What could cause slightly elevated liver enzymes in a 1 yr old dog?

He has had all the vaccinations, he has been throwing up since Monday afternoon and just recently, as of Wednesday, started acting really "depressed". I took him to the vet and the vet said he has very slightly elevated liver enzymes. He gave him a penicillin shot, and some anti-nausea shot as well as some amoxicillin. Is there anything else I can do for my dog? He was not around any sick dogs and our other dog is healthy and normal. Any ideas?He was vaccinated last year according the the vet's reccomended schedule. Also, the vet told me, because I did ask, that there is really nothing we can do but try to make his comfortable and hopefully he will pull through it.

change his diet

i think your vet answered your question. im glad you took him to the vet right away, that is a good thing. if you have any more questions as what do do, you should have asked while you were there. they dont charge for a phone call, its not to late you can still ask.

And when did he have all those vaccinations? Read the Wisconsin University weblinkshttp://svmweb.vetmed.wisc.edu/articles/68/5/39http://www.news.wisc.edu/releases/8413.html