Meloxicam for arthritis in dogs?

Jackson, my senior boxer, is on Metacam for arthritis in his shoulders. It's working well so far. He started out on a daily dose, but now is on an every other day dose, unless he's being boarded at our local doggie day care/boarding facility. He is given a dose daily while there, due to increased activity. The least amount that can be given, the better, due to stress it can cause on the liver.

My vet told me that when Metacam no longer works well enough, then it's time to change to an injectable called Adequan. I believe it's given once a week, and my vet said I could learn to give it at home.