Clinical pharmacokinetic and pharmacodynamic profile of lacosamide

Abstract

Lacosamide-a third-generation antiepileptic drug available in multiple formulations-was first approved in 2008 as adjunctive therapy for partial-onset seizures (POS) in adults. In 2014, lacosamide was approved as monotherapy for POS by the US Food and Drug Administration (FDA). A loading dose administration was approved in 2013 by the European Medicines Agency and in 2014 by the FDA. Unlike traditional sodium channel blockers affecting fast inactivation, lacosamide selectively enhances sodium channel slow inactivation. This mechanism of action results in stabilization of hyperexcitable neuronal membranes, inhibition of neuronal firing and reduction in long-term channel availability without affecting physiological function. Lacosamide is rapidly absorbed, with maximum plasma concentrations reached 0.5-4 h after intake. Oral bioavailability is high (100 %) for a dose up to 800 mg. Bioavailability is irrespective of food intake. Variability in pharmacokinetic parameters is low (coefficients of variation almost all <20 %). The pharmacokinetic profile of lacosamide is consistent in healthy subjects and across different patient populations studied. Lacosamide elimination from plasma occurs with a terminal half-life of approximately 13 h in young subjects and 14-16 h in elderly subjects; this difference does not impact the dose regimen. Lacosamide produces a pharmacodynamic effect that is closely correlated with its plasma concentration. The pharmacokinetic and pharmacodynamic relationship for reduction of seizure frequency can be described by a maximum effect (E max) model. Lacosamide does not induce or inhibit cytochrome P450 enzymes or known drug transporter systems, has low protein binding of less than 15 % and, because it has multiple elimination pathways, it has no clinically relevant interactions with commonly prescribed medications.