There are multiple meds that a vet can use.  We had great success with extended cytosine treatments for several months. They've mentioned that there are other options but they felt cytosine was most effective.

Sadly, Ginger started suffering from increased seizures a couple of weeks ago, and we finally had to let her go last Thursday.  Hurt terribly, especially after all she had been through.

Having said that, she was on a cytosine cycle every three weeks, her pred treatments had been reduced to 1/4 tablet twice daily, and her "real" personality had returned. Even with all of that, she had been and continued to be a very sick dog due to her GME disease.

I would certainly encourage you to ask about cytosine as an option, our neurologist was absolutely convinced that it be used as a supportive treatment with cytosine as the primary treatment, and it had a huge effect - literally saved her live, if only for 4 1/2 months.