Lacosamide: An Adjunctive Agent for Partial-Onset Seizures and Potential Therapy for Neuropathic Pain

OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, and safety of lacosamide, a new agent for use as adjunctive treatment in partial-onset seizures and a potential agent for treatment of neuropathic pain. DATA SOURCES: A MEDLINE search (1966-July 2009) was conducted using the key words lacosamide, harkoseride, SPM-927, ADD-234037, epilepsy, anticonvulsant, and neuropathic pain. Bibliographies of all articles retrieved were also reviewed. STUDY SELECTION AND DATA EXTRACTION: All studies including humans and published in English with data describing lacosamide for the adjunctive treatment of partial-onset seizures and for treatment of neuropathic pain were reviewed. DATA SYNTHESIS: Lacosamide is a functionalized amino acid molecule that selectively enhances the slow inactivation of voltage-gated sodium channels and interacts with the collapsin-response mediator protein-2. With its bioavailability of approximately 100%, minimal protein binding, and few drug-drug interactions, lacosamide has a favorable pharmacokinetic profile. Recent data suggest that lacosamide may have a role as adjunctive treatment of partial-onset seizures. Open-label studies showed a 14-47% reduction in seizure frequency, while placebo-controlled trials demonstrated a 26-40% reduction in seizure frequency. The 50% responder rates ranged from 32.7% to 41.2% with varying doses of lacosamide. Although lacosamide use is not approved by the Food and Drug Administration for treatment of neuropathic pain, studies demonstrated reductions of 2.01-3.60 in pain scale scores. The most common adverse effects, occurring in greater than 10% of subjects in the clinical trials, include arthralgia, ataxia, blurred vision, diplopia, dizziness, fatigue, headache, injection site pain (only in intravenous studies), nausea, tremor, upper respiratory tract infection, and vomiting. CONCLUSIONS: Lacosamide is an effective agent for adjunctive treatment of refractory partial-onset seizures. Its exact role in the treatment of neuropathic pain needs to be determined.