Addison’s Disease in Dogs

Photo Credit: In 1855 Dr. Thomas Addison was the first person to describe a human affliction he dubbed Addison’s disease. Since that time, this disease has become a well-recognized syndrome in both people and dogs. The scientific name for Addison’s disease is hypoadrenocorticism– an insufficient production of essential hormones manufactured by the adrenal glands.

Addison’s disease can occur in any size and breed of dog. Middle-aged females are most commonly affected. A familial or inherited predisposition for the disease has been described in Standard Poodles, Bearded Collies, Great Danes, and Portuguese Water Dogs.

Normal adrenal gland function

Let the physiology lesson begin! Every dog is born with two adrenal glands located adjacent to each kidney within the abdominal cavity. These glands are responsible for producing several important hormones. Dogs with Addison’s disease lose their ability to produce two of these hormones, namely cortisol (aka, cortisone) and aldosterone. Neither man nor beast can live without adequate levels of both of them.

Cortisol is essential for normal function of virtually every organ within the body. It’s responsible for normal appetite and an overall sense of well being. Cortisol production is amped up during times of stress. Canine “stress” can stem from fear, excitement, anxiety, or significant physical exertion. Examples might include: thunderstorms, dates at the grooming parlor, a free-for-all at the dog park, running an agility course, or visiting the veterinary hospital. (Please read my thoughts on Fear-Free office visits)

Aldosterone regulates sodium and potassium levels in the body. Without aldosterone, the potassium level in the bloodstream increases and the sodium level decreases. If severe enough, these changes can be life threatening. Every once in awhile a dog develops “atypical Addison’s disease” in which there is cortisol depletion, but aldosterone production remains normal. These dogs have normal blood levels of sodium and potassium.


The cause of Addison’s disease is incompletely understood. Autoimmune destruction is suspected. This means that the individual’s own immune system is somehow triggered to attack and destroy the body’s normal tissues; in this case, cells within the adrenal glands.

Cushing’s Disease is the polar opposite first cousin of Addison’s disease. A dog with this disease develops symptoms caused by the overproduction of cortisol by the adrenal glands. Overzealous treatment to reduce the cortisol production can result in Addison’s disease.


Early on in the course of the disease Addisonian dogs may show rather vague waxing and waning symptoms. As the disease progresses, symptoms tend to become more consistent and fulminant. Not all Addisonian dogs exhibit all of the symptoms- in fact, only one or two may be observed. The most common symptoms caused by Addison’s disease include:

  • diminished appetite
  • lethargy/weakness
  • vomiting
  • diarrhea
  • increased thirst
  • increased urine output
  • weight loss
  • hair coat changes
  • trembling
  • collapse


Addison’s disease is suspected based on symptoms. Abnormal physical examination findings may include a slowed heart rate (caused by the elevation in blood potassium), dehydration, weak pulses, thin condition, generalized weakness, and even collapse or coma.

The diagnosis of Addison’s disease begins with blood and urine testing. The urine is typically dilute rather than well concentrated. Blood test abnormalities may include increased levels of potassium, blood urea nitrogen (BUN), creatinine, and calcium along with decreased sodium and glucose levels. A chest x-ray may demonstrate decreases heart size.

Addison’s disease is definitively diagnosed by measurement of blood cortisol levels both before and after an injection of ACTH (adrenocorticotrophic hormone), a substance that stimulates the adrenal glands to release cortisol. This is known as an ACTH response test. Addisonian dogs have extremely low levels of circulating cortisol both prior to and following adrenal gland stimulation.

The great imitator

Addison’s disease is known as the “great imitator” because its symptoms are often vague and nonspecific and they may mimic those associated with a plethora of other diseases. Additionally, unless the dog is in a state of crisis, symptoms tend to be on-again, off-again. So, it’s easy to talk oneself out of a veterinary visit. And, if basic blood test abnormalities are mild, the veterinarian may not even consider Addison’s disease as a potential diagnosis.

Because of all of this, the biggest pitfall associated with Addison’s disease is its lack of recognition. The most famous Addisonian of all time, John F. Kennedy, had waxing and waning symptoms for years before his physicians finally thought about testing for Addison’s disease!


In the case of collapse or profoundly slowed heart rate, emergency therapy for the Addisonian dog may be necessary including intravenous fluid therapy, cortisone injections, and treatment for circulatory shock.

Long-term treatment for Addison’s disease involves life-long hormone replacement therapy and, in some cases, sodium supplementation- table salt added to the dog’s diet. Cortisol supplementation (prednisone is the drug most commonly used) is initiated and is ultimately weaned down to a physiologic dose or discontinued. Whether or not it is discontinued depends upon the aldosterone replacement therapy selected. A physiologic dose is intended to imitate the amount of cortisol normally released by the adrenal glands. If it is known that an Addisonian dog will be experiencing some version of stress, the dose of cortisone is increased accordingly.

Aldosterone replacement is achieved one of two ways. An injectable drug known as DOCP (desoxycorticosterone pivalate- how’s that for a mouthful!) can be administered via an injection under the skin approximately once every 25 days. Most veterinarians are willing to teach their clients how to administer this drug at home. Another injectable option is the newly released drug called Zycortal.  An orally administered daily medication called Florinef is another option for aldosterone replacement.

Unfortunately, these drugs can be pretty darned pricey. Given that they are dosed based on the dog’s body weight (large breed dogs are more commonly affected) and that dogs with Addison’s disease must receive life-long medication and blood test monitoring, the cost of treatment can be enormous.


Well-managed Addisonian dogs are expected to have a normal life expectancy and an excellent quality of life. The keys to success are affordability and conscientious life-long treatment and monitoring.

Sources of support

Not all veterinarians have vast experience recognizing and/or treating dogs with Addison’s disease. Additionally, successful treatment requires considerable finesse based on lots of experience with this disease. Consider getting help from a veterinarian who specializes in internal medicine and who likely has dozens of Addisonian patients under his or her belt.

An excellent, long-running, online source of support is the forum called AddisonDogs. The site is well moderated and provides a wealth of information for those in the position of caring for an Addisonian dog.

Have you ever managed a dog with Addison’s disease? If so, what was your experience like?

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at,, local bookstores, and your favorite online book seller.


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11 Comments on “Addison’s Disease in Dogs

  1. My 20 lb spaniel/terrier, 10 year old rescue dog texted positive for Cushing’s one year ago. She had been diagnosed a mostly blind several years before that. Two things have made *MAJOR* improvements in her health. 1) I switched to a fresh food diet. and 2) I started giving her Adrenal Harmony Gold for Dog’s with Cushing’s. Switching her food alone eliminated her excessive drinking and pottying and caused her ALP to drop from 628 to 255 (almost back to a normal range). The Adrenal Harmony Gold gave me back my normal, happy dog. I swear by it. It is expensive – $44 a bottle, but a drop in the bucket compared to thousands in testing that I spent to diagnose her. There were no Cushing’s dog food recipes so I created my own based on my own research. I now cook her a low fat, high protein diet every 2-3 weeks, freeze most of it. It consists of 9 items, turkey, spinach, eggs, sweet potatoes, plain yogurt, peas, oatmeal, a chopped apple and olive oil. She gets about 3/4 cup twice a day and I drop the Adrenal Harmony Gold on it. She’s always had a strong appetite and she loves it. All of her symptoms are gone – she likes to take walks again, has regained her leg strength that she lost, is at a normal weight – she is happy and healthy again and I’m convinced has many years to go. I have no affiliation with the company that makes the Adrenal Harmony but I urge you to try it if your pet has Cushing’s – it has hundreds of excellent reviews which is what persuaded me. None of the vets recommended this protocol to me. They had recommended Melatonin and then Vetoryl, both of which I tried and they made her feel notably worse.

  2. Thank you, Dr. Kay, for discussing this endocrine disorder in your newsletter. My Scottish Terrier, Peggy Sue, was made into an iatrogenic Addisonian dog when she was 7.5 years old, due to severe overdosing of Lysodren given to purportedly control her Cushing’s Disease. The vet in charge of her care tried to convince me to deliberately oblate her adrenal glands and give her Addison’s, which I, of course, refused, but he over-dosed her anyway, and she almost died. Then he refused to give her enough Florinef to keep her alive, so I did an emergency vet switch and got her stabilized. After five months it was clear her adrenal glands were permanently out of commission, and we transitioned her to Percorten-V and prednisone, and she remained in very good health until she finally declined at age 12, passing away at 12.5, although Addison’s was not the cause of her death.

    I would second the earlier comment about titrating the dose of aldosterone-substitute to the electrolyte levels, rather than just medicating based on weight alone. Peg stabilized at about 2/3rds of her original dosage by weight of Percorten, and while the monetary savings was not significant due to her small size, if one owned a Great Dane, that reduction might mean the difference between treating and euthanasia.

    Thank you again for discussing this disease, and for mentioning the AddisonDogs group, their assistance was crucial and incredibly welcome when Peg was first diagnosed, and I remember the moderators and members very fondly.

  3. As usual, the comments are enlightening and almost as good as the article! I have no experience with Addison’s but having fostered many dogs with various problems, I always check and compare prices of medications at Costco and Target. About half the time my vet is about the same as Costco, sometimes less; and if there is only a few dollars difference, I prefer to support my vet. But it is great to have options for expensive meds!

  4. My Chinese Crested, Ruby, was diagnosed with Addison’s 7 years ago. It took more than a year of testing, and several veterinarians to finally get the diagnosis! She is doing very well, at the ripe old age of 14. Oh, and she is one of the less common, but luckier dogs, as she has Atypical Addison’s. She only requires a very small amount of prednisone once every 24 hours, that I have compounded at the pharmacy.

  5. I had a two year old German Shepherd; and as you mentioned many vets tend to miss the connection of symptoms. However, her main symptom was behavioral with some weight loss. She would escalate into screaming, out of control (hers or mine) behavior when stressed. This could be set off simply by dogs moving quickly past her or any stress i.e. being in the car knowing she might go for a walk when the door opened, etc. Only later did she start occasionally expelling blood from her rectum (large amounts). Since she was atypical, only prednisone would work and sadly she couldn’t tolerate even small doses; she would become very lethargic from even a 20 mg or less dose. This caused her to die from worsening symptoms at just 2 years old. It started showing up when she was about one to one and a half years old. I was actually relieved to have a name to the disease since the behavior was so extreme; she’d even redirect to my feet in frustration while escalated. I tried calming caps, only helped a little.

  6. My 9 year old Scottish Terrier, Abby, was diagnosed with Addison’s when she was 5. She was diagnosed while in a full-blown Addisonian crisis at a local ER vet and ultimately surrendered to Scottie Rescue. I fostered her and after six months (when it became clear that no one wanted to adopt a 5 year old dog with Addison’s Disease) I officially adopted her. Abby has done extremely well on Florinef and Prednisolone (which is easier on the liver than regular Prednisone). She competes regularly in agility and recently earned her AKC Master Agility Preferred and Master Jumpers Preferred titles. I am so proud of that girl and so glad that she came into my life!

  7. My boy toto was diagnosed almost four years ago when he was six he went into a crisis and I almost lost him thankfully the vet who we had never seen before recognised the signs and treated him accordingly he had been on florinef but is now on zycortal and pred since last Friday I’m hoping this works for him as he was fine on florinef

  8. Wonderful information as always! Thank you! I would just like to add that we see a small percentage of dogs with Megaesophagus that Addison disease appears to be the cause. There have been cases where the megaesophagus resolves once treatment for Addison disease is dialed in. I enjoy reading your blogs!

  9. Thank you for this article. My female Labrador has been well managed with Addison’s for two years. I administer Percorten and Prednisone myself. My girl has had no issues since diagnosis and is very healthy and active. I would just note two things: We use a 30 day cycle for the Percorten which has worked well. A 28 – 30 day cycle seems more typical than 25 day among the members of our group. Also it’s important to stress the need for that small daily dose of Prednisone for dogs taking Percorten or Zycortal. There is some misconception out there about that. Once a dog is stabilized and at lowest effective doses the costs are manageable for the average owner.

  10. My Papillon, JJ, live a long, happy, healthy life with Addisons Disease. He was my foster boy and was diagnosed when he came to my rescue. As it turned out, he never left as I adopted him!
    He was diagnosed at age 7 and lived to be 15.5. We had a great life together and, because of treatment, his Addisons was invisible. Very treatable disease if you monitor the electrolytes on a regular basis and pay attention to the medication doses needed.
    I never regretted treating JJ’s Addisons Disease and was fortunate to be able to afford to do so. It was a learning experience that gave me a life with a wonderful dog so Addisons was a blessing in disguise you could say.

  11. Dear Nancy, Thankyou for raising awareness of Addison’s disease in dogs. My own standard poodle, TJ, was diagnosed in 1997 after several months of feeling unwell and spending 10 days in the vet hospital immediately prior to diagnosis with a poor prognosis. TJ went on to live 12 more wonderful years with Addison’s, taking florinef every day, until I lost him suddenly to cancer in 2009. I have been a member of several Addison’s support groups including the one you mention for over 18 years now.
    A couple of things I would like to mention though, is how important it is for the doses of percorten, florinef or the newest drug Zycortal, to be dose according to the electrolytes and NOT according to weight after the initial doses of meds are started. A common reason for dogs to have side effects from the drugs, is when the vet only doses by weight.
    In addition, I wonder if you could include in your article, information about the recent release of Zycortal in the UK and Europe. This drug is almost identical to Percorten with DOCP being the main ingredient. It has coincided with the discontinuation of production of Florinef and the change to the production of Fludrocortisone Acetate but with the prcies of the latter being hugely inflated causing the cost of managing Addison’s to rise to an unprecedented and unrealistic level. As Zycortal is a drug specifically for animals, many, if not most vets in the UK are changing dogs over to the use of this, but the need to change so quickly, has been sprung on them with little warning due to the drug companies changes with florinef and it is a very stressful time indeed for many owners of dogs with Addison’s in the UK, who are finding themselevs with much higher vet bills initially due to the extra blood tests needed in order to get the best doses of Xycortal and Prednisolone. Much of the reaction from those who have made the changeover already is favourable, other than sime dogs experiencing temporary side effects of PU/PD through being started on a higher dose than needed, provided the vets are willing to work with their clients in finding the optimum doses of meds and working out ways to be cost effective, including teaching clients how to give injections of Zycortal themselves at home and buying the drug online at a cheaper price with a prescription. Dechra, who manufacture Zycortal and have now also released the drug now in the US, launced the product at the BSAVA Congress at the beggining of April and have a support team for vets.

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