Corticosteroids and anabolic steroids are synthetic versions of natural hormones produced by the adrenal glands and gonads. Although they stem from the same precursor molecule, corticosteroids and anabolic steroids have very different purposes and uses.
Corticosteroids most commonly are used to reduce the pain and swelling of musculoskeletal problems caused by inflammation — arthritis (joint), tendinitis (tendon), fasciitis (ligament), and myositis (muscle). In internal medicine, corticosteroids often are used to relieve allergic reactions such as rhinitis (nose), dermatitis (skin), and uveitis (eyes). Basically, any condition with an “itis” at the end (“itis” means “inflammation of”) will respond to treatment with corticosteroids.
Most humans have been prescribed corticosteroids at some time. One of the most common uses in humans is to resolve a bad case of poison ivy. Because abruptly stopping the use of corticosteroids will cause adverse effects, some serious, physicians typically prescribe a dose pack, which contains a daily dosage that gradually decreases over the 10-21 days of treatment.
In athletic horses, triamcinolone is the go-to corticosteroid for inflammation of highly moveable joints; methylprednisolone is preferred to treat inflammation of the spinous processes of the spine; and dexamethasone is used orally and by injection to reduce inflammation and ease the symptoms of allergic reactions.
Corticosteroids are powerful substances that must be used judiciously. Although they are a vital tool in the veterinarian's armamentarium, they can cause laminitis if used improperly or if a secondary event causes the horse's body excessive stress while it is receiving them.
A horse on systemic corticosteroids for body soreness or skin infections that additionally has its joints injected with triamcinolone receives an unintended double whammy of steroids that can lead to laminitis. Likewise, if a horse is being treated with corticosteroids and develops laminitis from an unrelated cause, such as getting into the grain bin, the corticosteroids will cause the laminitis to be more severe.
Anabolic steroids are sometimes referred to as androgenic-anabolic steroids because they are synthetic derivatives of the male sex hormone testosterone. “Androgenic” literally means “causing to be male.”
A healthy, normal human does not need anabolic steroids, but they do have therapeutic use. Physicians use anabolic steroids to treat certain anemias or to supplement men whose testosterone level is low. Patients struggling to recuperate from cancer and other illnesses that cause muscle wasting or loss of appetite can benefit from them.
In horses, anabolic steroids are used therapeutically to help a horse recover from illness. Anabolics help the body repair itself, improve the horse's appetite, and increase the volume of red blood cells. Other uses, whose therapeutic validity is the subject of controversy, include giving the horse a macho demeanor that enables it to shrug off minor pain while continuing to train or race and the ability to artificially build up muscle mass.
Anabolic steroids also are used to promote growth (“anabolic” means “growth”) of tissues, most specifically muscle. This is where the potential for abuse lies.
In 1981, renowned toxicologist Dr. Thomas Tobin speculated in his book Drugs and the Performance Horse that anabolic steroids given to young horses might impact their growth potential, and the added muscle mass and resulting strength might tax immature bones, tendons, and ligaments.
“Administration of large quantities of these agents to young animals can hasten closure of the epiphyseal plates at which growth occurs and thus prevent growth in length of these bones,” Tobin wrote.
In adult horses, anabolic steroids cause muscles to bulk so the horse can perform better. But they tend to interfere with the horse's natural production of the stress hormone cortisol, which is essential for proper immune response. A horse threatened with a respiratory infection, for example, may develop a critical case of pneumonia after treatment with anabolic steroids.
By far the worst effects of anabolic steroids occur when the horse is taken off them. Muscles waste, the horse may lose its appetite, and the combination of the two causes fatigue. Research shows fatigue causes breakdowns.
“Any time a horse becomes acutely fatigued, it starts to lose its ability to hold itself upright,” said Dr. Gary Potter, professor emeritus at Texas A&M University. “In other words, it can't keep its joints upright or in correct position. That's what causes the horse to hyperextend its joints, that's what causes it to overload the skeleton because the muscular system has lost part of its power. That's actually the definition of fatigue.”
Big Brown won the Kentucky Derby and the Preakness Stakes in 2008 while on a regimen of anabolic steroids. But when trainer Richard Dutrow Jr. took him off steroids for the Belmont Stakes, the horse failed to finish the race. Big Brown dropped back abruptly going through the turn for home and was pulled up approaching the quarter pole. Jockey Kent Desormeaux was smart enough to respond properly to the horse's fatigue, and Big Brown was smart enough to protect himself.
Racing jurisdictions today have very different tolerance levels for therapeutic dosing of anabolic and corticosteroids. Under the Association of Racing Commissioners International's Uniform Classification Guidelines, anabolic steroids are considered Class 3 substances (which “may or may not have generally accepted medicinal use” but whose pharmacology “suggests less potential to affect performance than drugs in Class 2). Corticosteroids are considered Class 4, which is reserved for therapeutic drugs expected to influence performance less than Class 3 substances.
New to the Paulick Report? Click here to sign up for our daily email newsletter to keep up on this and other stories happening in the Thoroughbred industry.
Copyright © 2019 Paulick Report.