One of my dachshunds developed seizures at two yo, they were sporadic but as she aged, they became more frequent and longer duration, finally had to put her on phenobarbital at seven yo, we waited as long as we could. She had a great life and lived until she was fourteen. The 4:50 thing is very odd and I would be looking around for so something that is happening at that time in your home or neighborhood. Here are some things that I think triggered her seizures.
1). Sudden noise, and lights. (How about an alarm clock)
2) Food changes, although my vet said not possible, I think there was a big connection
3) colder weather
4) if you have an electrical fence, get rid of it.
Hope this helps.
I am totally with Toespi on this... find out what the 4:50 AM trigger is and modify the environment.