I'm not a vet, but my understanding is that in renal disease mouth ulcers are not curable. They happen because the renal disease has progressed sufficiently that the body chemistry is becoming toxic and highly acid. This hyperacidity and chemical toxicity can also cause the typical "renal breath" odor, upset stomach, nausea, vomiting (after eating), refusal to eat and/or loss of appetite.

Pepcid AD is sometimes recommended to help soothe the stomach and prevent stomach ulcers from forming. Some people I know have used slippery elm bark, which can sometimes help with stomach acidity and mouth acidity.

CRF is a one-way rollercoaster ride, and I've been there. You might ask your vet the questions you posed here. You may also wish to have a kidney panel done so you can track BUN, creatinine, etc., and see where the numbers are. Based on your dog's quality of life and the numbers the tests show, you will be able to make informed decisions about care.

dogaware.com is a very informative website. It is the property of Mary Straus, a highly respected researcher who writes regularly for Whole Dog Journal. She has a helpful section on managing kidney disease, which I used extensively in managing my CRF mastiff's diet and care.

Anything you put inside the mouth ( cream or lotion ) is going to go away in a split second, the animal is going to swallow it right away which can cause other problems.

Aside from saltwater gentian violet solution can be applied on those ulcers, something easier said than done, you and your dog are going to end up painted in a lovely purple or you can use methilene blue solution and end up painted blue, none require a prescription, gentian violet can be purchased in a drugstore, methile blue in an aquarium store, however the antiseptic properties of both are limited to fungi and their application requires previously rinsing the area with saltwater solution.

Spraying salt water into the mouth of a dog with renal disease is a really BAD idea. One of the fundamental parameters carefully controlled in a renal diet is LOW SODIUM. The dog is certainly swallowing at least SOME of this salt water, which is making that expensive renal diet useless.

I agree with anita that it sounds like your dog is having a uremic crisis and needs appropriate veterinary treatment. I saw on your page that you are in Mayalsia, and I am not familiar with what medications are available there. However I would certainly ask a vet about starting an antacid such as cimetidine or a proton pump inhibitor such as omeprazole to help control acidemia which may be causing the ulcers. I would also stop the salt water treatments as it is not likely to help and may contribute to worsening the kidney disease. Sucrulfate will help protect the oral and gastric mucosa from further harm and help heal the ulcer- mix 1 gram tablet in 6cc water and use a syringe to spray into the mouth.

Other considerations in renal disease are managing hypertension (enalapril will help with both hypertension and proteinuria; some dogs also need amlodipine), managing fluid and electrolyte balances, controlling hyperphosphatemia (renal diet is a good start, can add phosphorus binders if that is not enough), and managing other clinical signs as they occur.

I hope this helps a bit. Oral ulcers and uremia can be managed with proper veterinary care. Good luck.