This is a really good book on animals and allergies:  

http://tinyurl.com/yrr3b

Lauren
________
See my cats:  http://community.webshots.com/album/56955940rWhxAe
Raw Diet Info: http://www.holisticat.com/drjletter.html
http://www.geocities.com/rawfeeders/ForCatsOnly.html
Declawing Info: http://www.wholecat.com/articles/claws.htm

Does the vet think he has a stubborn URI? If so, I can only offer my
personal experience: A while back my male cat Harry got a nasty URI
(herpes variety) that caused him to be hospitalized for a week. The
vet decided to put him on zithromax, which at the time was more of an
experimental thing to give to cats, but had shown good results. A
couple of days later his URI started to clear up and he could go home.
It still took almost two weeks for him to really recover. Of course,
my guy wasn't even eating and couldn't breathe without an oxygen tube.
It was nasty.

So, if you're asking if the zithromax will work to clear up an
infection, I'd say give it another day or two and hopefully you'll see
some good results.