Managing Congestive Heart Failure in Cats with Lasix

Lasix, or furomeside, is a medication used to treat congestive heart failure in cats. It acts as a diuretic and can also be used to treat diseases of the kidneys, edema and high blood pressure in cats.

Congestive Heart Failure in Cats and Causes

Congestive heart failure in cats is an abnormality in the shape of the heart or how it functions. The abnormalities affect how much blood the heart pumps blood through a cat's body. In cats with congestive heart failure, the heart is not able to pump enough blood, causing fluid retention in the lungs, called "pulmonary edema".

Congestive heart failure has many causes. Some cats are born with the condition, while others may have hypertrophic cardiomyopathy (a disease that affects the heart itself) or a disease that damages the lining of the heart (pericardium). Heartworms, anemia, hyperthyroidism and arrhythmia can also lead to congestive heart failure.


The number one symptom of congestive heart failure in cats is lethargy. A cat will feel more tired and will lack energy, because the heart is not circulating blood in his or her body correctly. As fluid begins to accumulate in the lungs, a cat will also begin to cough and have difficulty breathing.

Weight loss is also an underlying symptom of congestive heart failure.

Treating a Cat with Congestive Heart Failure

After a cat has been diagnosed with congestive heart failure, your vet may recommend initial hospitalization of the cat. This would help stabilize a cat if a lot of fluid has built up in the lungs, if low blood oxygen levels are present or if the cat needs additional treatments.

A veterinarian may also prescribe a low-sodium diet and Lasix therapy, which will help reduce excess fluids that have accumulated in a cat's body.

Using Lasix to Manage Congestive Heart Failure in Cats

Lasix, or furosemide, is a strong diuretic that can only be obtained with a prescription. Kidneys receive assistance from Lasix, as the drug prevents the absorption of elements that cause fluid build-ups in a cat's body:

  • Water
  • Sodium
  • Potassium
  • Chloride

As a result, Lasix will cause a cat to void more often, to rid herself of these elements. Lasix can also help electrolytes become more balanced.

Side Effects of Lasix

Some of the main side effects of Lasix are increased thirst and urination.

Cats that have kidney problems, liver disease, diabetes or are dehydrated should not use Lasix, as these conditions can become worse while taking the medicine. Lasix can also cause:

  • Dehydration
  • Electrolyte imbalances
  • Low potassium levels in the blood
  • Kidney problems

When a cat is taking high doses of Lasix, anemia and hearing loss can be an adverse reaction to the medication.

A cat with congestive heart failure may be experiencing a lot of fluid retention. Treatment that involves Lasix can help ease the discomfort of edema, and help a cat feel more comfortable.