A vet told me that Rimadyl makes some dogs lethargic. I hope your chap is well soon.

in my experience neither of these will make your dog drowsy(rimadyl is an nsaid not an opiate like vetergesic)the one major side effect to look out for is vommiting and/or d+++ if this happens rimadyl has to be stopped IMEDIATELY
hope your dog is feeling better now

I know Rimadyl isn`t supposed to make them lethargic but this vet was a very good one, and it was something he`s noticed - that dogs on Rimadyl sleep more.

im not disagreeing with you its just not a common one,my theory is, that they may be sleeping more because they are content and in less pain..... maybe??????
anyhoo i have a date with some cows..............................