A Big Picture Look at Cushings Disease and Diabetes

By Dr . Joi Sutton|2016-12-29T16:26:25-05:00Updated: June 9th, 2016|Pet Care, Pet Newsletter|30 Comments
  • Probiotics - Cat and Dog

There are some diseases I just despise. It’s not that I like any disease, but some just make me want to crawl in a hole. Cushings disease is one of them. Cushings is short for hyperadrenocortisism, a state where the body makes too much steroid, either from a pituitary tumor or from an adrenal tumor. The tumor can be benign or malignant, but regardless the excess steroid can wreak havoc on the pet. It’s usually a forever treatment for the life of the pet (except for the less common adrenal mass that sometimes can be surgically removed), and it’s very expensive to treat. If you think treating diabetes is expensive, you should see the bills that pile up with Cushings disease! The initial and ongoing blood tests are expensive. The medication is expensive. And the vast majority of pets affected will be a ‘Cushingoid’ for life, requiring the medication for life. You see why I despise this disease!

Why am I going on about one of my least favorite diseases? Because there is a link between Cushings disease and diabetes. Cushings patients produce too much steroid. Steroids cause insulin resistance. Some diabetic pets actually became diabetic secondary to having Cushings disease from the insulin resistance caused by steroids. It is difficult to regulate a diabetic pet that is also Cushingoid. There are a few things you should know about this disease if your pet is diabetic.

Cushings can affect both dogs and cats, but it is better understood and much more common in our canine friends than our feline friends. Personally, I think it is often more affordable for families to go straight to an internist rather than have their regular veterinarian diagnose and treat this disease. Additionally, treatment of this Cushingoid state can result in a crisis situation and requires very close monitoring, ideally by someone well-versed in the disease. A general practitioner like me might come across one or 2 Cushingoid dogs per year, but internists manage many Cushingoid pets all the time. When dealing with diagnostic and ongoing monitoring tests that are as costly as with this disease, you want a specialist (or at least a GP who sees a lot of them) to manage your pet. Medicine is getting so specialized that as my neighbor once put it, “If you have one doctor to treat your right foot you need a second doctor to treat your left foot”.

Personally, when I suspect Cushings disease I send the pet to my local internist. I’m very lucky that I have an amazing veterinary internist just a couple miles from my general practice, and his practice is open 24/7. With that being said you will understand that I am not a pro at this disease. Nonetheless, I can point out important points I think a layperson with a diabetic pet should know.

How do we treat Cushings disease? For years vets used a drug called Mitotane which selectively destroyed part of the adrenal gland. It required daily vet contact at initiation of treatment as Mitotane could cause adrenal necrosis and a pet could go into a medical crisis and die if left untreated. Yikes! A new medication called Trilostane is now available to treat Cushings. Trilostane came out about 8 years ago and is less likely to cause adrenal necrosis, although it is still feasible. Trilostane reversibly inhibits the production of cortisol in the body. I don’t feel quite so strongly about referral to an internist these days as I used to back when all vets had in our tool kit was Mitotane. Most vets use Trilostane now.

So here goes with the nitty gritty bullet points on Trilostane!

  • Give Trilostane with food. It is absorbed 3 times better with food than on an empty stomach. For a diabetic pet this means at mealtime the pet should get the Trilostane and insulin at the same time, when Fluffy is eating.
  • When your vet does the monitoring blood work (chemistry, electrolytes and a test called an ACTH stim), give the Trilostane in the morning. The ACTH stim should be done 4 to 6 hours after the Trilostane is given. If you give Trilostane at the evening meal that means you’d need to do the ACTH stim test at midnight for an accurate result. That would make your vet grouchy!
  • Don’t break apart the capsules. You are treating Fluffy, not yourself. You don’t want to affect your own hormones!
  • Some vets get Trilostane compounded to save their clients money. It’s important that they check with the compounding pharmacy to verify they are using medical grade Trilostane rather than chemical grade. Unfortunately, a good chunk of the expense of treating these patients is the re-check lab work (up to every 3 months for the life of the pet). Compounding probably isn’t worth the minor savings. I’d stick with the brand name stuff with this disease. The one brand available in the USA is called Vetoryl.
  • Sometimes pets feel puny at the start of treatment. This may simply be from steroid withdrawal. Be prepared for this and know it will get better. On the other hand, the diabetes will be easier to control and the pet may feel better without overt steroid withdrawal signs. Anticipate lowering the insulin dosage as the steroid production comes down to normal! Keep a very close watch on the blood glucose and adjust the insulin accordingly to avoid hypoglycemia.
  • According to Dechra, the manufacturer of Vetoryl, 4 of 5 pets do well getting Trilostane once a day. That leaves 1 of 5 needing it twice daily. Diabetic pets should get it twice daily. Why? It’s about the duration of a dose. The dose is quickly absorbed orally and is out of the body in 10 to 18 hours. Nondiabetic pets might be okay with a little excess steroid for the last part of a 24 hour period. Diabetics don’t do well with any excess steroid!
  • If your pet is diabetic AND Cushingoid, the total daily dose should be split in 2 and given 12 hours apart.
  • Can we use Trilostane in cats? Some vets have used Trilostane on cats, but it is extralabel use for felines. Cushings disease is a known disease in cats but is much less common than in dogs. If your diabetic cat is difficult to regulate despite your best efforts, your vet may contemplate the possibility of concurrent Cushings disease.

As always, I enjoy getting emails from readers. Feel free to email me at [email protected]

NOTE: Consult your veterinarian first to make sure my recommendations fit your pets special health needs.

About the Author: Dr . Joi Sutton

Dr. Joi Sutton is a 1993 graduate from Oregon State University. She has practiced both in emergency medicine and general practice. Dr. Sutton has done extensive international volunteer work though Veterinary Ventures, a nonprofit organization that takes teams of veterinarians to undeveloped countries for humane medical care. She also runs a small animal practice in South Florida. Connect with Dr. Joi on LinkedIn


  1. Dave February 26, 2024 at 11:54 am - Reply

    I have a small schnauzer cross. The reports of dogs predisposed with DM & CS accurately describes him. Unfortunately he has developed DM, Cushings and pancreatitis. I am having trouble getting him to eat so I can administer insulin properly. Any suggestions would be greatly appreciated.

  2. Shirley October 11, 2023 at 6:11 pm - Reply

    Hello. I read about splitting the vetoryl dose. But how do you do that accurately? Also you’re not meant to open the capsules. My dog has diabetes and cushings but I give in the evening. Thankyou.

  3. Valana June 9, 2023 at 4:14 pm - Reply

    My boy, Bentley, was diagnosed with an adrenal tumor in June 2022. He was mostly symptomless, until about a month ago. He started panting heavily at night, so much so neither one of us was able to sleep. I took him to the vet’s office, and he was diagnosed with Diabetes. We are trying to regulate his glucose with a monitor and insulin twice a day. We elected to not pursue removing the adrenal tumor because the oncologist we went to see told us she only operates on 12 dogs a year and 41% die on the table. It is a very invasive surgery, and Bentley is an 11-year-old Shih Tzu. I have read several things where people question removing the adrenal tumor, but it isn’t a simple surgery.
    I wouldn’t ever get over losing Bentley on the table and never being able to say goodbye.

    • Dr . Joi Sutton June 10, 2023 at 7:56 pm - Reply

      I’m so sorry that Bentley has a tumor. And yet, I’m glad you are seeing an internist and treating his diabetes! I wish you the best…

  4. Terri Thomas May 23, 2023 at 11:07 am - Reply

    My lil girl has had Cushings for almost 3 yrs this year, diabetic for 16 months now. I can’t seem to get her diabetes under control even with her cushings in range at last ACTH test A cpuple weeks ago, cortisol was 4.4 at second reading. Her neck gland on the right side became very swollen and I took her back in for more bloodwork a week ago and her Na/k level was at a concerning level as going towards Addison of 28. The vet had me hold her Trilostane, which we use compounded, for 24 hours and then lower her dose. She was on 22.5 mg a day getting 12.5 in the a.m. and 10 mg in the p.m. now she is getting 10 mg in the a.m. and 10 mg in the p.m. She is on 8 1/2 units of novolin n and she is a 9 1/2 pound Chihuahua mix. Her numbers still range anywhere between 300 to 500 and I can’t seem to get her diabetes under control. My vet suggested trying nine units of insulin to see if that helps because I’ve been getting her regular insulin at times throughout the day to bring her down when she spikes. Do you have any suggestions? I could use all the help I could get. She eats half hard food and half home cooked and is pretty consistent on her meals but does need an appetite stimulant. Her treats consist of homemade chicken, jerky and frozen green beans and egg whites. It’s all just very frustrating. I was just wondering if nine units of insulin twice a day is a lot for a 9 1/2 pound dog and I know it’s not rebound because we’ve tried lowering her dose and it didn’t work. Thank you!–

    • Dr . Joi Sutton June 3, 2023 at 7:53 am - Reply

      You sound like a great pet owner!
      It is tricky business getting a cushingoid’s diabetes under control. 9 units does sound like a lot, but again, she is cushingoid and steroids cause insulin resistance. Good job splitting the trilostane. You can also run a urine culture and do a dental if needed as UTIs and dental disease are other common causes of insulin resistance. At my clinic I have a urine culture and purchase petri dishes with 2 different types of culture medium and culture urine in house all the time. It’s a lot more affordable for my clients than sending them all out—a negative is still a negative. If anything grows we can submit that to the outside lab for identification and sensitivity testing.
      You might consider consulting a local internist. Veterinary internal medicine specialists go to vet school then get an additional 4 years of education on top of vet school. Do consider an internist consult.
      Best, Joi

  5. Amy May 5, 2023 at 8:07 am - Reply

    My diabetic dog has Cushing’s. She is on Vetoryl once daily (5 mg in the morning). She was receiving 7 units twice a day of Vetsulin. Her blood sugar readings vary, however, they are starting to get low. Fasting BS before morning food and insulin is 116. Preprandial dinner it is 300. Nadir can vary around 100-250. It’s very strange. Is this because of the one a day dosing of the Vetoryl? I see you mention split dosing, but I’ve been to many vets and no one has mentioned it so far. I didn’t even know it was an option. She has had the stimulation tests and they are in good range and her blood work recently shows she’s healthy. In fact, I was told it looks like she isn’t even diabetic from her results. I find all of this a bit confusing. I did change her food to Royal Canin Glycobalance so it seems to have really evened out her previous sporadic blood sugars as well. I also stopped giving any snacks between feeding. I am rambling…..but just curious what your thoughts on this might be. Her blood sugars have actually seemed to improve and I don’t want her to go hypoglycemic. I have a glucometer and take readings and keep a log to look for patterns. I didn’t give her insulin this morning as she was below 150. Thank you for any information.

    • Dr . Joi Sutton May 7, 2023 at 12:02 pm - Reply

      I’m surprised that none of your vets have suggested splitting the vetoryl dose for your diabetic. Frankly, I despise cushings disease! Luckily, my associate at my practice loves treating cushings so I don’t have to mess with it very much. Nonetheless, I can answer your question.
      Here is why it matters to split the dosage of vetoryl for diabetic cushingoid dogs:
      Vetoryl prevents the body from making too much steroid. Vetoryl doesn’t last 24 hours. So if you give Vetoryl only once a day, for part of the day your pet is making too much steroid. Steroids cause insulin resistance. That is why we recommend splitting the vetoryl dosage for diabetic cushingoid dogs. If the cushingoid dog is not diabetic, then once a day if fine. Make sense?
      I’m glad your dog is doing well.
      🙂 Joi

      • Amy May 12, 2023 at 10:05 am - Reply

        Yes, makes perfect sense! Thank you 🙂

  6. Tamara June 11, 2022 at 3:40 am - Reply

    My dog’s Cushings is under control but despite increases in dosage of insulin (Vetsulin) her blood sugar doesn’t seem to be budging- It’s over 600. The vet says sometimes it takes some time after the Cushings is controlled for the effects of Cushings to improve. Thoughts or suggestions?

  7. Anonymous June 11, 2022 at 3:38 am - Reply

    Cushings treatment is working for my dog but her blood sugar levels are staying in the 600 range. My vet says sometimes there is a lag between when the Cushings is controlled and when the effects of Cushings improve. Very concerned about the effects of staying at such a high glucose level and increased dosages of insulin have had not effect. Suggestions?

    • Dr . Joi Sutton June 12, 2022 at 9:16 pm - Reply

      Make sure that you are splitting the Vetoryl dosing to twice daily rather than once daily for diabetics. Otherwise the steroid causes insulin resistance for the other part of the day and you’ll never achieve glucose regulation. How is your pet feeling? Are you doing home testing? Have you done a follow up ACTH stim test yet? It does take patience to sort Cushings disease… if you still don’t achieve control you could seek the assistance of an internist.

  8. Sandra McGill January 27, 2022 at 5:05 pm - Reply

    I have a 8 yr. old Poochon who is diabetic and also has Cushing’s disease. Due to expense involved, I would like to treat Cushing’s holistically, but am unsure if such would interfere with his insulin dosage. I cannot seem to find an answer to that. Perhaps you can help me

    • Dr . Joi Sutton January 31, 2022 at 9:16 am - Reply

      I hate to be a pessimist, but that just isn’t a good option. Dogs can go untreated for their Cushings for some time, but once they are manifesting clinical signs of diabetes you will probably never get the diabetes under control without vetoryl.

  9. Sheri Greenstein July 9, 2020 at 1:33 pm - Reply

    My dog has a very complicated situation, the details of which I won’t bore you. Been treated diabetic for 3 years and was simultaneously on Leflunemide for pemphigus. She was going great nil issues. About 8 weeks ago the vet (dermatology specialist) recommending ceasing the leflunemide as her white cells were low. Ever since things have gone a bit crazy. Her diabetes specialist was always suspicious of cushings but with insulin and leflunemide she was absolutely fine but now since ceasing the leflunemide she is panting like crazy and I increased her insulin to see if maybe it was just the diabetes (leflunemide lowers blood glucose) but her glucose is normal and her symptoms of cushings persist. My question is could the leflunemide have been suppressing the cushings?

    • Dr . Joi Sutton July 12, 2020 at 10:16 pm - Reply

      Good question. I’ve not used leflunemide personally, so I can’t answer. This is a question for your dermatologist and internist who have used this medication. It sound so like the timing coincides with the of the withdrawal of the drug, but it could also be a progression of the Cushings disease.

  10. Laurie March 17, 2020 at 1:18 pm - Reply

    My 7 1/2 year old Siberian Husky has had Cushings for about 2 years. We had it under control by August 2019. Then In Sept. 2019 he tore his ACL and had surgery in Sept. 2019. He had complications with it not healing and bleeding. The surgeon said once it heals he could go in and take the plate out which our dog was rejecting. In Jan. 2020 the surgeon did another exam and said it was not healing and most likely they would not be able to take the plate out. He had also done blood work and we found out he now has diabetes. His levels were 600 and the vet suggested we should put him down. The vet said it is hard t o control both diseases. I said I want to try so I did but that week our dog thew up a lot, wasn’t really eating or taking his meds. He then was up all night outside trying to go to the bathroom. When he would come in for a few minutes he would cry. We took him to the vets in the morning and they gave him some more meds. By the afternoon his stools had blood in them. We made the hardest decision to put him down. Now we have such guilt thinking we should have taken him to the hospital and maybe we could have gotten everything under control. So when do you put a dog dog with these diseases?

  11. Barbara March 2, 2020 at 4:14 pm - Reply

    Hi, i adopted a pup 2 years ago and then found out she was diabetic. We struggled for 2 years and have been unable to get her regulated. All along I wondered if she was still producing some insulin because she drops really fast after dosing and then her levels go back up. I took her to Oregon State Vet College and they found a mass on one of her adrenals. At first they recommended surgery but then did Dex test and wanted to start Trilostane instead. We’ve been on for about a week and she is still drinking & urinating a lot and just as hungry as ever all the time. How do we know the Trilostane is helping? When should we see some results? Why aren’t they treating the adrenal mass?

    • Dr . Joi Sutton March 6, 2020 at 8:45 pm - Reply

      These are all good questions and should be asked of the veterinarians at the college. You are in good hands at a teaching university.
      It can take a bit of time to see improvement on trilostane. Follow up lab or is needed to adjust the dose of trilostane.
      Most cushingoid dogs do better on twice daily trilostane, but all diabetic dogs should be on twice daily trilostane as trilostane doesn’t last a full 24 hours.
      You’d need to ask your veterinarians at the vet school why they chose not to remove the mass.

  12. Maggie August 17, 2019 at 2:17 pm - Reply

    My dog has been a well regulated diabetic for 2 years this summer. She has recently started panting a lot at night. Any chance she could have developed Cushings this far in?

    • Dr . Joi Sutton August 21, 2019 at 10:50 pm - Reply

      Yes, it is possible that your pet could have cushings, but there are other potential causes of panting. Pain, respiratory disease, or even just trying to cool off from the summer heat are other potential causes of panting. Do take your pet to your veterinarian for a check up!

  13. Cindy July 22, 2019 at 4:16 pm - Reply

    Our long haired dachshund, Max, was diagnosed with Cushings October 2018. Deveopled diabetes February 2019. He is now taking 15 mg Vetoryl every 12 hours and his Cushings is under control. However, he is insulin resistant. He is taking Vetsulin. Glucose curve on 7/7/19 using iPet Pro Glucometer was 5:30 a.m. HI/over 600, 7:30a.m. 540, 9:30 a.m. 315, 11:30 a.m. 393, 1:30 p.m. 491, 3:30 p.m. 420, 5:30 p.m. 376. This is a typical day for us. Max has not been regulated at all since diagnosed.

    • Dr . Joi Sutton July 28, 2019 at 1:08 pm - Reply

      It is typically quite difficult to regulate a diabetic that is also cushingoid. I’m glad to hear that your vet is splitting the vetoryl to twice daily—that’s quite important to diabetic cushingoid dogs. Be sure that you are addressing other causes of insulin resistance such as obesity, dental disease and occult urinary tract infection (rampant in uncontrolled diabetic pets). If you still can’t reach decent regulation consider asking your vet for a referral to a vet internist.
      Best, Dr Joi

  14. John Lisofsky October 11, 2018 at 10:48 pm - Reply

    My dog a 9 yr old Border Collie was diagnosed with diabetes back in July and we tried to regulate it with food, but no luck. She has now been on insulin for a month and her blood sugars levels are coming down. Tested her today and they are at 360 from 491. But she is panting excessively and seems very uncomfortable. And lost a lot of weight (she is starting to put some back on). I was wondering if I should suggest to my vet about the possibility of Cushing’s? He thought the panting might be cause she had some pain in her back, which she might and gave us antiinflammatories. But I am not convinced the excessive panting is from that. Thanks

    • Dr . Joi Sutton October 17, 2018 at 8:54 pm - Reply

      Panting can be from numerous causes from cushings to discomfort to feeling hot or anxious. There are often clues in the chemistry profile that might cause your vet to suspect cushings disease. Good idea chatting with your vet. 🙂

  15. aMANDA March 15, 2018 at 9:16 am - Reply

    My dog was diagnosed with diabetes a month ago. After a week of increase the insulin, it was confirmed he had Cushings also. He is on 30 mg twice a day of Trilaostane and 19 units of Novolin twice a day and still his glucose is in the 300-400 range. I need any suggestions in helping to get his glucose to normal levels.

    • Dr . Joi Sutton March 18, 2018 at 10:15 pm - Reply

      It can be quite difficult regulating the diabetes until the Cushings disease in under control. You are likely due for an acth stim test to evaluate the trilostane dosage.
      As a side note, levemir lasts longer than NPH in diabetic dogs and you might have more success with it than NPH. Levemir is quite potent in dogs.
      Chat with your vet and have your vet do the follow up acth stim test.
      Good luck! Joi

  16. ilona January 23, 2018 at 3:29 am - Reply

    my dog was diagnosed with cushing 4 years ago, for threes years she been treated with vetoryl but last winter she was hospitalized with stomach ulcers that gave her bad animia so together with doctor we decided to keep her on homeopathic products. She did good for a year but now she hospitalized again because her little mamory gland tumar turn bad over a night and today i also learned that she is a diabetic;((…. i dont know what to do…. if she will get better can i just treat her with diabetes insulin shots? without treating cushing

    • Dr . Joi Sutton January 24, 2018 at 6:04 am - Reply

      Oh my, she has a lot going on. Unfortunately, it is extremely difficult to regulate diabetes without also treating the underlying cushings disease.

    • Lauree February 10, 2018 at 8:29 pm - Reply

      I have a 5 year old doberman with Diabetes and newly diagnosed Cushings. You absolutely must have the cushings in check to regulate the diabetes. There are 2 awesome Facebook groups for both diseases. One is called Diabetic Dog owners and the other is Cushings disease awareness for dog parents. Both groups are packed with information in their files and most of your questions can be answered there. Good luck to you and your pup.

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