seizures
"After a stroke in 2005 I had  seizures until starting with Keppra @ 500mg bid, now i'm up to 1000 twice a day, and haven't been bothered by any side effects at all.  I'm glad that it is available as a generic, now-  I use Levetiracetam, only $4 a month as opposed to the $720 a month Keppra was until recently."