Thal Equine LLC
Regional Equine Hospital • Horse Owner Education & Resources
Santa Fe, New Mexico • 505-438-6590

Bute & Banamine®: What Horse Owners Should Know

“Hey Doc… my horse has been colicky since last night. I gave her some Banamine® (or bute) and she seemed OK for awhile, but now she doesn’t look so good…”

This scenario of self-help is very common in my practice.  I always ask my clients to call me to discuss the problem before they administer these drugs to their horses.  However there are many horse owners who regularly use these two common – but poorly understood – prescription drugs without any veterinary guidance.

Bute & Banamine

Bute & Banamine – Commonly Used & Misused in Horses

“Bute” (phenylbutazone) and Banamine® (flunixin meglumine) are the most commonly used anti-inflammatory drugs in the horse. These are prescription drugs, meaning that they can only be bought legally with a veterinarian’s prescription. Despite this, they can be found everywhere in the horse world, and they are often administered to horses without the guidance of a  veterinarian. Many horse owners do not understand how these drugs work or why they are used. Although highly effective when used correctly, they can be very dangerous if misused.

Generally, I encourage my clients to call me at the first sign of any problem with their horses.  This discussion does not always result in a veterinary appointment. Once I understand the nature of the problem, I may advise them to try treating the horse themselves, and I tell them what to look for to assess improvement. They may save money because their call does not result in a veterinary appointment, however our communication helps ensure that their horse gets the care needed.


Inflammation is a natural and intricate series of biochemical reactions that takes place in all animals as a response to injury. The process involves complex reactions between local damaged cells, blood vessels, inflammatory cells and biochemical signals sent and received from both near the site of injury and far from it. The first results of inflammation include opening of blood vessels to the area, increased leakiness of blood vessels resulting in swelling, and attraction of infection fighting cells to the site. Products of inflammation include prostaglandins and other inflammatory mediators that help bring about these effects.  Some of these mediators directly cause pain. All of these products of inflammation are intended to rid the body of infection or injury, and to prepare it to for healing.

Inflammation is a natural process and it is critical for survival. The problem is that often this process becomes excessive, creating a vicious cycle and causing more tissue damage, pain and suffering than the injury itself might. This is where anti-inflammatory drugs are helpful. Their role is to dampen inflammation by reducing the formation of mediators, and thus reducing the signs of disease (swelling, pain and fever, for example) while still allowing healing to take place.


Bute and Banamine® are potent anti-inflammatory drugs. They both belong to a class of drugs known as non-steroidal anti-inflammatory drugs (“NSAIDS”), which includes familiar human drugs like aspirin and ibuprofen. Less commonly used equine drugs in this class are firocoxib (Equioxx) ketoprofen, carprofen, naproxen and many others. Because these drugs moderate inflammation, they also reduce pain by reducing the formation of certain pain-causing products of inflammation. Anti-inflammatory drugs do much more than simply control pain. They have great value in reducing the disease process  and thus treating many problems, from abdominal pain (colic) to joint injury.

NSAIDS reduce inflammation by blocking prostaglandin synthesis. Prostaglandins come in many types. Some are products of the inflammatory cascade, while others have vital maintenance functions in the body. For example, one type has the role of protecting the stomach and intestinal lining from acid and digestive enzymes. This same prostaglandin has a protective role in the kidney.  Unfortunately, NSAIDS not only decrease the production of “bad prostaglandins” of inflammation, they also reduce the formation of these “good prostaglandins” and can cause problems to organs normally protected.

In recent years, new types of NSAIDS have been developed. The goal of this newer generation of NSAIDS has been to target the “bad” prostaglandins of inflammation and spare the protective ones, and thus be safer medication. Currently, the most prominent of these in the equine world is Equioxx (firocoxib). Having used the drug now for several years, I find it too has a niche in my practice. I use it for longer courses of administration or when I am especially concerned about side effects. No drug has yet provided a perfect balance of great effectiveness and excellent safety. Bute and Banamine® remain the mainstay of anti-inflammatory therapy in the horse.

Used correctly, these drugs rarely cause noticeable problems. On the other hand, all have potential side effects including:

  • Intestinal and stomach side effects including gastric and colonic ulcers. Foals are especially sensitive to the intestinal side effects and easily develop ulcers from the use of these medications.
  • Kidney problems. This is especially true of young horses, but caution must also be used in treatment of old horses and those that are otherwise ill or dehydrated.
  • NSAIDS have the ability to “mask” a problem, making it look less severe than it really is and give cause for false hope and delayed treatment.

For these reasons, it is very important to consult your equine veterinarian before you administer these drugs to your horse.


Phenylbutazone (a/k/a butazolidin) is primarily used to relieve musculoskeletal pain and inflammation in the horse. Bute comes in several forms including an injectable liquid for intravenous dosing only. It is most commonly found in oral forms, the familiar paste, tablets and powder. Used correctly, bute is a powerful and effective means of relieving pain and inflammation. Nevertheless, problems can arise due to misuse or overuse of bute:

  • It is unsafe in all horses at high doses for long periods of time.
  • It is considered more likely to cause ulcers, especially in the large colon, than Banamine® and other NSAIDS.
  • It is processed, inactivated, and removed from circulation by the liver and kidneys. Young horses have not fully developed their ability to process this drug, and tend to accumulate toxic doses of it. The same concern applies to old horses and those with underlying illnesses.
  • It is highly effective for treatment of lameness. As a consequence, it can mask signs of mild or moderate lameness. A horse with a non-displaced fracture on high doses of bute may over-stress the injury causing worsening of the fracture, which could even be fatal.
  • Bute is somewhat less effective than Banamine® at controlling abdominal pain (colic) but can still be useful.

After discussing these concerns, I dispense oral bute paste, powder or tablets to my clients as needed for treatment. For older horses and those in chronic pain (and after counseling clients on how to use it) I regularly dispense bute powder and tablets. I do not recommend that non-veterinarians use the injectable form of this drug. It is for intravenous use only, and must never be given in the muscle. It is severely damaging to tissues if even a small amount gets out of the vein into the surrounding tissues. When this happens, severe swelling develops and the tissue may even die and slough out, leaving a huge open wound that can take months to heal.


Banamine® is a trade name for the anti-inflammatory drug flunixin meglumine.  Banamine® was the only brand of this drug available for many years. As a result, the brand name has stuck, despite the fact that the drug is now available from many manufacturers and has many different trade names. It comes in injectable solution for IV use, a paste formulation, and granules. Although the injectable drug is intended for IV use, many horse owners give flunixin intramuscularly, and it is absorbed given orally. This drug is somewhat irritating to the tissues when given in the muscle and in rare cases can cause significant muscle damage and severe bacterial infection.

Banamine® is best known for its use in horses with abdominal pain – colic.  No doubt, this drug is a potent pain reliever and it has extra anti-inflammatory benefits that make it especially good for treating intestinal problems (anti-endotoxic effect).  It is thought to break the pain-dysfunction cycle that occurs commonly in colic cases, thereby allowing the gut to regain function.

Unfortunately, this drug is also excellent at masking the signs of colic, giving horse owners the false belief that they have “cured the colic” only to find their horse is critically ill or dead the next day.

The most important concept regarding the use of Banamine® in the treatment of colic symptoms is to understand that colic is not a disease but is the horse’s way of demonstrating abdominal pain. If the cause of colic pain is simply gas or a spasm, a “simple shot of Banamine®” may be all it takes to break the cycle and solve the problem. If, however, there is a mechanical problem in the gut such as a feed impaction or displacement, Banamine® will temporarily make the horse look better but does nothing to fix the underlying problem.

The time wasted thinking that the horse has improved can be the difference between life and death.


Bute and Banamine® are extremely important drugs in equine medicine. They offer excellent anti-inflammatory and pain relieving effects for horses. However, they must be used appropriately. Horse owners should understand the basic concepts of how these drugs work, their strengths and limitations, and always call their veterinarian before they administer these drugs. A veterinarian should examine any lameness or disease process that does not respond to a dose or two of an NSAID.

A veterinarian should evaluate any horse with persistent colic signs in order to diagnose the underlying cause and determine whether other types of medical or surgical treatments are required.

By Douglas O. Thal DVM Dipl. ABVP
Board Certified in Equine Practice
Thal Equine LLC
Last Updated August 2011

Would you like to learn more about bute and Banamine® on your smartphone? Take a look at Horse Side Vet Guide™, a 5-star rated mobile application for horse owners and equine professionals, created by Dr. Thal.

  A few records that may interest you include:

       Observation – Abdominal Pain, Colic Signs
       Observation – Bute, Banamine®, NSAID Overdose
       Treatment – NSAIDs, Non-Steroidal Anti-Inflammatories
       Skills – Give Intramuscular (IM) Injection


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Santa Fe, New Mexico 87508

69 Bonanza Creek Road

Santa Fe, New Mexico 87508


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