FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

CHOOSING CORRECT TYPE OF INSULIN IMPORTANT FOR DIABETICS

Question: I have had diabetes for the last 15 years. I take insulin twice each day to keep my sugar under control. For the last few months I have been hearing about a new insulin, Humalog. From the ads I've seen, I think it could work better for me, but my doctor hasn't recommended it for me, yet. So my question to you is who should use Humalog insulin?

Answer: For the benefit of my other readers, I am going to briefly review some important facts about diabetes. By definition, a person has diabetes when his or her blood sugar level is elevated above 125 mg/dl on more than one occasion. To be valid, this measurement must be taken each time after an eight-hour fast. If you are familiar with diabetes, you might note that this is a lower number than the 140 that was the standard for many years. The new lower value was recently adopted because studies now show individuals with fasting sugars between 126 and 140 have risks of health problems almost as great as those whose sugars are over 140.

The healthy body carefully and continually adjusts the amount of insulin that is produced by the pancreas and the amount of sugar that is released from the liver to keep blood sugar within a narrow range of normal values. In those with diabetes this process doesn't work as well as it should. Because food is the source of the body's sugar and exercise helps the cells use sugar as fuel, eating a proper diet and getting daily exercise are important components of treatment for all individuals with diabetes. Many diabetics require medicine to keep their sugars within the normal levels despite being scrupulously careful about their diet and physical activities.

There are a number of medicines that can be taken by mouth that help regulate the blood sugar. However, many diabetics, just like you, require insulin, which is only effective if taken by shot.

There are several types of insulin available today. They differ primarily in how fast they start to work and how long they last. There are advantages for each, and most diabetics use two or more types, often a blend containing a bit of fast-acting insulin and a somewhat larger amount of a long-acting type. Humalog (lispro), the new insulin you asked about, is a very fast acting form. Regular insulin typically has its peak action about 2 hours after it has been injected. Therefore, it is best to give it 30 minutes before a meal so that it reaches its crest at the same time your body reaches its peak level of food absorption.

Humalog insulin, by contrast, has its peak action about one hour after injection. Therefore, it works best when injected with the start of a meal, however, it can even be delayed until after a meal. This can be a great benefit in some situations, particularly in children who don't always eat the food that mom or dad sets before them.

There are two additional considerations about the use of lispro insulin. First, because of its fast action it is somewhat more prone to causing episodes of low blood sugar than are other insulin forms. Second, it is relatively expensive. It is about 21 percent more costly than regular insulin, which translates on the average to an additional $4.50 per bottle. I'd suggest that you talk to your doctor again if you think lispro would be better for you.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.