When the meds stop working/elderly rat

Hello everyone!.. In a previous thread I asked you about my rattie's med and for how long she should take them..After completing the 6 week course of Baytril and Zithromax, even near the end of week 6, my rattie starting making the usual resp inf-noise...I consulted my vet and he seemed kind of clueless on what to do next, eventually telling me to just let her be. But she's still active, and curious and she has a steady weight and I just can't give up on her.
I was thinking of trying Zithromax and Doxy combo, in the past, doxy had worked well for her. I honestly went through all exotic vets in my area and they all don't know exactly how to treat a resp inf on an elderly rat, they tell me to let her succumb from this. I can't give up yet. Not until I can see that she's not living the best of her life. I've read that Zithro and Doxy are a good combo, has anyone had experience with this? Did it work for them? And since she the resp inf doesn't seem to go away, should I give her meds for the rest of her life?
Thank you everyone for your support. You're really a great group of people.

baytril + zithro (10 mg/ml) + doxy, orally, twice a day ….. if it helps then 6 weeks

Is it in her lungs or just up in her nasal passages etc?

Vet had told me lungs..
Zithro I got 40 mg/ml so by previous calculation I should give her 0.17 ml.
Regarding Doxy, I got 100 mg tablets, which I read I got to dilute in 4 ml of water. Then she would take 0.07 mL? (according the drug chart and the med calculator!)
She weighs 304 gr.

The zithro dose is fine, 0.17 ml ONCE a day
The doxy needs to be changed. Use 0.12 ml twice a day. You can mix water into the pill until it dissolves then add the balance of the fluid as a sweet syrup to make it palatable.

Does it sound like popping in her nose, or do you see sneezing and rubbing her paws over her nose?

She's not sneezing (rarely) it sounds like she's breathing heavily :/
Ok so baytril twice, doxy twice and zithro once daily. Got it!

lilspaz68 said:

The zithro dose is fine, 0.17 ml ONCE a day
The doxy needs to be changed. Use 0.12 ml twice a day. You can mix water into the pill until it dissolves then add the balance of the fluid as a sweet syrup to make it palatable.

Does it sound like popping in her nose, or do you see sneezing and rubbing her paws over her nose?

Click to expand...

just to be sure, I'll dilute the 100 mg pill in 4 ml of water right?