All of the treatments are equally helpful for cats. In fact if you are able to do all that I have listed cats seem to do a bit better in the long run than dogs. The only problem with cats is that it is hard to get them to take the herbs. Pill pockets help, if they like them.
The appetite stimulant: Mirtazapine is even more effective in cats than dogs! But you must have a prescription. The dose of Mirtazapine for cats is 1/4 of a 15mg. tablet every 3 days. If you get the Mirtazapine you may not need the Si Miao San, but the other two herbs should be very helpful.
Additionally, since they are cats, purchase the herb in the form of TEAPILLS or tinctures. Teapills are very small and they would need 4 teapills 2 to 3 times per day. If you can find the tinctures, try to get the kind that is in a glycerine base with very little alcohol. Many tinctures are only alcohol based and cats hate alcohol. They would probably need 5 drops of each tincture twice daily.
I am very sorry for the loss of your rescues!
With renal failure bloodwork will show many electrolyte abnormalities including potassium. Because the kidneys act as blood filters for electrolyes in the body, as the kidney lose their filtering capacity many electrolyes will become elevated. The most important indicators of the progression of renal failure, however, are blood test elevations of BUN, Creatinine, and Phosphorus. Calcium will also become elevated in end stage renal failure.
Assuming both of your remaining dogs are in end stage renal failure there is not much that can help in Western Veterinary Medicine. I assume that their most recent blood work showed some, or all, of the elevations listed above? We may be able to help them enjoy a better quality of life for a time with herbal supplements, diet, appetite stimulants, phosphorus binders, and S.C. Fluid therapy.
I would suggest the following herbal remedies at double the recommend dose:
Wei Ling Tang (one of the ones for kidney failure)
Si Miao San (to help with appetite)
Da Bu Yin Wan (for hind limb weakness, related to kidneys)
Most importantly they must keep eating even if you must force feed them. Baby food meats, scrambled eggs and cottage cheese are easy to use to syringe feed. In renal failure it is important to use high quality proteins in moderate amounts.
Daily Sub Cutaneous fluid therapy of Lactated Ringers solution is also important, and can be performed at home. Sometimes a SC fluid therapy treatment is all that is needed to get them eating for a couple of days.
Phosphorus binders and prescription appetite stimulants are available by prescription.
Thank you very much for the information and remedies, especially for the hind legs. I just realized I did not tell you but they are cats. They appear to be fine except for the weakness. They eat, play, get into trouble and use the litter box and I have noticed nothing untoward in their daily activities. Shadow, the male, is king of the house and his appetite is a little more open - as in what I eat.
Blood work was done and I mentioned the hind leg weakness to the vet when I got him(Shadow) out of the hospital but she looked at me oddly and it was apparent to me that no one had noticed it at the vet's.
Thank you again.