What is Cushing’s Disease in a Dog?

More commonly known as Cushing’s disease, hyperadrenocorticism is a chronic condition occuring when the body makes too much of a natural steroid called cortisol. Cortisol production is controlled by the adrenals, two small glands sitting atop the kidneys. The primary purpose of the hormone is to help the body deal with increased stress. Cortisol also helps maintain weight, skin condition, tissue structure, and performs other vital activities ensuring good health. But when the adrenal glands produce too much cortisol it can weaken the immune system and increase the risk of serious illness.

What causes Cushing’s disease in dogs?

Human beings, horses, and cats can all get Cushing’s disease, but the condition is far more commonly found in dogs. The two most common types of the disorder are adrenal-dependent and pituitary-dependent.  About 80 percent of diagnosed cases are the result of a tumor on the pituitary, a tiny gland at the base of the brain.

The pituitary is responsible for producing numerous hormones, one of which is adrenocorticotropic hormone. If a tumor develops on the gland, it can result in an overproduction of the hormone, which can stimulate the adrenals to produce more cortisol than the body can manage.

The remaining 20 percent of canine disease cases are caused by tumors in the adrenals, which can also stimulate an overproduction of cortisol. The treatment prescribed by your veterinarian may be determined by the type of Cushing’s disease affecting your pet.

Symptoms of Cushing’s Disease in Dogs

Both types of Cushing’s produce similar symptoms which can seriously affect your canine friend’s health. They include increased thirst, urination, appetite, reduced activity, excessive panting, frequent skin infections, hair loss and abdominal distention.

Which Dogs are at Risk?

Because it is a slow growing disease, most cases of canine Cushing’s occur in older dogs over the age of six.

Diagnosis of Cushing’s Disease in Dogs

Since hormones travel through the bloodstream, the most effective way to diagnose Cushing’s disease is with a blood test. Frequent blood screening is often required during the first few months of treatment and then three or four times each year after initial diagnosis. A veterinarian uses these tests to determine the medication and dosage schedule needed to manage the symptom of the disease.

Treatment of Cushing’s Disease in Dogs

The only way to cure Cushing’s disease is to excise the tumors, which can be dangerous and costly. As a result, most veterinarians do not recommend surgery as an option. They are far more likely to prescribe medications designed to manage the most serious symptoms of the disorder.  Dosage amounts and schedules may need to be adjusted from time to time, depending on your dog’s response to the treatment. Let us take a moment to review a few of the most common prescription medication used to treat Cushing’s disease.

Vetoryl (trilostane) for Cushing's Disease in DogsTrilostane

Dog lovers with pets diagnosed with Cushing’s disease got good news when the FDA approved Vetoryl (trilostane), the first medication that can be used to treat both adrenal-dependent and pituitary-dependent Cushing’s in canines. The prescription drug works by preventing the adrenal glands from producing cortisol. In numerous studies, most dogs experienced a complete reversal of serious symptoms. Side effects were generally quite mild and included diarrhea, vomiting, lack of energy, and weight loss. Trilostane should not be given to dogs with liver or kidney disease, take prescription medications to treat heart disease, or are pregnant.


The only other drug to be approved to treat canine Cushing’s by the FDA is Anipryl (selegiline). However, it is only effective for dogs suffering from the pituitary-dependent type of the disease. The drug has proven highly effective at ameliorating the most serious symptoms of the chronic condition.


Mitotane is used to treat the symptoms of Cushing’s disease as well as adrenal tumors. It works by reducing the level of cortisone produced in the adrenal glands. Sold in both capsule and suspension form, the drug is relatively inexpensive and highly effective in treating this disease.

Does your dog have Cushing’s Disease? Which medications has your pet’s veterinarian prescribed? Any secrets or suggestions to help those pets newly diagnosed? Please leave comments below.