Rimadyl concerns me and unless my vet could give me a
very compelling reason for one of mine to be taking it, I wouldn't give it to them. I suppose a small dosage for a couple of days wouldn't be as concerning as long term usage. Still yet I would rather not put any chemical into my dog that is not absolutely necessary, especially one so questionable.
This link is more for senior dogs, but there is good information, if you haven't already read these same things.
The Senior Dogs Project