Our Edward was on Metacam from mid-November up until last week (he was PTS - not related to the drug - he had cancer).
As said, it's an NSAID - anti inflammatory, and painkiller, non-steroid (I got whole bottles and read the leaflet that was inside the box). He got trhough a whole bottle of the stuff and was into his second. It was to treat the tumour and arthritis that he had in the same hip. I'm fairly certain it was that that kept him apparently pain free, and able to get about on his own, till right at the end.
I squirted it straight into his mouth once a day using the weight marked syringe thing (after which he'd look extremely offended at me for about half an hour). I always gave him it straight after he'd had a good dish of food - it said to do so somewhere on the leaflet in the box.