Add-on lacosamide: A retrospective study on the relationship between serum concentration, dosage, and adverse events

► Lacosamide serum concentrations and dosages (mg/kg) did not correlate with clinical tolerability. ► Intake of classic sodium blockers is associated with a significant P value (0.03) for the occurrence of “dizziness.” ► The data do not permit definition of a safety range for lacosamide.