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. Let’s jump right in and talk about this one about insulin resistance and regulating a diabetic kitty:

I have a diabetic rescue cat who was diagnosed a little over two years ago. So far, I have been unable to regulate his sugar levels. I’ve tried everything including switching him from ProZinc to Vetsulin. He is on a canned food diet as well. He is currently getting 12 units twice a day and I still can’t get his BG under 250. He has been vetted and we can’t find any underlying conditions that would explain his insulin resistance. Pushkin is 12 years old, neutered and indoor only. Beyond his diabetes, he seems healthy and content, however, he is always hungry and thirsty and always peeing. My vet and I are at a loss. Is there anything left to do?

Answer: 12 units is a pretty high dose for a cat. When I hear of such a high dose I think of a couple situations. The best case scenario would be a Somogyi swing. That happens if we have a pet at too high of an insulin dose for that pet’s needs, and the blood glucose plummets. If the dose is too high and the pet becomes hypoglycemic, the liver reacts to a low blood glucose by making more sugar. It can be really hard to catch this situation! When I suspect Somogyi I’ll drop the dose and do a curve a week later.

Honestly, when we start treating diabetes we don’t know if the pet will require just a smidge of insulin or a bigger dose. The pancreas may yet be making some insulin. Absorption and metabolism of insulin also varies from pet to pet. We don’t know what the correct insulin dose will be for any particular pet! It’s an important point, so I’ll repeat myself: Insulin absorption and metabolism varies between pets. Blood glucose curves don’t always result in us raising the dose. Sometimes we lower the dosage.

When you started him in insulin did you start at a low dose and slowly sneak up in the dose? Do you remember how quickly you bumped up his dosage way back when he was first diagnosed? I think folks can be so excited to fix the situation quickly that they raise the dosage too fast. Slowly and surely sneak up on the dosage. Curves tell us how long insulin lasts in a pet and how low the blood glucose goes for a particular pet with a particular insulin at a particular dosage. If I alter the insulin dosage I will wait 5 to 7 days until I do another curve.

The other conditions I’d consider are Acromegaly and Cushings disease – both can cause awful insulin resistance. Both of these diseases are rare but do exist in cats. I’ve never seen an Acromegaly cat. I have diagnosed a cat with Cushings disease. Both these diseases make managing diabetes very, very difficult. I advise an internist consult if your vet suspects Cushings or Acromegaly. Cushings is one of my least favorite diseases of all-time and I usually punt them to my local internist. Frankly, if your vet has expressed frustration in regulating your cat, seeing an internist is a great idea. Becoming a vet takes 8 years of college. Internists get yet another 4 years of training to put those extra letters behind their names.

Pzi/Prozinc is usually a better choice for a cat than Vetsulin, although there are cats that do well on Vetsulin. Vetsulin just doesn’t last very long in most cats. There are some cats that are regulated with Vetsulin, but by the tail-end of the 12 hour dosage, the glucose is usually high. Other good choices for cats would be Levemir or Glargine. They cans be purchased in 3cc pens to save on costs.

You are smart to look for underlying causes of disease and insulin resistance. Big ones include dental disease and urinary tract infections.

I’m so glad you are using canned only food! Which is it? Have you checked the carb content? The lower the better. My personal favorite for cats is Purina DM canned which has 4 percent carbs. Of course cats get a vote in what they decide to eat, and you can find the carb content of most cat foods on the Internet with a Google search.

Have you and your vet ever dropped the dose down to a low starting dose throughout this? As veterinarians we don’t often use urine glucose testing anymore once the home glucose meters became so prevalent and easy to use. Nonetheless, one way to diagnose Somogyi swing is checking the urine for glucose. If it is high in the morning and then you find no or little glucose in the urine a few hours later, it might make us suspect this situation.

Chat with your vet and keep me posted!

Have a question or comment? Post below or email me at joi.suttondvm@adwdiabetes.com. I always enjoy hearing from my readers!


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

Dr . Joi Sutton

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 and is the President and Founder of 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.
Dr . Joi Sutton