They’re found in just about every barn. They’re so common that almost every horse owner has at one time or another purchased them, dispensed them and asked the veterinarian for more. They’re non-steroidal anti-inflammatory drugs, or NSAIDs for short.

NSAIDs–such as phenylbutazone, Banamine and Ketoprofen–have analgesic and anti-inflammatory properties that reduce pain, fever and swelling. They’re vital in the treatment of colic and arthritis, but many people don’t know that their overuse and misuse can cause intestinal damage, kidney failure and death.

Because NSAIDs are so commonly dispensed, there’s been a significant amount of research in their use. And, some of the results might surprise you.

In 2004, Anthony Blikslager, DVM, Ph.D. and Samuel Jones, DVM, from North Carolina State University in Raleigh, N.C., researched NSAID use on horses with colic-related intestinal injuries. Their findings concluded that NSAIDs do not allow healing of intestinal tissue damage.

Eight horses with damage to the small intestine were given Banamine to reverse pain and to reverse the systematic effects of absorption of bacterial toxins from the damaged intestine. The findings concluded that the horses that were not given Banamine healed more quickly than the horses that were given Banamine. Banamine stopped the intestinal lining from healing for at least 18 hours. This is plenty of time to allow for increased endotoxin absorption.
Thus the move to find safer NSAIDs is on.

Blikslager, an associate professor of equine surgery at N.C. State University, has always been interested in the complexities of colic. “It’s the most fatal disease horses have. It’s the leading cause of death on a yearly basis,” he said.

He’s focused on the effects of current treatments for colic, and he’s looking for ways to improve the choices for colic treatments, with the use of NSAIDs being a part of the equation.

Most people understand the importance of NSAIDs because they’re a part of our daily lives. The most common human NSAID is aspirin. Aspirin, like the NSAIDs we use on horses, blocks an enzyme called cyclooxygenase (COX). Aspirin and other NSAIDS prevent the rate of production of pro-staglandins from a fatty compound called arachidonic acid.

In recent years, researchers have discovered different types of cyclooxygenase. There are now forms that are referred to as COX-1, COX-2 and COX-3. Each of these forms targets something specific. For example, COX-1 targets the prostaglandins that regulate normal body functions, such as protection of the intestinal tract. COX-3 appears to involve control of pain and fever and is targeted by the over-the-counter Tylenol®.

NSAIDs travel through the horse’s body through the blood stream. Unfortunately, they hit unintended targets and can cause more harm than good. The main areas they harm are the gastrointestinal tract and the kidneys.

“Pharmaceutical companies are investigating ways to manufacture NSAIDs that specifically target inflammation in the horse. The first example of this is Surpass®,” said Blikslager.

Surpass is a targeted topical NSAID cream with the scientific name of diclofenac liposomal (diclofenac is the anti-inflammatory drug; liposomal is a cream that seeps through the skin.) It isn’t available without a prescription, however, because the U.S. Food and Drug Administration regulates diclofenac, and it’s also regulated by the U.S. Equestrian Federation for competing horses.

Although Surpass is absorbed topically, it travels through the horse’s body systemically and is detectable in drug tests. If applying Surpass, make sure to wear gloves for this same reason.

Which Is For What?

The most common types of NSAIDs are available in tablets, paste, granules, injectables and now topical preparations.

Phenylbutazone (Butazolidin® or Bute®) is given orally or intravenously. It’s commonly used for horses with general muscle pain, arthritis and swelling. It’s also widely used on horses with tendonitis, laminitis, navicular and degenerative joint disease.

If the horse has normal kidney functions, giving a full dose of Bute for three to five consecutive days is routine to treat an injury. However, using an NSAID, such as Bute, for a leg condition can be counterproductive because NSAIDs mask pain, while encouraging the horse to continue to use the injured leg.

“The best thing to do is to figure out the exact site of injury and learn how to rehab it–whether it be injections for joint soreness or rest and time off for ligament soreness,” said Blikslager. “NSAIDs can make horses sound, but that may not be helpful if the cause of the lameness is not corrected.”

Blikslager added that if using NSAIDs for soundness issues, owners should get a veterinarian’s input instead of trying to play “chemist.” He noted that stacking NSAIDs together (using more than one at a time) is a recipe for disaster.

“A vet will come up with a scheme to inject, give Legend® or oral cartilage supplements. Add Bute at the lowest dose possible (2g/day) and tie it into their training program. If they have Monday off, give them that day off from Bute too,” noted Blikslager.

For joint issues, Blikslager suggests supplements for a horse that has to be on a regular schedule of Bute.

“The use of glucosamine is a good balanced therapeutic approach for a horse that has arthritis. However, it doesn’t reverse the side affects of Bute,” advised Blikslager.

He also notes that horses on a regular schedule of Bute could benefit from joint injections instead of NSAIDs. A regimen of proper training and injections will lessen the need for Bute and may prevent the horse from developing a gastrointestinal reaction.

Flunixin megalumine (Banamine®) is given either as an injectable or orally. Its most common use is for horses who are showing signs of colic or digestive upset.

Most horsemen immediately think of an injection of Banamine for a colicky horse (1cc per 100 lbs. of body weight) to help ease the pain, and that’s the right course of action as there’s rarely an allergic reaction to Banamine.

“Where horse owners get in trouble is if that horse doesn’t appear to be better in an hour, they’ll give the horse another dose of Banamine,” warned Blikslager, who noted that it’s important that horses do not have Banamine administered more than once every 12 hours.

Blikslager added, “If your horse doesn’t show signs of improvement shortly after a dose of Banamine, call the vet. The vet will then administer another [drug]–whether it be Rompun® or Dormosedan®. If these painkillers don’t work, then it’s likely the horse is a candidate for colic surgery.”

Blikslager noted that Banamine, while incredibly useful, does have its limitations as well. “Colic patients who have surgery have to heal their digestive systems themselves while they are supported with intravenous fluids and treatments like Banamine,” he said. “However, we have now found evidence that although Banamine can make horses more comfortable and reduce signs of shock, it slows the recovery of the intestine.”

Bute and Banamine will likely never be completely replaced because they are effective, and the majority of horses tolerate them very well. Just as with people, Advil is used by millions of people who have few problems with the drug. However, there’s always a subset of horses that could benefit from a more targeted NSAID, possibly including those recovering from colic surgery.

Another common NSAID is Ketoprofen (Ketofen®), which is given intravenously to sooth colic, muscle pain and swelling. Meclofenamic acid (Arquel®) is given orally to control muscle pain and swelling. Like aspirin, naproxen (Naprosyn® or Equiproxen®) is also given orally to aid in muscle pain and swelling.

The Golden Rule of NSAID use is to always use the lowest dose for the least amount of time. USEF rules pertaining to USEF competitions state that for competing horses not more than two nonsteroidal anti-inflammatory drugs, from a list of those approved, can be administered at one time. However, the use of Bute and Banamine together is forbidden.

Whenever two permitted NSAIDs are administered, any additional NSAIDs should not have been administered during the seven days prior to competing. And whenever any NSAID is administered that is not permitted to be used by USEF, it should not have been administered during the seven days prior to competing.

(For more information on the USEF and drug rules, see www.usef.org.)

Beware Of Toxicity

There are many advantages to NSAIDs. They’re without a doubt one of the most frequently used and relied upon medicines and they’re typically very effective when used correctly.

But there are issues surrounding the use of NSAIDs that horse owners should take into consideration.

“Kidneys can be damaged if horses are administered NSAIDs while dehydrated. A good idea would be to add electrolytes to
horses’ water who are getting NSAIDs,” said Blikslager. It’s also prudent to pull a horse’s blood to assess kidney function and hydration status before starting an NSAID therapy.

Even when you follow directions, there can be problems. Most side effects occur with Bute more than any other NSAID, possibly because it’s used so frequently. The most-documented side effect of Bute is dorsal colitis, in which a specific area of the colon becomes damaged. A study by Jones has shown that ultrasound can be used to detect and monitor this type of damage.

NSAID toxicity is a serious and sometimes fatal problem for horses. Signs of NSAID toxicity can be very difficult to detect, but include a reduced appetite and diarrhea.

When a horse taking an NSAID stops eating, that’s an immediate red flag. Depression and lethargy are other signs that may indicate a problem with NSAIDs. If a horse loses weight over a period of time while on a program of NSAIDs, this too can be attributed to NSAID toxicity as a result of abnormal colon function.

Owners play a huge role in monitoring this problem. An owner should document a horse’s manure output to check that it remains consistent (six to eight piles/day). In order to monitor for kidney damage, owners should also check a horse’s urine to make sure it isn’t bloody and remains consistent in color.

Ultrasounds can now be used to monitor horses with subtle signs of colitis to check for NSAID toxicity. Other intensive testing includes blood analysis and endoscopy.

“To reverse NSAID toxicity once it’s occurred, the NSAID should be discontinued. Alternate pain relievers such as Buturphonal® [not an NSAID] can be used, although pain control in severely lame horses can be very difficult without NSAIDs. A dose of Buturphonal only lasts 45 minutes, so in horses with continuous pain, it needs to be given at a constant rate infusion, such as an IV drip,” said Blikslager.

Giving the horse Prostaglandin E1 (the synthetic drug form is Misoprostol) may help the intestine to recover.

There are alternative NSAIDs that are believed to be safer for the horse’s intestinal tract, although the effectiveness of these newer NSAIDs isn’t yet known in the horse.

The creation of COX-2 inhibitors has dramatically reduced the incidence of ulcers in people and dogs, which could lead to new treatments for horses with colic or arthritis. For example, etodolac (Etogesic®) is normally used in dogs as an NSAID with an improved safety profile. Research at N.C. State has been done suggesting it’s as effective in joint inflammation in horses as phenylbutazone. Etodolac also appears to be less harsh on the horse’s digestive system.

The human drug Vioxx® (refecoxib, a COX-2 inhibitor) has been pulled from the market because of its adverse side effects in humans, including stroke and heart attacks. Horses may have COX-2 in their heart system, but heart attacks are very rare in horses. Therefore, this is less of a factor in NSAIDs for horses.

However, the costs of some of these newer NSAIDS may preclude them from being used in horses and is one reason they’re not widely used already.

Corn oil and generic psyllium (like the fiber found in Metamucil) are a couple of feed supplements that can be added to a horse’s diet if the horse has a problem with NSAID toxicity. Blikslager noted, “Horse owners should not give over-the-counter laxatives such as Meta-mucil® because they have too much sugar in them.”

When the horse digests psyllium in the colon, he produces short-chain fatty acids that provides an energy source. Psyllium therefore increases the health of colon lining and stimulates new cells and healing.

Natural NSAIDS

There are many herbal alternatives a horse owner can use instead of a non-steroidal anti-inflammatory drug. However, if owners use their horses for competition, they need to check with their discipline’s governing body (such as the U.S. Equestrian Federation) to check for the legality or limit of each substance. The USEF has a long list of banned natural/herbal products because everything that’s used in controlled or banned chemicals–such as NSAIDs or tranquilizers–originated from something natural.

Natural Substances with NSAID qualities that are banned from USEF

Calendula Flower
Comfrey Herb and Leaf
German Chamomile
Ginger
Valarian Root
Peppermint Leaf
Passion Flower
Devil’s Claw
Cloves
Lavender
Yarrow
Basil
Turmeric
Marjoram
Lemon Grass
Oregano
Kava Kava
Rosemary
Chaste Tree Berry Hops
Thyme
Horsetail-traces of nicotine
Hawthorn Berries
Ginseng
Meadowsweet
Golden Rod
Vervain
Feverfew
Red Poppy
Skullcap
Sage
Gotu Kola
Lemon balm
Leopard’s bane
Night shade
Capsaicin
Laurel
Rawuolfia