Objective: To determine the effectiveness of lacosamide (LCS) in refractory trigeminal neuralgia (TN) patients. Background There are several medications used for the medical treatment of TN; however, they are often ineffective due to lack of efficacy or intolerable adverse effects. LCS has a novel mechanism by selectively enhancing slow inactivation of voltage dependent sodium channels. Design/Methods: We performed a retrospective chart review of eleven subjects who had been diagnosed with TN and received LCS as adjunctive therapy. Descriptive analysis was performed. Results: Eleven cases were identified. The median age was 63 (range 25-88) years. The etiology for most patients was idiopathic (n=9); two patients had a structural lesions. The median duration of TN was 10 years (range 1-22). The average number of medications tried prior to LCS was six. Seven of the patients had surgical interventions including microvascular decompression and gamma knife. Barrow Neurological Institute Pain Scale scores for pain were available for seven patients and showed improvement in four of these patients with at least one level decrease in severity. Two of the patients had no improvement. One patient initially improved then worsened. Median duration of follow up was six months (range 2-12). Subjective impressions showed initial improvement from nine patients, one with significant improvement, one patient discontinued due to complete resolution of symptoms. Adverse events were mild and included dizziness, drowsiness, constipation and occasional fatigue. None of the patients required hospitalization. Conclusions: In this small case series of patients with refractory TN, a majority of the patients responded at least initially, despite multiple previous medication trials and surgical procedures in some. LCS was well tolerated and should be considered as a treatment option in chronic TN. Positive results in a small case series such as this justifies designing a clinical trial to determine safety and efficacy of LCS in TN. Disclosure: Dr. Joshi has nothing to disclose. Dr. Cohen has nothing to disclose.