For most dogs with Cushing’s disease, treatment is worth it, but not because it dramatically extends life. The main reason to treat is quality of life: reducing the constant thirst, frequent urination, panting, and restlessness that make both your dog and your household miserable. Interestingly, median survival time for pituitary-dependent Cushing’s (the most common form) is estimated at roughly 2 years whether or not a dog receives medical treatment. So the real question isn’t how long your dog will live. It’s how well they’ll live in the time they have.
What Treatment Actually Changes
Cushing’s disease means your dog’s body is producing too much cortisol, the stress hormone. That excess cortisol drives a cluster of symptoms that are hard to ignore: excessive drinking and urination (some dogs empty entire water bowls repeatedly and need to go outside every few hours, including overnight), a bloated pot-belly appearance, muscle weakness, thinning skin, hair loss, and panting that keeps everyone awake. These symptoms tend to worsen over time without treatment.
Medication works by lowering cortisol production. Most owners notice their dog’s water intake and urination frequency drop within the first few weeks. The pot belly gradually improves as abdominal fat redistributes and muscle tone returns. Hair regrowth is slower, often taking several months. Energy levels and overall demeanor typically improve noticeably within the first month or two. For many owners, the dog they get back on medication feels like the dog they remember from before the disease took hold.
The Two Types and Why It Matters
About 80 to 85 percent of Cushing’s cases in dogs are pituitary-dependent, meaning a small tumor on the pituitary gland at the base of the brain is telling the adrenal glands to overproduce cortisol. These dogs are managed with daily medication, and average survival with treatment is 2 to 2.5 years. Some dogs do considerably better: one study of dogs treated with twice-daily medication reported a median survival of 998 days, with some dogs living nearly five years after diagnosis.
The remaining 15 to 20 percent have adrenal-dependent Cushing’s, caused by a tumor on one of the adrenal glands. Medical management in these dogs has a shorter average survival of about 1 year. However, surgical removal of the affected adrenal gland can be highly effective. In a study of 70 dogs undergoing adrenalectomy, over 95 percent survived to discharge, and disease-specific survival rates were 89 percent at two years and 81 to 89 percent at three years. Surgery is more expensive and carries real perioperative risk, but for adrenal tumors that haven’t spread, it offers the best long-term outcome.
What the Medications Cost and Involve
The ongoing financial commitment is one of the biggest factors owners weigh. Medication costs vary widely depending on your dog’s size, since dosing is weight-based. For a medium-sized dog, expect to spend roughly $50 to $100 per month on medication alone. Larger dogs can cost significantly more.
Beyond the pills, Cushing’s requires regular monitoring. Your vet will run blood tests to check cortisol levels, typically at 10 days, 4 weeks, and 12 weeks after starting medication, then every 3 to 6 months after that. The lab cost for the cortisol test itself can be as low as $32, but the full office visit with blood draw usually runs $150 to $300 each time. Over the course of a year, total costs for medication plus monitoring commonly land between $1,000 and $3,000, depending on your location and your dog’s size.
Side Effects and Risks of Medication
The two main medications used are trilostane and mitotane. Trilostane has largely become the preferred option because it’s safer. Across combined clinical studies, only about 16 percent of dogs on trilostane developed adverse effects potentially linked to the drug. The most significant risk is the cortisol dropping too low, essentially creating the opposite problem (a condition called hypoadrenocorticism). With trilostane, this is usually reversible. Stopping the medication for a few days allows cortisol levels to recover, and then the dose is adjusted.
Mitotane carries a higher risk profile, with adverse effects reported in 25 to 42 percent of dogs. Side effects can include profound weakness, depression, and loss of appetite, sometimes appearing within the first week. Mitotane actually destroys a portion of the adrenal gland tissue, which makes its effects harder to reverse than trilostane’s. It’s still used in some cases, but most veterinarians now reach for trilostane first.
What Happens Without Treatment
Cushing’s disease won’t resolve on its own. Left untreated, the symptoms that brought you to the vet will continue to progress. Your dog will drink and urinate more, lose more muscle mass, and become increasingly lethargic. The cosmetic changes like hair loss and thin, fragile skin will worsen.
More concerning are the secondary complications that develop over time. Chronically elevated cortisol suppresses the immune system, making your dog more vulnerable to skin infections, urinary tract infections, and slow wound healing. It also raises the risk of high blood pressure, blood clots (particularly dangerous pulmonary clots), pancreatitis, and diabetes. These complications are what most often lead to a crisis or a decision to euthanize in untreated dogs. Treatment doesn’t eliminate all of these risks, but it substantially reduces them by bringing cortisol closer to normal levels.
When Treatment May Not Be Worth It
There are legitimate scenarios where an owner might reasonably choose not to treat. If a dog is diagnosed very late in life, has other serious health conditions, and the Cushing’s symptoms are still mild, the monitoring burden and medication side effects may outweigh the benefit. Some dogs with very mild symptoms are genuinely comfortable without intervention, at least for a while.
Financial constraints are real, too. If the ongoing costs would mean skipping the regular monitoring that keeps treatment safe, undertreated Cushing’s can actually be more dangerous than untreated Cushing’s. Medication without proper monitoring risks dropping cortisol to dangerously low levels, which can cause an acute crisis requiring emergency care. If you can’t commit to both the medication and the monitoring, it’s worth having an honest conversation with your vet about the best path forward.
Dogs with very large pituitary tumors (macroadenomas) present a more complex situation. These tumors can cause neurological symptoms like disorientation, circling, or seizures as they grow, and medication doesn’t shrink the tumor. In these cases, the Cushing’s symptoms may be only part of the picture, and the neurological decline may ultimately determine the dog’s prognosis regardless of cortisol control.
Making the Decision
The clearest cases for treatment are dogs with bothersome symptoms and otherwise reasonable health. If your dog is waking you up three times a night to go outside, drinking water compulsively, and losing the energy to enjoy walks or play, medication can meaningfully restore normalcy. Most owners who treat report significant improvement in their dog’s daily comfort and their own quality of life at home.
The clearest cases against treatment are dogs with minimal symptoms, dogs with serious competing illnesses, or situations where the financial and logistical demands of monitoring aren’t feasible. There’s no shame in either choice. The goal is the same either way: keeping your dog comfortable for as long as possible.