seizures
"I have been using this medication for approximately 35 years.  I have had two healthy children during this time.  I am now in my 50's and find that I am experiencing tiredness, fatigue, and incoordination to the extent that I stumble or run into people or things easier than before.  Whether this medication is a cause to my clumsiness or not, I am not sure.  It has helped to control my seizures since my last one in 1975."