Cat Diabetes and Glucose Fluctuations

Dr. Neely,

My 15 year old cat was just diagnosed with feline diabetes. I check his glucose level twice a day. It can vary from as low as 57 to as high as 395 in a single day. He usually gets 2 things of insulin, but when it is really low I just skip it. The insulin he is on is Lantus.

He has already had an ultrasound, full body xrays, blood panel checking his pancreas and thyroid, etc., and urine tests. But there seems to be no underlying cause.

What to do? Could there be something wrong with the glucose meter? I really am at wits end. My vet has not come up with any answers. Can you help???


It doesn’t sound to me as though there is anything very wrong with your cat’s diabetes treatment thus far. Fluctuation in the blood glucose levels of a diabetic cat is normal, but there are many ways now to help regulate your cat. As time has progressed with treating diabetic felines, we have learned that we should actually be treating our cats more similarly to how we would treat a person with diabetes. The best thing to do is to feed a low carbohydrate diet, test multiple times daily, and make insulin dosage adjustments according to your cat’s blood glucose readings.

Skipping doses when your cat is low can certainly create a significantly higher reading later on, especially if there has been 12 hours between your readings. Generally, if your cat is low, according to a tight regulation protocol, you would test again in a few hours to catch your cat before he gets too high again. But even if that is not the cause of your cat’s high readings, sometimes giving too much insulin can cause these spikes as well. What happens in this case is that your cat’s glucose actually gets too low, and it causes rebound effect, creating a skyrocketing blood glucose level later in the day.

Regulating a diabetic cat can be quite overwhelming and time consuming, but if you follow the tips on this page, there is even a possibility that your cat will go into remission with his feline diabetes. My best suggestion is to read all you can and to join some forums for support and to learn you are not alone!

All the best,
Dr. Neely