Furosemide is the most commonly used diuretic in veterinary medicine. It is used in dogs and cats as a part of the medical management of congestive heart failure, and other conditions where the body is retaining too much fluid. It is similarly used in horses to treat fluid retention or edema, and to possibly diminish exercise induced pulmonary hemorrhage in racehorses. Diuretics act upon the kidneys, causing increased excretion of both electrolytes and fluids.

Furosemide is used intravenously in emergency settings and orally for longer term maintenance. The diuretic effects of furosemide take place within minutes after intravenous injection, with a peak effect at about thirty minutes. Onset of action after oral administration is about an hour. Furosemide is not recommended for the treatment of most kidney disease. Although it may cause a transient increase in blood flow to the kidneys, it does not improve kidney function and may put the animal at increased risk for dehydration or electrolyte imbalances. Diuretics will do little to relieve fluid accumulation and edema caused by low blood protein or vasculitis and may even worsen the animal’s overall condition.


Furosemide (brand names: Lasix®, Salix®, Frusemide®, Disal®, Uritol®) is a loop diuretic used to treat conditions such as congestive heart failure, lung fluid retention, and certain kidney diseases. It can also be used to aid in the treatment of high blood potassium and high blood pressure. In racehorses, it has been used to prevent exercise-induced lung bleeding. Its use in cats and dogs at labeled doses is FDA approved, however, its use at other doses or use in ferrets and other small mammals, horses, birds, and reptiles to treat various conditions is ‘off label’ or ‘extra label’. Many drugs are commonly prescribed for off label use in veterinary medicine. In these instances, follow your veterinarian’s directions and cautions very carefully as their directions may be significantly different from those on the label.

DOGS – Furosemide Tablets are indicated for the treatment of edema (pulmonary congestion, ascites) associated with cardiac insufficiency and acute noninflammatory tissue edema. In cases of edema involving cardiac insufficiency, the continued use of heart stimulants such as digitalis or its glycosides is indicated. The rationale for efficacious use of diuretic therapy is determined by the clinical pathology producing the edema.

Uses/benefits of Furosemide 

Furosemide is most often used to lessen the symptoms of Congestive Heart Failure, whether the condition is acute or chronic.  Heart diseases in dogs are often “silent” or asymptomatic for a long period. This is because the heart is well-protected by the ribcage and is difficult to see. Meaning, heart diseases are often difficult to detect, for both owners and clinicians. 

This is the reason that some dogs will walk around with undetected long-term heart conditions. Sometimes for years. Meanwhile, the heart is trying to compensate. All this leading to the development of Congestive Heart Failure. Congestive Heart Failure is an abnormality in the heart. It ultimately results in the heart being unable to pump enough blood around the body. It’s not a disease as such, but rather a condition of the final consequences of heart failure.

Dosage and Administration

The usual dosage of Furosemide Tablets is 1 to 2 mg/lb body weight (approximately 2.5 to 5 mg/kg). A prompt diuresis usually ensues from the initial treatment. Administer orally once or twice daily at 6 to 8 hour intervals. The dosage should be adjusted to the individual’s response. In severe edematous or refractory cases, the dose may be doubled or increased by increments of 1.0 mg per pound of body weight. The established effective dose should be administered once or twice daily. The daily schedule of administration can be timed to control the period of micturition for the convenience of the client or veterinarian. Mobilization of the edema may be most efficiently and safely accomplished by utilizing an intermittent daily dose schedule, i.e., every other day or 2 to 4 consecutive days weekly.

Diuretic therapy should be discontinued after reduction of the edema, or maintained after determining a carefully programmed dosage schedule to prevent recurrence of edema. For long-term treatment, the dose can generally be lowered after the edema has once been reduced. Re-examination and consultations with the client will enhance the establishment of a satisfactorily programmed dosage schedule. Clinical examination and serum BUN, CO2 and electrolyte determinations should be performed during the early period of therapy and periodically thereafter, especially in refractory cases. Abnormalities should be corrected or the drug temporarily withdrawn.

Side Effects and Drug Reactions

Furosemide may result in these side effects:

  • Dehydration
  • Increased water intake
  • Increased sensitivity to light
  • Lethargy
  • Restlessness
  • Increased heart rate
  • Tilting of the head in cats
  • Reduced ability to hear in cats
  • Vomiting
  • Diarrhea
  • Seizures
  • Loss of appetite

Furosemide may react with these drugs:

  • Corticosteroids
  • Other diuretics
  • Muscle relaxants
  • Drugs that may be toxic to the kidneys
  • Drugs that may be toxic to the ears
  • Aminophylline
  • Corticotropin


  • Drug Name: Furosemide
  • Common Name: Lasix®, Salix®
  • Drug Type: Diuretic
  • Used For: Congestive Heart Failure
  • Species: Dogs, Cats
  • Administered: Injectable, Oral liquid, 12.5 mg, 20 mg, 40 mg, 50 mg and 80 mg tablets
  • How Dispensed: Prescription only
  • FDA Approved: Yes

Prices of Furosemide For Dogs

$24.95 – $80.99

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