Highlights Behavioral adverse effects can limit use of levetiracetam, particularly in Veteran populations. Vitamin B6 supplementation has been suggested to reduce irritability. 22 Veterans were supplemented with vitamin B6 for levetiracetam-associated irritability. 20 (91%) of Veterans had data regarding irritability. 9 (45%) Veterans noted improvement in irritability with supplementation. 11 (55%) Veterans noted no improvement.