Important disclaimer: The information on this website is accurate to the best of my knowledge at the time of this writing. It is gleaned from my research and my experience with my beloved cat, Pumpkin. However, I am not a veterinarian. Please always check with your cat’s vet before implementing any diet or supplement changes!
On this page I will be focusing on Chronic Kidney Disease, known as CKD, because that is the type I have the most experience with. If your cat is experiencing Acute Kidney Failure, also called Acute Kidney Injury, please take her to a vet as soon as possible.
Acute kidney failure is a medical emergency. Signs of this include lethargy, decreased appetite, vomiting, thirst and sometimes seizures. Causes include infections, kidney trauma and ingestion of toxins such as plants, pesticides, some human medicines – if you suspect your cat has ingested anything toxic, please take her to a vet or call an animal poison control right away. The sooner an animal is treated, the better the prognosis.
If you’d like, you can read about the causes of kidney failure (chronic and acute) here at Kidney Disease Causes
My ultimate advice is to be proactive about your cat’s health. If your pet has been diagnosed with kidney disease, be their best advocate. I naively thought that my vets would do all the tests, that they would tell me things to watch for, that they would test his blood pressure and so on, and that they would tell me all the important things to know about kidney disease. For whatever reason (they were probably busy and overwhelmed) they did not. I thought I was being proactive, but I was not proactive enough.
I can’t go back in time, but I can at least try to help other cat owners with what I learned during Pumpkin’s life. Part of this means advising you to ask your vet questions and make sure they are performing all the right tests. Even good vets can make mistakes, especially in a very busy vet office.
Caring for cats with kidney disease
Kidney disease is very common in felines; in fact, it is the leading cause of death in senior cats. If you’d like to learn some reasons why kidney problems are so common for cats specifically, you can read about it here as well as ways to prevent it click here. Otherwise, let’s dive right into how to care for these cats. The sooner CKD cats are treated, the easier it is to keep them comfortable and healthier longer.
- Keep them hydrated
It cannot be stated enough how important it is to keep your cat well-hydrated. All cats should be encouraged to get plenty of fluids, but CKD cats are especially prone to dehydration and must consume enough to compensate for excess loss through urine.
Provide water in several areas throughout your home.
Get a pet fountain. Many cats enjoy drinking flowing water rather than stagnant water. I recommend a stainless steel or ceramic fountain rather than a plastic fountain. The latter can harbor bacteria more easily (and some cats are sensitive to plastic).
Encourage them to eat wet food and add extra water to it. If your cat simply refuses to eat wet food, try to add some moisture to her dry food.
Signs of dehydration include, but are not limited to, sticky saliva, bad breath, fatigue, and dry gums. Ask your vet to show you how to check for signs of dehydration.
- Switch to a Kidney Diet
Cats with kidney disease require high nutrition with reduced protein, as well as reductions in sodium and phosphorous. Many pet food brands offer prescription diets, and some cats do very well, and feel much better, after switching to renal care food. If you are struggling with the cost of prescription foods, there are a few non-prescription options that might be okay for a while.
The brands I know of that currently offer lower phosphorous foods include Tiki Cat and Weruva.
VCA Animal Hospitals recommends that CKD kitties are fed food with a phosphorous range between 0.3-0.6% on a dry matter basis and protein between 28% – 35%. Dry matter basis means the nutrients in food if all the water were removed.
Helpful Supplements
Some vitamins and other supplements can help your kitty. Make sure to check with your vet before starting anything new, however, as every cat’s health needs are unique! Just consider this a list of things to ask your vet about.
- Phosphate Binder
If a low-phosphorous prescription kidney diet isn’t keeping your cat’s phosphorous levels in check, you should consider using a phosphate binder. Most binders contain aluminum or calcium. Chitosan is one alternative to aluminum -based binders. However, your vet should know which would be best for your cat’s needs and how much to give. Phosphate binders are often sold in powder form which makes it easy to mix with wet food.
Why worry about phosphorous levels?
Phosphorous can build up in kitty’s blood when their kidneys aren’t working well. This damages the kidneys even more, weakens bones, increases the risk of heart attacks and can cause other serious health problems.
- Protein Byproduct binder
Porus One (RenalTec) This supplement is newly available in the United States but has been sold overseas for several years. It is carbon-based and is supposed to work by binding to protein byproducts in the gut so these products don’t break down into substances that the kidneys must then filter.
The idea is that this is one way to reduce the kidneys’ workload. If this medicine works like it is presumed to work, I feel it is something very worthwhile to add to a kidney diet. (I only discovered this product towards the very end of Pumpkin’s life so I don’t know if it would have helped him or not, but I believe it could have). If your cat is on prescription medicines, consult with your vet before adding this (to make sure it won’t interfere with absorption of the prescribed medication).
- Kidney Probiotics
Azodyl is a probiotic formula for cats that contains Enterococcus thermophilus (KB 19), Lactobacillus acidophilus (KB 27), Bifidobacterium longum (KB 31) and Psyllium prebiotic.
These probiotic strains have been formulated to help eliminate uremic toxins and can presumably help your cat. The downside of this supplement is the cost and that the capsule is supposed to be administered whole instead of sprinkled over food. The positive side of this supplement is it shouldn’t have any negative side effects.
- B Vitamins — B vitamins are easily lost in the urine, and cats with kidney disease can quickly become depleted. A good quality B supplement might bring better quality of life to your kitty. Make sure to choose only vitamins formulated for pets (to avoid overdosing or any additives that might be toxic to cats). Choose vitamins from reputable companies with reputable suppliers to avoid fakes or poor-quality ingredients.
- Omega 3
Omega 3 fatty acids reduce inflammation, reduce protein loss in urine and reduce blood pressure. These known benefits are why this supplement is added to most commercial preparations of feline renal food. It is worth seeing if your kitty might feel better with a little extra omega 3 from a reliable brand.
- Sub Q Fluids
Subcutaneous fluids help CKD cats when they can no longer get enough fluids via drinking and eating. This happens at some time during the disease due to excess fluid loss. Eventually drinking just isn’t sufficient and your cat will benefit from fluid therapy. Fluids used for subcutaneous use are special sterile formulations (lactated ringers)
You can ask your vet to administer the fluids at the clinic, but it is usually more convenient to do it in the comfort of your own home (a vet tech can show you how). Your veterinarian will prescribe you the appropriate fluids and needle tips. These fluids are given by inserting a needle just under the skin (it is not the same as an IV drip although the bag the fluids come in is the same – the fluids you give at home will not be administered into a vein). I recommend looking at videos online to see how this is done or ask a vet tech to show you.
Pumpkin wasn’t on fluids very long but when he was, he did better with the needle when we distracted him with a tasty treat. It takes a little while for the right amount to drip in, so you’ll want to find ways to ensure your cat will sit or lie still for it. It’s a good idea to get them preoccupied with a bowl of their favorite pate, for example, or crunchy treats. A small amount of lidocaine on the skin prior to inserting the needle (they are big) also helped (a vet tech suggested that to me) – but make sure kitty doesn’t lick it afterward!
A very important note about subcutaneous fluids: Make sure that they have completely absorbed and that your cat is not showing signs of fluid overload before giving more. Signs of fluid overload include a runny nose, swollen eyes, coughing and increased respiratory rate or noisy breathing.
Supplemental fluids can greatly improve your cat’s quality of life but just take care. Have your vet ensure the cat’s heart is doing well. Unfortunately, Pumpkin’s kidney values took a sudden bad turn, but the very thing meant to help him – sub q fluids, iv fluids and a transfusion for his anemia, was too much for his heart and he developed congestive heart failure while at the specialty vet hospital. So, please, please be careful of fluid overload.
I feel the vet hospital might not have watched pumpkin close enough for signs of too much fluid. He was still happy and wanting cuddles going in, then just a few days later we picked him up (after the horrible phone call no one wants to get that he was dying) and he was a mess.
The diuretic treatment for congestive heart failure is terrible for kidneys because it dehydrates the body. As it was, it wasn’t working for him as it should, and he went downhill very quickly. I had just one more day with him before he had to be taken to a different emergency vet to help ease his discomfort. It was all too much for him and he passed away.
So. please DO give lifesaving fluids when the time comes. But, please do also watch for fluid overload whether your kitty is having subcutaneous fluids or intravenous (IV)
Second opinions
Many people feel loyal to their veterinarian, but please don’t hesitate to get a second opinion from another veterinarian if you have any doubts about whether a procedure is needed, or the best or if the diagnosis is accurate.
Health Issues Common to Cats with CKD
- Bladder and Urinary Tract Infections
Stay alert to your cat’s bladder health. Chronic kidney disease makes cats more prone to bladder infections. These alone are rough on a cat, but additionally they can lead to a kidney infection and cause further damage. Culture the urine. Ask your vet to perform tests for infections regularly. You might also want to use monitoring litter that alerts you to changes in your cat’s urine.
- Anemia
Cats with kidney disease can develop nonregenerative anemia. The kidneys are responsible for producing a hormone that helps red blood cells form in bone marrow. As kidney function worsens, anemia can become a very serious problem that needs to be addressed right away. (I didn’t know that I needed to watch for this, and I found out the hard way).
What to look for? Signs of anemia include pale gums, lethargy, and, in many cases, diminished appetite. Although supplements can help some cats with anemia, it is best to consult a vet and have blood tests done first and to find out if kitty needs prescription medicine or other treatments for his/her anemia.
There are a few treatments for anemia and, at the time of this writing in 2025, the FDA has recently given the green light to a new drug.
- Hypertension
One of the important jobs of the kidneys is managing blood pressure. When kidneys develop problems, blood pressure rises. Hypertension can, in turn, damage the kidneys as well as other organs of the body including the eyes and the heart. Fortunately, there are medications available for this. Make sure that your veterinarian is testing your cat’s blood pressure at every visit.
- Potassium Depletion
Cats with CKD tend to lose a lot of potassium in their urine and can develop low potassium, which is called hypokalemia. Make sure your vet is testing for this. Don’t give your cat potassium without getting blood tests first to make sure it is needed. Too much potassium can also cause serious problems.
Some signs of low potassium include weakness, appetite loss and lethargy. Cats don’t always show signs at first, so don’t wait for symptoms to appear before getting the blood tests. Since low or high potassium can cause such serious problems, I feel blood tests should be performed regularly for any cats with a chronic illness.
- Constipation
Some cats can develop constipation from being chronically dehydrated. Monitor your cat’s bowel movements and talk to your vet if the cat doesn’t poop often or if the feces seem dry and hard.
- Ascites
Ascites is fluid that has built up in the abdomen. If your cat’s tummy seems rounder or seems to be swollen, make a vet appointment before it worsens. Your cat will need treatment right away.
Thank you for caring for your cat. People like you help make the world a better place.