Insulin Therapy

Insulin injections are used when a patient does not produce sufficient insulin or the effects of oral treatment do not provide adequate blood sugar control. It is not given as an oral treatment because it is destroyed by the acid in the stomach and the action of enzymes in the intestine. (Several novel formulations in development are described below.) The needles used to deliver the insulin are so fine that many people claim not to feel the injections that are administered into the fat lying just under the skin (subcutaneous).

Although insulin from the porcine gland is available, many people are now using recombinant human insulin preparations that are produced in the lab. Some of these are identical to human insulin and others have been slightly modified. There are numerous insulin products available. They differ in three ways: 1) when they start working (onset), 2) when they have a maximal effect (peak), and 3) how long they have an effect (duration). A physician customizes each insulin prescriptions to match a person’s blood glucose patterns and levels of activity. More than one type of insulin is often used to achieve the best result.

Insulin comes dissolved in liquids at different strengths. Most people use U-100 insulin. This means there are 100 units of insulin per milliliter (ml) of fluid. Syringes are available with various unit markings, and the syringe should match the insulin strength (ie U-100 insulin is used with a U-100 syringe).

Insulin pens have made the use of insulin (particularly outside of the home) easier for many people. The pen can be easily carried in a purse or pocket. It generally contains a dose knob for dialing in the desired amount to be injected. Some pens contain a single dose while others contain multiple doses. Many types of insulin are available in pen formulations. They are more expensive than the traditional forms available.

The use of an insulin pump has become an effective way to provide intensive diabetes management. They are frequently used by people who require multiple injections per day. Insulin pumps are also used by people who have variable schedules because it allows doses to be adjusted according to daily needs. It requires a knowledge of pump operation, a commitment to careful monitoring of blood glucose and the ability to adjust doses. A catheter is placed into a subcutaneous space of the abdomen or buttocks and connected to the pump that can be worn in the manner of a small pager. A limiting factor for many patients is the expense of these devices.

There are currently tremendous research efforts to develop an insulin inhaler. Preliminary studies suggest this form of therapy is likely to be available in the near future. The inhaler sprays a mist containing insulin that is inhaled through the mouth and is carried to the lung where it is absorbed. Other areas of research include the development of insulin nose spray, insulin patches and oral tablets that would resist acid degradation in the stomach.