I had a Rottwieller that had sizures. They started when she was 6 years old. There was never a pattern and they were unpredictable. It was scarey as when they were over she had know clue where she was or who we were for several mintues. I had to block her off in the room when this happened.
This was years ago and I'm not sure what the medication we gave was. Unfortunalty the outcome wasn't a good one.
I know this isn't what you wanted to hear, but it was our experince.
I wish you the best of luck.
Barry