Flunixin Meglumine

Flunixin meglumine is a nonsteroidal anti-inflammatory drug used predominantly in large animals. It provides analgesic, anti-inflammatory and antipyretic effects, with a major role in equine visceral pain and in fever or inflammation associated with cattle disease. Injectable, oral and transdermal products have distinct species-specific clinical applications.

Group

Nonselective NSAID

Mechanism of Action

Flunixin inhibits cyclooxygenase activity and reduces synthesis of prostaglandins from arachidonic acid. Lower prostaglandin production decreases pain sensitization, fever and several vascular manifestations of inflammation. In endotoxemia, it modifies prostaglandin-mediated host responses rather than directly neutralizing endotoxin. Its analgesic effects can improve comfort while treatment addresses the underlying disease.

Dose Rates

Dog

Use / stage	Dose	Route	Schedule	Instructions
Acute pain	1.1 mg/kg	IV, IM, SC	Once	Do not use in: Heat stroke, GI ulceration
Ocular surgery adjunct	0.5 mg/kg	IV	Once	Do not use in: Heat stroke, GI ulceration
Historical intermittent oral treatment	Reference only	PO		Do not use in: Heat stroke, GI ulceration; 1.1 mg/kg on three days per week. Calendar regimen is not a continuous daily prescription; prolonged use carries substantial GI risk.

Cat

Use / stage	Dose	Route	Schedule	Instructions
Acute pain	1.1 mg/kg	IV, IM, SC	Once	Do not use in: Heat stroke, GI ulceration
Ocular surgery adjunct	0.5 mg/kg	IV	Once	Do not use in: Heat stroke, GI ulceration
Historical intermittent oral treatment	Reference only	PO		Do not use in: Heat stroke, GI ulceration; 1.1 mg/kg on three days per week. Calendar regimen is not a continuous daily prescription; prolonged use carries substantial GI risk.

Horse

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	1.1 mg/kg	IV, IM	Every 24 h	Up to 5 days; Do not use in: Heat stroke, GI ulceration; IV avoids IM injection-site complications.
Pain and inflammation	1.1 mg/kg	PO	Every 24 h	Up to 5 days; Do not use in: Heat stroke, GI ulceration; Paste or granules.
Low-dose colic or sepsis adjunct	0.25 mg/kg	IV	Every 8 h	Do not use in: Heat stroke, GI ulceration; Not a direct endotoxin-neutralizing treatment; this specific low-dose schedule differs from standard once-daily analgesic dosing.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Fever and inflammation	1.1–2.2 mg/kg	IV	Every 24 h	Up to 3 days; Do not use in: Heat stroke, GI ulceration; Slow injection. If divided every 12 hours, preserve the same total daily amount, rather than repeating the full daily amount twice.
Topical pain and fever treatment	3.33 mg/kg	TOPICAL	Once	Do not use in: Heat stroke, GI ulceration; Use the dedicated transdermal product along dorsal midline.
Florfenicol combination	Reference only	SC		Do not use in: Heat stroke, GI ulceration; Florfenicol 40 mg/kg plus flunixin 2.2 mg/kg using Resflor Gold. Combination-product regimen; not interchangeable with flunixin-only injections.

Pig

Use / stage	Dose	Route	Schedule	Instructions
Pyrexia	2.2 mg/kg	IM	Once	Do not use in: Heat stroke, GI ulceration

Ferret

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	0.5–2 mg/kg	PO, IM	Every 24 h

Rabbit

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	1.1 mg/kg	SC, IM, IV	Every 12–24 h

Chinchilla

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	1–3 mg/kg	SC	Every 12 h

Guinea Pig

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.5–5 mg/kg	SC	Every 12 h

Gerbil

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.5 mg/kg	SC	Every 12–24 h

Mouse

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.5 mg/kg	SC	Every 12–24 h

Rat

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.5 mg/kg	SC	Every 12–24 h

Hamster

Use / stage	Dose	Route	Schedule	Instructions
Pain and inflammation	2.5 mg/kg	SC	Every 12–24 h

Sheep

Use / stage	Dose	Route	Schedule	Instructions
Analgesia	1–2 mg/kg	IV	Every 24 h
Analgesia	1–4 mg/kg	PO	Every 24 h	Oral paste alternative.

Goat

Use / stage	Dose	Route	Schedule	Instructions
Analgesia	1–2 mg/kg	IV	Every 24 h
Analgesia	1–4 mg/kg	PO	Every 24 h	Oral paste alternative.

Bird

Use / stage	Dose	Route	Schedule	Instructions
Inflammatory pain	1–10 mg/kg	IM	Every 24 h	Repeated doses have caused renal disease and death in psittacines. Use the lowest effective dose for the shortest course with hydration and renal monitoring.

Indications

Relief of visceral pain associated with colic in horses.
Treatment of pain and inflammation associated with equine musculoskeletal disorders.
Adjunctive control of inflammatory manifestations of endotoxemia in horses and cattle.
Control of fever associated with bovine respiratory disease and acute mastitis, and inflammatory signs associated with mastitis.
Reduction of pyrexia associated with swine respiratory disease using an indicated product.
Control of pain associated with bovine foot rot with an appropriate transdermal product.

Contraindications

GI ulceration, dehydration or renal compromise
Avoid near-term pregnancy and heat-stroke treatment.

Interactions

Other NSAIDs and corticosteroids increase toxicity.
Can impair diuretic/ACE-inhibitor effects.
Enrofloxacin can increase flunixin exposure in dogs.

Adverse effects

GI ulceration, perforation and hypoproteinemia
Renal injury
Myositis or abscess after IM equine injection

Toxicity

Excessive or prolonged treatment can cause serious GI and renal injury.

Preparations

Preparation	Form	Strength	Route
Flunixin-equivalent injection 10 mg/mL Check species-specific injection route; dose expressed as flunixin.	Injection	10 mg / mL	IV, IM, SC
Flunixin-equivalent injection 50 mg/mL Check species-specific injection route; dose expressed as flunixin.	Injection	50 mg / mL	IV, IM, SC
Flunixin granules 250 mg/10 g	Granules	250 mg / 10 g	PO
Flunixin paste 1500 mg/30 g	Paste	1500 mg / 30 g	PO
Flunixin transdermal 50 mg/mL	Other	50 mg / mL	TOPICAL
Resflor Gold Combination-specific regimen.	Injection	flunixin 16.5 mg / mL + florfenicol 300 mg / mL	SC
Hexasol Combination-specific regimen.	Injection	flunixin 20 mg / mL + oxytetracycline 300 mg / mL	IM, SC

Monitoring and Administration

Monitor GI signs, hydration, renal function and serum albumin in horses. IM/SC use in cattle alters residue persistence compared with IV use.

Small-animal use is limited by ulcer risk; alternatives with better established safety are often preferable.

Dose is expressed as flunixin, not the mass of meglumine salt.

The source contains a veal-calf 2.2 mg/kg IV entry but also explicitly prohibits use in calves processed for veal; this contradictory population instruction is not a calculator regimen.