Résumé
Pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics are useful to guide the design of dosing regimens that maximize patient outcomes. This chapter aims to describe the influence of PK/PD properties on the mode of infusional drug delivery regimens and due considerations for the design and optimization of antibiotic infusions in the critically‐ill. Further, it summarizes the clinical benefit of the different modes of antibiotic infusion. Existing evidence suggests that short intermittent infusion can achieve required exposure for antibiotics with a PK/PD dosing target of maximum concentration to minimum inhibitory concentration (
C
max
/MIC) ratio. For time‐dependent antibiotics, prolonged infusions achieve better exposure in terms of time the free antibiotic concentration remains above MIC (
f
T
>MIC
). For specific PK/PD targets of area under the concentration–time curve (AUC) to MIC ratio, loading dose may be required with prolonged infusion in patients with increased volume of distribution. PD consideration such as the extent of post antibiotic effect and altered susceptibility profile can influence the need for prolonged infusion administration. Short intermittent infusions or short duration of prolonged infusion may be adequate when significant post‐antibiotic effect exists. Better patient outcomes may be achieved with extended or continuous infusion regimens for time‐dependent antibiotics such as β‐lactams compared to intermittent infusions that are often sub‐optimal in critically‐ill patients. However, although some existing evidence demonstrate better clinical cure rates with continuous infusion regimens, no study has yet shown a mortality benefit. The ongoing effort to address this knowledge gap in a large randomized controlled trial is highly recommended.