|Systematic (IUPAC) name|
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|Molecular mass||296.24 g/mol|
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Flunixin is a non-steroidal anti-inflammatory drug (NSAID), analgesic, and antipyretic used in horses, cattle and pigs. It is often formulated as the meglumine salt. In the United States, it is regulated by the U.S. Food and Drug Administration (FDA), and may only be lawfully distributed by order of a licensed veterinarian. There are many trade names for the product, as stated below.
Dosage and uses in horses
Flunixin is administered at a dose of 1.1 mg/kg. The full analgesic and antipyretic effects usually occur 1-2 hours following treatment, but there is often an effective analgesic effect within approximately 15 minutes. Despite its short plasma half life of 1.6-2.5 hours, effects can persist for up to 30 hours, with maximal effects occurring between 2 and 16 hours. This is likely due to accumulation of the drug as an inflammatory foci.
Because it targets the inflamed tissue, flunixin is mainly used for colic pain, muscle pain, and joint disease, as well as to alleviate fevers and pain, and prevent endotoxemia. It is also effective in injuries of the eye.
Side effects and precautions
Flunixin should not be given for more than five days. Like most NSAIDs, it can produce gastrointestinal (GI) side effects if the drug is given in high doses or over several days. GI ulceration is the most common side effect, especially in the animal's large colon or stomach, and is most likely to occur if the drug is given for a prolonged period. Other side effects include kidney damage and bleeding problems. It should be used with caution in horses with kidney or liver disease.
Flunixin does not treat the underlying problem causing the fever or pain, only the symptoms. Additionally, pain is often useful for a veterinarian to diagnose a horse's condition, and masking it with flunixin may do more harm than good. For this reason, there are many veterinarians who do not wish for the animal to be given flunixin if colic is suspected, instead preferring to withhold the drug until the need for colic surgery has been determined. It is therefore advisable to ask the horse's veterinarian before giving the drug.
Flunixin is a prohibited class A drug under International Federation for Equestrian Sports rules, and its use is prohibited or restricted by many other equestrian organizations. It can be detected in the blood for 2-3 days, and in the urine up to 15 days following administration.
Combining with other drugs
Flunixin should not be combined with other NSAIDs or corticosteriods, as this increases the risk of gastric ulcers, right dorsal colitis, and kidney disease. Additionally, veterinarians should use caution when combining it with anticoagulants or aminoglycoside antibiotics. Flunixin is commonly used with omeprazole, sucralfate, and cimetidine to protect the gastrointestinal tract.
Flunixin may be given orally as a paste or as granules in feed. It can also be used intramuscularly or intravenously, although because it is very irritating to tissue, the IV route is preferred, and in cattle it is the labeled route of administration.
Dosages are usually reduced for ponies, who are more at-risk for NSAID side effects, as well as horses with decreased liver or kidney function (such as older horses).
In the USA the trade names are Banamine, Flunixamine, Citation, Equileve, and Meflosyl Solution. In the UK the trade names are Flunixin, Finadyne and Cronyxin. In South Africa and Australia a common trade name is Finadyne. A trade name in India is Megludyne.
- Forney, Barbara C, MS, VMD.Equine Medications, Revised Edition. Blood Horse Publications. Lexington, KY. Copyright 2007.
- McIlwraith CW, Frisbie DD, Kawcak CE. Nonsteroidal Anti-Inflammatory Drugs. Proc. AAEP 2001 (47): 182-187.
- May SA, Lees P. Nonsteroidal anti-inflammatory drugs. In McIlwraith CW, Trotter GW, eds. Joint disease in the horse. Philadelphia: WB Saunders, 1996;223–237.
- Flunixin meglumine
- Flunixin Meglumine For Veterinary Use
- Flunixin licensing in the UK provided by Norbrook