CAT INSULIN

The following letter is from a diabetic cat's owner who is concerned about her cat insulin and its effectiveness.

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My cat has diabetes now for three months. Her sugar count is still really high. We have changed her cat insulin already three times. She is on 7 units twice a day. What do you think the problem could be?

ANSWER

There's a number of problems I see just from your question. I can't imagine changing the cat insulin type 3 times in only 3 months. It takes 3 months or more to get up to the correct dosage for a cat on one type of insulin. You can only increase the dosage gradually every 7 to 10 days, so it takes time before the dosage is reached that should be effective for the cat.

If one of my patients continues to need increases and gets to 6 units twice daily, I begin to look for causes of insulin resistance or suspect the cat insulin is not being given correctly.

For example, any concurrent illness anywhere in the cat's body can increase the insulin requirement for a cat or make it impossible to ever find a stable dosage. The concurrent condition must be located and treated and then the insulin is more likely going to be more effective and a stable dosage can be achieved. These conditions can be such things as a urinary tract infection, dental disease, infection elsewhere in the body .....and many other things. The problem must be located and treated or the kitty's diabetes may never be controlled well enough.

The type of cat insulin given is of great importance. The source of the insulin is very important in cats. The one type that seems to work best is the Beef-Pork PZI from IDEXX Pharmaceuticals. It should be the first insulin a cat starts on and will most likely be the only insulin the cat will need.

Another thing I look for when a cat reaches 6 units of insulin and still needs more is called the Somogyi effect.

The only way to prevent the Somogyi effect (high blood sugar) is to avoid developing hypoglycemia (low blood sugar) in the first place by checking to see if too much insulin is being given.

When too much insulin is given the blood glucose drops rapidly and hypoglycemia (low blood sugar) results. The body's natural reaction to this is to create more glucose, leading to hyperglycemia (high blood sugar). So, you have hyperglycemia induced by hypoglycemia, or the Somogyi effect.

The method of determining if the Somogyi effect is occurring is to do a blood glucose curve. Your cat will need blood glucoses measured every hour or so over the course of a day. The measurements when graphed will form a curve which will show if before the high blood glucose (so high you think more insulin is needed) occurs, there is actually low blood glucose (occuring from too much insulin) which is causing the body to react by producing excess glucose. The treatment for this type of hyperglycemia is to decrease the insulin dose. This prevents the hypoglycemia from occurring and triggering the Somogyi effect.

In summary, the reason your cat still has high blood sugar in spite of receiving 7 units of insulin twice daily can be one of the following:



(1) The wrong type of insulin (2) changing types of insulin too quickly without giving each increase in dosage 10 days before measuring its effect (3) infection or illness somewhere in the body (4) the Somogyi effect (5) the insulin is being stored or handled or injected incorrectly or not consistently. You should draw up the insulin and give the injection in front of your veterinarian so any problem in that area can be eliminated.

I would also like to mention that diet can be extremely helpful in lowering a cat's insulin requirements. The prescription diet M/D from Hill's has helped many of my patients lower their insulin requirement and even lose the need for insulin altogether.

Good luck and Be Careful! Too much insulin is deadly!

Best, Dr. Neely