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Which diuretic is best for cats and dogs?

Diuretics are a medication that eliminates excessive fluids and salts in your pet’s body. They are a first-line treatment for animals with congestive heart failure, kidney disease, high blood pressure, non-inflammatory edema, head or lung injuries and even cancer. Choosing the best diuretic for your cat or dog is important.

If your dog or cat needs an affordable, easy-to-administer treatment for fluid buildup, talk to your vet about Furosemide Tablets For Dogs And Cats.

What to know before you buy a dog and cat diuretic

The type of diuretic

Dog and cat diuretics come in three specific types.

  • Thiazide diuretics: Hydrochlorothiazide removes sodium from urine and also increases urine output.
  • Loop diuretics: Furosemide is a loop diuretic that blocks the absorption of salt and fluid. This also increases urine.
  • Potassium-sparing diuretics: One of these, spironolactone, blocks the hormone aldosterone. Aldosterone causes the kidneys to retain fluids and salt.

Another diuretic that is in its own class is Mannitol. It moves through the kidneys along with excreted fluids and electrolytes.

Prescription vs. over-the-counter

  • Prescription: Most diuretics are only available with a prescription from your vet. This means that the dose and instructions for use are tailored to each specific pet. You may not need to visit the vet in person as it’s possible to get a prescription medication online without a physical vet visit.
  • Over-the-counter: Some diuretics are available over the counter. You might also notice that diuretics meant for people contain ingredients that are similar to those prescribed for cats and dogs. In most cases, over-the-counter diuretics are not a good choice. Better to go with what your vet recommends.


Dog and cat diuretics are available in three forms: tablets, an oral solution and as an injectable.

  • Tablets: Tablets can be tricky for cats, but this may be the easiest way to administer diuretics for dogs. They are also one of the most affordable forms. 
  • Oral solution: Oral solutions can be mixed in with wet food or placed in the mouth with a hollow syringe. If you have a cat who is a picky eater, administration with a syringe may be best. 
  • Injectables: Injectables allow you to change the dose as needed, but many people are not comfortable giving their pets a shot. These may also be administered orally.

What to look for in a quality dog and cat diuretic

Easy to administer

If your dog eats anything, you’re one of the lucky ones. Simply hide the pill in a treat, and you’re done. For all other pets, easy-to-administer diuretics are small, uncoated and tasteless.

Available in different dosages

Your pet’s needs may change as their health improves or worsens. A quality dog and cat diuretic will be available in different dosages or in a form that allows you to adjust the dose as needed. 

Flexible administration

While feeding time is arguably the most convenient time to administer medication, what happens if your pet needs more medication than that? Look for diuretics that can be administered with or without food.

How much you can expect to spend on a dog and cat diuretic

The price varies depending on the form of the diuretic and the quantity you buy. Most tablets cost around 20 cents, while injectables and oral solutions can cost 50% to 100% more than that per dose.

Dog and cat diuretic FAQ

How do you monitor your pet when administering diuretics?

A. Whenever you administer medications, it is critical to keep an eye on your pet to make sure they are tolerating the medicine and not having adverse side effects. 

Common reactions or side effects include:

  • Weight loss due to loss of fluid and electrolytes 
  • Drop in blood pressure 
  • Mild dehydration 

Your pet will be more thirsty when taking diuretics. Offer them fluids and electrolytes regularly to prevent excessive thirst while keeping them hydrated. 

How do you know which diuretic is best for your pet?

A. Guessing the correct medication is never a good idea. The only way to find the best dog and cat diuretic for your animal is to visit your veterinarian. They know your pet’s medical history and can recommend the one suitable for it.

What’s the best dog and cat diuretic to buy?

Top dog and cat diuretic

Best Furosemide Tablets For Dogs And Cats

Furosemide Tablets For Dogs And Cats

What you need to know: These are affordable and effective.

What you’ll love: This option can be prescribed in dosages that include 20 milligrams, 40 milligrams and 80 milligrams in tablet form, and 10 milligrams in liquid form. It can be given with or without food.

What you should consider: This only works for a few hours after each dose, so you’ll need to administer it several times a day.

Where to buy: Sold by Chewy 

Top dog and cat diuretic for the money

Best Spironolactone Tablets

Spironolactone Tablets

What you need to know: This affordable diuretic safely performs its function without removing potassium in your pet’s body. 

What you’ll love: It is used to treat both CHF, fluid in the abdomen and high blood pressure. It is also prescribed under the name Aldactone. The tablet is uncoated for easy absorption and can be hidden in a treat to administer.

What you should consider: Excessive urination is an issue with this option, but this is common with all diuretics. Keep the litter box clean and take your dog out frequently to prevent accidents.

Where to buy: Sold by Chewy

Worth checking out

Best Salix Injectable for Dogs, Cats And Horses

Salix Injectable for Dogs, Cats and Horses

What you need to know: This injectable form of furosemide can flexibly treat multiple animals at different dosages.

What you’ll love: This is a more powerful strength than furosemide tablets. It is helpful for poor heart performance and swelling and fluid retention that is not related to inflammation.

What you should consider: If you want to administer stronger medicine and are squeamish about injections, it can also be given orally.

Where to buy: Sold by Chewy

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Suzannah Kolbeck writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money.

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