A discussion on the traditional treatments for feline diabetes, with an introduction to some newer options coming to the market
Cats are not small dogs and therefore must be treated accordingly. This statement is even more true when it comes to diabetes, as diabetes presents differently in felines than it does in canines, explained Cynthia Ward, VMD, PhD, DACVIM, professor at the University of Georgia College of Veterinary Medicine in Athens.
Dogs often have type 1 diabetes mellitus (insulin dependent), whereas cats more commonly have type 2 diabetes mellitus. Type 2 diabetes occurs when the pancreas secretes insulin normally but cell receptors do not recognize it as insulin, so glucose cannot activate the cell. This leads to an overproduction of insulin that can, overtime, lead to relative insulin failure, hyperglycemia, and results in type 2 diabetes mellitus, Ward explained in her 2023 Veterinary Meeting & Expo lecture.1
“We all recognize how important the owners are in terms of us designing and implementing a treatment strategy. You can evaluate your patient perfectly. You can have the best treatment strategy ever, and the owner can ruin that for you every time by not doing what you say. How many people have had owners that lie to them about what they’ve done? Or they swear they’ve done all these things and they bring the insulin bottle in and it hasn’t even been touched. We all know the owners can sabotage us in terms of treatment, so I like to remind myself how important it is for us to get the owner on board,” Ward said.
With any method of diabetes treatment, Ward explained that the objective is to control polyuria and polydipsia, polyphagia, neuropathies, regain energy and regain muscle mass. Treatment also needs to prevent emergencies involving ketosis, hypoglycemia, and hyperosmolality.
First, Ward explained that a cat needing treatment should be stable, meaning their blood glucose is less than 350 mg/dL and they are not ketotic. From there, some initial treatment options include switching to a low-carbohydrate diet, regular exercise, and insulin injections twice a day. “Another big thing is calorie control. We know fat is an inflammatory organ on its own. We want [diabetic cats] to have enough nutrients, but we don’t want them to be overconditioned, because any extra fat they have is going to fight the insulin’s ability to do its job,” Ward said.
“Insulin therapy has become overly complicated because we have all these insulins on the market. It’s so confusing—all the choices you have, all the insulins you can use. And in the United States, [we] are not restricted to not using insulins off-label, [which] opens up the ability for us to use human insulin in our animal patients. And we all know people want to save every dime they can, so if they’re on insulin, the first thing they want to know is [whether] they can use their insulin on their cat,” she said. Ward personally recommends protamine zinc recombinant human insulin (Prozinc; Boehringer Ingelheim) to her clients, but she also mentioned that porcine insulin zinc suspension (Vetsulin; Merck Animal Health) and U-300 insulin glargine (Toujeo; Sanofi-Aventis) were also options.
Sodium-glucose cotransporter-2 (SGLT2) inhibitors are now used in human medicine to treat adult type 2 diabetes. According to the FDA,2 SGLT2 inhibitors are a class of prescription medicines that are approved by the agency for use with diet and exercise to lower blood glucose by causing the kidneys to remove sugar from the body through the urine. Medicines in the SGLT2 inhibitor class include canagliflozin, dapagliflozin, empagliflozin, and ertugliflozin. These are available as single-ingredient products and in combination with other medicines, such as metformin, for managing diabetes.
There are a few recent studies3-6 testing the effects of SGLT2 inhibitors in cats. The study on bexagliflozin in cats5 found a significant reduction in insulin requirement and decrease in blood glucose and fructosamine, all with no hypoglycemia.6 On December 8, 2022, the FDA approved the first oral animal drug to improve glycemic control in cats with diabetes mellitus not previously treated with insulin. Bexagliflozin (Bexacat; Elanco Animal Health Incorporated) is also the first SGLT2 inhibitor animal drug approved by the FDA.7 On August 14, 2023, the FDA approved the first oral liquid medication to treat diabetes in cats; velagliflozin oral solution (Senvelgo; Boehringer Ingelheim) is a once-a-day treatment administered in food or directly in the cat’s mouth.8
Ward said these new treatment options have the potential to save a lot of cats’ lives, and that other positives include controlling hyperglycemia and clinical signs and the ability to use oral medications with no injections or needles. However, Ward also mentioned the potential challenges, including that not every cat could qualify for these treatment options, as they must have enough functional ß cells.