Hello I am Dr. Joey. Thanks for trusting me to help you and your pet today. I am a licensed veterinarian with over 15 years of experience. I look forward to working with you.
The first step is any cat with kidney issues is to get him in for his vet to check his kidney values and blood pressure. The most common cause of sudden appetite changes is that the kidney issues are worsening (phosphorous level elevating, nausea worsneing, anemia) or he has a urinary tract infection (easily treatable).
In the meantime you can easily start him on Pepcid AC (famotidine) ten mg and give one-fourth tablet once daily. You can find this at any people pharmacy. Has no bad side effect but can help remarkably with nausea. Tempt him to eat. Bring out his favorites, being less concerned about type of diet feeding.
So this is more likely gastric rather than arthritic or something more immediately life threatening?
Yes, this is not likely to be arthritis. But if your vet finds no problems other than existing arthritis then this can be addressed with pain relief. Arthritis is very unlikely to be the cause. It is more likely to be related to his existing problems or a primary stomach/intestinal problem. So, I do reocmmend have him seen today, if possible.
I'll call them when they open. Thanks for the help.
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