Treatment for Cushing’s disease may involve a few different options, depending on the type of disease. Surgery may be performed if an adrenal tumor is identified. However, nonsurgical treatment is the most common approach to treating canine Cushing's disease.
Most cases of Cushing's disease in dogs are pituitary dependent, and since both adrenal and pituitary dependent Cushing’s may respond positively to oral medication treatments, many veterinarians choose not to perform the High Dose Dexamethasone Suppression Test to determine which gland has the tumor.
Nonsurgical Treatments for Cushing’s Disease in Dogs
Lysodren, also known as Mitotane and o,p'-DDD, is probably the most commonly used oral medication. Lysodren works by destroying the adrenal gland cells that produce cortisol, therefore the gland is forced to reduce cortisol production despite the increased ACTH. After the eighth day of treatment, a veterinarian can then perform an ACTH stimulation test to determine if the drug has been effective. If the medication has improved the cortisol levels, the dog may then be put on a maintenance dose for their remaining lifetime.
Trilostane is a competitive inhibitor of the enzyme 3-beta hydroxysteroid dehydrogenase, which means it works on the adrenal gland to block the pathway of cortisol.
Ketaconazole (Nizoral) is a daily administered anti-fungal treatment, with the serendipitous side effect of reduced hormone production. Dogs who show resistance to lysodren, or need better healing ability before surgery, may benefit from Ketaconazole.
Radiation is an option for pituitary dependent Cushing’s disease. Radiation shrinks the tumors, reducing direct impact on the brain, and allowing for better results from oral medications.
Surgical Treatment of Cushing’s Disease in Dogs
Because adrenal dependent Cushing's disease may be curable only through surgery, it is often recommended. The tumors on the adrenal glands tend to be large enough for surgery, and as there are two adrenal glands, the risk is lower to perform surgery on just one. Often, if the tumor is known to be benign, removal of the entire adrenal gland is highly effective.
A symptom of Cushing’s disease is slowed healing, which can make surgery risky. As a result, some veterinarians recommend oral treatments to increase healing power before surgery.
This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by,your veterinarian. Always seek the advice of your veterinarian or other qualified professional with any questions you may have