Resource Center Menu

Fludrocortisone for Dogs and Cats

Reviewed by Dr. Whitney Miller

Just like humans, your pet’s endocrine system plays a major role in daily activities like playing with you, going for walks and even sleeping. The endocrine system is made up of many glands throughout the body. These glandsthat secrete hormones that which send instructions— mainly via the circulatory system— to many vital organs in the body and regulate even passive bodily functions.  

The adrenal glands are aA major part of the endocrine system is the adrenal glands, whichand they produce two vital hormones—aldosterone and cortisol. These glands are constantly regulating your pet’s blood pressure and volume, as well as the impulse all living beings experience when in danger called fight or flight. If the adrenal glands aren’t functioning properly, it can fatally affect your pet’s circulatory system, and lead to thethey may development of potentially deadly ailments—like Addison’s disease in dogs.  

Luckily, the medicine fludrocortisone can help regulate nutrients in the blood that affect the function of the adrenal glands. If prescribed by your veterinarian, you can find fludrocortisone—as well as other pet medications like furosemide, cyproheptadine and pimobendan—in Petco’s pet pharmacy

Find a Vet

What is fludrocortisone used for in dogs?

Fludrocortisone acetate acts as a replacement hormone to regulate important electrolytes like potassium and sodium in your dog’s blood—somewhat similar to the use of furosemide. Potassium and sodium levels are delicately balanced in pets’ bodies—, and when the levels of one increase, there is a decrease in the other. This medication can help the endocrine systems of cats, dogs and ferrets maintain a proper balance of these vital chemicals. Fludrocortisone uses include the treatment of Addison’s in dogs and other pets, as well as hyperkalemia and other adrenal insufficiencies.  

Addison’s Disease

What is Addison’s disease in dogs and cats? Feline and canine Addison’s disease is caused when your pet’s body isn’t getting the regulatory hormones it needs. Remember, hormones act as messengers to the organs—if the body isn’t receiving proper instructions, organs can malfunction and fail.  

Signs of Addison’s disease in dogs are very diverse, considering how many organs are affected by hormonal imbalances in the endocrine system. Some of these symptoms include dehydration, gastrointestinal upsets, dark patches on the skin, hair loss, and low energy. Cats with Addison’s disease can develop the same symptoms, but it is a much rarer disease for felines.  

Any dog breed can develop this disease, but certain large breeds like Great Danes and Bearded Collies are more genetically predisposed to canine Addison’s disease. Diagnosing this ailment can be tricky—the symptoms are very broad and sometimes aren’t inconsistent. They may go away, then come back.  

If your pet is displaying symptoms of Addison’s, your vet will perform bloodwork, urinalysis and other tests to determine the severity of the disease and what they need to prescribe for treatment. Often, your veterinarian may prescribe drugs such aslike fludrocortisone and prednisone. 

General Dosage Guidelines

Fludrocortisone is the generic designation for this medication., and iIt is sold under the brand names Florinef, Astonin, Astonin H, Florinefee and Lonikaon, among others. In its generic form, the drug is prescribed as a white scored tablet, but the appearance of tablets can differ depending on the brand. While you should always follow your vet’s instructions when administering fludrocortisone, a typical dose is as follows:.


0.01 milligrams per kilogram of body weight by mouth every 12 hours. Your vet may have to perform serum electrolyte level tests every two weeks and adjust medication in increments until stable. 


0.02 milligrams per kilogram of body weight by mouth once daily. 

You should never attempt to dispense fludrocortisone doses to your pet unless instructed by your vet—testing needs to be done to determine how much of the medication is required., and yYour vet may also prescribe additional medicines with this drug. Serious side effects can occur if your pet is given too much or too little fludrocortisone. Signs of an overdose include limb-swelling due to excess fluids and indications of high blood pressure. 

FludrocortisoneIt can be given with or without food. If you notice your pet gets an upset stomach after taking medication, you may want to try giving it to them with food with it to help settle their system. 

If you miss a fludrocortisone dose, give it to your pet as soon as you remember—, unless it is close to the time of the next dose. —yYour pet should nevernot be given two doses at a time.  If you have any questions about a missed dose or your pet’s overall dosing, consult your veterinarian.

What are fludrocortisone side effects in dogs?

Side effects are rare but may occur when your vet is adjusting the dosage to find the right levels. Side effects may include the following:.

  • Swelling—particularly in the abdomen 
  • Gastrointestinal issues 
  • Increased need to urinate 
  •  Increased thirst  
  • Change of moods  
  • Change in coat  
  • Weakness 
  • Weight loss or weight gain 

As these side effects can be varied and sometimes indicate other health issues, your vet will likely want to monitor the effects of fludrocortisone during the first few weeks.  

How long does Florinef take to work in dogs?

Florinef is a commonly prescribed brand name version of fludrocortisone. The medication typically begins to take effect in as little as one to two hours, and you should be able to start seeing a reduction in symptoms. However, it may take weeks or months to find the correct exact dose that is appropriate for your pet—, and testing will need to be done frequently to ensure it is still working effectively.  

Your pet will most likely be on this medication for the remainder of their life. Other drugs may be added to the regimen, especially when your pet is stressed or ill. If your pet takes fludrocortisone, you may want to consult your vet before stressful life situations occur—such as moving houses, additional pets, travel or boarding situations.  

Additional information

This medication is available by prescription only. Fludrocortisone should be stored at room temperature, preferably in the bottle it comes in from the pharmacy. Always Kkeep away from children and other pets. You should also aAvoid storing it in excessive heat, as this can affect the medication’s efficacy.  

Because Ffludrocortisone can interact negatively with certain prescription and over-the-counter medications, so make sure your veterinarian is aware of any other medications or supplements your pet is taking. It’s also important to let your vet know if your pet is pregnant or lactating, as it’s recommended that some female pets not nurse while taking this medication. 

Related Articles

Reviewed by: Dr. Whitney Miller

As Petco’s Chief Veterinarian, Dr. Miller is the lead veterinary subject matter expert, overseeing the company’s standards of excellence in animal care and welfare, growth in pet services and much more. Dr. Miller leads Petco’s medical team, supporting over 200 full-service hospitals and mobile vaccination clinics operating in over 1,000 Petco Pet Care Centers nationwide.