Fludrocortisone Acetate

By Rania Gollakner, BS, DVM, MPH

What is fludrocortisone acetate?

Fludrocortisone acetate (brand names: Florinef®, Astonin®, Astonin H®, Florinefe®, Lonikan®) is a mineralocorticoid used to treat adrenal gland insufficiency or hypoadrenocorticism (Addison’s disease). It may also be used with other medications to treat hyperkalemia.

Its use in cats, dogs, and ferrets to treat Addison’s disease 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.

How is fludrocortisone acetate given?

Fludrocortisone is given by mouth in the form of a tablet. It may be given with or without food; however, if vomiting occurs when dosed on an empty stomach, give future doses with food. Most pets will need to be given glucocorticoid supplementation in addition to this medication, especially during times of stress.

Do not stop giving this medication abruptly, as serious side effects can occur.

This medication will take effect quickly, in about 1 to 2 hours, and improvement in clinical signs should follow.

What if I miss giving my pet the medication?

If you miss a dose, give it when you remember, but if it is close to the time for the next dose, skip the dose you missed and give it at the next scheduled time, and return to the regular dosing schedule. Never give your pet two doses at once or give extra doses.

Are there any potential side effects?

Side effects are uncommon but may include vomiting. Serious side effects associated with chronically high doses include increased thirst and urination, body swelling, weight gain, pot belly appearance. Serious side effects associated with a dose that is too low includes weakness, tiredness, shaking collapse, lack of appetite, vomiting, diarrhea, weight loss, and a low heart rate.

This moderate-acting medication should stop working in a few days, although effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

Do not use fludrocortisone in pets that are allergic to it. If use in lactating animals is required, use a milk replacer. Fludrocortisone should be used cautiously in pregnant pets, as there is limited information on safety. Fludrocortisone  should be used cautiously in pets with heart failure, kidney disease, or swelling.

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with fludrocortisone acetate: amphotericin B, aspirin, bupropion, potassium-depleting diuretics, insulin, phenobarbital, or vaccines.

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking.

Is there any monitoring that needs to be done with this medication?

You veterinarian will monitor your pet’s electrolytes and kidney values regularly: every 1-2 weeks initially and then every 3-6 months once stabilized. Monitor your pet at home for changes in weight or signs of edema (swelling). Your veterinarian may monitor your pet to be sure that the medication is working.

How do I store fludrocortisone acetate?

Store the tablets at room temperature between 59°F and 86°F (15°C and 30°C ), protected from moisture and excessive heat.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility.

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