This study sought to explore if behavioral side effects with LEV help predict similar side effects with PER.

Perampanel (PER) is a novel anti-epileptic drug with a warning label regarding behavioral adverse effects. Levetiracetam (LEV) has well-known behavioral adverse effects. Cross-sensitivity for these behavioral effects is not well-defined.

We reviewed the charts of all patients seen at the Yale Comprehensive Epilepsy Center who were newly started on PER between (1/17/2014 and 6/29/2018). We only report on AEs leading to a lowering dose or cessation of the medication (“intolerable” AEs).

Of the 38 patients prescribed PER, 11 had taken LEV and 8 were taking it concomitantly with PER. Before starting PER, 7/19 patients (36.8%) reported AEs attributed to LEV, including 5/7 (71.4%) reporting behavioral AEs from LEV. Out of five patients who had behavioral AEs with LEV and were given PER, 4/5 reported the same behavioral AEs with PER.

With patients who were previously prescribed PER, 10/19 (52.6%) had intolerable AEs, including 5/19 (26.3%) reported behavioral AEs and 5/19 (26.3%) had other AEs (ataxia, cognitive slowing and slurring of speech). Out of the 8 patients who had PER and LEV simultaneously, none of them had intolerable behavioral AEs to either PER or LEV. In the other group (19 patients) who were prescribed PER with no history of LEV use, seven patients reported intolerable AEs (36.8%): 4/19 behavioral AEs (21.1%) and 3 of those 4 had a history of mental illness.

The majority of patients who reported behavioral AEs to LEV also reported similar AEs to PER. Conversely, patients who tolerated LEV also tended to tolerate PER. People with epilepsy have fluctuations in mood and behavioral experiences, and further research is required to better characterize the complex relationship between AEDs and symptoms.