I am currently on 400mg of dilantin a day and we modify that as necessary, I am trying to research the symptoms of too low a dilantin level and alll I can find are ads to buy it at a low price and symptoms of toxicity.

What are the stupid syptoms if it is too low? I have a blood test once or twice a week to check the level nad it keeps bouncing around like a ping pong ball, We want it to settle around 15. One week it is around 20-30 and another it is 8-9. How do you feel if it is too low?

I take the test to measure it and the lab people know me by name I am there so often.