Isoflupredone Acetate
9alpha-fluoroprednisolone acetate
Also known as: Predef 2X Β· U-6013 Β· 9alpha-fluoroprednisolone acetate
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
π NA β North Americaπ EU β Europe
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Labeled systemic indications | 5-20 mg (total dose) | IM | repeated as necessary | β | π NA |
| Intrasynovial administration | 5-20 mg or more | Intrasynovial | β | β | π NA |
| Intraarticular administration | 4-20 mg | Intraarticular | β | β | π NA |
| Treatment of 'heaves' (RAO) | 10-14 mg (total dose) | IM | once daily | β | π NA |
| Treatment of recurrent airway obstruction (RAO) | 0.03 mg/kg | IM | once daily | 14 days | π NA |
- Intrasynovial administration: depending on the size of the joint cavity
- Intraarticular administration: has a short to medium duration of action
- Treatment of 'heaves' (RAO): for a horse weighing between 450-500 kg
- Treatment of recurrent airway obstruction (RAO): Patients developed significant decreases in serum potassium
Cattle
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Labeled systemic indications | 10-20 mg (total dose) | IM | repeated in 12 to 24 hours if indicated | β | π NA |
- Labeled systemic indications: according to the size of the animal and severity of the condition
Swine
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Labeled systemic indications | 5 mg (total dose) | IM | β | β | π NA |
- Labeled systemic indications: for a 300 lb. animal. Adjust dose proportionally for a smaller or larger animal.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Isoflupredone acetate is a potent, fluorinated synthetic glucocorticoid used primarily in large animal medicine (cattle, horses, and swine).
- Potency: It possesses approximately 17 times the anti-inflammatory potency of hydrocortisone and 10 times that of prednisolone. Its glucocorticoid activity is rated at 50 times that of hydrocortisone.
- Clinical Utility: Commonly utilized for its profound anti-inflammatory and immunosuppressive effects. Labeled indications include adjunctive treatment for bovine ketosis, musculoskeletal inflammation, acute hypersensitivity, overwhelming infections with severe toxicity, and recurrent airway obstruction (RAO) in horses.
- Clinical Pearl: Unlike dexamethasone or betamethasone, isoflupredone is less likely to induce early parturition, though it should still be avoided in late pregnancy. Notably, it retains significant mineralocorticoid activity, making patients highly susceptible to hypokalemia, even after a single dose in dairy cattle.
Mechanism of action
Isoflupredone exerts its effects via classic genomic and non-genomic steroid pathways:
- βAnti-inflammatory (Glucocorticoid Receptor - GR)β: Binds to cytosolic GR β translocates to the nucleus β induces transcription of βlipocortin-1 (annexin A1)β. Lipocortin-1 inhibits phospholipase A2, thereby blocking the release of arachidonic acid and halting the production of inflammatory prostaglandins and leukotrienes. It also transrepresses pro-inflammatory transcription factors like NF-ΞΊB and AP-1.
- βMineralocorticoid Effects (Mineralocorticoid Receptor - MR)β: Binds to MR in the distal renal tubules β upregulates Na+/K+ ATPase and ENaC channels β promotes sodium retention and potassium excretion (leading to hypokalemia).
- Metabolic: Stimulates hepatic gluconeogenesis (useful in bovine ketosis) and decreases peripheral glucose utilization.
Safety & warnings
Contraindications
- Systemic fungal infections (unless used for Addison's replacement)
- Idiopathic thrombocytopenia (when administered IM)
- Hypersensitivity to the compound
- Downer cows or animals susceptible to hypokalemia
- Calves to be processed into veal
- Late stages of pregnancy (relative contraindication)
Adverse effects
- Hypokalemia (even with single doses)
- Reduced milk production
- Delayed wound healing
- Gastrointestinal ulceration
- Increased infection rates
- Diabetes mellitus exacerbation / hyperglycemia
- Pancreatitis
- Hepatopathy
- Renal dysfunction
- Osteoporosis
- Laminitis (horses)
- Hypothyroidism
- Hyperlipidemia
- Decreased growth in young animals
- Premature parturition with retained placenta (if used in late pregnancy)
Precautions
Use with extreme caution in patients with active GI ulcers or those susceptible to them. Use cautiously in patients with diabetes mellitus. Because it can cause hypokalemia, it should not be used in downer cows or animals susceptible to the effects of hypokalemia. Chronic use in young, growing animals must be undertaken cautiously, as decreased growth may occur. Avoid using during pregnancy as it may induce premature parturition with retained placenta.
Drug interactions
Increased chance of digitalis toxicity may occur should hypokalemia develop; diligent monitoring of potassium and digitalis glycoside levels is recommended
Administered concomitantly with glucocorticoids may cause hypokalemia
Glucocorticoids may reduce salicylate blood levels
With glucocorticoids may increase the risk of gastrointestinal ulceration
A diminished immune response may occur; patients receiving immunosuppressive dosages should generally not receive live attenuated-virus vaccines
Monitoring
- Efficacy and adverse effects
- Serum potassium (highly recommended due to hypokalemia risk)
- Renal and liver function
- CBC
- Blood glucose
- Serum electrolytes
- ACTH stimulation tests (to determine HPA axis suppression)
- Thyroid hormone monitoring (if use is prolonged)
Pharmacokinetics
Metabolism
Gluconeogenic activity persists for 48 hours after dosing in cattle.
Overdose
A single overdose of isoflupredone is unlikely to cause harmful effects. Should clinical signs require intervention, use supportive treatment. Chronic usage of glucocorticoids can lead to serious adverse effects, generally manifested as signs of hyperadrenocorticism.
Available products
Formulations
- Aqueous suspension for injection (2 mg/mL)
Veterinary
- Isoflupredone acetate 2 mg/mL aqueous suspension for injection in 10 mL and 100 mL vials; Predef 2x (Pfizer)
Regulatory status
No regulatory data for: πΊπΈ US Β· πͺπΊ EU Β· π¬π§ UK Β· ππ° HK Β· πΉπΌ TW Β· π―π΅ JP Β· π°π· KR Β· π¦πΊ AU
Storage & stability
The injection should be stored at controlled room temperature 20Β°-25Β°C.
Client information
Important Note: This medication is a potent steroid and must be used exactly as prescribed by your veterinarian.
- Dairy Cattle: Be aware that milk production may temporarily decrease following administration.
- Horses & Swine: Monitor for signs of weakness, muscle trembling, or lethargy, which could indicate low blood potassium (hypokalemia).
- General Monitoring: Watch for increased thirst, increased urination, or changes in appetite.
- If you are administering the medication at home, follow your veterinarian's directions strictly. Do not abruptly stop this medication if it has been given for an extended period without consulting your vet.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturerβs current label.