I too have had major problems with dilantin and keeping the levels steady. Especially when I was taking the generic phenytoin. Contrary to what people say, they are NOT equal, and many neuros will tell you the same thing. I had been on a dose of 600 a day for 3 months, no prob, then suddenly became toxic with level up at 32. They thought I had tried to overdose. Oh my. Same thing happened with Tegretol about a year ago, but med just needed adjusted, so no harm done. My levels tend to go up very quickly, and drop very quickly. If I miss two doses, I'm below theraputic, and I'm having seizures, if we don't watch levels close, get to high and I'm having them. It gets so frustrating. Dilantin is a tough drug for me to regulate because level needs to be between 16-20 roughly to keep me sz free in combination with the other two meds I'm on. Also, drinking alot of milk, especially within about an hour of taking Dilantin either before or after can interefere with it's absorbtion. Also, sometimes combined with other meds can make things tough because they may lower one drug, and raise the other. I'm sorry you are having such a tough time, hang in there, and God bless.