How do you treat chronic kidney disease in cats?
DOGS
1/13/20258 min read
Kidney failure in cats - treatments
When treating chronic kidney failure in cats, we divide the treatments into:
Kidney-protective treatments
Treatments of uremic complications. Here we implement measures to relieve and try to improve the cat’s quality of life.
However, the damage that has already occurred to the kidneys cannot be undone.
In cases of kidney failure, we aim to detect the disease as early as possible to initiate treatments that reduce the strain on the kidneys and delay the onset of the uremic phase. Uremia occurs when the kidneys’ filtering of substances and toxins decreases. As a result, harmful substances accumulate in the body. This happens in the later stages of kidney disease, and if we detect kidney issues in time and take action, not all cats will necessarily be affected. In my two articles on kidney failure, I therefore focus on how to detect kidney failure early and how to protect the kidneys from further damage. Cats in the later stages often need various treatments to feel well, which are also important for their well-being.
How can we protect the kidneys from further damage?
There are several things we can do to slow the progression of kidney disease, to prevent further damage and allow the cat to live longer and with better quality of life. As mentioned in the previous issue, early detection of kidney damage is important to initiate kidney-protective treatments such as:
Kidney diet
Reduce phosphorus in food
Reduce any protein in urine
Lower high blood pressure
Kidney diet
In kidney failure, it’s important to change the cat’s food to a diet that is gentle on the kidneys and reduces complications. Kidney food has a kidney-protective effect. Many studies show that kidney food prolongs life and improves quality of life in cats with kidney disease.
Through blood tests, your vet can tailor a diet for your cat. Even if you don't know your cat's specific kidney values, it’s still important to feed a kidney diet if kidney problems are suspected.
Challenges with diet
Older cats often face natural difficulties:
Reduced nutrient absorption: Due to impaired intestinal function, older cats need more food to compensate for lower nutrient uptake.
Arthritis: About 60–70% of cats over 10 years old have arthritis, which can cause pain and reluctance to move. Place food bowls higher up to avoid the cat having to bend down, and place them in multiple spots near favorite places.
Decreased appetite: Kidney failure may cause nausea, dehydration, metabolic acidosis, all of which reduce appetite.
Do cats eat kidney food?
There are many good kidney diets, and most cats like the taste. Sometimes switching between different diets helps stimulate appetite. (Tips for improving appetite were discussed in the previous issue of Kattliv.)
I usually introduce the kidney diet as soon as I find signs of kidney problems, even if kidney values aren’t yet very high. If the cat is already in a later stage with many complications, diet changes must be made slowly and carefully. Cats in earlier stages adapt more easily to new food.
What does kidney food do?
Lower protein content – reduces complications: Reducing protein lowers the risk of uremia, where nitrogen-based toxins cause serious complications. One study showed cats on kidney food had 26% fewer uremic complications than those on regular food. It also reduces proteinuria, which can worsen kidney damage. Cats on kidney food live longer and have better quality of life. One study showed they lived 2.5 times longer.
Less phosphorus: Possibly the most important aspect. High phosphorus damages kidneys and weakens bones. Low-phosphorus diets slow kidney damage.
Added potassium: To treat low potassium levels (hypokalemia).
Less sodium: To prevent hypernatremia (high sodium).
Alkaline formulation: To counteract metabolic acidosis, many kidney diets are alkaline.
Dry or wet food?
There are various flavors and both dry and wet versions. Wet food increases fluid intake, which helps if the cat struggles to concentrate urine and loses more fluids. Severely underweight cats may need more calorie-dense dry food.
The calorie struggle
Many cats with kidney failure have reduced appetite. Increasing it is crucial. (See coming article for appetite-boosting tips.) The principle is: better the cat eats something than nothing—even if it’s not kidney food. Try cooked chicken (lower phosphorus), shrimp, tuna, or other treats. Cats not getting enough daily energy will break down their own muscle mass for nutrients, leading to more nitrogen waste, worsening the condition. Such cats may require force feeding or tube feeding. These are stressful, and if appetite can’t be improved, euthanasia may need to be considered.
Why is high phosphorus harmful?
When kidneys fail, phosphorus increases, disrupting bone metabolism. Bones lose calcium, which deposits in damaged tissues, worsening kidney damage in a vicious cycle. High phosphorus signals a poor prognosis. It shortens life in kidney cats. Therefore, reducing phosphorus intake is essential, which your vet can monitor via blood tests.
In late-stage kidney disease, most cats have too much phosphorus and affected bone metabolism. Bone demineralization causes pain and fragility, requiring pain management as well.
How do we lower phosphorus?
Primarily through kidney diet. If that’s not enough, phosphorus binders may be needed. These bind to phosphorus in food so it passes out via feces instead of being absorbed. Ask your vet which binder suits your cat. Some cats may get constipated, especially those needing high doses. Make sure they stay hydrated—sometimes IV fluids are needed. (See Annas tips on hydration.)
Why is protein in urine harmful?
When much of the kidney has stopped working, the remaining part compensates by filtering faster (hyperfiltration). Initially helpful, this eventually damages the kidney, allowing proteins to leak into urine and tissues, causing inflammation and more damage. Scar tissue forms, reducing kidney function further in a vicious cycle. Protein in urine (proteinuria) worsens the prognosis. It must be treated quickly to maintain the cat’s well-being. (Proteinuria can be detected and monitored via urine tests.)
How do we treat proteinuria?
Fortunately, research is progressing. Insights from human and dog studies help cats too. We now know proteinuria harms kidneys in both humans and cats and should be treated early. Treatment options include:
Medications:
Drugs that reduce kidney pressure (hyperfiltration) are key. New research on cats provides two main options:
Angiotensin Receptor Blockers (ARBs): Now available in palatable liquid form. Can be given directly or mixed with soft food.
ACE Inhibitors: Available in palatable tablets. Can be given directly or hidden in food.
High blood pressure must also be treated since it can damage organs and cause proteinuria.
Kidney Diet:
Lower protein helps reduce proteinuria risk.
Omega-3 Fatty Acids:
In humans and dogs, these reduce kidney inflammation and proteinuria. It’s unclear if this applies to cats—more research is needed. One study showed cats eating diets rich in omega-3s lived longer. If you try giving omega-3s, choose fish-based sources, as cats can’t process plant-based omega-3s.
Appetite stimulants for cats with kidney disease
Cats with kidney disease commonly suffer from poor appetite due to various complications such as nausea, dehydration, mouth ulcers, metabolic acidosis, or general malaise. If dietary adjustments and environmental strategies are not enough to encourage eating, veterinarians may recommend medical appetite stimulants. These can be very helpful in maintaining a cat’s nutritional intake and preventing dangerous weight loss and muscle wasting.
Why appetite matters
Maintaining adequate caloric intake is critical in cats with kidney disease. Insufficient energy intake can cause the body to break down muscle for energy, increasing the levels of nitrogen-based toxins in the blood and worsening the cat’s condition. Prolonged under-eating may lead to cachexia (muscle wasting), dehydration, and a poor prognosis.
Medical appetite stimulants
Several medications can be used to stimulate a cat’s appetite, especially when the cat refuses to eat even highly palatable or home-cooked foods.
Mirtazapine
An antidepressant that also acts as an effective appetite stimulant and anti-nausea medication in cats.
Available as a tablet or a topical transdermal gel (applied to the inside of the ear), which is convenient for cats who are difficult to medicate orally.
Typically starts working within hours and is effective in many cases.
Capromorelin (Entyce)
A newer drug that mimics the hormone ghrelin, which stimulates hunger.
FDA-approved for dogs, but increasingly used off-label in cats with promising results.
Available as an oral liquid; palatable and easy to administer.
Cyproheptadine
An antihistamine with appetite-stimulating effects.
Sometimes used in cats that don’t respond to other medications.
May cause sedation in some cats.
Ondansetron and Maropitant (Cerenia)
While not direct appetite stimulants, these anti-nausea medications often help improve appetite indirectly by making the cat feel better.
Useful when poor appetite is linked to nausea, a common symptom in kidney disease.
When to use appetite stimulants
When the cat has refused food for more than 24 hours.
When weight loss is observed despite dietary interventions.
When nausea is suspected and addressed but appetite does not return.
Always under the guidance of a veterinarian—appetite stimulants should be part of a broader treatment plan.
Important notes
Appetite stimulants are not substitutes for a proper kidney diet—they should support, not replace, nutritional therapy.
They work best when underlying causes of inappetence (such as nausea or pain) are also being treated.
Monitor your cat's eating habits and weight closely and report any changes to your veterinarian.
Anemia in cats with kidney disease
Anemia is a common complication in cats with chronic kidney disease (CKD), especially in the more advanced stages. It contributes significantly to lethargy, weakness, reduced appetite, and overall poor quality of life. Recognizing and managing anemia is an important part of supporting cats with kidney problems.
Why does anemia occur in kidney disease?
The kidneys play a crucial role in producing erythropoietin, a hormone that signals the bone marrow to produce red blood cells. When the kidneys are damaged, erythropoietin production decreases, leading to reduced red blood cell formation. Additionally, cats with kidney disease may also experience:
Chronic inflammation
Gastrointestinal blood loss
Nutritional deficiencies (iron, B vitamins)
Shortened lifespan of red blood cells due to uremic toxins
Symptoms of anemia in cats
Cats are very good at hiding illness, but signs of anemia can include:
Pale gums or tongue
Lethargy or weakness
Increased sleeping
Reduced activity or reluctance to jump/climb
Rapid breathing or heart rate
Poor appetite
If you notice any of these signs, especially in a cat with known kidney disease, speak to your veterinarian.
How is anemia diagnosed?
A veterinarian can diagnose anemia through a complete blood count (CBC), which measures the number and quality of red blood cells. Additional tests may be needed to determine the type and cause of anemia, especially if it appears severe.
Treatment options for anemia in CKD
Treatment depends on the severity of the anemia and the overall health of the cat. Options may include:
Erythropoiesis-Stimulating Agents (ESAs)
Synthetic hormones that mimic erythropoietin and stimulate red blood cell production.
Commonly used in moderate to severe anemia.
Examples: Darbepoetin alfa (Aranesp) or epoetin alfa.
Requires close veterinary monitoring to avoid side effects like high blood pressure or the development of antibodies.
Iron Supplementation
Often used alongside ESAs, especially if iron stores are low.
Available in oral or injectable forms.
Helps the bone marrow respond properly to ESAs.
Nutritional Support
Ensure the cat is receiving a well-balanced kidney diet that contains essential vitamins and minerals like B12 and iron.
In some cases, additional vitamin B12 (cobalamin) supplementation is helpful.
Treating Underlying Causes
Address any GI bleeding, infections, or inflammation that may be worsening the anemia.
Blood Transfusions
Rarely used, but may be necessary in cases of life-threatening anemia or while waiting for ESAs to take effect.
Monitoring and prognosis
Regular blood tests are essential to monitor red blood cell levels and adjust treatments.
Treating anemia can greatly improve a cat’s energy, appetite, and overall comfort.
Anemia is a serious but often manageable complication of chronic kidney disease in cats. With early detection and proper treatment, many cats can experience improved quality of life. Always consult with your veterinarian if your cat shows signs of weakness or if bloodwork indicates anemia.
See also coming up article about constipation in elderly cats wichi is a common problem in kidney cats.
Foto Zooey L