Depending on the cause of hyperadrenocorticism in your dog, several treatment options are available. The choice also depends on how well your dog could handle surgery or other procedures. The aim of treatment is not to “cure” every case, but to bring cortisol back toward normal so your dog feels well again.
Trilostane (Vetoryl)
Today, trilostane is the most widely used medication for pituitary-dependent Cushing’s disease and is also used for many adrenal-based cases. It works by reversibly reducing the production of cortisol. It is given by mouth, usually once or twice daily with food, and it became a U.S. FDA-approved therapy for canine Cushing’s disease. Dogs on trilostane need periodic ACTH stimulation tests (or other monitoring your vet chooses) so the dose can be fine-tuned. Because dosing is individual and adjusted over time, it must always be directed by your veterinarian.
Mitotane (Lysodren)
Before trilostane became common, mitotane was the mainstay for pituitary-dependent disease and is still used. It works differently: it gradually reduces the cortisol-producing layer of the adrenal glands. Treatment is typically divided into an initial “loading” phase followed by ongoing maintenance, with close monitoring throughout. It remains an effective option in the right hands.
Surgery for Adrenal Tumors
For adrenal-based Cushing’s disease, surgery to remove the affected adrenal gland (adrenalectomy) can potentially resolve the condition when the tumor is benign and the dog is a good surgical candidate. It is a specialized operation, and because Cushing’s dogs can heal slowly and are prone to complications, it is usually performed by an experienced surgical team, often after referral to a specialist center.
Treating Iatrogenic Cushing's
When Cushing’s is caused by long-term steroid medication (the iatrogenic type), the treatment is to gradually taper that steroid under veterinary guidance so the adrenal glands can recover. This must be done slowly and never stopped abruptly, because a sudden withdrawal can be dangerous.
Other and Older Options
Ketoconazole, an antifungal medication that also suppresses hormone production, is sometimes used in dogs that cannot tolerate first-line drugs, though not all dogs respond. Selegiline (Anipryl) has also been approved for canine Cushing’s, but many veterinarians consider its effectiveness limited and reserve it for select situations. For pituitary tumors that are large, radiation therapy may occasionally be recommended.
The Importance of Monitoring
Whatever medication is chosen, regular monitoring is essential. The goal is to give just enough medication to control the disease without pushing cortisol too low, which can cause the opposite problem — a cortisol deficiency similar to Addison’s disease. Contact your veterinarian promptly if a dog on treatment becomes weak, stops eating, vomits or has diarrhea. With good communication and follow-up, most dogs settle into a stable routine. Learn more about day-to-day diet and nutrition and about prognosis and life expectancy.