Dexamethasone is a fast-acting glucocorticoid corticosteroid. Glucocorticoids have effect on virtually every cell type and body system.¹ In general, dexamethasone is used in the management of immune-mediated conditions such as asthma, dermatologic and other related diseases (e.g., hives, itching), inflammatory diseases, certain cancers, thrombocytopenia, immune-mediated hemolytic anemia and some neurologic diseases. It also is used topically to treat some skin and eye problems.

Although glucocorticoids have been used to treat many conditions in humans and animals, dexamethasone has five primary uses with accompanying dosage ranges: 1) as a diagnostic agent to test for hyperadrenocorticism, 2) as a replacement or supplementation for glucocorticoid deficiency secondary to hypoadrenocorticism, 3) as an anti-inflammatory agent, 4) for immunosuppression, and 5) as an antineoplastic agent.^2,3

Dexamethasone is long acting, and 30 times more potent than hydrocortisone with no mineralocorticoid activity.¹ It is typically administered orally, intravenously or intramuscularly.

Dexamethasone Indications

In horses, dexamethasone is indicated for the management of recurrent airway obstruction (RAO), a name given to a frequently-occurring respiratory disease syndrome. It is also known as chronic obstructive pulmonary disease (COPD) and “heaves.” The syndrome is analogous to asthma in humans and is a common reason for some horses persistently coughing. RAO is typically characterized by an overproduction of mucus, narrowing of the airway (bronchoconstriction) and bronchospasm. 

As with humans, COPD causes horses to experience labored breathing and is often exacerbated during the winter. In many cases, COPD occurs in horses that have developed an allergic reaction to environmental dust allergens. The reaction causes inflammation and narrowing of the airways creating breathing difficulties. Usually, the affected horses are experiencing allergic reactions to environmental allergens such as fungal spores or pollen. 

In cattle, dexamethasone is used to treat primary bovine ketosis, a condition that typically occurs during early lactation (clinical signs include diminished appetite, decreased milk production, weight loss, hypoglycemia, and hyperketonemia).

In dogs and cats, dexamethasone is widely used to treat a variety of skin conditions. In dogs, dexamethasone can cause more GI complications and bleeding as compared with prednisone, so careful attention to the minimum dose necessary is required. Cats generally require higher doses than dogs for clinical effects but typically develop fewer adverse effects. Glucocorticoids appear to have a greater hyperglycemic effect in cats than in other species. Rabbits can reportedly develop serious adverse effects to dexamethasone, even after single doses.¹

Warnings and Contraindications 

Contraindications for dexamethasone include systemic fungal infections, and caution is advised for use in animals with active bacterial infections, corneal ulcers, hyperadrenocorticism (i.e., Cushing’s disease), diabetes mellitus, osteoporosis, chronic psychotic reactions, predisposition to thrombophlebitis, hypertension, and renal insufficiency.¹ In humans, dexamethasone and other corticosteroids have been used in the study and treatment of atopic dermatitis and rheumatoid arthritis.

Animals that have received systemic glucocorticoids for more than 2 weeks should be slowly tapered off the drug to allow return of normal endogenous ACTH and corticosteroid function. If the animal undergoes a stressful event (e.g., surgery, trauma, illness) during the tapering process and/or before normal adrenal and pituitary functions resume, additional glucocorticoids should be administered. Some animals, particularly cats, at risk for diabetes mellitus (e.g., obese patients, patients with Cushing’s disease) should receive glucocorticoids with caution due to these agents’ potent hyperglycemic effect. Dexamethasone should be withdrawn at least 14 days prior to intradermal skin testing in horses.¹

NOTE per dexamethasone use in horses: The Association of Racing Commissioners International Uniform Classification Guidelines for Foreign Substances has designated dexamethasone a CLASS 4 DRUG.

Where to buy Dexamethasone

Dexamethasone is available in the U.S. through several pharmaceutical manufacturers and through veterinary custom compounding companies. DEXAMETHASONE 24 MG/ML by NexGen Pharmaceuticals is indicated for a variety of inflammatory and immune-mediated conditions in a variety of species.

Dexamethasone carries numerous potential drug interactions. Please consult your veterinarian prior to beginning any treatment regimen.

FOR RX ONLY: A valid prescription from a licensed veterinarian is required for dispensing this medication.

¹Plumb’s Veterinary Drugs.

²Greenberg C.B., et. al. Phase II clinical trial of combination chemotherapy with dexamethasone for lymphoma in dogs. J Am Anim Hosp Assoc. 2007;43(1):27-32.

³Park E.H., et. al. Mechanisms of injury and emergency care of acute spinal cord injury in dogs and cats. J Vet Emerg Crit Care. 2012;22(2):160-178.