ObjectiveTo analyze and evaluate the clinical characteristics, efficacy, and tolerability of lacosamide monotherapy in the treatment of primary paroxysmal kinesigenic dyskinesia (PKD). Methods The Clinical data of children with primary PKD who received lacosamide monotherapy between July 2021 and June 2025 in the Children's Hospital of Soochow University were analyzed, and their efficacy and tolerability were followed up. Results During the study period, a total of 7 children with primary PKD received lacosamide monotherapy. Among them, 4 had simple-type PKD and 3 had complex-type PKD; 2 had familial PKD and 5 had sporadic PKD; 4 were male and 3 were female. The age of onset was 11.0 (0.5 ~ 12.0) years. All 7 cases presented with dystonia as the form of onset, with 1 case also exhibiting athetosis. The attack frequency ranged from once every few days or weeks to 20 times per day, with a duration of 3 ~ 60 seconds. Bilateral limb involvement was most common, and 2 cases also had facial involvement. In auxiliary examinations, 3 cases showed abnormal EEG results, and 4 cases had abnormal genetic test results. Among genetic test results, 2 cases had PRRT2 gene mutations, 1 had a TMEM151A gene mutation, and 1 had a CLCN1 gene mutation. During lacosamide treatment, the initial and long-term maintenance doses were similar, at 2.87 (0.50 ~ 4.44) mg/(kg·d) and 2.67 (0.50 ~ 4.00) mg/(kg·d), respectively. At both the 4-week and long-term follow-ups, all 7 children showed good efficacy and tolerability.ConclusionLacosamide is effective and well-tolerated in children with both familial and sporadic, simple-type and complex-type primary PKD. A low dose of 2.67 (0.50 ~ 4.00) mg/(kg·d) is sufficient to control attacks, which is lower than the minimum maintenance dose of 4 ~ 6 mg/(kg·d) used in the treatment of epilepsy with lacosamide.
