I'm giving our 19 year old Cartrophen Vet injections, once every two weeks. It's sub-q, I do it myself and it's much cheaper this way than going to the Vet. Plus much less stress on the cat. Cartrophen is very similar to Adequan.
Oh, and yes, I do see enough of an improvement to keep on with it.
The Vet pre-loads the syringes for me and 5 cost $27.