Bute For Horses, Its Uses, and Its Side Effects

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Can I borrow some bute for horses? This is a commonly heard phrase both at horse shows and at horse barns, particularly show barns.  Bute is as common in the horse world as flowers are in a garden. 

The bute is basically the equine equivalent to Ibuprofen (Advil, Tylenol, etc.) for people.  Bute can help your horse’s aches and pains, fevers, and sore muscles. But, Bute can also be detrimental if not administered properly.

Overuse of bute can cause serious side effects, and it is just as important to be aware of these side effects as it is to be aware of the drug’s benefits.  In this article, I’ll be discussing what bute is, how it works, what it is effective in curing, and what side effects of overuse can be.

What is Bute for Horses?

The Ontario Ministry of Agriculture, Food, and Rural Affairs defines bute as the following:

“Phenylbutazone (Bute) is an analgesic (relieves pain) and anti-inflammatory medication, commonly used for the treatment of lameness in horses. It belongs to a group of medications known as non-steroidal anti-inflammatory drugs (NSAIDS). Phenylbutazone is available in many preparations for horses, including 1-gram tablets, oral paste syringes (containing 6 grams or 12 grams/syringe), an injectable (200 mg/ml in 100-ml vials) and oral powder.”

It is a powder or paste administered to a horse to relieve multiple different categories of pain and discomfort.  But, because of its dangerous side effects, Bute must be prescribed by your vet in order for you to purchase it; it is not a medicine that can be bought “over the counter.”

Bute can be an extremely helpful tool for increasing a horse’s comfort through times of injury or sickness, but it also has detrimental side effects.  

Because bute is so common in the equine industry today,  is important for horse owners to understand when it is appropriate to use bute, and when bute can become a problem for their horses.

What Is Bute For Horses Used For?

Like Ibuprofen, Bute “blocks” a horse’s pain and brings down any inflammation or swelling.  It also acts to lower a horse’s temperature if a horse has a fever.  Because of these characteristics, Bute is the top pick for treating many different conditions in horses. 

Bute is used to treating muscular discomfort in horses, whether this simply be sore muscles from a hard day of work, or musculoskeletal disorders such as arthritis, laminitis, navicular, or degenerative joint disease.

It is also used to treat infections in flesh injuries that can occur from bites, kicks, or unfortunate rolls or run-ins with the fence or a tree.  Bute acts to not only reduce infection, but also to reduce swelling, and therefore pain in affected areas.  

What is Bute Powder for Horses used for?

How Does Bute for Horses Work?

After Bute has been administered either via syringe or via powder, the majority of the drug remains in a horse’s blood.  Damaged or injured areas of a horse’s body automatically have increased blood flow, as the horse’s body is naturally trying to fix the problem.

Because of this, there are also higher quantities of bute being transported to these areas. Bute them blocks chemicals called prostaglandins, which can cause pain.  

While this makes the horse more comfortable, prostaglandins also have important internal functions, which is why it is important to use Bute in low doses, to let the prostaglandins do their jobs. 

The blood eventually flows the bute into a horse’s liver, where it is processed and excreted from the horse’s body within 24 hours of consumption.

In terms of medications, this is a relatively long time for a drug to stay in a horse’s system after administration, and it is a rather long processing time.  This is why it is important not to overuse bute and thereby overwhelm a horse’s liver.

Common Side Effects of Bute

Prostaglandins not only cause pain, but also have an important job of regulating blood flow to a horse’s kidneys, stomach, and gastrointestinal tract.  When these prostaglandins are blocked by the use of bute, they can’t complete these jobs.

Lack of blood flow to the stomach and intestinal tract can increase risk and even cause horses to develop kidney damage or ulcers in their GI tract.  Especially if your horse is prone to either one of these conditions, it is vital to take special care when administering bute to your horse.


For example, my Thoroughbred has been prone to GI ulcers his entire life.  He is on a daily supplement to support GI health, and he gets an ulcer-reducing paste every time his stress levels may increase.  These instances include travel, lack of available turnout, and weather changes.

But, he is also a performance show horse.  After a long day of show, I want to make sure his muscles and joints stay relaxed and comfortable.  Bute is a perfect way to do this, but I have to be extremely careful with the dosage I use. I also need to consider how many days I choose to use it. If not, he runs the risk of his GI ulcers coming back in full strength.


Bute can be a performance horse owner’s best friend! Bute can be a senior horse owner’s best friend! But it can also be both of these horse’s enemies.  It is an extremely useful tool, but it must be used with caution and with the proper knowledge of its side effects.

Thankfully, Bute can only be obtained by a vet prescription.  Because of this, vets will prescribe an exact dosage for your horse. There is no question as to what is an appropriate amount and what is not; your vet will define this for you and your horse.

I hope this article helped you better understand what bute is, what it does, and what its side effects can be if used improperly.  If so, please share this article, and share with us your experiences (good and bad!) with using bute!

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