Efficacy and Safety of Lamotrigine Adjunctive Therapy in Lennox-Gastaut Syndrome

Purpose: Lamotrigine (LTG) is often used as adjunctive therapy in Lennox-Gastaut syndrome (LGS); however, it may worsen myoclonic and atypical absence seizures in LGS patients. This study reviewed the overall efficacy and safety of LTG in children with LGS.Methods: This retrospective study included 38 patients (aged <18 years) with LGS who underwent LTG adjunctive therapy between October 2020 and March 2022 at Severance Children’s Hospital. The primary outcome was the change in seizure frequency at 3, 6, and 12 months after starting LTG treatment. A favorable treatment response was defined as a ≥50% reduction in seizure frequency.Results: The main seizure semiology at the start of treatment was tonic-clonic in 15 (39.5%) patients, spasm in 14 (36.8%), atonic in five (13.2%), myoclonic in three (7.9%), and absence in one (2.6%). The median number of anti-seizure medications (ASMs) was 3.95 (interquartile range, 3 to 4.75). The most common concomitant ASMs were valproate (35/38, 92.1%), levetiracetam (23/38, 60.5%), and topiramate (20/38, 52.6%). After 3 months, seizure frequency was reduced by >50% in 47.4% of patients (18/38). After 6 months, 20 patients (20/36, 55.6%) showed a favorable response. After 12 months, five patients (5/11, 45.5%) responded to treatment. Three patients showed myoclonic seizures at the start of treatment and >50% amelioration in seizure frequency at the 3- and 6-month follow-up visits.Conclusion: This study reaffirms the efficacy and safety of LTG in children with LGS. Therefore, LTG is strongly recommended as an adjunctive therapy for children with LGS.