Isoflupredone Acetate: veterinary dose and monograph

At a glance

Drug class

Anti-inflammatory

Also known as

Predef 2X, Predef, Iso-D-Sure, Isoflupredone

Species with doses

Cattle, Horses and Pigs

Routes

IM

Last reviewed

1 October 2026

Indications

• Bovine ketosis (adjunctive)
• Musculoskeletal pain and lameness
• Acute hypersensitivity reactions
• Overwhelming infection with severe toxicity (adjunctive, with antimicrobial cover)
• Shock
• Supportive therapy in stress conditions (e.g. surgery)
• Dystocia and retained placenta
• Inflammatory ocular conditions
• Snakebite
• Parturient paresis
• Equine recurrent airway obstruction (RAO / heaves)

Isoflupredone Acetate 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.

Cattle

• Labelled systemic indications (ketosis, lameness, shock, hypersensitivity): Plumb's p.667 (Predef 2X label): 10–20 mg TOTAL dose IM according to the size of the animal and severity of the condition; may repeat in 12–24 h if indicated. At 2 mg/mL that is 5–10 mL per adult cow. WITHDRAWAL (Plumb's p.668): meat 7 days; not for veal calves. No milk withdrawal is specified in the USA, but Canada specifies 72 hours. Papich 5e: 10–20 mg total per animal IM q12–24h. Even single doses can cause hypokalaemia in dairy cattle — avoid in downer cows; isoflupredone offered no benefit in early-lactation cows (Seifi 2007).

Horses

• Labelled systemic indications: Plumb's p.668 (Predef 2X label): 5–20 mg TOTAL dose IM, repeated as necessary. Intrasynovial: 5–20 mg or more depending on joint size (Goodrich 2006 gives 4–20 mg intra-articular, short to medium duration). RCI Class 4 — check competition rules. Papich 5e: 5–20 mg total per horse IM q12–24h; intra-articular 5–20 mg per joint.
• Recurrent airway obstruction (RAO / heaves): Papich 5e: 0.02–0.03 mg/kg q24h. Plumb’s p.668: 0.03 mg/kg IM once daily for 14 days — significant improvement but marked falls in serum potassium (Picandet 2003); 10–14 mg total IM daily for a 450–500 kg horse (Lavoie 2003). Watch for laminitis and hypokalaemia.

Pigs

• Labelled systemic indications: Papich 5e: 0.036 mg/kg/day IM. Plumb’s p.668 (Predef 2X label): 5 mg total IM for a 300 lb (136 kg) pig, adjusted proportionally for size. Meat withdrawal per the existing label entry (7 days) — confirm locally.

Buffalo

No buffalo-specific doses are on file, so buffalo are dosed as cattle.

• Labelled systemic indications (ketosis, lameness, shock, hypersensitivity): Plumb's p.667 (Predef 2X label): 10–20 mg TOTAL dose IM according to the size of the animal and severity of the condition; may repeat in 12–24 h if indicated. At 2 mg/mL that is 5–10 mL per adult cow. WITHDRAWAL (Plumb's p.668): meat 7 days; not for veal calves. No milk withdrawal is specified in the USA, but Canada specifies 72 hours. Papich 5e: 10–20 mg total per animal IM q12–24h. Even single doses can cause hypokalaemia in dairy cattle — avoid in downer cows; isoflupredone offered no benefit in early-lactation cows (Seifi 2007).

Contraindications

Plumb's pp.666–667. Systemic fungal infection (unless replacement therapy for hypoadrenocorticism). IM use in idiopathic thrombocytopenia. Known hypersensitivity. Extreme caution with active or susceptible GI ulceration. Caution in diabetes mellitus. MUST NOT be used in downer cows or any animal susceptible to the effects of hypokalaemia — isoflupredone causes hypokalaemia and will worsen recumbency. Not to be used in calves being processed for veal. Chronic use in young growing animals retards growth. Avoid in pregnancy.

Species-specific warnings

Cattle: CONTRAINDICATED in downer cows — causes hypokalaemia and will deepen recumbency. Meat withdrawal 7 days; not for veal calves. No US milk withdrawal is specified (Canada 72 h) — verify against your national label before returning milk to the tank.

Buffalo: Same hypokalaemia and downer-animal contraindication as cattle. Withdrawal extrapolated from the bovine label — 7 days meat.

Horses: Laminitis risk with repeated dosing, as with all glucocorticoids. RCI Class 4 substance — check competition withdrawal rules.

Pigs: FDA-approved for swine. Meat withdrawal 7 days.

Adverse effects

• Hypokalaemia (mineralocorticoid effect — the signature adverse effect of this drug)
• Reduced milk production
• Delayed wound healing
• GI ulceration
• Increased infection rates
• Hyperglycaemia / exacerbation of diabetes mellitus
• Pancreatitis
• Hepatopathy
• Renal dysfunction
• Osteoporosis
• Laminitis (horses)
• Hypothyroidism
• Hyperlipidaemia
• Growth retardation in young animals

Drug interactions

• Vaccines, toxoids, bacterins: diminished immune response — do NOT give live attenuated vaccines at immunosuppressive doses, as virus replication may be augmented
• Potassium-depleting drugs (loop/thiazide diuretics, amphotericin B): additive hypokalaemia — isoflupredone already lowers potassium
• NSAIDs: additive GI ulcerogenic risk
• Insulin / oral hypoglycaemics: glucocorticoid-induced hyperglycaemia opposes them
• Laboratory: raises serum cholesterol and serum/urine glucose; LOWERS serum potassium; suppresses TSH with reduced T3/T4; suppresses skin-test reactions; can give false-negative nitroblue tetrazolium tests for systemic bacterial infection

Pregnancy and lactation

Plumb's p.667: avoid during pregnancy. Glucocorticoids induce abortion or early parturition in late gestation, most commonly in ruminants. Isoflupredone appears to have a LOWER abortifacient potential than dexamethasone, betamethasone or flumethasone (behaving more like hydrocortisone, prednisolone and triamcinolone), but it may still induce premature parturition with retained placenta.

Monitoring

• Serum potassium — before and during repeated dosing, especially in dairy cattle
• Blood glucose in diabetic or ketotic animals
• Appetite, milk yield and demeanour
• Signs of GI ulceration (melaena, anorexia)
• Digital pulses / hoof comfort in horses (laminitis)
• Withdrawal compliance — 7 days meat; confirm the milk position against your national label

Toxicity and overdose

Plumb's pp.666–667: the dose-limiting toxicity of isoflupredone is hypokalaemia, which is a direct mineralocorticoid effect rather than an idiosyncratic one — dairy cattle given repeated or high doses can become profoundly hypokalaemic and recumbent. This is why the label bars use in downer cows. Otherwise, toxicity is the general glucocorticoid picture: immunosuppression, GI ulceration, delayed healing, hyperglycaemia and laminitis in horses. There is no specific antidote; stop the drug, correct potassium, and support.

Clinical pearls

• The hypokalaemia risk is the whole reason to choose or avoid this drug — NEVER give it to a downer cow, which is exactly the animal a clinician is tempted to reach for it with
• A study in early-lactation dairy cows (Seifi et al. 2007, Plumb's p.666) found isoflupredone 20 mg IM, with or without insulin, offered NO metabolic, production or reproductive benefit — temper expectations in ketosis
• Less abortifacient than dexamethasone, but still not a pregnancy drug
• At 2 mg/mL a 10–20 mg bovine dose is only 5–10 mL — easy to overdose if the strength is misread
• Sold in India as Assure Biotech ISO-D-SURE 2 mg/mL; the Assure catalogue prints no dose and no withdrawal period at all

Mechanism of action

Plumb's p.666: isoflupredone's anti-inflammatory potency is roughly 17× that of hydrocortisone; the label claims glucocorticoid activity 50× hydrocortisone and 10× prednisolone as measured by liver glycogen deposition in rats. Acts through the classical glucocorticoid receptor — suppressing phospholipase A2, cytokine transcription and leukocyte migration. Critically, it retains appreciable MINERALOCORTICOID activity, driving renal potassium wasting and hypokalaemia; this is what separates it clinically from dexamethasone and is the reason it is contraindicated in downer cows.

Formulations and products

• Predef 2X 2 mg/mL aqueous suspension (10 mL / 100 mL vial)
• Predef 2X (Pfizer (Pharmacia & Upjohn)) — 2 mg/mL isoflupredone acetate, Aqueous injectable suspension — IM
• ISO-D-SURE (Assure Biotech, Jagadhri (HR)) — Isoflupredone acetate IP (Vet) 2 mg/mL, Injectable suspension

Before you use this dose

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.

Other anti-inflammatory drugs

• Dimethyl Sulfoxide (DMSO)
• Firocoxib
• Flunixin Meglumine
• Grapiprant
• Ketoprofen
• Mavacoxib
• Meloxicam
• Methylprednisolone Acetate

Frequently asked questions