How to Aim For A Well Regulated Pet – Ask Dr. Joi

By Dr . Joi Sutton|2018-03-06T14:17:39-05:00Updated: October 19th, 2017|Pet Care, Pet Diabetes, Pet Newsletter|9 Comments
  • Beagle Sitting in a Field of Flowers

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’s question is what is the best time to check blood glucose after an insulin injection.

Doctor, what is the best time to check the blood glucose for our Insulin dependent beagle after an insulin injection? Is it a good idea to give less insulin at night and more in the morning? Our beagle crashed on Sunday, had a seizure and spent the day at emergency vet hospital. She then spent Monday at her vet’s office. Her insulin has been changed from Humulin N to Vetsulin. Polly has been so erratic for three years. Do you feel she will do better on Vetsulin?? We are worried, tired and broke!!

I’m so sorry you and Polly had this experience. Hypoglycemia is scary, and I’m glad you were home to identify it and get her to immediate care. It was no doubt an expensive and worrisome weekend!

Now on to your questions:

I prefer equal dosing every 12 hours as the norm. I also recommend equal portions for the morning and evening meal. Consistency is your friend! I would feed equally portioned meals and give equal doses of insulin at the time of the meals, every 12 hours. Of course if the blood glucose is low you might wish to back off for the dose and consult your vet. After a hypoglycemic episode, we nearly always lower the insulin dosage and increase blood glucose monitoring. Since you’ve changed insulins, it would be harder to evaluate what a “lower” dose might be. When starting insulin or changing to a different type of insulin, I advise folks to start low and then sneak up on the insulin dose.

Vetsulin and Humilin N have pretty similar duration of effect, but each pet will respond to a particular insulin differently. Some pets may absorb a particular insulin better than other pets. Some may metabolize a particular insulin faster than other pets. It’s hard to predict how your pet will do with the insulin change. Before changing insulin, I like to make sure we are doing our best with other aspects such as feeding and curves and consistency in general. Levemir might be a good choice if you don’t find improvement with Vetsulin as it tends to last longer than Humilin N or Vetsulin in most dogs.

As far as a “best time to check” blood glucose, I’m not a big fan of spot checks unless you think your pet is acting funny (i.e. hypoglycemia or hyperglycemia). In general, I’m a much bigger fan of running blood glucose curves. That’s when we check the blood glucose every 2 hours from one insulin dose and meal until the next insulin dose and meal 12 hours later. I put in a special twist as well: if the blood glucose drops below 150 mg/dl I like to check it hourly until it starts to rise again. This way I don’t miss where it bottoms out. A blood glucose curve tells us how long insulin lasts in your pet, and also helps us decide if we should increase or decrease the insulin dosage based on where it bottoms out. We want to run a curve on an “average” day. Don’t run the curve when you have former college buddies are visiting or when there is noisy construction work going on outside your home or when your crazy aunt is visiting and you know she sneaks your pet food. We want to run it on a day that is your pet’s “norm”. We run blood glucose curves a few times each year, even when we think we have a pet under good control in case the insulin requirements have changed a bit, so we can tweak the dosage and get the best regulation possible. Or, if we’ve altered the insulin dosage, we will check a curve 5 to 7 days after the dose change to see if we’ve improved the situation.

Now, if you have a pet with chronically erratic blood glucose numbers or a finicky appetite, I’ll sing a different tune. Some pets are difficult to regulate and will need to be checked before each insulin dosage. Folks doing “tight glucose control” on their cats, which offers the best chance of getting a cat into diabetes remission, will also check blood glucose prior to each insulin dosage.

In general, doing a spot check 6 or 8 hours post insulin injection to assess dosage is very “old school”. I know some vets used to assess insulin dosage based on a single number, but it is just that, a single number. We use curves to assess glucose control. Or sometimes we use A1C levels or fructosamine levels to assess control when a pet has erratic blood glucose numbers. Still, blood glucose curves yield more information than an A1C or fructosamine levels. And curves are significantly less expensive when run at home than these other tests.

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. Lisa Loffreno November 20, 2017 at 7:05 pm - Reply

    Dr Dr. Joi:

    I am constantly being urged to do a fructosemine test on my diabetic dog. However, since I test her blood glucose several times a day using the Alpha Trac II, I don’t understand the need for the test. I feel if my blood glucose results are reviewed, it would give a better understanding of how well regulated she is than the fructosemine test would. I also don’t understand how you can use the fructosemine test alone to modify insulin dosage unless you also monitor blood glucose at nadir. Please tell me what I am missing. Thanks

    • Dr . Joi Sutton November 21, 2017 at 7:29 am - Reply

      You absolutely nailed this. I rarely run fructosamine levels unless I have an erratic or difficult to regulate diabetic pet. The fructosamine is a look back at blood glucose control over several weeks. There is a newer test for pets (A1C, available about a year now) that looks back about 110 days for dogs and about 70 days for cats. I have run it a handful of times. What do I prefer? I prefer a blood glucose curve as this tells me
      1) how long does the dose of insulin last in this particular pet and
      2) should I increase, decrease or leave the insulin dosage alone (based on where the curve bottoms out)
      Fructosamine and A1C tests are pricey. Again, I occasionally will run an A1C, but I strongly prefer a blood glucose curve to evaluate how we are doing.
      Good job, Lisa!

  2. Suzanne Sproles October 19, 2017 at 10:35 pm - Reply

    Love your sight wish you were closer I have a diabetic dog since 2009 he is now 12 a chocolate lab .hes my world .they say he has nerve dsmage in the foot from the diabetes and there’s nothing they can do .he walks he still gets up and down I give him joint pills it helps a lot also he get metacam but only when he needs it cause it’s bad for the liver.any suggestions for nerve damage thank you Suzanne Sproles

    • Dr Joi November 11, 2017 at 1:30 pm - Reply

      Neuropathy is a tough one. You might see if there is a local neurologist to examine him. As far as an anti-inflammatory, in 2017 a newer drug hit the market for dogs. It is called Galliprant. It is an option to metacam. Galliprant may be safer for his liver and kidneys. Chat with your vet about it. 🙂 Joi

  3. Jessica October 19, 2017 at 8:43 pm - Reply

    I have a diabetic cat going on 8 years and he’s been brittle since day 1. He gets Levemir 12 hours apart, same dose, same food. In regards to testing, at the beginning, we ran lots of curves and from them, we know the insulin begins to “kick in” 2 hours after shot time, his nadir is 4 hours after shot time, and his food affects his numbers for about 30 minutes after he’s eaten. All this is extremely beneficial information to have in our pockets and helps to guide decisions when necessary.
    I would NEVER give a dose of insulin without first testing him – as I mentioned, he’s very brittle. Knowing his shot time number (and armed with all of the curve information we did in the past) we absolutely know when we need to hold the shot, wait the shot, alter the shot, or test 2 hours after the shot to make sure he’s safe. Bottom line, knowing how your pet reacts to insulin throughout the cycle, is the most important thing you can do to keep them regulated and safe.

    • Dr Joi November 11, 2017 at 1:27 pm - Reply

      Great job, Jessica!

  4. Denise Connolly October 19, 2017 at 12:27 pm - Reply

    My dog as been a diabetic for over 3 years. We changed to Vetsulin and it worked better. But I check her glucose once a day 6 hours after her shot. She can be 172 one day and 350 the next. I have come to realize, this is my dog. I give her 2 1/2 units at 9 am and at 9 pm. If it goes over 350, I give her 3 units at 9 pm and go back to 2 1/2 at 9am. If she goes under 200 , I give her 1/8 of a teaspoon of maple syrup . If I do a curve, I have to do it over 5 days , 1 hour later then the day before. I check her blood in her mouth, so I can’t poke her 5 times in one day. I found the curve is a waste of time for me. I spoke to her doctor and they agree. This is the way my dog is. I feel it is a day by day, hit or miss, when it comes to my dog.

    • Dr Joi November 11, 2017 at 1:26 pm - Reply

      We actually want her blood glucose to be below 200, so using 200 as a level to give food (or syrup) is not advisable. I’d like you to chat again with your veterinarian who is managing your pet’s blood glucose to clarify your plan. 🙂

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