Banamine Allergy in Horses

Banamine Allergy in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

Most common symptoms

Depression / Destructive / Pain / Premature Labor / Redness / Wound


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Most common symptoms

Depression / Destructive / Pain / Premature Labor / Redness / Wound

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Banamine Allergy in Horses - Symptoms, Causes, Diagnosis, Treatment, Recovery, Management, Cost

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What is Banamine Allergy?

Banamine, also known as Flunixin Meglumine, is a non-steroidal anti-inflammatory medication (NSAID) that is frequently used to treat pain, swelling, and fever in equine patients. Horses can develop allergies to Banamine after either just a few exposures to the drug or after many months or years of successful treatment with it. Allergic reactions to medications like Banamine typically result in hives for horses and on rare occasions may trigger dangerous anaphylactic responses which can be fatal without prompt medical treatment.

Banamine is a commonly prescribed pain medication for horses. Equine allergies to medications generally present as hives, although anaphylactic shock is also a possible reaction.

Symptoms of Banamine Allergy in Horses

Reactions to anti-inflammatory drugs like Banamine typically generate a skin reaction in horses known as hives, which appears most often twelve to fourteen hours after exposure to the allergen. In most cases, the hives will present initially either on the side of the neck or at the site of injection if the anti-inflammatory was injected and then travel across the throat and shoulders. Early bumps may start as small as half an inch in diameter, however, they frequently increase in size and often join as the reaction progresses. Welts may or may not itch, and the animal may also experience depression and have a slightly increased temperature. 

  • Hives
  • Bumps
  • Welts
  • Depression
  • Itchiness may or may not occur
  • Elevated temperature


Banamine (Flunixin Meglumine) is not the only nonsteroidal anti-inflammatory medication available to equines, although it is particularly useful for treating soft tissue damage and colic symptoms once a veterinarian has assessed the situation. Other equine medications that may be included in the NSAID class are:

  • Acetylsalicylic Acid - Aspirin can be utilized by horses as well, and although the relief is generally short-lived, it can be particularly useful in conditions where blood clots are likely to form

  • Diclofenac - Commonly known by the brand name Surpass, this is a topical anti-inflammatory that is generally used for osteoarthritis relief
  • Firocoxib - This drug may be more expensive than other NSAIDs, however, it has fewer detrimental GI effect than other medications and can be given to horses that may be sensitive to other pain medications

  • Phenylbutazone - Commonly referred to as bute, this is one of the most popular of the NSAIDs for horses, particularly for acute injuries, but is also one of the most likely to cause ulcers when given in large doses or over extended periods of time

Causes of Banamine Allergy in Horses

Equine allergies are the result of an overly aggressive response of specialized cells of the immune system, mast cells, to a protein. In this case, the protein that is stimulating the allergic response is Banamine. The skin related symptoms of allergy are the same whether it is a contact allergy, an allergy to medication, or even a food allergy. Either synthetic or naturally occurring proteins may stimulate the mast cells into releasing histamine, which is the compound that triggers the inflammatory effect that causes the majority of the itching and swelling characteristic of an allergic response.

In rare cases, allergies that are related to drugs like NSAIDs may induce an anaphylactic reaction, in which the horse experiences respiratory distress due to swelling of the lung tissues and the blood pressure drops dramatically. This type of reaction occurs rapidly and can become fatal if left untreated.

Diagnosis of Banamine Allergy in Horses

The veterinarian will typically start the visit by performing a physical examination as well as ordering routine tests such as complete blood counts and biochemistry profiles. These tests may expose increased levels of eosinophils, a specialized type of white blood cell that would be indicative of an allergic reaction, although eosinophils may also be increased in horses that are hosting gastrointestinal parasites. Both serum testing and intradermal testing are available to help define a particular horse’s sensitivities.

Intradermal testing involves sedating the patient and shaving a patch on their necks, then injecting a tiny amount of the allergens that are suspected to be the cause of the reaction or of allergens that are common to equines. This is executed in a grid pattern in order to easily assess the specific allergens as triggers. This patch will be evaluated at several intervals, from fifteen minutes from injection until twenty-four hours after injection. Serum testing is less invasive, just requiring a sample of the horse’s blood for testing, however, it is much less reliable than the intradermal testing methods.


Treatment of Banamine Allergy in Horses

Cold water is frequently used as an effective method to reduce allergy-related fever and inflammation until your veterinarian has been able to examine the animal to ascertain an appropriate treatment plan. If the horse is in distress, your horse’s doctor will typically commence supportive treatments as soon as possible. Some horses have an anaphylactic reaction in response to the compounds in the medication and breathing becomes obstructed due to swelling in the membranes of the lungs, and the use of epinephrine injected directly into the animal’s jugular is needed to safeguard the horse’s health. The veterinarian may also recommend that an IV line be set up to provide the large volumes of water that are necessary for the proper functioning of the horse’s circulatory system. Although animals who are allergic to one type of NSAID are often prone to allergies triggered other NSAIDS, many horses are able to employ alternate anti-inflammatory medications without harm.

Corticosteroids and antihistamines are also helpful in reducing the symptoms of allergy but are more commonly used in treating allergies with allergens that are difficult to either diagnose or avoid. An essential part of treating equine allergies to medications is to cease administering the drug to the patient, making the accurate diagnosis of the allergy crucial for appropriate treatment. This is particularly important when dealing with an animal who is allergic to a medication like a NSAID which is often used as a remedy for the swelling and the fever that are frequently characteristic of allergic reactions.

Recovery of Banamine Allergy in Horses

Although rare, anaphylactic shock is a serious condition which requires prompt medical attention. If epinephrine in the proper dosage is available, inject it directly into the jugular vein. This dosage may need to be repeated every 15 minutes until a veterinarian is able to set up an IV to allow for further medications. If no epinephrine is on hand, general antihistamines are often helpful to reduce the symptoms long enough for emergency treatment and general therapies for shock, such as keeping the patient quiet and calm, covering them with a loose coat or blanket, and allowing them to find the most comfortable position to rest in.

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Banamine Allergy Questions and Advice from Veterinary Professionals