Psychiatric disorders of the combination of levetiracetam either with lacosamide or perampanel: a retrospective cohort study

Background The number of patients with epilepsy receiving perampanel or lacosamide as an add-on treatment following levetiracetam treatment has increased. Although levetiracetam causes psychiatric disorders, it is unclear whether they occur with the combined use of these antiepileptic drugs. Objective To determine the frequency of psychiatric disorders in patients received lacosamide or perampanel in combination with levetiracetam. Setting A single-center retrospective cohort study. Method Patients who received levetiracetam + lacosamide or levetiracetam + perampanel were selected. Medical records from the start of combination therapy contained characteristics of patients and the incidence of psychiatric disorders. Main outcome measure The frequency of psychiatric disorders, the time to onset, dose reduction or discontinuation following psychiatric disorders, and the clinical course following disorder onset. Results Forty-four patients used levetiracetam + lacosamide and 50 used levetiracetam + perampanel. The incidence of psychiatric disorders was significantly lower (p < 0.001) with levetiracetam + lacosamide (6.8%) than with levetiracetam + perampanel (44%). The incidence of affect lability was significantly higher with levetiracetam + perampanel than with levetiracetam + lacosamide (p = 0.018). The time to the onset of psychiatric disorders was within 1 month of dose initiation or increase in one case (33.3%) with levetiracetam + lacosamide and 16 cases (72.7%) with levetiracetam + perampanel. There was no significant difference in clinical characteristics and antiepileptic drug dosages owing to the presence or absence of psychiatric disorders. Conclusion As the frequency of psychiatric disorders was higher with levetiracetam + perampanel therapy, levetiracetam + lacosamide may be preferable. These disorders tended to develop within 1 month of therapy and were not dose-dependent. Antiepileptic drugs should be cautiously prescribed to avoid psychiatric disorders.