There is a drug that is so effective against bone pain in horses that they
can be ridden and even raced when they are lame because they suddenly
aren't. *I'm not in favour of using it for that purpose but it is equally
effective in dogs. *

Tweed

Phenylbutazone is what you're thinking of Tweed. It's very effective
stuff, but banned for use in competition horses who are competing. I
have a retired elderly mare on it who is arthritic and chronically
lame and she bounces around like a youngster. When you take her off it
she can barely walk.

Helen M