Fludrocortisone
Fludrocortisone acetate
Also known as: Florinef · Fludrocortisone acetate · 9α-fluorocortisol · 9α-fluorohydrocortisone
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 (Addison's disease) | 0.01 mg/kg (starting dose); most stable patients require <0.05 mg/kg | PO | q12h (some may only require q24h) | Lifelong | 🌍 EU |
- Hypoadrenocorticism (Addison's disease): Monitor absolute Na and K concentrations 4-6 hours post-pill. If on q24h dosing, check pre-pill concentrations as well.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hypoadrenocorticism (Addison's disease) | 0.01 mg/kg (starting dose); most stable patients require <0.05 mg/kg | PO | q12h | Lifelong | 🌍 EU |
- Hypoadrenocorticism (Addison's disease): Doses as for dogs; very few reports in cats.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Fludrocortisone is a potent synthetic corticosteroid with high mineralocorticoid activity and moderate glucocorticoid activity. It is primarily used in veterinary medicine for the management of hypoadrenocorticism (Addison's disease) in dogs and cats, particularly when the authorized injectable product (desoxycortone pivalate) is unsuitable.
Clinical Warning: Fludrocortisone is about 125 times more potent as a mineralocorticoid than hydrocortisone, and 12 times more potent as a glucocorticoid (approximately 3 times more potent than prednisolone). Supplemental doses of prednisolone may still be required during periods of metabolic or physical stress.
Mechanism of action
Acts as an aldosterone analogue at the mineralocorticoid receptors in the distal convoluted tubule and collecting duct of the kidneys.
- Mineralocorticoid effect: → Increases sodium (Na+) retention and potassium (K+) excretion.
- Glucocorticoid effect: → Possesses roughly 3 times the glucocorticoid potency of prednisolone, contributing to anti-inflammatory and metabolic effects.
Safety & warnings
Contraindications
- No specific contraindications listed in the monograph, but use with caution in patients with congestive heart failure, severe hypertension, or renal disease.
- No specific contraindications available in the monograph, but generally contraindicated in patients with systemic fungal infections or known hypersensitivity.
Adverse effects
- Hypertension
- Oedema (including cerebral oedema)
- Hypokalaemia
- Hypercortisolism / Iatrogenic Cushing's syndrome (with long-term overdose)
- Polyuria/polydipsia (PU/PD)
- Clinical signs of hypercortisolism (with long-term overdose)
Precautions
- Monitor absolute sodium and potassium concentrations (not just the Na:K ratio) 4-6 hours post-pill.
- If dosing q24h, check Na/K concentrations pre-pill.
- Supplemental doses of prednisolone may be required at times of metabolic or physical stress.
- Some formulations require refrigeration.
- Clinical Pearl: Dose requirements often increase over the first 6-18 months of therapy as residual adrenal function ceases.
Drug interactions
Increased risk of severe hypokalaemia
Increased risk of hypokalaemia due to additive potassium-depleting effects
Increased risk of hypokalaemia due to additive potassium-depleting effects
Monitoring
- Blood pressure
- Clinical signs of hypercortisolism or hypoadrenocorticism crisis
- Body weight and hydration status
- Absolute serum sodium concentrations (4-6 hours post-pill, and pre-pill if q24h)
- Absolute serum potassium concentrations (4-6 hours post-pill, and pre-pill if q24h)
- Clinical signs of hyperadrenocorticism or hypoadrenocorticism
Pharmacokinetics
Half-life
Absorption
Rapidly and completely absorbed from the gastrointestinal tract.
Distribution
Widely distributed; highly bound to plasma proteins.
Metabolism
Hepatic metabolism.
Elimination
Excreted primarily via the kidneys.
Overdose
Overdosage can lead to hypertension, oedema (including cerebral oedema), and hypokalaemia. Long-term overdosage may result in clinical signs of hypercortisolism (iatrogenic Cushing's syndrome, e.g., PU/PD, polyphagia, alopecia, pot-bellied appearance). Treatment involves dose reduction and supportive care.
Available products
Formulations
- 0.1 mg oral tablets
- 0.25 mg oral tablets (named patient basis)
- 0.5 mg oral tablets (named patient basis)
Veterinary
- No authorized veterinary product in the UK/EU (desoxycortone pivalate is the authorized alternative)
Human-labeled
- Florinef 0.1 mg tablets
Regulatory status
Human approved product used off-label in veterinary medicine.
Used under the cascade when authorized veterinary products (e.g., desoxycortone pivalate) are not suitable.
Used under the prescribing cascade. Some strengths available on a named patient basis.
No regulatory data for: 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Normal precautions should be observed. Some formulations require refrigeration (check specific product packaging).
Client information
- Do not stop abruptly: This medication is life-saving and must be given exactly as prescribed. Missing doses can lead to a life-threatening Addisonian crisis.
- Stressful events: Your pet may need extra medication (like prednisolone) during stressful times (boarding, surgery, illness, travel). Consult your vet beforehand.
- Monitoring: Regular blood tests are essential to ensure the dose is correct, especially in the first year of treatment.
- Side effects: Watch for excessive thirst, increased urination, weight gain, or swelling, and report these to your veterinarian.
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.