migraine
"I've had migraines for about 6 years.  I take Fioricet for pain management, which works well, but I wanted to try preventing migraines altogether instead of treating them with painkillers, so my doctor prescribed Gabapentin.  After about 2 or 3 days, I started to notice side-effects of blurred vision, so much that I couldn't read text in my web browser.  It wasn't drowsy or light-headed, but more as if my eyes simply couldn't focus at the correct depth.  I also noticed I was extremely clumsier, banging my knees, elbows, and shins on everything until I was covered in bruises.  After a month of taking it, I saw no change in the frequency nor intensity of my migraines (I keep a pain log to make sure), so I stopped"