Flunixin meglumine, often sold under the brand names Banamine®, Flunazine®, Vetameg™, and Prevail®, is a common non-steroidal anti-inflammatory drug (NSAID) used in horses. Banamine® is prescribed by veterinarians to help manage clinical signs of pain, swelling, and/or fever.

In horses, flunixin meglumine is typically used to treat osteoarthritis and soft tissue injuries, and to alleviate visceral pain associated with colic. NSAIDs such as Banamine® can help to minimize physiological stress, improve welfare, and increase treatment success for horses. [1]

However, when Banamine® is used incorrectly, the risk of serious adverse effects, including gastrointestinal ulcers, kidney damage, and right dorsal colitis, increases greatly. Understanding both the benefits and side effects of Banamine® use is important for horse owners.

The dosage and duration of treatment with Banamine® should be determined by a veterinarian based on the specific condition being treated. Always follow your veterinarian’s guidelines when administering prescription medications to your horse.

Common Uses of Banamine®

As a non-steroidal anti-inflammatory drug (NSAID), Banamine® is effective in treating pain and inflammation, as well as reducing fever in horses.

Horse owners are often familiar with Banamine® in the context of colic treatment, as it is a common choice among veterinarians for alleviating pain associated with abdominal or gastrointestinal issues in horses.

This drug can also be used for other equine health conditions including: [1][2][3]

  • Muscle or soft tissue injuries
  • Lameness
  • Corneal ulcers and uveitis
  • Cellulitis
  • Fever
  • Pain management after surgery
  • Endotoxemia


Endotoxemia refers to the presence of bacterial endotoxins in the bloodstream, and most commonly occurs in horses with severe colic, gastrointestinal infection, or retained placenta. Endotoxemia is a life-threatening disease process that can rapidly lead to death.

Flunixin has been shown to exhibit anti-endotoxic properties, even at low doses, making it a useful medication in the treatment of horses with signs of endotoxemia. [4][5][6]

How Does Banamine® Work?

Flunixin meglumine has analgesic (pain-relieving), anti-inflammatory, and antipyretic (fever-reducing) properties.

As an NSAID, it works by blocking two specific enzymes, COX-1 and COX-2, that are involved in regulating inflammation.

These enzymes play key roles in the arachidonic acid pathway, which contributes to inflammation, pain, and fever.

COX-1 Enzyme

COX-1 (cyclooxygenase-1) is present in most tissues, including the gastrointestinal tract, and its job is to produce prostaglandins. These are hormones that are important for maintaining normal bodily processes and functions, such as cardiovascular health, blood clotting, gastric health (including the protection of the stomach lining), and kidney function.

Notably, COX-1 enzymes are expressed continuously, whether the horse is heathy, sick, or injured. This ensures that the body can maintain homeostasis, the process by which biological systems maintain stability. [4][7][8]

COX-2 Enzyme

COX-2 (cyclooxygenase-2) is responsible for producing prostaglandins primarily involved in the body’s inflammatory response, including reactions to pain. COX-2 enzymes are produced in higher amounts under certain conditions such as when inflammation is actively occurring in the body. [4][7][8]

COX Enzyme Inhibition

The anti-inflammatory and pain-mediating effects of NSAIDs come specifically from blocking or inhibiting the COX-2 enzyme, and not COX-1.

Traditional NSAIDs like Banamine® function by inhibiting both COX-1 and COX-2 enzymes. These medications are known as “non-selective” COX inhibitors because they do not distinguish between the two enzymes but instead block both. Phenylbutazone, commonly known as Bute, is another example of a non-selective NSAID frequently used in horses. [1][4]

Another class of NSAIDs includes firocoxib (Equioxx® or Previcox®). Firocoxib is a COX-2 selective drug, which means it does not block COX-1 activity.

This selectivity towards COX-2 is crucial because it reduces the risk of certain adverse side effects, particularly those related to the gastrointestinal tract. The implications of COX selectivity in the development of side effects will be discussed later in this article.

Formulations of Banamine®

Flunixin is a prescription medication that can only be obtained through a licensed veterinarian.

Three approved formulations of flunixin meglumine are available for use in horses:

  • Injectable solution
  • Oral paste
  • Oral granules

Additionally, flunixin meglumine is available in compounded forms, such as oral powder or capsules, from specialized pharmacies.

Intravenous (IV) Administration

The injectable form of flunixin is administered by veterinarians intravenously (IV), typically into the jugular vein. IV administration provides the most rapid onset for pain relief. [6]

Horse owners and non-veterinary professionals should not administer Banamine® IV due to the risks involved. Improper administration can result in tissue damage around the jugular vein, thrombosis (blood clot formation) within the vein, or even life-threatening seizures if the drug is mistakenly injected into the carotid artery. [9]

Oral (PO) Administration

Oral administration (“per os” or “by mouth”) of flunixin is typically more manageable and safer for horse owners. Banamine® can be administered orally in either paste