My old dog has fluid in lungs and heavy breathing. What meds help?

Thanks for using Petco Pet Education Center, formerly Petcoach. I am so sorry to hear about Bizou! Unfortunately, if he is in congestive heart failure, the only treatment is the lasix pill (furosemide). Depending on how severe his condition is, he may not survive without hospitalization with oxygen and injectible lasix. Your vet may have a strong suspicion of this if Bizou has a heart murmur and many crackles in the lungs (we can hear with the stethoscope).

However, even that is not enough to definitively diagnose it. I have seen a couple dogs I was sure were in heart failure and when I took the x-rays, it turned out to be pneumonia or cancer.

If you can at all afford it, go for the xrays so you at least know what you are dealing with - if it's cancer instead of heart failure, that may change your approach. If it is heart failure, it will give a clue as to how serious.

If you can't afford the x-rays, treat for whatever the vet thinks is most likely. If heart failure is it, the most commonly prescribed medications are furosemide, enalapril, and pimobendan (though there are others).

Finally, if he is still struggling for air, his tongue/gums are any color other than bright pink, or the vet thinks it is serious enough to require oxygen, and you cannot pay for treatment, I would strongly consider euthanasia. Dying by gasping and struggling for air while drowning in your own fluids is a horrible way to go - I've seen it several times.

Please feel free to reach out to me via consultation if you'd like to to have a more detailed conversation with you.

Best wishes to you and Bizou.