Flunixin Meglumine
Non Steroidal Anti-Inflammatory Drugs (NSAID)
View Brand Names (5)Dose and dosage
a) For labeled indications: 1.1–2.2 mg/kg (1–2 mL per 100 lbs. BW) given slow IV either once a day as a single dose or divided into two doses q12h for up to 3 days. Avoid rapid IV administration.
b) As an analgesic: 1.1–2.2 mg/kg IV q6– 12 hours; recommend 72 hour milk withdrawal at this dose rate.
c) As an analgesic for visceral pain: 0.25–1 mg/kg IV q12–24h.
d) Using the combination product containing florfenicol/flunixin: 40 mg/kg florfenicol/2.2 mg/kg flunixin (6 mL/100 lb. B.W.) SC once.
Do not administer more than 10 mL at each site. The injection should be given only in the neck. Injection sites other than the neck have not been evaluated.
a) For labeled indications: 1.1–2.2 mg/kg (1–2 mL per 100 lbs. BW) given slow IV either once a day as a single dose or divided into two doses q12h for up to 3 days. Avoid rapid IV administration.
b) As an analgesic: 1.1–2.2 mg/kg IV q6– 12 hours; recommend 72 hour milk withdrawal at this dose rate.
c) As an analgesic for visceral pain: 0.25–1 mg/kg IV q12–24h.
d) Using the combination product containing florfenicol/flunixin: 40 mg/kg florfenicol/2.2 mg/kg flunixin (6 mL/100 lb. B.W.) SC once.
Do not administer more than 10 mL at each site. The injection should be given only in the neck. Injection sites other than the neck have not been evaluated.
a) As an analgesic: 1–2 mg/kg IV q24h; oral paste has also been at 1–4mg/kg PO once daily.
a) As an analgesic: 1–2 mg/kg IV q24h; oral paste has also been at 1–4mg/kg PO once daily.
a) Injectable: 1.1 mg/kg IV or IM once daily for up to 5 days. For colic cases, use IV route and may redose when necessary.
Oral Paste: 1.1 mg/kg PO (see markings on syringe—calibrated in 250 lb. weight increments) once daily. One syringe will treat a 1000 lb. horse for 3 days. Do not exceed 5 days of consecutive therapy.
Oral Granules: 1.1 mg/kg PO once daily. One packet will treat 500 lbs of body weight. May apply on feed. Do not exceed 5 consecutive days of therapy.
b) For adjunctive treatment of medical colic: 0.25–1.1 mg/kg IV q8–12h; usually 1.1 mg/kg IV q12h.
c) To decrease pain, inflammation, and edema in laminitis: 0.5–1.1 mg/kg IV or PO q8–12 hours. A dose of 0.25 mg/kg can be administered IV q8h to interrupt eicosanoid production associated with endotoxemia.
d) For adjunctive treatment of patients with, or at risk for laminitis: 1.1 mg/kg IV three times daily with proper monitoring for hydration and renal status and monitoring for gastrointestinal ulceration.
e) For adjunctive treatment of uveitis in foals: 0.5–1 mg/kg (route not noted) twice daily
a) As an antidiarrheal/antipyretic: 1 mg/kg IV (do not administer more than once in an animal that has received corticosteroids
b) For surgical pain: 1 mg/kg IV, SC or IM initially once; 1 mg/kg subsequent daily doses
For pyrexia: 0.25 mg/kg IV, SC or IM once, may be repeated in 12– 24 hours if needed
For ophtho procedures: 0.25–1 mg/kg IV, IM or SC once; may be repeated in 12–24 hours if needed
1.1 mg/kg SC, IM, IV q12–24h
a) Rodents: 2.5 mg/kg SC or IM q12h
b) Chinchillas: 1–3 mg/kg SC q12h
Guinea pigs: 2.5–5 mg/kg SC q12h
Gerbils, Mice, Rats, Hamsters: 2.5 mg/kg SC q12–24h
To control pyrexia associated with swine respiratory disease: 2.2 mg/kg IM once, only in the neck musculature with a maximum of 10 mL per site.
As an antiinflammatory analgesic: 1–10 mg/kg IM once daily. Note: Renal disease and death occur occasionally in psittacines after repeated doses of flunixin. Use the lowest possible dose for the shortest duration of time. Recommend supplemental hydration.
0.5–2 mg/kg PO or IM one time daily
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Horses: foal diarrheas, shock, colitis, respiratory disease, post-race treatment, and pre- and post ophthalmic and general surgery;
Dogs: disk problems, arthritis, heat stroke, diarrhea, shock, ophthalmic inflammatory conditions, pre- and post ophthalmic and general surgery, and treatment of parvovirus infection;
Cattle: acute respiratory disease, acute coliform mastitis with endotoxic shock, pain (downer cow), and calf diarrheas;
Swine: agalactia/hypogalactia, lameness, and piglet diarrhea.
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Do not use in calves to be processed for veal. Do not use in bulls intended for breeding because reproductive effects in this class of cattle have not been studied
Flunixin is a potent NSAID widely used in large animals. Like other NSAIDs, it produces analgesic and anti-inflammatory effects by inhibiting the synthesis of prostaglandins. The enzyme inhibited by NSAID is the COX enzyme. The COX enzyme exists in two isoforms: COX-1 and COX-2. COX-1 is primarily responsible for synthesis of prostaglandins important for maintaining a healthy GI tract, renal function, platelet function, and other normal functions. COX-2 is induced and responsible for synthesizing prostaglandins that are important mediators of pain, inflammation, and fever. However, it is understood that there is some crossover of COX-1 and COX-2 effects in some situations, and COX-2 activity is important for some biological effects. Flunixin is not selective for either COX-1 or COX-2.
Pharmacokinetics: In horses, the half-life is 2 hours, oral absorption of paste is 77%, and absorption of granules is 85%. However, access to hay delays peak concentrations and oral absorption from granules and paste mixed with feed may be more erratic. In adult cattle, the half-life is 3–4 hours IV but 6 hours in calves. The half-life is longer when administered IM or SQ compared to IV administration. Oral absorption in cattle is 60%. There are age-related differences in pharmacokinetics in cattle, with young calves showing a slower clearance and longer half-life than older calves. In healthy weaned calves, the half-life was 6–7 hours, but in veal calves, the half-life was 13 hours, with a volume of distribution of 0.6 L/kg. The transdermal formulation of flunixin exhibits different pharmacokinetics in cattle than the injectable form. The half-lives of the transdermal form are 9.3 and 13.2 hours in 2-and 8-month- old calves, respectively, with absorption of 40% and 63%, respectively. After transdermal application of 3.3 mg/kg to Holstein calves, the bioavailability is 48% with a half-life of 6.4 hours.
Drug/drug interactions have not been appreciably studied for flunixin and the label does not mention any drug interactions. However, the following drug interactions have either been reported or are theoretical in humans or animals receiving other NSAIDs and may be of significance in veterinary patients receiving flunixin:
ASPIRIN: When aspirin is used concurrently with NSAIDs, plasma levels of the NSAID could decrease and an increased likelihood of GI adverse effects (blood loss) could occur
CYCLOSPORINE: NSAIDs may increase cyclosporine blood levels and increase the risk for nephrotoxicity
DIGOXIN: NSAIDs may increase serum levels of digoxin; use with caution in patients with severe cardiac failure
ENROFLOXACIN: Has been shown in dogs to increase the AUC and elimination half-life of flunixin and flunixin increases the AUC and elimination half-life of enrofloxacin; it is unknown if other NSAIDs interact with enrofloxacin in dogs. Enrofloxacin and flunixin did not interact in rabbits.
FUROSEMIDE & OTHER DIURETICS: NSAIDs may reduce the saluretic and diuretic effects of furosemide
METHOTREXATE: Serious toxicity has occurred when NSAIDs have been used concomitantly with methotrexate; use together with caution
NEPHROTOXIC AGENTS (e.g., amphotericin B, aminoglycosides, cisplatin, etc.): Potential for increased risk of nephrotoxicity if used with NSAIDs
PROBENECID: May cause a significant increase in serum levels and halflife of some NSAIDs
WARFARIN: Use with NSAIDs may increase the risk for bleeding
Most severe adverse effects are related to the GI system. Flunixin causes gastritis and GI ulceration with high doses or prolonged use. Reduced renal perfusion has also been documented. In horses, flunixin administration may affect recovery after ischemic injury to the intestine. In horses, if given IM, it can result in myositis and abscess at the injection site. It can also cause irritation and injection-site lesions if injected SQ or IM in cattle. If used in dogs, treatment should not go beyond 4 consecutive days.
Gastric ulceration is a distinct possibility in horses that have received overdoses of flunixin. Consider using anti-ulcer medications in overdosed horses.
In a system evaluating the safety of drugs in canine and feline pregnancy (Papich 1989), this drug is categorized as in class: C.
Avoid use in pregnant animals near term.
Meat: Up to 4 days.
Milk: 1.5 days