Advantages & Disadvantages of Using “Bute” in Horses

By Heather Smith Thomas............................................................................................................................................................................................................................................................................................................

henylbutazone (“bute”) is an anti-inflammatory drug—a non-steroidal anti-inflammatory similar to aspirin, Advil, Motrin, Banamine, etc. Bute has been used for decades in horses to relieve pain, particularly in musculoskele-Ptal injuries, navicular syndrome, arthritis, and so on. Melinda Freckleton, DVM (a private practitioner in

Virginia) says this drug is a comparatively safe and effective way to reduce pain and inflammation. Veterinarians prescribe it for a wide number of problems, but horse owners should be aware of possible side effects. “Even though most humans can tolerate using a little aspirin or ibuprofin once in awhile and it makes our lives more comfortable, there are a few individuals who cannot use these. The same is true with horses and bute. There are also risks when using these drugs inappropriately—such as at too high a dose or for too long a duration,” she says. “This is why there are very specific dosing recommendations that horse owners need to be aware of, realizing that even though the drug is helpful, giving more than the recommended dose won’t give more benefit. Several studies have shown that there are diminishing returns when increasing dosage. One gram will give a certain amount of pain relief, but 3 grams will not give you more,” explains

Freckleton. Giving an increased dose may result in more side effects (and could be quite dangerous to the horse) without giving more pain relief. This is why horse owners should try to administer the lowest dose that gives benefit to the horse.

Giving more may cause problems that include gastric ulcers, kidney dysfunction, and right dorsal colitis. Gastric ulcers are probably the most common risk.

“There are certain horses that probably won’t get gastric ulcers no matter what we do to them (like certain humans who can tolerate continual use of aspirin with no problems). But you have to realize that often the horses that are receiving the most bute, the most frequently, have other risks at the same time (such as stress, pain) that also make them more prone to ulcers. A drug like bute is a risk factor for gastric ulcers, but so is any kind of physiologic stress.

This could include the condition you are treating, or being confined in a stall. Often whatever painful condition you are treating requires you to confine the horse or change its routine and restrict its activity,” she says. Thus the risks are often multiplied. “The horses at risk for gastric ulcers should probably receive a different drug, or we might in addition to the bute recommend giving some kind of gastric protective product, such as omeprazole (Gastrogard or Ulcergard) or ranitidine (a generic ulcer treatment). We have options for dealing with this risk and need to keep these in mind,” says Freckleton.

Less common side effects of bute include right dorsal colitis. “This is a serious GI tract condition that bute and other NSAIDs can cause; the horse has diarrhea and sometimes fever. I have only seen two horses in which this problem was confirmed. I’ve never confirmed it as having been directly related to use of bute, but any horse that has a history of right dorsal colitis should not be given bute.” That horse could be treated with the newer drug Equioxx instead.

Kidney failure is also a possibility when overusing bute. “I have not seen kidney failure in any horse where bute was administered correctly, but there are some reports of owners accidentally giving the entire tube of bute paste in one dose—20 grams at once. That can cause kidney failure,” she says.

Some people forget that they have to adjust the dosage on the tube. “When you use a tube of dewormer, you typically give the horse the whole tube. We also have Equioxx that is marketed in individual doses—one tube or one small tablet per average size horse,” she explains. But with bute paste, you must not give it all at once; the tube is calibrated for multiple dosings and you have to change the setting to give the correct dose. If you give all 20 grams at once you will make the horse very ill.

If this ever happens, it is a serious emergency. You must have veterinary assistance immediately, to save your horse’s life. “We can lavage the stomach (flushing some of the drug back out) and give the horse charcoal to help bind some of the rest of the bute (so it can’t be absorbed by the horse). We’ll also start the horse on IV fluids to make sure the kidneys are well flushed,” says Freckleton.

“A horse that gets an accidental overdose should also be given gastric protection such as Gastrogard, because the excess bute will have GI tract effects as well. Treatment may also be needed for right dorsal colitis,” she says.

“When using bute, make sure you read labels and are giving the correct amount,” she says. In earlier years, the only form of bute available was pills, which were often difficult to give to the horse. We typically crushed these with a hammer, to create a powder to be mixed with feed or with applesauce or molasses and water and given by oral dose syringe. This was more time consuming and inconvenient than the powders or tubes of paste we have today, but the dosage was much more specific. One tablet was one gram.. You might waste a little when crushing it into a powder, but you knew how much you were giving the horse. Bute tablets are still available, and these newer versions break or crush up more readily than the older types, and also dissolve nicely in water—and can be mixed with a little molasses and water and squirted into the back of the mouth with a dose syringe.

By Heather Smith Thomas............................................................................................................................................................................................................................................................................................................

Today there are also some different formulations of bute powder, but they come in varying concentrations. “In our area, in people’s tack or feed rooms I see some brands in which a tablespoon of the powder contains a gram of bute, and some in which a teaspoon equals a gram of bute,” she says. This can get you into trouble if you can’t remember what the dosage should be. Always keep labels from the package, and read them before administering the powder.

“I’ve seen some people keep bute powder in a plastic baggie, and then wonder how much to give. If they no longer have the original label, they should just throw it away. There is no way to know the concentration of that powder, without a laboratory analysis,” says Freckleton. She advises saving the original package, and not moving the product from package to package, and always read the label. The label may say to give one scoop. So don’t lose the scoop!

If you own a horse that you know has trouble with bute, avoid this drug. “You can use Equioxx, which acts a little differently. It’s a COX2 inhibitor, and does not produce a lot of the side effects that bute may cause. It’s a little more expensive than bute, about the same price as Banamine paste, but is cheaper than giving a horse bute and Gastrogard,” she says. Not every horse needs to have this instead of bute, but for the ones that can’t handle bute, this is a good alternative.

The possible side effects with bute are the reason this is a prescription product, to be given to a certain horse in a certain dosage, as recommended by your veterinarian. “Because it is a prescription for a certain horse, you should not hand it to your neighbor to give, without a veterinarian saying the horse should receive it. But it is a fairly safe prescription product and has been used on thousands of horses for many decades.”

One thing to remember when using bute or any other NSAID, is to take your horse’s temperature before you give the drug. The anti-inflammatory drug will lower a fever, and may also make the horse feel better and mask the pain of lameness. “If the owner has given bute and then calls the veterinarian, who takes the horse’s temperature, it won’t give a true picture. And if your horse has a minor lameness please don’t give bute before you call the vet to come diagnose the lameness. The veterinarian must be able to see the lameness to pinpoint the problem,” explains Freckleton.

“We see this a lot, and it’s very frustrating. The owner feels bad for the horse, and gives it bute, and then is annoyed when the veterinarian can’t see the lameness well enough to diagnose it.” It just prolongs the interim before they can figure out what is really wrong with the horse.

One advantage with bute is that it has been around such a long time and it has been studied more than some of the newer drugs or alternative therapies. “We’ve certainly studied it a lot more than the herbal treatments some people like to give as an alternative. There are a number of herbal products that may or may not help the horse, and we don’t know what the side effects might be. There are lots of people who feel very good about giving these alternative medications to their horse, and maybe it’s a good thing and maybe not. We have no idea. We don’t know if these herbal products are effective and we don’t know if they have adverse effects.” Just because something is “natural” doesn’t mean it is better, or safer. There are many “natural” poisons.

Willow bark was one of the first pain relievers used by humans, and aspirin (that contains the same compound) is a great drug. But it does have some serious side effects, similar to the side effects of bute. So just because something is natural does not mean it is any safer than a prescription drug.