JP,
I dug into this a little bit. I'm thinking the levetiracetam (Keppra) is being utilized as prophylactic seizure prevention as high blood ammonia levels make this a strong possibility.
That being said, it might be the levetiracetam is causing some agitation, irritability, and unsteadiness. But I have to give considerable weight to the thought that the increased ammonia levels might be producing these effects.
The loose stools are most likely from the lactulose. This medication is most commonly used as a stool softener. Fortunately, it was found to have the property of removing ammonia from the blood (I call this a twofer, two actions from one drug). This is the only medication I know of that can remove ammonia.
Again, all of this is making sense. Get more blood passing through the liver, the liver removes the ammonia by converting it to urea, and the kidneys remove the urea.
I'm really amazed the vets figures this out.
Hang in there Dooley. You've got skilled vets trying to get you better, along with all of our hopes.