„Das nehme ich mal mit“

“Let’s double-click on that” is one of the most frequently used management jargon phrases that tries to turn “I want to look at something in more detail” into a hip expression. A topic that should be looked at in more detail is the dosing of anti-infective drugs in patients undergoing kidney replacement therapy (KRT). It is mission critical to realize that 30–60% of all patients in the intensive care unit (ICU) develop acute kidney injury (AKI). In about 50% of these critically ill patients with AKI requiring KRT, sepsis is the underlying disease. So why not generously dose anti-infective drugs? The answer is nephrotoxicity. A quarter of the most frequently prescribed drugs in the ICU have the potential to cause AKI, among those many anti-infective agents. Several factors affect the clinical pharmacology of drugs including pharmacokinetics (PK) and pharmacodynamics (PD). Parameters such as molecular weight, protein binding and volume of distribution are important as they have an effect on the clearance of drugs by KRT. Furthermore, a plethora of KRT coordinates (modality, filter material and surface, flow rates of blood/dialysate/filtrate, ultrafiltration rate and circuit downtime) and patient factors (residual renal function, vascular access, vascular leakage, hypoalbuminemia) all influence the clearance of drugs during KRT, making correct dosing a challenge. As evidence-based guidance for dosing of anti-infective drugs during KRT is often limited, this article lays the foundation for dosing by presenting basic principles of PK/PD, drug selection and clearance estimation and/or measurement.