How About Hard to Regulate Diabetic Dogs?

By Dr . Joi Sutton|2017-04-03T14:28:38-04:00Updated: March 30th, 2017|Pet Care, Pet Diabetes, Pet Newsletter|13 Comments
  • Labrador Retriever with Ball in Mouth

I get some great questions from clients. They inspire me with article ideas and keep me in tune with diabetic pet owners. I enjoy interacting with our readers, and sometimes the questions are worthy of a newsletter. I bet if one person has this question and takes the time to write me, there are likely lots of folks with a similar question. Today we’re going to talk about hard to regulate diabetic dogs.

Dr. Joi, I enjoyed your article about hard to regulate diabetes in cats. I have an 11-year old Labrador that was diagnosed with diabetes this past Nov. He does not seem to be responding as well as he should be. He was checked for Cushings which was negative. He is getting 29 units of Novolin 2x per day now. Do you have any more ideas of what could be causing the insulin resistance? I am interested if you have any ideas. My vet has me checking his blood glucose 3 times per day. Do you think the every 2 hr. curve would give more specific info?

Answer: Well, I guess the first thing to ask is how are his blood glucose curves? That is your best indicator of how well he is responding to the insulin. He may not have insulin resistance. It may just be that you haven’t yet found his best dosage of insulin.

Blood glucose curves give us so much information when done right! When I run a curve I test the blood glucose every 2 hours from one injection until the next, for a 12 hour period. And, if the blood glucose goes below 150 mg/dl, I test hourly until it rises again. This way I know when it truly bottoms out, aka the “nadir”. Curves tell us how long a particular insulin lasts in a particular pet and also if we can increase the dose or if we need to lower the dose. For example, if the curve bottoms out at 50mg/dl, we need to lower the dose. If it bottoms out at 200 mg/dl, we would increase the dose. We need numerous samples to see where it bottoms out. Sometimes folks email me their glucose curve numbers. I cannot evaluate curves for pets I haven’t personally examined, as that would be bad medicine, but you now have the parameters I use. You and your veterinarian can evaluate the curves together to alter the dosage if needed. Remember, pets may vary in their absorption and metabolism of insulin. No two pets are exactly the same.

Ideally for a curve, we want most of the numbers below 300 and we want it to bottom out somewhere around 100. The renal threshold for sugar spilling over into urine is somewhere around 250 to 300 mg/dl in pets. So if we keep most of the numbers below 300 the clinical signs of diabetes like excessive thirst and urination are abated and quality of life is improved. Make sense? Testing just 3 times per day doesn’t give us that information. Curves will help you and your vet fine tune his diabetes and find out if he is insulin resistant. I strongly prefer these curves be done at home to avoid stress hyperglycemia. After adjusting an insulin dosage we will wait 5 to 7 days before doing another curve to assess the new dosage.

Have you also ruled out infections? Urine culture and dental care are helpful if you truly think there is insulin resistance. Urine cultures are horribly expensive. I’ve seen vet clinics charge anywhere between $100 and $150 for a urine culture. Most of that money goes to the lab, not to your vet. Because of the high cost of urine cultures, I ordered an in house urine incubator, called the Uricult Vet, 5 years ago. I found it at a vet conference exhibition area where they sell all kinds of gadgets and gizmos that keep veterinary medicine fun and exciting for us veterinarians getting long in the tooth. It was a dandy idea to make microbiology so simple that any vet can do it in a small private clinic setting.

The incubator comes with a box of paddles. Each paddle has 2 different culture media on either side and it fits into a plastic vial that goes into the incubator set at 36 degrees Celsius. The paddles cost less than 10 bucks each. It will cost you more than that as your vet needs to pay for the incubator and the effort and time to collect the urine via cystocentesis and then monitor the paddle for growth of bacteria. Nonetheless, it’s a lot less than sending it out to an outside lab. If I expect a urine culture to be negative and am checking to be thorough, say for a diabetic or maybe a blocked cat or newly diagnosed kidney patient, I nearly always start an in-house Uricult Vet. If I have seen bacteria on an in-house urinalysis and sincerely need to know the best antibiotic choice to combat it, I’ll send urine to an outside lab for culture and then sensitivity testing against various antibiotics. Sometimes I may send urine out and additionally start a Uricult vet in-house as sometimes, but rare, germs may die in transit to the outside reference lab. You might tell your vet about it! It could then potentially save you big bucks since you have a diabetic pet. I recommend urine culture every 6 months for diabetic pets.

Now, is he proper body weight? Labradors are known to be food motivated and can be tubby. Obesity is a very common cause of insulin resistance. Is he getting mid meal snacks? Those can cause unwanted blood glucose elevations! Additionally, I consider how he is feeling. Does he play? Is he drinking and peeing excessively? Is he gaining or losing weight? Is he forever hungry? Does he feel well?

Have a sit down with your vet and if you haven’t done a recent blood glucose curve, do one.

Keep me posted!

Have a question or comment? Post below or email me at [email protected]. I always enjoy hearing from my readers!

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. Teresa Gallegos March 25, 2023 at 11:37 pm - Reply

    My schnauzer was just diagnosed with diabetes right now she is only taking 5 units and her blood glucose is at 93 at 9:00 pm will she okay to sleep or should I feed her?

    • Dr . Joi Sutton April 2, 2023 at 6:22 pm - Reply

      Well, I don’t know what time she got her insulin to give you an answer. If that is the nadir (where it bottoms out) then no. However, it could go lower! I’d give her a snack! No 2 pets require exactly the same amount of insulin. Isn’t that frustrating!? For an antibiotic we have a “dose” based on body weight. With diabetes, some pets might yet be making some insulin on their own. And diets vary. We need to start at a low dose and test. I like to say that we “sneak up on a dose”. If we give too much right away, we can cause the blood glucose to go too low and then the liver makes glucose in response and it can be very difficult to identify the right dose. (That is what the somogyi swing is.) Chat with your veterinarian who has examined your pet first thing in the morning, and check a blood glucose in the morning. I suspect your vet will lower the dosage. I’m very glad you are doing home glucose testing! Good job.

  2. Mo December 18, 2018 at 7:24 am - Reply

    Dear dr joi, our 13 yr old min schnouser was diagnosed with diabetes back in May, we use Vetsylin, in the last 30 days we can’t seem to regulate him, his curve numbers are very high, 500 range in the morning and only comes down to 300 during the day and back to 500 within 12 hours, our vets just raised the dosage to 14 units 3 days ago. Any thoughts you could with us would be highly appreciated,

    • Dr . Joi Sutton December 18, 2018 at 8:34 pm - Reply

      Whenever you change the dose you want to curve again in 5 to 7 days. We want the curve to bottom out at around 100. Curves tell us not only how low the blood glucose goes (so if we should increase or decrease the dose), they tell us how long a particular insulin lasts in your pet. Every let is a different experience.
      When I do a curve I check the blood glucose every 2 hours from one injection til the next 12 hours later. If the blood glucose goes below 150 mg/dL I will check hourly until it starts to rise so I do not miss where it bottoms out. Then I go back to every 2 hours.
      Be sure to avoid mid meal snacks. They can cause unwelcome increase in blood glucose. (Of course if the blood glucose happens to go too low, feed mid meal snack and adjust the dose.)
      I hope you do home testing! It is more accurate that curves at the clinic as ou avoid stress hyperglycemia. And, home testing can save you financially.
      Good luck!

    • Dr . Joi Sutton December 18, 2018 at 8:39 pm - Reply

      Whenever you change a dose you will want to check another curve in 5 to 7 days.
      Are you giving mid meal snacks? Ideally you should give meals wide daily every 12 hours. Mid meal snacks can cause an unwanted rise in blood glucose.
      Are you doing home glucose testing? It avoids stress hyperglycemia and saves you financially. Curves tell us if we need to increase or decrease the insulin dose (based on where it bottoms out) and how long a particular insulin lasts in your particular pet.
      Be sure to curve again in a week!

  3. Judy Drennen November 12, 2018 at 11:40 am - Reply

    can a dog take Novolog, and if so, what dosage per pound?

  4. sheila April 15, 2018 at 10:53 pm - Reply

    I have a 10 year old yorkie who has suger problem and takes one shot a day so fare is it normal for her to act sad and depressed she use to be a really happy doggy but not anymore what should I do

    • Dr . Joi Sutton April 18, 2018 at 9:03 pm - Reply

      Sheila, it is rare for a pet to be regulated with a single dose of insulin per day. Have a chat with your vet about giving 2 injections per day. Also, are you testing her blood glucose at home? If she is unregulated she probably feels crummy. Have your vet examine her, perhaps check for other issues, and check a blood glucose curve. Good luck!

  5. Dr Joi March 31, 2017 at 7:21 pm - Reply

    YES, that was a typo! Was supposed to be Novolin. Thanks all for catching that! I’ll see if our computer gurus can fix this! 🙂 Joi

  6. Charlotte Hendricks March 30, 2017 at 4:42 pm - Reply

    Hope that’s a typo.

  7. eileen March 30, 2017 at 3:30 pm - Reply

    “He is getting 29 units of Novolog 2x per day now.”….Novolog? that has to be a typo and must be Novolin N. If not this needs to be addressed ASAP. Novolog is a rapid acting insulin not used as the basal insulin with our dogs.

  8. Janey Phillips March 30, 2017 at 3:02 pm - Reply

    Thanks for another excellent and comprehensive reply to a question that plagues diabetic dog owners periodically. In addition to all you suggested, I wanted to recommend that when control is difficult, maybe ask your vet for a fructosamine test? This will give you an idea re: the degree of control or lack thereof. It might help pinpoint if the insulin dose needs to be higher or lower (which is not always clear), or maybe will indicate control is actually overall ok, right? Loss of control at the end of the 12 hour interval between insulin doses happens to my dog a lot, and makes it hard to tell what is really going on unless you are doing a curve at the time. It also makes a big difference if your dog is playful, not drinking excessively, etc. which would suggest control is better than you think based on the numbers. My dog is finally back under control (after a surgery and a couple of post op infections) after sticking with a given dose for several weeks and concurrently gradually lowering his calorie intake somewhat by substituting some lower calorie dry food into his usual weighed and measured twice a day meals. I will ask for another fructosamine test when we make it to two weeks of better numbers to make sure we are doing as well as it seems.

    • Dr Joi April 2, 2017 at 8:31 pm - Reply

      Janey, what you describe is the perfect use of the fructosamine test. I don’t run fructosamine tests often because they are so darned spendy and because a curve (if done with overall consistency of portions fed and timing 12 hours apart) gives us more information. Also, if I have a fractious pet or a pet that becomes extremely stressed in the vet clinic and the owner is unwilling to do blood glucose levels at home, I might choose a fructosamine level. So, if given the option of evaluating a curve (for roughly 7 to 10 bucks) versus a fructosamine (which yields less info for a whole lot more money) I’ll take the blood glucose curve most of the time. Great thoughts! Thanks for chiming in! 🙂 Joi

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