Drug Dosing During Continuous Renal Replacement Therapy in Critically Ill Patients: A Practical Narrative Review

Drug dosing during continuous renal replacement therapy (CRRT) is difficult in critically ill patients because drug exposure is influenced by both the patient and the extracorporeal treatment. This narrative review provides a practical overview of drug dosing during CRRT, while intermittent hemodialysis and sustained low-efficiency dialysis are discussed only where they provide relevant contextual or comparative information. It summarizes the main drug-related, patient-related, and treatment-related factors that influence extracorporeal drug clearance and discusses their clinical implications for commonly used drug classes. Loading and maintenance doses should be considered separately: loading doses depend mainly on volume of distribution and the need for early therapeutic exposure, whereas maintenance dosing depends on total clearance, including residual renal, extracorporeal, and non-renal clearance. Therapeutic drug monitoring can help guide dose adjustment when validated targets are available, while model-informed precision dosing may provide additional support in selected patients. The review also proposes an eight-step practical framework based on residual kidney function, the actual delivered CRRT prescription, drug pharmacokinetics and pharmacodynamics, therapeutic monitoring, and repeated reassessment. Future approaches may combine real-time CRRT data with pharmacokinetic models to support more individualized dosing.