Membrane-Dependent Adsorption of Lacosamide in CRRT: Implications for Drug Dosing in Critically Ill Renal Patients

BACKGROUND Lacosamide is an antiepileptic drug widely used to treat partial-onset seizures. During extracorporeal therapies or intravenous administration, lacosamide adsorption to filtration membranes and its stability in solutions may influence therapeutic efficacy. This in vitro study evaluated lacosamide adsorption to different dialysis filter membranes in saline and plasma solutions, as well as its stability in these solutions. MATERIAL AND METHODS Lacosamide (200 µg/mL) was prepared in 0.9% NaCl and bovine plasma, then perfused through 3 types of dialysis filters: polysulfone (PS), polyacrylonitrile (PAN), and polyacrylonitrile polyethyleneimine (PAN-PEI). Samples were collected at 0, 5, 15, 30, 45, 60, and 90 minutes. Lacosamide concentrations were measured using high-performance liquid chromatography. Repeated-measures analysis of variance and post hoc tests were used to evaluate concentration changes over time among filter types. RESULTS Lacosamide remained stable in saline and plasma solutions over 90 minutes, showing under 7% variation in concentration. In 0.9% NaCl, significant adsorption occurred across all filters, with total reductions of 14.73% for PAN-PEI, 20.71% for PAN, and 33.52% for PS filters at 90 minutes. In plasma, adsorption was lower for PS filters (17.96%) but greater for PAN-PEI (23.04%) and PAN (27.71%) filters. No significant differences in adsorption were detected among filters (P>0.05). CONCLUSIONS Lacosamide demonstrated chemical stability with measurable adsorption to dialysis membranes. Adsorption was more pronounced in plasma than in saline for PAN-PEI and PAN membranes. These findings indicate that lacosamide concentrations may decrease during extracorporeal circulation and should be considered in settings involving hemodialysis or continuous renal replacement therapy.