Furosemide is classified as a loop diuretic and its a commonly prescribed drug in the veterinary field for the treatment of fluid retention and pulmonary edema associated with heart failure.

Pharmacology of Furosemide

Furosemide’s primary mechanism of action is on the part of the kidney known as the loop of Henle. This medication increases the excretion of chloride, potassium, sodium and water, among others, thereby increasing the volume of urine. It is effective at reducing fluid accumulation, or edema, which often accompanies heart failure.

This drug is also used in some cases to treat animals suffering from electrolyte imbalances, especially in cases of extraordinarily high calcium or potassium levels.

Possible Side Effects Associated With Furosemide

Furosemide is a potent diuretic and, while safe and effective when used according to a veterinary prescription, some animals may experience certain side effects. Common adverse effects associated with furosemide include dehydration, low potassium levels in the blood, potential kidney problems and electrolyte disturbances. In very rare cases in which the patient is given very high doses of the drug, anemia and hearing loss have been reported.

Furosemide Drug Interactions

Furosemide may interact with one or more medications the patient is taking, so it is important to consult with the veterinarian regarding the animal’s existing drug regimen before administering this medication. Common medications known to interact with furosemide include, but are not limited to, corticosteroids, theophylline, aspirin and digoxin.

Additional Precautions for Furosemide

Furosemide should be avoided if the patient is allergic to the drug or suffering from dehydration, impaired kidney function, diabetes, liver disease or certain electrolyte abnormalities. If the animal is unable to urinate, furosemide should not be given. Dosing should be re-evaluated in patients experiencing acute conditions such as diarrhea or vomiting, which may affect the electrolyte and water-balance of the body.

How Is Furosemide Supplied?

Furosemide is only available with a prescription. It is available under the brand name formulation known as Lasix® and Salix®, or in a variety of formulations through a veterinary compounding pharmacy. Furosemide can be compounded in oral capsule, chewable, or suspension, as well as a transdermal gel.

Author: Giano Panzarella