How do you choose which insulins to use for your patients who use insulin?

In my practice, it has become relatively simple to choose insulins. For basal insulin, I use Lantus (insulin glargine), a long-acting insulin analog, almost exclusively. For bolus insulin, I use the rapid-acting insulin analogs, either Humalog (insulin lispro) or NovoLog (insulin aspart) and presumably will use Apidra (insulin glulisine) when it’s available.

The reason is simple: These insulins are more predictable in action than Regular (R), NPH (N), Lente (L) or Ultralente (UL) insulins. And predictability is critical for me in using insulin for tight control of diabetes.

The goal in insulin therapy is to mimic nature’s insulin pattern; the risk is hypoglycemia. The more you try for optimal control the more risk you run of hypoglycemia, and, therefore, the more you need the most precise tools.

Frankly, I didn’t fully realize how difficult it was to use the old insulins until I was able to use Lantus, Humalog and NovoLog. Lantus provides a predictable, consistent basal amount of insulin with one injection covering 24 hours in most people. Humalog, NovoLog and Apidra offer an onset of action that is fast enough to allow them to be taken right at meals and a rapid cessation of action that lowers the risk of hypoglycemia in between meals.

I find R, N and L to be the most difficult insulins to work with in terms of unpredictable onset, peak and duration of action. Furthermore, the larger the dose of insulin, the longer the duration of action. For R, this has proven especially problematic, since larger doses can have the same duration of action as N or L. The rapid onset and offset of Humalog, NovoLog and Apidra are less affected by this, as is the flatter basal action of Lantus.

In real-life medicine there are exceptions to everything. Some people find a special place for R in covering an especially large or fatty meal (pizza comes to mind) when the need for the insulin—bolus—really does extend for hours after the meal. I also find a special place for N or L in coverage of the dawn phenomenon, when insulin needs rise sharply in the hours before awakening, corresponding to the peak onset of N and L if given at bedtime. To get a more stable basal insulin without Lantus, some individuals, especially in Europe, have had success with giving N, L, and/or Ultralente multiple times daily so as to attempt to “smooth out” the peaks and troughs of insulin action.

My use of mixed insulins is limited because I believe that once you’re going to the effort of using insulin, you already have the desire and ability to adjust basal and bolus individually, which is the most precise method. However, I can appreciate the virtues of convenience and accuracy in various combinations of rapid- and intermediate-acting insulins, such as Lilly’s 75/25 (75 percent NPH with 25 percent Humalog) and Novo’s 70/30 (70 percent NPH with 30 percent NovoLog). As the recognition of postprandial hyperglycemia increases, especially in type 2 diabetes, the role of these mixed insulins will likely grow.

Finally, it should be emphasized that, for type 1 diabetes, I still believe that the insulin pump is the best strategy for most people. Life does not usually have a flat basal rate, and insulin pumpers are well aware of just how much basals can vary during the day and night. It’s perhaps remarkable that Lantus seems to work as well as it does, though it often has to be given twice daily for full 24-hour coverage in people with type 1 diabetes. It will take further clinical research to compare the details of glucose control between pumps and frequent insulin injections, with early reports favoring the pumps.

Daniel Einhorn, MD, FACP, FACE, is the medical director and director of clinical research at Scripps Whittier Institute for Diabetes. He is an associate clinical professor of medicine at the University of California, San Diego.

Islet Law Clears House and Senate Committees

On September 30, 2004, the House's Energy and Commerce Committee approved the Pancreatic Islet Cell Transplantation (PICT) Act of 2004.

The bill was cosponsored by representatives George Nethercutt (R-WA) and Diana DeGette (D-CO).

The Juvenile Diabetes Research Foundation (JDRF) adds that the passage of this act will “help move the procedure of islet transplantation toward becoming standard therapy that could be covered by insurance.”

Peter Van Etten, president and CEO of the JDRF, adds, “Islet transplantation has already proven itself as a remarkable pathway for curing type 1 diabetes, and once it is passed, the Pancreatic Islet Transplantation Act will help move this field even further towards a cure.”