Drugs and Competition

The use of drugs in the competition horse carries with it some extra concerns and responsibilities. Many of the major issues related to drug use in the performance horse involve the treatment of lameness. It is imperative that the moral and ethical line between treating minor pains and more serious injuries be quite clear. Many of the anti-inflammatory drugs can have extremely powerful effects and could easily alleviate the pain/lameness of an injury that could be made significantly worse if the animal continues working.

When horse shows lameness, it's very important to obtain an accurate clinical diagnosis before using anti-inflammatory medication if the intent is to obtain soundness in order to continue performance activities. For example, a horse which is lame behind with the ultimate cause being arthritis of the "lower" hock joint might be able to be made sound and comfortable by using a minimal amount of phenylbutazone (Bute) and continuing exercising without any severe detrimental consequences. Conversely, a horse with the same degree of lameness caused from inflammation of the high suspensory ligament could be made comfortable by using a minimal amount of Bute, but the ligament inflammation would become progressively worse, leading to a poor long-term outcome.

There are many conditions that respond to inflammatory medication--providing soundness with little risk of progression or severe injury--but it is essential that an accurate diagnosis be made before continuing with exercise.

Medication Control

Another aspect of drug use in the performance horse is medication control and drug testing. The two main organizations controlling drug usage in the show horse are USA Equestrian (formerly the American Horse Shows Association or AHSA) and the Fédération Equestre Internationale (FEI). The USA Equestrian medication rules (online at www.equestrian.org/2003RuleBook/rule-iv.pdf) apply to all USA Equestrian-recognized shows and events in the United States, and FEI medication rules apply to all FEI-sanctioned international shows and events in the United States or abroad.

With USA Equestrian rules, virtually any medication can be administered under veterinary supervision for a legitimate therapeutic reason ("the medication must be therapeutic and necessary for the diagnosis or treatment of an existing illness or injury"). If the administering veterinarian thinks the horse can exercise without complication, the horse may do so 24 hours after treatment. The horse must be withdrawn from competition for no less than 24 hours after the medication is administered. Some drugs such as fluphenazine or reserpine are known to have a profound clinical effect for longer than 24 hours; however, these drugs have no therapeutic indications in horses. You might also want to note that anabolic steroids in Arabians three years old or younger are not allowed at all.

USA Equestrian provides a form to be filled out and signed by the treating veterinarian and the show steward allowing a medicated horse to compete 24 hours after treatment. That form provides allowances for a positive drug test. It should be noted that sedation for hair clipping, shoeing, transportation, or similar activities is not considered a "therapeutic" purpose to administer a forbidden substance, and in most cases you will need seven days (depending on the drug or combination of drugs being used) to clear drug testing.

USA Equestrian allows the use of anti-inflammatory medications within specified doses for limited treatment of minor musculoskeletal aches and pains from competition, and for low-grade chronic conditions that should not put the horse at risk of serious injury if he is treated and exercised. Again, if your horse is lame, you shouldn't medicate him until an accurate diagnosis has been made by your veterinarian, who will determine if exercise should be restricted.

The medications allowed by USA Equestrian rules were determined through a great deal of clinical research and debate, with the goal of allowing treatment of relatively minor injuries while at the same time preventing the abuse of these drugs (and the horse given them). The rules are constantly re-evaluated and modified based on current veterinary science and new drug emergence. If your horse is actively competing, you need to keep on top of rule changes published yearly.

In addition, questions on medication usage can be addressed by your veterinarian or the show veterinarian. Or you can contact USA Equestrian at 800/633-2472 or e-mail medequestrian@aol.com.

The following is a brief overview of what medications are allowed and the limitations that apply to them. For a more in-depth review, see the Drugs and Medications section of the USA Equestrian rule book and the web publication "Practical Advice Regarding the 2002 Equine Drugs and Medications Rule" at www.equestrian.org/aboutus/meds/advice.html.

Drug Testing

The doses of allowed drugs are monitored by testing, which determines the concentration of these drugs in blood and/or urine at the time of drug testing. When a drug is administered, it is eliminated from the body in a predictable way that is characteristic for that individual drug. An important term when looking at drug elimination is "half-life." The half-life of an individual drug is the time required for the drugs' blood concentration to be decreased by 50%. It is dependent on the rate of elimination by liver and kidney metabolism of that drug from the body.

All drugs have a different half-life that can be affected to some degree by the individual animal's metabolism. Knowing the half-life and other kinetic data for the individual drug allows for its use at a specified dose and administration time, which can then be confirmed by measuring the concentration of the specific drug or its byproducts in blood and/or urine.

All doses of permitted medication should be calculated based on actual body weight of the animal receiving them. Current allowed medications and guidelines for their use are as follows (again, for complete details and further explanation, see the current rule book and online advice page at www.equestrian.org/aboutus/meds/advice.html).

Anti-Inflammatory Drugs

The non-steroidal anti-inflammatory drugs (NSAIDs) allowed under USA Equestrian rules for a 1,000-pound horse are:

Phenylbutazone (Bute)--A dose of 2 grams or less can be administered every 24 hours, with dosages being given at 2 grams intravenously not closer than 12 hours out, or if given orally, one gram twice daily before competition to a 1,000-pound (454-kg) horse (or 200 milligrams per 100 pounds, or 45.4 kg, of body weight). Phenylbutazone should not be used for more than five successive days, and it can be used concurrently with naproxen, ketoprofen, or meclofenamic acid (more on these later) when their limits are followed. Also, NSAID use is limited to no more than two of the listed drugs concurrently, and phenylbutazone and flunixin meglumine (Banamine) together are not permitted seven days or less prior to competition.

Flunixin meglumine (Banamine)--A dose of 500 mg or less, administered before competition to a 1,000-pound horse, is allowed 12 hours or more before competition (or 50 milligrams per 100 pounds of body weight). Flunixin meglumine can be given every 24 hours, and should not be administered for more than five successive days. It can be used concurrently with naproxen, ketoprofen, or meclofenamic acid when their limits are followed. Again, phenylbutazone and flunixin meglumine are not allowed together less than one week before competition.

Naproxen--A dose of 4 grams or less, administered no less than 12 hours before competition to a 1,000-pound horse, is allowed every 24 hours (or 400 mg per 100 pounds of body weight). Naproxen should not be administered for more than five successive days, and can be used concurrently with phenylbutazone, flunixin meglumine, ketoprofen, or meclofenamic acid when their limits are followed. Remember, NSAID use is limited to no more than two of the listed drugs concurrently.

Ketoprofen--A dose of 1 gram (or 100 milligrams per 100 pounds of body weight) can be administered to a 1,000-pound horse every 24 hours. The dose can be administered four hours or more before competition. Ketoprofen should not be used for more than five successive days. Ketoprofen can be used concurrently with phenylbutazone, flunixin meglumine, or meclofenamic acid when their limits are followed.

Meclofenamic acid--A dose of 0.5 grams or less is allowed before competition to a 1,000-pound horse (or 50 milligrams per 100 pounds of body weight). Meclofenamic acid should not be administered for more than five successive days, and can be administered at 12-hour intervals. Meclofenamic acid can be used concurrently with phenylbutazone, flunixin meglumine, or ketoprofen when their limits are followed.

A positive test for any more than two of these NSAIDs can result in penalties and/or suspension. The use of other NSAIDs is prohibited. As other NSAIDs are developed and approved for use in the horse by the Food and Drug Administration (FDA), their allowance will be considered by USA Equestrian. (For example, the new drug eltenac will be allowed at certain doses when it finishes the FDA approval process. It will be permitted to be given every 24 hours, no closer than 12 hours before competition, and at a dose of 250 mg for a 1,000-pound horse, or 25 mg/100 pounds.) If any other NSAID that is not permitted is used, the withdraal time needed for a clear drug test is typically seven days. Check with your veterinarian to be sure.

Other Medications

Methocarbamol--This drug is used as a muscle relaxant at a dose of 5 grams or less, administered no less than six hours before competition to a 1,000-pound horse, is allowed every 12 hours (500 mg per 100 pounds of body weight). Methocarbamol can be administered along with any of the allowed anti-inflammatory drugs.

Steroids (corticosteroids)--These include drugs such as dexamethasone, methylprednisolone, betamethasone, etc., are allowed when administered for a therapeutic purpose. The use of corticosteroids must be reported (intravenous, intramuscular, subcutaneous, oral, inhaled, topical, or intra-articular) if they are administered within seven days of competition. The rules pertaining to corticosteroids will change on Dec. 1, 2003.

Homeopathic/Herbal Remedies--A current area of great concern with respect to both USA Equestrian and FEI drug testing is the use of homeopathic and/or herbal remedies (in addition to various feed supplements and other potential sources of drugs). Remember, you are responsible for a positive drug test even if it is an inadvertent circumstance. The equine marketplace is exploding with herbal remedies and feed supplements, not to mention the chocolate bar or poppy seed muffin your horse snatched that could result in a positive drug test for theobromine or morphine, respectively. Some examples of the thousands of plants that could cause a positive drug test listed by the USA Equestrian are vervain, kava kava, passionflower, skullcap, chamomile, valerian, lemon balm, leopard's bane, nightshade, capsaicin, comfrey, devil's claw, hops, laurel, lavender, red poppy, and rauwolfia. This of course is true for the FEI rules as well (remember, zero tolerance policy). You should scan the ingredient list very carefully for any substance that could cause a problem. Unless you are 100% sure of a supplement's ingredients, don't risk it.

With the FEI it is a bit more complicated. The FEI has stricter rules regarding medication; however, it does allow some medications to be used in competition horses if the proper paperwork is filled out. Unless you are a treatment veterinarian registered with the specific event, it is against the rules for drugs or even needles and syringes to be possessed by those associated with the horses. If a horse requires treatment, he must be examined by a treatment veterinarian (or a team veterinarian) who in turn reports to the veterinary committee (typically two or three veterinarians who are event officials and who will also examine the horse). Depending on the problem and the need for medication, the horse might or might not be given permission to compete.

When using certain medications, the medicated horse will be withdrawn from competition for at least 24 hours. Typically, if the horse requires any significant anti-inflammatory medication (phenylbutazone, flunixin meglumine, etc.), he will not be allowed to compete. However, antibiotics, some fluids, and anti-ulcer medications are allowed and only need to be reported if used during competition. Horses do not have to be withdrawn for any period of time for these medications to be used.

At the FEI level, you also have to think ahead (or backward) because of the long withdrawal times for some drugs. For example, many of the hormones such as estrone, methylprogesterone, and altrenogest (Regumate) can have a clearance time of 45 days or more depending on the dose and how they were used.

At the racetrack, it is very different depending on the state. Some states have a zero tolerance (no drug) policy, while others have a controlled medications program that allows some medications, but only at limited doses.

The bottom line for any discipline is to know the regulations, work with your veterinarian, and use good judgment with respect to the medication and supplementation of your performance horse.

About the Author

Kim and Kari Baker

Kim and Kari Baker are equine photographers as well as writers. The twins live on a ranch in northwest Montana and have been in the equine industry for more than 35 years, raising, showing, and training Appaloosas.

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