Beta-lactam dose reductions in critically ill patients with acute kidney injury: a scoping review

Background Acute kidney injury is a common complication in critically ill patients, often coinciding with the need for antibiotic therapy. The dose of beta-lactam antibiotics is frequently adjusted and often reduced based on estimated Glomerular Filtration Rate. However, early dose reductions may lead to underdosing, especially during the critical first 48 hours of infection treatment, when AKI may be transient and adequate antibiotic treatment is critical. While some reviews suggest delaying dose reductions improves clinical outcomes, evidence remains limited. This scoping review evaluates the current literature on beta-lactam dosing strategies in critically ill patients with acute kidney injury, focusing on pharmacological and clinical outcomes. Methods We conducted a systematic scoping review following PRISMA-ScR guidelines. We searched Medline, Embase, Web of Science, Cochrane CENTRAL, and Google Scholar from database inception through March 24, 2025. Two reviewers independently screened all articles and assessed study quality using ROB-2 and ROBINS-E tools. Eligible studies included critically ill adult patients with acute kidney injury, receiving beta-lactams, and reporting clinical or pharmacological outcomes. Data were extracted using a standardized template and categorized by pharmacological or clinical outcomes. Further stratification by antibiotic type or patient characteristics was not feasible. Results Out of the 1,436 screened articles, 11 studies involving 25,381 patients were included. The risk of bias was high in most studies. Most studies were observational; one was a randomized controlled trial. Seven studies reported beta-lactam plasma concentrations. Higher concentrations were generally observed in patients with acute kidney injury, even though dosages were oftentimes already reduced. One study associated early dose reductions with decreased neurotoxicity. One study reported increased treatment failure with early dose reductions and three studies linked delayed dose reductions to reduced mortality. Conclusions Current evidence on beta-lactam dose reduction in critically ill patients with acute kidney injury is limited and of low quality. Delaying reductions may improve clinical outcomes, but further prospective studies are urgently needed.