# Fludrocortisone: veterinary dose and monograph

> Fludrocortisone is a veterinary drug. Potent synthetic mineralocorticoid (with some glucocorticoid activity) — the oral maintenance treatment for primary hypoadrenocorticism (Addison's disease). Indications include maintenance therapy of primary hypoadrenocorticism (Addison's disease); mineralocorticoid replacement to normalise sodium and potassium; selected cases of hyperkalaemia/hyponatraemia from aldosterone deficiency. This monograph lists 3 reference doses for dogs, cats and ferrets, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/fludrocortisone · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Florinef, Fludrocortisone acetate
- **Species with doses:** Dogs, Cats and Ferrets
- **General dose range:** 0.01–0.02 mg/kg PO q12–24h — check the species tables for the indication
- **Routes:** PO
- **Last reviewed:** 1 October 2026

## Indications

- Maintenance therapy of primary hypoadrenocorticism (Addison's disease)
- Mineralocorticoid replacement to normalise sodium and potassium
- Selected cases of hyperkalaemia/hyponatraemia from aldosterone deficiency

## Fludrocortisone dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Fludrocortisone doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Addison's maintenance | 0.01–0.02 mg/kg | PO | q12–24h | — |

- Addison's maintenance: Papich 5e: 10 µg/kg/day PO, increasing up to 30 µg/kg/day by electrolytes. Plumb’s p.534: 0.01 mg/kg PO twice daily (Panciera; Scott-Moncrieff); 0.01–0.02 mg/kg/day adjusted in 0.05–0.1 mg steps — most dogs end up on 0.02–0.03 mg/kg/day (Kintzer 2004). Recheck Na/K every 1–2 weeks until stable, then every 3–4 months. About half need prednisone as well.

### Cats

*Fludrocortisone doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Addison's maintenance (rare) | 0.02 mg/kg | PO | q24h | — |

- Addison's maintenance (rare): Plumb’s p.534: 0.02 mg/kg PO once daily with prednisolone 1.25 mg per cat (Scott-Moncrieff 2010); 0.1 mg per cat once daily with prednisolone 0.2 mg/kg (Caney 2009). Papich 5e: 0.1–0.3 mg per cat q24h. Dose to electrolytes.

### Ferrets

*Fludrocortisone doses for ferrets*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Hypoadrenocorticism (post-adrenalectomy) | 0.05–0.1 mg/kg | PO | q24h (or divided q12h) | — |

- Hypoadrenocorticism (post-adrenalectomy): Plumb’s p.534 (Johnson 2006): 0.05–0.1 mg/kg PO q24h or divided q12h if Addisonian signs persist on prednisone.

## Contraindications

Congestive heart failure, hypertension, significant renal impairment with sodium-retention concerns, and oedematous states (mineralocorticoid sodium/water retention). Systemic fungal infection (glucocorticoid component). Use caution where potassium is already low. Known hypersensitivity.

## Species-specific warnings

> **Caution:** Dogs: During stress, illness or surgery, increase glucocorticoid cover — fludrocortisone alone may not supply enough glucocorticoid for stress demands.

## Adverse effects

- Polyuria/polydipsia (common — partly mineralocorticoid, partly glucocorticoid)
- Hypertension, sodium/water retention, oedema
- Hypokalaemia at higher doses
- Glucocorticoid effects (panting, weight gain) from its intrinsic glucocorticoid activity

## Drug interactions

- Potassium-wasting diuretics (furosemide, thiazides): additive hypokalaemia
- NSAIDs: increased sodium retention/GI risk
- Insulin/oral hypoglycaemics: glucocorticoid effect may raise glucose
- Drugs lowering potassium: monitor closely

## Pregnancy and lactation

Used when essential to maintain an Addisonian dam; corticosteroid exposure warrants caution but untreated hypoadrenocorticism is life-threatening — continue replacement and monitor.

## Monitoring

- Serum sodium and potassium (Na:K ratio) — the key efficacy markers; recheck after dose changes and periodically
- Blood pressure
- Body weight, PU/PD, signs of glucocorticoid excess
- Renal values

## Toxicity and overdose

Overdose/excess produces mineralocorticoid effects — hypertension, sodium/water retention with oedema, hypokalaemia and possible weakness/arrhythmia — plus glucocorticoid excess (PU/PD, iatrogenic Cushingoid signs). Under-dosing risks an Addisonian crisis (the more dangerous direction).

Management: No specific antidote. Reduce/withhold dose; correct electrolytes (treat hypokalaemia, manage hypertension/oedema); supportive care. For glucocorticoid excess, taper. Recheck Na/K and adjust the maintenance dose.

## Clinical pearls

- Titrate fludrocortisone to the electrolytes (Na:K ratio), not to a fixed dose — many dogs creep upward in dose requirement over the first year
- Its built-in glucocorticoid activity means some Addisonians need little/no extra prednisolone — but add low-dose glucocorticoid and always increase steroid cover during stress/illness
- DOCP injection is the alternative mineralocorticoid; fludrocortisone suits owners who prefer daily tablets and dogs needing combined gluco/mineralocorticoid effect
- PU/PD is common — distinguish acceptable drug effect from over-dosing by checking electrolytes and blood pressure
- Never abruptly stop in an Addisonian — risk of life-threatening crisis

## Mechanism of action

Binds the mineralocorticoid (aldosterone) receptor in the distal nephron, driving sodium (and water) reabsorption and potassium/hydrogen-ion excretion — correcting the hyponatraemia and hyperkalaemia of aldosterone deficiency. Its fluorination greatly amplifies mineralocorticoid potency; it also retains meaningful glucocorticoid activity at the receptor.

## Formulations and products

- 0.1 mg tablet (Florinef)
- Florinef — 0.1 mg tablet, Tablet (human-label)

## Storage

Tablets: 15–25 °C, dry, protected from light.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Fludrocortisone for dogs?

Reference doses for Fludrocortisone in dogs: 0.01–0.02 mg/kg PO q12–24h (Addison's maintenance). Confirm against the label and the patient before use.

### What is the dose of Fludrocortisone for cats?

Reference doses for Fludrocortisone in cats: 0.02 mg/kg PO q24h (Addison's maintenance (rare)). Confirm against the label and the patient before use.

### What is the dose of Fludrocortisone for ferrets?

Reference doses for Fludrocortisone in ferrets: 0.05–0.1 mg/kg PO q24h (or divided q12h) (Hypoadrenocorticism (post-adrenalectomy)). Confirm against the label and the patient before use.

### When should Fludrocortisone not be used?

Congestive heart failure, hypertension, significant renal impairment with sodium-retention concerns, and oedematous states (mineralocorticoid sodium/water retention). Systemic fungal infection (glucocorticoid component). Use caution where potassium is already low. Known hypersensitivity.

### What are the side effects of Fludrocortisone in animals?

Polyuria/polydipsia (common — partly mineralocorticoid, partly glucocorticoid); Hypertension, sodium/water retention, oedema; Hypokalaemia at higher doses; Glucocorticoid effects (panting, weight gain) from its intrinsic glucocorticoid activity.

## Sources

- Plumb's Veterinary Drug Handbook
- Merck Veterinary Manual, 11th edition
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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