My cat has bony buildup in his sinus cavity. He is therefore prone to infections from Haemophilus felis, which is normal flora in most cats, but because of his condition the bacteria becomes entwined in the bones. He was on many antibiotics, which didn't work, then when on tetracycline, the infection cleared right up and he stopped snorting and the drainage went away. I gave him the full 14 days worth. A few weeks later, the infection came back. He was put on tetracycline again, and it's went away again. Again he took the FULL prescription I don't want it to keep coming back though, so does anyone know the effects of long-term tetracycline use in cats? I am a microbiologist, so I know it's fine to do in humans (long-term use for acne). And don't say "ask the vet", cause my vet is an idiot, I am the one who cultured my cat, and told the vet the proper medication I needed. And please don't say "ask a different vet" because there are none in my area. Thanks so much!