Medication for Cushings Disease in Horses

Equine Cushing's disease is a hormonal disorder caused by a malfunction of the pituitary gland. This tiny gland is located inside the brain and it is responsible for the production and distribution of hormones and chemicals responsible for a variety of bodily functions. Sometimes caused by a benign tumor on this small but important gland, Cushing's disease symptoms were once attributed to old age. Today, horse owners and veterinarians are more aware of the signs of Cushing's and horses are being diagnosed and treated early to good results.

  1. Symptoms and Diagnosis

    • The most noticeable symptom of Cushing's disease is long, shaggy hair growth. Your horse may drink and eat more, but not gain weight. Muscle tone will decrease, and your horse may become lethargic. Chronic laminitis is common and disorders related to a compromised immune system---respiratory disease, skin infections and periodontal disease---might develop.

      Clinical testing can confirm Cushing's. Your veterinarian may recommend a series of blood tests called the dexamethasone suppression test (DST).

    Pergolide and Cyproheptadine

    • Pergolide mesylate is a popular and effective off-label treatment for equine Cushing's. Used to treat Parkinson's disease in humans, the drug was voluntarily recalled by its manufacturer in August 2007 and it became difficult for veterinarians to obtain the drug. It is now available in compounded form from of veterinary pharmacists.

      Cyproheptadine is also used to treat Cushing's disease in horses. Both Cyproheptadine and Pergolide must be administered daily and regular blood tests must be conducted to determine the horse's response to treatment. Once treatment stops, symptoms will return.

    Trilostane

    • A study conducted in the United Kingdom tested the efficacy of trilostane in 20 horses diagnosed with equine Cushing's disease and concluded that, "trilostane is a useful therapy for the treatment of equine Cushing's disease, particularly with respect to improving the quality of life of affected animals."

    Dietary Managment

    • A low-sugar, low-starch diet rich in antioxidants is best for horses with Cushing's disease. Avoid alfalfa and grains, focusing instead on grass hay such as Timothy and orchard hay and grass hay pellets.

      Test your hay for sugar content by obtaining and sending a core sample to a testing lab. They will perform an NSC (non-structural carbohydrate) test to test for sugar and starch content. To further reduce sugars in your horse's hay, soak it in cold water for 30 minutes prior to feeding.

    Prognosis

    • There is no cure for Cushing's disease in horses but if the condition is diagnosed and treated early, your horse can lead an active life. A combination of dietary management, immune system support and proper foot care combined with regularly scheduled veterinary visits will provide the best possible outcome for your horse.