The objective of this study was to evaluate the tolerability and efficacy of lacosamide (LCM) in residential patients at our epilepsy centre. We assessed retrospectively 80 patients (mean age 36.2 years, range 18-63 years; 29 female) with intellectual disability (ID) and drug-resistant epilepsy using an industry-independent, non-interventional study design based on standardised seizure records. Evaluation, including calculation of retention rate, was carried out for the intervals 3-6, 9-12 and 21-24 months after LCM initiation. The Clinical Global Impression scale (CGI) was used to allow assessment of qualitative changes in seizure severity and clinical status. CGI improved for 61% of the patients. The responder rate was 48%; ten patients (13%) became seizure free. The response was not related to the degree of ID. The retention rates after 12 and 24 months were 71% and 65%, and were significantly lower in patients taking other sodium-channel blockers (SCBs; 76% vs. 55%). The occurrence of adverse events (AEs) was related to the administration of concomitant SCBs (48% with SCBs vs. 26% without). Sedation (15%), ataxia (13%), vertigo (11%), and nausea (9%) were the commonest AEs. While 60% of our patients had concomitant psychiatric diagnosis, we found no relevant effect of this on challenging behaviour. Adjunctive LCM may provide an antiepileptic treatment option for patients with ID with or without additional psychiatric diagnosis. The occurrence of AEs and the LCM retention rate were affected by concomitant SCB use but not by psychiatric comorbidity.
Keywords: Antiepileptic drug; Intellectual disability; Lacosamide; Refractory epilepsy.