Can’t I Just Give My Pet a Prescribed Dose of Insulin and Be Done with It?

By Dr . Joi Sutton|2018-07-09T08:46:24-04:00Updated: June 7th, 2018|Pet Care, Pet Diabetes, Pet Newsletter|6 Comments
  • Diabetic dog and cat

Many veterinary clients get irritated when veterinarians ask them to run blood glucose curves to assess the insulin dosage for their diabetic pets. When we prescribe antibiotics or anti-inflammatory medications we don’t make clients poke the pet periodically to assess the dosage! Why do we pick on diabetic pet owners? Is it a conspiracy to bleed you dry financially or ruin your day off? Are veterinarians simply rotten humans out to torture diabetic pet owners? Well, no it’s no character flaw of your family vet. It’s that no two animals are the same. Pets vary in how they absorb insulin. Pets may also metabolize insulin at different rates. Some pets may be borderline diabetics in that the pancreas still has some function where others may not produce any insulin at all. It’s not an all or nothing situation with pancreatic function. Each patient is a new experience, and various factors can affect the dosage and glucose regulation. If only I had a crystal ball!

Absorption of Insulin Affects the Dose

Absorption of insulin varies between pets. Some pets may absorb one insulin better than they would absorb another type of insulin. If the weather is very cold, a pet will likely absorb less than in a warm environment. If a pet exercises after a dose of insulin it will likely absorb the insulin faster than a pet snoozing all day. Intramuscular injection would be faster absorption than a subcutaneous injection. We advise subcutaneous injections for pets, but if the owner accidentally gave it IM it would likely absorb more quickly.

Metabolism and Duration of Insulin Affects the Dose

We can’t say how long an insulin will last in your pet. Various factors influence metabolism and clearing from the body. Insulins are metabolized via the liver and kidneys. Pets with kidney or liver disease may take longer to metabolize the insulin and the insulin may last longer in the pet. After a while, patients could even develop antibodies to a particular insulin which can shorten the duration of action. Levemir insulin is protein bound in the body, so if the pet has low protein levels the insulin may not last as long. Sound confusing? No worries, this is why we run blood glucose curves!

What You Feed the Pet Affects the Insulin Dose!

It doesn’t take rocket science to know that feeding a diet high in simple carbs will wreak havoc on your pet’s sugars. One client told me that the only advice her vet gave her was, “Don’t feed him donuts.” This is good advice, but it really skims the top for nutritional advice! What to feed your diabetic pet is another newsletter, but know that diabetic cats usually do best on canned low carb diets! Can I stress this? Cats are not small dogs, and diabetic cats don’t do well with carbs. If you feed your cat kibble expect a higher insulin dose and a difficult time regulating the blood sugar. Diabetic dogs tend to do best when their diets have complex carbohydrates high in fiber.

How is Your Pet Doing?

If your pet is doing well on a particular insulin, stick with it. How do you know of your pet is doing well? We know by running blood glucose curves! How often? Even if you think your diabetic pet is doing fabulously well, I’d like you to run a curve at least every 3 months. As I mentioned at the start of this newsletter, insulin needs change over time. It’s much better to tweak the dose early than to find yourself in an unforeseen crisis later.

Have a question or comment? Then post below! 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. Kim August 4, 2018 at 12:53 pm - Reply

    What happens if I should miss an insulin injection

    • Dr . Joi Sutton August 6, 2018 at 7:00 pm - Reply

      Know that your pet’s blood glucose will be elevated for a day or 2 after missing a dose. If you are a few hours late, you might check the blood glucose and decode of a fraction of a dose would be appropriate. This is something if like you to ask your veterinarian who has examined your pet. If you don’t have a blood glucose monitor, please get one. It will make it easier to assess such situations. 🙂

  2. Patricia July 9, 2018 at 12:37 am - Reply

    Good Evening Dr. Sutton:
    Thank you for your absolutely amazingly awesome newsletter as my parents and I are owned by a canine that has been diabetic for over six years. We weren’t aware she was diabetic until she went blind so we bought her corneal implants and paid for a diet to be designed for our dog by a nutritionist. Fiona, our rescue dog, was also in a moving vehicle accident so she has four steel plates screwed into both sides of her pelvic bones and of course, arthritis has set in, but we had to discontinue physical therapy because she also has Horner’s disease.

    Fiona is adored by our neighbors, she gets Christmas gifts and I don’t even get a card-smile. Fiona also has a bunch of buddies at the nursing home that have treats waiting for her when she comes to visit, however, I am disabled, on a fixed income, don’t drive and her specialists are all over an hours drive away, but my 82 year old dad drives Fiona to her appointments. Sometimes it just all seems too much: catching her urine every day to then decide what the insulin dose should be, being home at exactly 6:30 a.m. & 6:30 p.m. for her insulin injection, the bills, the hours in the car every month, and those glucose curves-it gets overwhelming, however, after reading this I didn’t feel quite as alone so a big thanks!

    I also Advised Fiona’s Specialists About Your Newsletters and Hopefully You Will Be Brightening the Day for Others Too!!!

    • Dr . Joi Sutton July 9, 2018 at 2:09 am - Reply

      You are too kind. 🙂 Fiona sounds fantastic.

      You are not alone. That’s the whole purpose of this newsletter.

      I noticed you said you catch her pee to decide what her insulin dose should be. A blood glucose curve would be much more helpful in determining the dosage. Do you do home blood glucose testing? It’s not as difficult as owners initially fear!

      Pets to Fiona.

  3. Amy Robinson June 13, 2018 at 3:38 pm - Reply

    Hi Dr Joi,

    I love your talks of diabetic cats as my beloved tomcat was diagnosed 9 months ago. We have tried ProZinc and Vetsulin and still always in the 3-400 range. Tom loves kibble and will sneak our dogs’ kibble whenever he can. I wonder if you have heard of the Young Again Zero Carb dry kibble? Tom loves it but I’m not sure how it affects his blood sugar. How can I determine Tom’s metabolism to gauge the effects of his eating dry kibble? As far as I can tell, his numbers are always high no matter if it’s wet canned only or small amounts of kibble. Hoping to try another insulin soon, will ask our vet about the Levimir, but hoping you have some insight on his diet affecting his numbers.

    • Dr . Joi Sutton June 14, 2018 at 4:21 pm - Reply

      Well, one way to tell how your cat reacts is to add in a smidge of kibble and see what his sugars do. Calculating carb content is all so confusing to me. There is the “as fed” percentage and then the “metabolzable energy” percentage. It blows my mind a bit.
      In general, they can’t make dry food truly as low carb as canned food because it won’t take shape. The lowest carb dry foods I feel comfortable recommending are Purina DM (with 11 percent carbs on a metabolizable energy basis) and Hill m/d (with 13 percent carbs on a metabolizable energy basis).
      I found a calculator online that may help you at
      I’m not a nutritionist!
      If you do give a few kibbles (relying mostly on canned food), you can use them as treats and toss them down the hall to get your cat some exercise and mental stimulation at least. I feel most comfortable with canned food for diabetic cats.
      Have you looked for causes of insulin resistance such as overweight, dental disease, urinary infections?
      As he is not controlled (based on the numbers you’ve mentioned), I’d stick with canned food.
      Good luck!

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