Individualized drug dosage in patients treated with continuous hemofiltration

Background. Subtherapeutic drug dosing may be even more dangerous than over dosage, especially for intensive care patients requiring hemofiltration. Proposal. According to Dettli's fundamental equation, body clearance of any drug (Cl) is a linear function of creatinine clearance (Cl = Cl anur + a . Ca), with [a = (Cl norm - Cl anur)/C-Cr norm]. We propose to individualize drug dosage during high-flux hemofiltration by basing it on Dettli's equat ion and on total C-Cr (C-Cr tot = C-Cr ren + C-Cr filt). Using this approac h, drug clearance will eventually be overestimated for drugs with substanti al tubular secretion and for high-efficiency hemofiltration (C-Cr tot > 30 ml/min). Conclusion. In patients undergoing hemofiltration, the total C-Cr approach might be a practical alternative to standardized dosing schemes for derivin g an individualized dosage from published pharmacokinetic data and function s.