Quote Originally Posted by krazyaboutkatz View Post
All of my cats were put on doxycycline for 1 month because my 3 kittens brought chlamydia with them and eye drops alone just didn't work. I never noticed that any of them were drinking more water but I did notice that some of them didn't want to eat as much food as they usually do.

Last year my cats Alani & Blaze had coughs and I never knew what caused it. My vet diagnosed them with a laryngeal infection. At the time I had 4 other cats too but none of them got sick. Here's the thread about it: http://petoftheday.com/talk/showthre...-Update-2-5-12. I hope that you'll be able to find out what's causing this. Do you think it could be heartworms?
Doxy is an antibiotic and, like most antibiotics, may cause some tummy/GI upset, which presents itself as inappetance in milder cases

Heartworms are pretty uncommon in cats, but it only takes one to three adult heartworms to be fatal to a cat. Your best diagnostic step to determine this is xrays. Many cats with heartworms are commonly misdiagnosed with feline asthma. Sadly, there is no safe and effective method of treating feline heartworms. As I said, it isn't very common though.