Fludrocortisone Acetate
9alpha-fluorohydrocortisone 21-acetate
Also known as: Florinefe · Astonin H · Lonikan · Fluohydrisone acetate · Fluohydrocortisone acetate · 9alpha-fluorohydrocortisone acetate · Fludrocortisoni acetas
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hypoadrenocorticism | Initial dose of 0.01 mg/kg PO twice daily | PO | twice daily | — | 🌎 NA |
| Maintenance of hypoadrenocorticism | Initially, 0.01-0.02 mg/kg/day PO and adjusted by 0.05-0.1 mg (total dose) increments | PO | daily | — | 🌎 NA |
| Hypoadrenocorticism | 0.01 mg/kg PO twice daily | PO | twice daily | — | 🌎 NA |
- Hypoadrenocorticism: Adjust dose based on monitoring serum electrolyte concentrations every 1-2 weeks until stable. Once stable, recheck every 3-4 months. Addition of NaCl (0.1 g/kg/day) can be useful in reducing the dose of fludrocortisone and reducing PU/PD.
- Maintenance of hypoadrenocorticism: Adjust based on serial electrolyte determinations. Most dogs will ultimately require 0.02-0.03 mg/kg/day.
- Hypoadrenocorticism: Titrate dose to effect; typically dose needs to be increased over time. Only 50% of dogs on fludrocortisone require supplemental prednisone.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Maintenance therapy of hypoadrenocorticism | 0.02 mg/kg PO once daily | PO | once daily | — | 🌎 NA |
| Maintenance therapy of hypoadrenocorticism | 0.1 mg total dose/cat PO once daily | PO | once daily | — | 🌎 NA |
- Maintenance therapy of hypoadrenocorticism: Prednisone or prednisolone (1.25 mg per cat PO once daily) can be used for glucocorticoid replacement.
- Maintenance therapy of hypoadrenocorticism: Administer with prednisolone (0.2 mg/kg PO once daily).
Ferrets
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hypoadrenocorticism | 0.05-0.1 mg/kg PO q24h or divided q12h | PO | q24h or divided q12h | — | 🌎 NA |
- Hypoadrenocorticism: For those animals that still exhibit Addisonian signs even with prednisone therapy.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Fludrocortisone acetate is a potent, orally administered synthetic corticosteroid primarily utilized in veterinary medicine for its profound mineralocorticoid properties.
- Primary Indication: It is a mainstay treatment for adrenocortical insufficiency (Addison's disease) in dogs and cats, serving as an oral alternative to injectable desoxycorticosterone pivalate (DOCP).
- Dual Action: While used for its mineralocorticoid effects (125 times more potent than hydrocortisone), it also possesses significant glucocorticoid activity (10-15 times that of hydrocortisone).
- Clinical Pearl: Because of its inherent glucocorticoid activity, approximately 50% of dogs managed on fludrocortisone do not require additional daily prednisone/prednisolone supplementation, unlike those treated with DOCP. However, this same glucocorticoid activity can lead to iatrogenic hyperadrenocorticism signs (PU/PD, polyphagia) at higher doses.
Mechanism of action
Fludrocortisone acts as a potent agonist at mineralocorticoid receptors.
- Binds to cytosolic mineralocorticoid receptors in the principal cells of the renal distal tubules and collecting ducts → translocates to the nucleus.
- Upregulates the transcription of epithelial sodium channels (ENaC) on the apical membrane and Na+/K+-ATPase pumps on the basolateral membrane.
- This mechanism → promotes active sodium reabsorption (and obligate water retention) while accelerating the excretion of potassium and hydrogen ions into the tubular lumen.
- Also binds to glucocorticoid receptors, contributing to anti-inflammatory and metabolic effects (gluconeogenesis, protein catabolism).
Safety & warnings
Contraindications
- Known hypersensitivity to fludrocortisone
Adverse effects
- Polyuria (PU)
- Polydipsia (PD)
- Hypertension
- Edema
- Hypokalemia
- Hypernatremia
- Signs of iatrogenic Cushing's syndrome (due to glucocorticoid effects)
Precautions
Stress Dosing: All animals with hypoadrenocorticism should receive additional glucocorticoids (2-10 times basal dose) during periods of stress, surgery, or acute illness.
- Glucocorticoid Supplementation: Some dogs or cats may require additional ongoing supplementation with a glucocorticoid agent (like prednisone) if fludrocortisone's inherent glucocorticoid activity is insufficient.
- Nursing Mothers: May be excreted in significant quantities in milk. Puppies or kittens of treated mothers should receive milk replacer after colostrum is consumed.
- Cost: Expense may be a limiting factor, especially in large breed dogs requiring high doses.
Drug interactions
Patients may develop hypokalemia if administered concomitantly.
Fludrocortisone may reduce salicylate levels.
May cause hypokalemia; diuretics can cause sodium loss, counteracting the effects of fludrocortisone.
Potentially increases the insulin requirements of diabetic patients.
Monitoring
- Serum electrolytes (Sodium, Potassium)
- BUN and Creatinine
- Body weight
- Physical examination for signs of edema or hypertension
- Clinical signs of PU/PD
Pharmacokinetics
Absorption
In humans, well absorbed from the GI tract with peak levels occurring in approximately 1.7 hours.
Elimination
In humans, biologic activity persists for 18-36 hours despite a shorter plasma half-life.
Overdose
Overdosage is typically characterized by excessive mineralocorticoid effects:
- Clinical Signs: Hypertension, edema, severe hypokalemia, and hypernatremia. Excessive glucocorticoid signs (severe PU/PD, panting) may also occur.
- Management: Discontinue the drug until clinical signs associated with overdosage have resolved. Electrolytes should be aggressively monitored. Potassium supplementation may be required. Once resolved, restart the drug at a lower dosage.
Available products
Formulations
- Tablets
Human-labeled
- Fludrocortisone Acetate Tablets: 0.1 mg (Florinef Acetate, generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store tablets at room temperature (15-30°C) in well-closed containers; avoid excessive heat. The drug is relatively stable in light and air.
Client information
Fludrocortisone is a life-saving medication used to treat Addison's disease (hypoadrenocorticism), a condition where your pet's adrenal glands do not produce enough essential hormones.
- Consistency is Key: Give this medication exactly as prescribed. Do not skip doses or stop the medication abruptly, as this can lead to a life-threatening Addisonian crisis.
- Stressful Events: Your pet may need extra medication (like prednisone) during times of stress, such as boarding, travel, or illness. Discuss a stress-plan with your veterinarian.
- What to Watch For: Contact your veterinarian immediately if you notice signs of an Addisonian crisis (weakness, severe lethargy, vomiting, diarrhea, loss of appetite) or signs of an overdose (excessive thirst and urination, swelling/edema, or sudden weight gain).
- Follow-up: Regular blood tests are absolutely necessary to ensure the dose is correct. The dose often needs to be adjusted over your pet's lifetime.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.