Drug use and nephrotoxicity in the intensive care unit: are we under-dosing antimicrobials in patients with acute kidney injury with the need of extended dialysis?

Abstract

To the Editor: An important aspect that we would like to raise, in addition to what Dr Perazella described as drug dose adjustment1 in a recent review in this journal, is the use of antibiotics in extended dialysis (ED). With ED, patients with acute kidney injury have a potentially supraphysiologic drug clearance during ED procedures, and this may be detrimental in patients for whom bactericidal concentrations of antibiotics are needed. Therefore, when the antibiotic is given in relation to ED may be as important as the dosing. This premise has been demonstrated by Lorenzen et al.,2 who reported that ampicillin/sulbactam given too early or late in relation to ED could result in supra- or subtherapeutic concentrations. Also considered should be the pharmacodynamic properties of the antimicrobial in question. Antimicrobials require specific attention to their pharmacodynamic activity, as drugs that are time-dependent killers may require a different timing and dosing compared with those that kill in a concentration-dependent manner.3 Taking these considerations into account may be difficult enough, but complexity is added by the intensive care unit (ICU) environment, to which access is limited, and procedures may interfere with drug and dialysis scheduling.