epilepsy
"I've been on an ever-increasing dose for over a year now; this med doesn't want to stay in my system. I'm currently at 2k mg/day, and it still doesn't register in the blood test as a therapeutic dose. Despite this, even when I first started at very low doses, I had immediate reactions. Some very bad; killed my immune system and I got a cough so bad I cracked 2 ribs. Some very good; somehow, my long-distance vision improved. Neurologist suggested I'm in a state of "near-constant aura" from migraines and this med reduced that, along with some facial numbness I didn't know I had until it went away. Seizures are controlled while it's in my system."