We've used glucosamine and chondroitin supplements with success for hip troubles, also.
If you end up giving something that is hard on the liver, as some of these drugs are, milk thistle is good for that. For drugs that cause nausea, ginger is helpful. Our dog was getting chemo drugs. The lab results for the liver came back much better after I started with the milk thistle. Appetite was much better with the ginger, in addition to stopping the "urping." Milk thistle is available in capsules. I used to just give my dogs candied ginger and they would eat it right out of my hand. There are a lot of forms of ginger and different ways to give it.
I had to edit this, as I was rushed and interrupted when I first wrote it. It originally said I gave ginger for the liver issues, also, when it's actually milk thistle that should be used. There are a lot of studies that have been done on both milk thistle and ginger, for these purposes, if you google them. I guess I had a little too much chaos in my livingroom yesterday. Sorry!