Updated March 20, 2021
‘At A Glance (Details Below)’ What To Do
If A Cat Drinks More Than Usual
- It could be due to diabetes, kidney or thyroid disease
- These are all easily diagnosed on routine blood & urine testing
- The top three causes can all be managed or treated if detected in time
- If testing is normal, there’s usually nothing to worry about
Now dive deeper…
All jokes aside, cats really do have a drinking problem. I’ve talked before about cats not drinking enough water but that’s nothing compared with what happens when cats are too thirsty.
A cat who starts drinking or urinating more than they used to is almost certainly in big trouble. The good news is, it’s not an emergency and there’s plenty you can do if you find the cause before your cat gets sick.
Why Do Cats Drink Too Much?
There are five common reasons why you might notice your cat wanting more water. Read more about each at the links.
- Kidney disease (renal failure)
- Hyperthyroidism (overactive thyroid)
- Diabetes mellitus (sugar diabetes)
- Changing from a wet to a dry diet
The last one should be obvious but it really is surprising how much more water cats need to drink on dry foods. Diarrhoea should also be obvious but many cats don’t use litter boxes so you might need to go poking about (quite literally).
Whatever the cause, drinking excessively is a sign to take seriously. Any change in a cat’s behaviour almost never happens just by chance. If there’s one thing I want you to take away from this blog, that’s it.
More About Kidney Disease
I’d like to say a few more words about kidney disease; it’s the most common cause of drinking excessively and the most common illness of older cats. Most cat lovers will at some point have to face it so it’s good to be prepared.
Correct treatment of kidney problems depends on knowing both the stage of the disease and the unique features of each cat. It can be fiendishly complex and no two cats are treated the same. You can read all about this at our kidney disease page but here’s a quick summary of what your vet should be thinking and doing.
Tests For Kidney Problems
- Blood and urine testing. No animal can be diagnosed as having kidney failure without both of these. That’s because dehydration from other causes looks exactly the same until you check the urine concentration. Blood tests like these also show us related problems like low potassium or high phosphate.
- Blood pressure measurement. Kidney cats are often hypertensive; if you don’t fix this, they can go blind from retinal detachment and kidney problems worsen quickly.
- Sterile urine culture. Not only are kidney infections more common than realised, they are great to discover. My own cat had one and by controlling it, her kidney problem got better, not worse.
- Urine protein: creatinine ratio. Urine protein loss is a sign of glomerular damage and can be treated just by adding another tablet.
Treatment Of Kidney Disease
It all depends on the individual. The most important therapy for the majority of cats is a change to a renal support diet. By reducing blood phosphate levels and adding extra nutrients, these diets can make a huge difference to your cat’s lifespan and quality of life.
There are also several drugs we use to treat cats with kidney problems, though most cats only need a few of these.
- Phosphate binders are needed if the special diet doesn’t do enough on its own
- Potassium supplements fight the increased loss of this electrolyte from the kidneys
- Drugs like benzepril or telmisartan reduce glomerular hypertension
- Antihypertensives like amlodipine control high blood pressure
- Appetite stimulants help cats maintain body weight, especially in later stages
The most important thing, however, is close monitoring. There’s no such thing as ‘wait and see’ with a cat who might have kidney problems. If they get sick, the faster we get them rehydrated the better their chances are of returning to normal.
Early detection is even more important. So if you have a cat who starts drinking more, even if they haven’t yet lost weight, let us take a look! It might be nothing, or it might just be the clue that saves your cat.
Related: Why cats pee inside
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By Andrew Spanner BVSc(Hons) MVetStud, a vet in Adelaide, Australia. These help topics are from a series regularly posted on email and Twitter. Subscribe via email here to never miss a story! The information provided here is not intended to be used as a substitute for going to the vet. If your pet is unwell, please seek veterinary attention.