Indications for monitoring beta-lactam blood concentrations

Beta lactams have a wide therapeutic window, and routine monitoring is not requiredLuxton 2022Mangalore 2022. However, monitoring may be beneficial in patients at high risk of treatment failure due to suboptimal concentrations or at increased risk of toxicityMcDonald 2016Richter 2019Roberts 2014.

Between 15 and 50% of critically ill patients are reported to have suboptimal beta-lactam plasma concentrations, particularly if they have augmented renal clearance1, which can double the patient’s renal drug clearance.

Patients with acute kidney injury or receiving continuous renal replacement therapy (CRRT) may also benefit from monitoring if the actual glomerular filtration rate (GFR) is unknown, or if the effect of the prescribed CRRT settings on drug clearance is poorly characterised. Neurotoxicity (eg seizures, encephalopathy) has increasingly been associated with high beta-lactam concentrations (eg cefepime, flucloxacillin, meropenem, piperacillin), particularly in critically ill patients with kidney impairmentImani 2017Lau 2021.

1 Augmented renal clearance is a term used to describe the enhanced renal function seen in critically ill patients. The use of unadjusted doses of renally eliminated antimicrobials in these patients may result in treatment failureMahmoud, 2017.Return