Written By Grace Park
Published: 12/05/2020Updated: 12/07/2020
Furosemide | Wag!

Furosemide is a loop diuretic, or water pill, used to treat fluid retention related tocongestive heart failure, kidney and liver disease, high blood pressure and high blood potassium.


The cost of furosemide can vary greatly, depending on the formulation, dosage and amount purchased. A 60 ml oral solution can range from $10 to $20. Injectable solutions can be sold in pre-loaded syringes or in bottles and can cost between $30 and $84. Oral tablets are usually priced per tablet, with costs ranging from $0.05 to $0.55 each. For 100, 500, or 1000 count bottles, prices can be upwards of $12 to $160 per bottle. 


Furosemide is available as a 10 mg/ml oral solution, in tablets of 12.5 mg, 20 mg, 40 mg, 50 mg, and 80 mg dosages, and as an injectable solution of 50 mg/ml. Some veterinary clinics may also offer soft chews in varying dosages. Individual dosing is difficult and is dependent on the severity of the condition, the health of the patient, and whether treatment is for short-term or long-term therapy. Often, a high dose is given initially during hospitalization or during severe heart failure, and a lower dose is given daily for long-term care. Dosages can be:

Dosage is tapered to the lowest effective dose in long-term administration. Higher doses may be needed in dogs affected by renal disease.

Dosage instructions

Furosemide is generally given as an injection by your veterinarian during acute, short-term treatment. For long-term care at home, this medication is usually prescribed as a tablet or oral solution to be administered once to twice daily. In order to reach the lowest dose possible, owners and veterinarians will work together to chart responses to the medication and evaluate testing.

Be sure to always have fresh water available to your dog as furosemide causes an increase in urination. This medication can be taken with or without food. If your dog vomits, give the next dose with food or treats. If vomiting persists, contact your veterinarian.


Furosemide for dogs has shown a high level of effectiveness in reducing fluid retention in relation to heart disease.One study found that high doses of furosemide were associated with longer survival times for dogs with advanced heart failure.

When studying the diuretic effects of furosemide,another study saw an immediate increase in urine volume after short-term administration of the drug.

Side effects of Furosemide

There are several side effects associated with furosemide that can range from normal to severe. Furosemide actively increases urination to release fluid from the body, and this symptom is a sign that the medication is working. Common symptoms of side effects include:

  • Diarrhea
  • Constipation
  • Headache
  • Dizziness
  • Blurred vision

If you notice these serious symptoms, contact your veterinarianimmediately:

  • Dehydration
  • Persistent vomiting
  • Balance issues
  • Lethargy
  • Restlessness
  • Irregular or fast heartbeat
  • Decrease or lack of urination
  • Bleeding
  • Hair loss
  • Lesions or vesicles on skin
  • Hearing loss
  • Stomach pain
  • Head tilt
  • Fever
  • Lack of appetite
  • Darkened urine
  • Jaundice
  • Weakness or collapse

Furosemide decreases fluid in the body by increasing urination, which can lead todehydration. Be sure to always have water available to minimize the risk of dehydration and other side effects.


Furosemide should not be given to dogs who are allergic to furosemide or sulfa medications. This drug should be used cautiously in dogs who have kidney or liver disease, respiratory disease, diabetes, an electrolyte imbalance, problems urinating, or are pregnant or lactating.

Furosemide can make your dog’s skin moresensitive to sunlight and can increase the risk of sunburn.

Drug interaction

Furosemide for dogs (Lasix, Salix, Disal, Uritol) may interact with these medications:

  • ACE inhibitors
  • Antibiotic (amikacin, gentamicin, tobramycin, aminoglycosides)Corticosteroids (prednisone)
  • Anti-fungal medication (amphotericin B)
  • Cardiac glycosides (digoxin)
  • Chemotherapy medication (cisplatin)
  • Insulin
  • Muscle relaxant (succinylcholine)
  • NSAIDs (indomethacin, aspirin)
  • Medications to increase urine (Probenecid)
  • Ulcer protectant (sucralfate)
  • Xanthines (theophylline)

Furosemide should be used with caution with any drug that can increase kidney toxicity. Special care should be taken when combining digoxin or ACE inhibitors with furosemide.

Allergic reactions and sensitivity

Some dogs can be allergic to furosemide. If your dog develops signs of an allergic reaction, including hives, swelling in the throat, face, lips or tongue, or has difficulty breathing, discontinue use of furosemide and seek veterinary attention immediately.

Othersymptoms indicative of an allergic reaction can include diarrhea, intense scratching, and head shaking.

Frequently asked questions

What do I do if my dog misses a dose of furosemide?

If you miss a scheduled dose, give it to your dog as soon as you remember. However, if it is close to the next scheduled dose, skip the missed dose and give the next one on time. Do not administer two doses at one time.

Will my veterinarian monitor my dog while on this medication?

Your veterinarian will need to monitor your dog’s electrolyte and blood sugar levels, as well as kidney and liver values, through blood and urine tests to determine if the medication is working, and to adjust the dosage of furosemide to the lowest possible dose.

Does furosemide require a prescription?

Furosemide for dogs does require a prescription from your veterinarian.

How is furosemide stored?

Furosemide, in both tablet and oral form, should be stored at room temperature in a closed container, and away from light. Do not use past any expiration dates printed on packaging. Do not freeze oral formulations of furosemide, and discard open bottles after 90 days.

What do I do in an emergency?

If your dog is showing symptoms of an overdose or adverse reaction to furosemide, discontinue use and seek immediate emergency veterinary attention. Signs of an overdose include weakness, dizziness, loss of appetite, confusion and fainting. 

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