Preliminary evidence about irritability in patients with epilepsy treated by perampanel as first add-on therapy compared to levetiracetam and valproic acid

Aims Irritability has been described as a frequent adverse event in patients affected by epilepsy and treated with perampanel (PER), levetiracetam (LEV), and less frequently with valproic acid (VPA). Since the questionnaire for irritability (I-EPI) is a validated instrument to measure this psychiatric manifestation in patients affected by epilepsy, in this study we aimed at investigating the effect of PER as first add-on therapy on I-EPI. Moreover, we compared the effectiveness and I-EPI scores obtained at 12-month follow-up visits in patients treated by PER, LEV, or VPA in order to measure irritability as a consequence of these treatments. Methods We collected data from 17 patients treated by PER, 16 patients treated by LEV, and 16 patients under VPA treatment followed for 12 months. Results We did not document significant changes of I-EPI questionnaire between baseline and follow-up in the PER group. As concerning the comparison of I-EPI among PER, LEV, and VPA groups, we documented lower global scores in PER than both LEV (P < 0.05) and VPA (P < 0.05) groups. Moreover, patients under PER treatment showed lower scores than LEV and VPA (P < 0.05) in I-EPI items measuring the gentle personality, anxiety of having epileptic seizures in front of others, and irritability in thinking that they can have an epileptic seizure. Conclusions This retrospective study described a stable and possibly lower degree of irritability in patients starting PER than LEV and VPA treatments, although we documented the comparable effectiveness of PER, LEV, and VPA as first add-on treatments in patients affected by uncontrolled epileptic seizures. However, the small sample of patients included in this study and the absence of I-EPI scores obtained at baseline visits in LEV and VPA groups require further investigations to confirm this preliminary evidence.