Furosemide for Dogs

If your dog has been diagnosed with congestive heart failure, chances are that your veterinarian has mentioned using a medication called furosemide as part of their treatment plan. Furosemide has been widely used in veterinary medicine for many years as a diuretic and comes in a variety of formulations to meet the needs of individual dogs. 

Here we will discuss furosemide in detail, including how it works, why it’s beneficial, and what side effects pet parents should be aware of.  Read on to learn more about this medication and how it may benefit your dog. 

What Is Furosemide? 

Furosemide is a loop diuretic that is commonly administered in veterinary emergency clinics and primary care hospitals to remove excess fluid from the body.

Furosemide has been used for decades in human medicine to treat fluid retention related to underlying health conditions, such as heart, liver and kidney diseases, but it was more recently approved by the FDA for use in dogs.  

It is sold under the brand names Salix, Lasix, and Disal for dogs but it is also available in a generic form. Most primary care veterinarians keep this medication stocked in their clinics. Pet parents may also receive it from a veterinary cardiologist. 

What Does Furosemide for Dogs Look Like?

Furosemide is most commonly found as a tablet that is round and white. Each tablet is stamped with letters and numbers that vary based on the manufacturer and dosage. 

Furosemide can also be compounded into a liquid, capsule, or chew. The appearance of these compounded formulations will vary based on the manufacturer. 

Injectable furosemide comes in a dark tinted bottle and is thin and clear in color. 

How Does Furosemide Work?

Furosemide is a loop diuretic whose main function is to remove excess water from the body. It does so by interfering with sodium, potassium and chloride channels and increasing blood flow through the kidneys. As a result, the body produces more urine to flush excess sodium and water out of the body.  

It starts working within just a couple hours of administration. You may notice that your dog needs more frequent potty breaks while taking this medication.  

What Is Furosemide Used for In Dogs?

Veterinarians normally prescribe furosemide to dogs when they have fluid retention within their bodies. Specifically, furosemide is most commonly used for dogs with heart failure because they develop fluid buildup within their lungs and abdomen. Other conditions that may benefit from furosemide treatment include the following:

• Edema
• Kidney disease
• High blood pressure 
• High blood potassium levels
• High blood calcium levels

Not every dog with these conditions can receive this medication safely. Your veterinarian can advise you if furosemide may be a safe option for your pet based on their overall health status. 

How to Give Furosemide to Dogs

Furosemide can be given orally to dogs every eight to 12 hours. Pet parents should give the medication with food to avoid an upset stomach. Capsules and tablets can be disguised in pill pockets or in a ball of wet food to entice your dog to take them. Medication can be compounded by special pharmacies into a flavored liquid or chew for easier administration if necessary. 

Injectable furosemide is given through the dog’s vein, into the muscle or underneath the skin. The frequency of dosing varies based on the underlying health issue being treated. The injectable form is only administered at a veterinarian’s office. 

Furosemide Side Effects for Dogs

Furosemide is a safe medication when given as prescribed. However, there are some side effects that may occur in dogs taking this medication that pet parents should be aware of. Side effects of furosemide may include:

• Increased thirst
• Increased urination
• Diarrhea

Less common, but serious side effects may include: 

• Loss of hearing
• Difficulty with balance
• Lack of or reduced urine production
• Irregular heart rhythms
• Weakness
• Vomiting
• Muscle spasms
• Lethargy
• Restlessness

Furosemide can cause dehydration and electrolyte imbalances in some instances. If left untreated, this can lead to collapse and formation of blood clots. Serious side effects are more common in dogs with pre-existing kidney or liver diseases and diabetes. 

Reactions with Other Drugs and Medications

Furosemide should not be taken with any other type of diuretic as the combination can cause severe dehydration and electrolyte imbalances. 

The following medications have also been shown to interact with furosemide.

• Digoxin
• Prednisone
• Potassium supplements
• Aminoglycoside antibiotics
• Bromide 
• Insulin
• Succinylcholine
• Theophylline

Always discuss any medications or supplements your dog is taking with your veterinarian prior to giving furosemide.

Furosemide Dosage for Dogs

Furosemide is given according to the weight of the dog. Pet parents should always follow their veterinarian’s instructions closely when administering this medication. 

What if My Dog Misses a Dose of Furosemide?

If you forget to give a furosemide dose on time, give the dose as soon as you remember and continue the medication as previously prescribed. However, never give two furosemide doses at one time. If you are ever in doubt about giving the medication to your dog, call your veterinarian for guidance. 

Furosemide for Dogs Cost

Furosemide is relatively inexpensive. The exact costs will depend on the specific dosage and duration of treatment but in general, pet parents can expect to pay $10 to $30 per month for furosemide tablets. Brand name medications tend to cost more than generic forms. Compounded medications, especially the oral furosemide chews, will be more expensive because they need to be prepared by a special pharmacy.

Furosemide Storage Instructions

Oral and injectable furosemide should be stored at room temperature out of direct sunlight. Injectable furosemide should be used within 28 days. Always keep this medication safely out of reach of children and other pets.