@jdwandmew
When my Dilantin became toxic my Neurologist said it had become unstable. I understand this isn't common and wonder if it occured because Dilantin is a nonlinear drug.
We tried every conceivable dosage and ways of taking it but it remained toxic.
I was told our only option was to switch medication. He changed me to Carbitrol, a brand name, extended release version of Carbamazepine.
My Neurologist insisted seizure patients take brand-name Anticonvulsants.
I wouldn't let your Dilantin remain high. Tell the Neurologist about your seizure-free status and you don't want to jeopardize it and insist on more frequent blood level tests.
At one point I was being tested daily.
Sometimes aging is a factor.
I would do whatever it takes to get your meds to a more.
acceptable level.
How's your level now?
Take care,
Jake