasma levels of antimicrobials are commonly observed in patients with sepsis, which potentially leads to both treatment failure and emergence of antimicrobial resistance. The knowledge of antimicrobial pharmacokinetics and pharmacodynamics is helpful in order to tailor antimicrobial dosing strategies. Areas covered: This narrative review summarizes pharmacokinetic alterations of antimicrobial agents and provides useful information on antimicrobial dose optimization. Literature was searched using PubMed database, focusing on pharmacokinetics and pharmacodynamics of antibacterial and antifungal agents in sepsis. Expert opinion: In patients with sepsis, increased volume of distribution and variable changes in renal clearance are the two major factors for antimicrobial pharmacokinetic alterations. Traditional 'one-dose-fits-all' dosing strategy is not suitable for patients with sepsis and hence individualized antimicrobial dosing adjustment is preferable. In general, the initial dose of hydrophilic antimicrobials such as ss-lactams, aminoglycosides, and vancomycin should be given at a high dose regardless of renal function. Improved methods of drug administration (e.g. extended/continuous infusion of beta-lactams) help to increase the chance of pharmacodynamic target attainment. The use of therapeutic drug monitoring should be considered where available.