Considering corticosteroids: What horse owners should know...

Corticosteroids are used for a variety of different ailments either orally or by injection, to treat systemic allergies/allergic reactions, respiratory diseases, eye problems, and inflammatory conditions. They are often part of a "cocktail" of substances used in joint injections. While generally vets have a good grasp of how much steroid can be safely injected, you may have information that "completes the medical picture. Here are three things to think about when  your vet recommends corticosteroids...

1. Is your horse under stress or "fighting something off?" Some horsemen have noticed that horses often come down with disease 2 weeks to one month after joint injections. There is only anecdotal evidence to support this, but it's true that corticosteroids can lower the immune system. When the immune system is depressed, a disease that is weakly present in the body can gain a foothold, bringing on a full on attack of the disease. If you suspect your horse may be fighting something off -- EPM or Lyme, for example -- be cautious of administering joint injections containing steroids. Similarly, if your horse is under stress from competition, a move to a new barn, or travel, mention it to your vet when s/he prescribes a steroid-based treatment.
2. In some circumstances steroids, especially triamcinolone, can contribute to the onset of laminitis or founder. Does your horse have a history of laminitis? Is your horse actually a fat pony? Is your horse otherwise at risk? Use corticosteroids only when absolutely necessary and in small, short acting doses. For the average healthy horse, though, the incidence of steroid-induced laminitis is only .5% when given a dose that was two to four times greater than that used by most practitioners in the USA (see this article for reference). 
3. Is your horse being treated with another steroid-based medication? Technically your vet should know this, but definitely mention any meds that your horse is taking or has taken (some cortiscosteroids are long-acting). The effects can be cumulative.
4. Corticosteroids are known to slow or prevent normal healing with respect to soft tissue (tendon and ligament) injury. Because corticosteroids suppress inflammation, your horse may overwork damaged tissue because pain associated with inflammation is gone.  If your horse is in hard work or  if you suspect soft tissue injury, tell your vet before beginning steroid treatment.

RESOURCES


How steroids can lead to laminitis from Thoroughbred Times

Equine joint injections from The Horse magazine

Steroids from The Horse magazine

Therapeutic steroid use distinct from anabolic steroids from The Horse magazine