Diabetes in Cats - Dosage and Regulation

Dosage and Regulation

Cats may in some cases have their mealtimes strictly scheduled and planned to match with injection times, especially when on insulins with a pronounced peak action like Caninsulin/Vetsulin or Humulin N. In other cases where the pet free-feeds and normally eats little bits all day or night, it may be best to remain on this schedule and try to use a very slow-acting insulin to keep a constant level of blood glucose. Consult your veterinarian. Note that some veterinarians still use the outdated recommendation of using Humulin "N" or NPH insulin for cats. This insulin is too fast-acting for most cats (though fine for dogs and humans). Cats metabolize insulin about twice as fast as humans, and the often-effective slower-acting Lente and Ultralente (Humulin L and Humulin U) insulins are being discontinued (as of 2005), so most cats are now using either the veterinary PZI insulins, or the new full-day analogs glargine (Lantus) and detemir (Levemir).

The goal at first is to "regulate" the pet's blood glucose, which may take a few weeks. This process is basically the same as in type-1 diabetic humans. The goal is to keep the blood glucose values in a comfortable range for the pet during the whole day, or most of it.

The most successful documented method is Tight Regulation with Lantus or Levemir.

• Typical obstacles to regulation:

• Chronic overdose masked by Somogyi: A dose that is too high can easily cause a Somogyi rebound, which can look like a need for more insulin. This condition can continue for days or weeks, and it's very hard on the cat's metabolism. See more on this topic in the Somogyi section below.

• High-carbohydrate cat food: Many commercial foods (especially "light" foods) are extremely high in cereals and therefore carbohydrates. The extra carbohydrates will keep the cat's blood sugar high, and if you're free-feeding may also make the blood sugar curve over the course of the day volatile and unpredictable. In general, canned foods are lower in carbohydrates than dry ones, and canned "kitten" foods lower still. Recent studies show that cats' diabetes can be better regulated and even sometimes cured with a low carbohydrate diet. If switching to a lower-carbohydrate food, do it gradually and lower the insulin dosage appropriately, using home blood-glucose testing several times daily to be sure your insulin dose is being adjusted properly. If your cat is on a special diet for pancreatitis, chronic renal failure, or any other condition, consult your vet for the appropriate diet for that condition plus diabetes.

• Wrong insulin: Different brands and types of insulin have idiosyncratic effects on different cats. If you've settled on a dose that seems to keep the pet's blood sugar within range at peak effectiveness, but the sugar readings remain dangerously high at shot times, the insulin may not be lasting long enough for your pet, or may not be the best choice. Testing blood sugar more frequently (for example, at 6, 8, 10 and 12 hours after shot) will determine if the insulin is lasting long enough. Switching to a slower-acting or a better-tolerated insulin for that pet, and lowering the dose initially to be safe, may be the next step.