Dexamethasone for Horses
Dexamethasone is a synthetic corticosteroid hormone used to manage inflammation in diseases or conditions in which the immune system has a significant role. The anti-inflammatory effects of dexamethasone are about twenty-five times stronger than those of natural cortisol.
Dexamethasone commonly is used in horses to treat allergic reactions such as respiratory allergies, chronic obstructive pulmonary disease (heaves), hives, itching and inflammatory diseases including arthritis. Your veterinarian also may use dexamethasone in high doses in emergencies for anaphylactic reactions, spinal chord trauma or shock. The doses that are used in emergency medicine and the treatment of autoimmune diseases are considerably higher than the doses used under other circumstances. Dexamethasone is used topically to treat certain conditions of the skin and eyes. Preparations for topical use may include other active ingredients such as antibiotics, anti-fungals or miticides.
Dexamethasone is FDA-approved for use in animals including horses. When the appropriate dosage-form is not available through a veterinary pharmaceutical manufacturer, it may be compounded by a specialty pharmacy.
Give this medication to your horse exactly as your veterinarian prescribes. If you miss giving your horse a dose of dexamethasone, give the next dose as soon as you remember or, if it is close to the next scheduled dose, return to the regular schedule. Do not double dose to catch up.
Wash your hands after giving your horse this medication.
Be sure to discuss any side effects with your veterinarian immediately.
Corticosteroids such as dexamethasone are powerful drugs. While they have many positive effects, there is a definite potential to cause negative side-effects when overused or used improperly. Systemic side effects generally are dependent on dose and length of treatment.
Laminitis is a possible side-effect from any corticosteroid use in the horse. Be sure to discuss with your veterinarian the risk factors and how to monitor your horse for laminitis.
Increased urination (polyuria), increased water-consumption (polydypsia) and muscle wasting can be seen with prolonged dexamethasone use.
Keep this and all drugs out of reach of children. Dexamethasone is a prescription drug and should be used according to your veterinarian’s directions, and given only to the animal for which it was prescribed. Do not give this medication to a person.
Dexamethasone should be avoided or used with extreme caution in any horse or pony that may have other risk factors for laminitis. These would include animals with pituitary problems, equine Cushing’s syndrome or equine metabolic syndrome. Pony breeds in general are thought to be at higher risk for laminitis.
Corticosteroids such as dexamethasone can cause or worsen gastric ulcers. In some instances your veterinarian may chose to prescribe drugs such as omeprazole to protect your horse’s digestive tract while it is on dexamethasone.
Corticosteroids suppress immune response. Horses receiving dexamethasone may be more susceptible to bacterial or viral infections. Horses receiving dexamethasone may not respond normally to vaccinations. Your veterinarian may choose not to use modified live-virus vaccinations in your horse while it is receiving dexamethasone. Systemic corticosteroids can also mask signs of infection, such as an elevated temperature.
The use of corticosteroids in pregnant animals, especially in late pregnancy, is somewhat controversial. Most veterinarians try to avoid them although there are instances in which the benefits outweigh the possible risks.
Administration of dexamethasone can suppress the body’s normal production of corticosteroid hormones. If an animal has been receiving dexamethasone for a chronic condition, the dose of dexamethasone may need to be tapered so that the animal’s body can return to its normal production of corticosteroid hormone. Be sure to consult your veterinarian before discontinuing this drug.
Be sure to review with your veterinarian any medications or supplements your horse may be receiving.
The risk of gastric ulcers may be increased if dexamethasone and other drugs prone to causing ulcers such as NSAIDs (phenylbutazone, flunixin and others) are given at the same time.
There is an increased risk of electrolyte imbalances due to calcium and potassium losses in animals receiving the diuretic furosemide while on dexamethasone.
Dexamethasone should not be given intravenously with fluids containing calcium.
If you suspect your horse or another animal was accidentally overdosed or has eaten this medication inadvertently, contact your veterinarian or the A.S.P.C.A.’s Animal Poison Control Center at 888.426.4435. Always bring the prescription container with you when you take your horse for treatment.
If you or someone else has accidentally ingested this medication call the National Capital Poison Center at 800.222.1222.
Different strengths or dosage forms of dexamethasone may have different storage requirements. Read the labeling or ask your pharmacist for the storage requirements of the prescription you receive.
More Information About This Medication
Corticosteroids are hormones produced by the adrenal gland. Cortisol is the naturally occurring corticosteroid hormone. Corticosteroids are essential for life and affect the animal’s metabolism and the function of all cells and organ systems. Their anti-inflammatory effects are due to multiple actions at the cellular level.
There are two major types of hormones produced by the adrenal gland, the mineralocorticoids and the glucocorticoids. The information here discusses dexamethasone that is a glucocorticoid or corticosteroid. There are many different corticosteroid drugs available and different medical conditions are treated with different corticosteroid drugs based on the individual drug’s pharmacology (e.g. potency, speed of onset and duration of action).
The other types of hormones produced by the adrenal gland are called mineralocorticoids. They primarily control salt and water balance in the body. There is some cross over in function between mineralocorticoids and the glucocorticoids. A major goal in developing new corticosteroid drugs is to increase the anti-inflammatory effect and reduce their crossover effect on salt and water balance.
When corticosteroid drugs are used systemically, the basic rule is to use the preparation with the shortest duration of action, at the lowest dose level and for the shortest period of time possible. Chronic or inappropriate use of corticosteroids can cause life-threatening hormonal and metabolic changes.
About the Author
Dr. Barbara Forney is a veterinary practitioner in Chester County, Pennsylvania. She has a master's degree in animal science from the University of Delaware and graduated from the University of Pennsylvania School of Veterinary Medicine in 1982.
She began to develop her interest in client education and medical writing in 1997. Recent publications include portions of The Pill Book Guide to Medication for Your Dog and Cat, and most recently Understanding Equine Medications published by the Bloodhorse.
Dr. Forney is an FEI veterinarian and an active member of the AAEP, AVMA, and AMWA.
You can purchase books by Dr. Forney at www.exclusivelyequine.comThe information contained on this site is general in nature and is intended for use as an informational aid. It does not cover all possible uses, actions, precautions, side effects, or interactions of the products shown, nor is the information intended as medical advice or diagnosis for individual health problems or for making an evaluation as to the risks and benefits of using a particular product. You should consult your doctor about diagnosis and treatment of any health problems. Information and statements have not been evaluated by the Food and Drug Administration ("FDA"), nor has the FDA approved the products to diagnose, cure or prevent disease.
Wedgewood Pharmacy compounded veterinary preparations are not intended for use in food and food-producing animals.