The only answer I can give you is what is her quality of life? Late stages means the kidneys are at the point of almost no longer working at all. For this in people we need a kidney transplant to live.
Your vet may have talked to you about euthanasia because they felt that as the dog dies there isn't any quality of life in their remaining days. But you can speak to your vet who may have what is called a 'end of life treatment plan' this is to prepare you for your dogs final days, how to feed when they lose their appetite, how to cope when your dogs incontinent. And many other things. Best thing is to always make your dog as comfortable as possible
Please see the Grouos option in the side of the page and click on that. You will see Chronic Kidney Failure in dogs and click on that. Tony started this community and you can join and get more help then you will here.
Oh my heart is with you as you face this hard journey ;( we just had to put our 13 year old best buddy on the rainbow bridge last Tuesday because of kidney failure! My husband and I both researched sites and treatments but really here is the advise I would give now- enjoy each day with your angel in a fur coat and if he or she is in the last stages then do whatever is comfortable and adds to quality of life ;) we tried the liquid meds and the special food but honestly it was too late and it just made our Torque more sick and did not add to his quality of life! We stopped all meds and just tried to feed him ;( we took short walks and played calm tennis ball did his favorite stuff! Really we just didn't want to let go so it was Torque who decided it was time he looked at us in a way that said I'm tired mom and dad ;( it was the hardest most heart wretching last day we have ever experienced ;( but we were together til the end and my life is forever changed by the love of a crazy tennis ball loving friend! We raged against the dying of the light for as long as we could - grieving profoundly is a price we humans pay for loving profoundly! (Quoted from Barbara King )
My heart goes out to you and everyone else faced with losing a dog to kidney failure. Had to say goodbye yesterday to my second dog to endure it. Doc's kidneys went from, "not great, but don't be alarmed" to END Game in one month. We're reeking and traumatized, particularly since our plan for a calm quiet release from suffering went up in smoke. No need to go into all that here though.
Personally, I think aluminum hydroxide powder is the better option for a binder, since much of the time calcium is already high in dogs with kidney failure. Definitely something to ask your vet about. If he doesn't have it, you can easily get it online.
Cerenia wasn't around for our first dog, so we had to use oral Reglan in the beginning. Because it's metabolized in the kidneys, she built up a toxic dosee in her blood. Not pretty. However, injectable Reglan wasn't a problem and was more effective. Go figure. Luckily, my husband was able to do the injections at home.
This time around, we tried cerenia. It reduced Doc to a sick, trembling, shaking mess with the first dose. Next up was Phenergan. I have to say it was a miracle for Doc. He had no further vomiting episodes and actually regained his appetite and gained back some weight. It was a double edged sword. Doc atries well, but by that time his kidneys were so gone that every bite of food was poison. Within an hour of eating even a small meal, the trembling started. It slowly worsened into jerking, eye rolling seizures that took hours to resolve. With all the toxins in his system, Doc's breath was pure ammonia. It was time to say goodbye, but my husband could only see the wagging tail and good times before meals.
Yes, there are things you can do to keep your dog comfortable, but you also have to be able to recognize that meds can cover up a lot of misery. Dogs themselves cover up illness, because they still have the pack instinct that tells them to kill weak members of the pack to save the whole. I've seen that play out right before my eyes with my own dogs. With 2 other dogs in our pack, we had to keep a close eye on things and had to intervene a few times. It's a hard thing to see amongst formerly bonded pack members, but you can't take it personally.
Definitely check out the Chronic Kidney Failure group. Tony has a ton of great advice based on solid research that can help maintain what kidney function remains. From my experience with 2 dogs, it seems not so much a painful disease as a miserable one with so much nausea and vomiting. Vets seem to avoid prescribing Phenergan for dogs, I imagine because some idiots like to abuse it. It's actually an antihistamine, and an old med that is very cheap yet also very effective. If nothing else helps your dog's nausea, ask your vet about it. Zofran is another one to consider in the realm of people drugs that dogs can take, but I have no personal experience with it and my dogs. It's also expensive.
CKF is a horrible roller coaster ride that can make it very difficult to determine when to say goodbye. Do talk to your vet about a plan well before you'll need it. Keep up regular lab work to see exactly what's going on in your dog's body and if your maintenance measures are having any effect. Make sure your vet tells you what symptoms indicate that it's time too. In my dog's case, it was seizures after eating. God bless you.