Hello,
Actually, metacam wont really do anything for a respiratory infection. It can help with pain, inflammation, etc, but
isn't going to do much for a respiratory infection. Does he seem to have any mucous in or around his mouth or nose?
For now, you can try to increase his basking temperatures a degree or two. How old is he? Also, if you can keep him
a little warmer overnight, usually a range of 75-80 is good to help boost his immune system.
We can also review your tank setup if you would like, to be sure everything is all good.
Let us know how he is doing.
Tracie