People, nowadays, are well acquainted with the word "Insulin". They may not know the technicalities, but they obviously know that proper functioning of insulin can prevent the much dreaded condition of diabetes mellitus. An increase in the rate of diabetes has led people to show more interest in insulin and insulin therapy.
What is Insulin?
Insulin is a hormone secreted by the beta-cells in the Islets of Langerhans. As the blood circulates through the pancreas, the beta-cells "read" the levels of glucose and secrete the appropriate amount of insulin. The main function of insulin is to help the cells of the liver, the muscle and the fat tissue to generate glucose from the blood and to stores it as glycogen in the liver and the muscles.
When the function of insulin fails or when the control of insulin gets reduced, the normal metabolic function of carbohydrate, protein and fat is hampered and it results in diabetes mellitus. People affected with diabetes have little or no insulin production in their body leading to hyperglycemia.
Insulin therapy is the treatment of diabetes by the administration of insulin externally. This course of treatment is followed when the hormone is no longer produced internally in the body. In people with diabetes, insulin therapy is used to replicate the normal physiological insulin response.
Types and Action of Insulin Therapy
There are many different types of insulin and insulin regimens. The insulin that is available in the market today can be categorized as synthetic and genetically modified. They are identical to the insulin that are naturally produced in the body.
They are divided into four different categories based on their action. And they are generally referred to as:
- Rapid acting insulin like Lispro, aspart, Humalog and Novolog.
- Short acting insulin like Humulin R and Novolin R.
- Intermediate acting insulin like NPH Humulin N, Novolin NPH and Lenteand Ultralente
- Long acting or Basal insulin like Insulin Glargine, Lantus, Insulin Detemir and Levenir.
Insulin Regimens
There are different regimens for insulin administration for different individuals. The regimen should be individualized to suit the lifestyle of the person and what he is willing to do.
- Once-Daily Insulin or Basal-Insulin: This is a common regimen used for people with type 2 diabetes. This is recommended after oral medications fail to show positive effects in the maintenance of blood sugar levels.
- Twice-Daily Insulin or Split Mixed Dose: It is a very common regimen in which short acting insulin is given in the day time just before breakfast and before the evening meal, and the intermediate one is given in the evening which works throughout the entire night and during the morning hours as well. This is sometimes referred to as split mixed regimen.
- Basal-Bolus regimen: A basal-bolus regimen is traditionally called "intensive therapy", "multiple-daily injections" (MDI) or flexible insulin therapy. Intensive therapy is given when a person knows how to adjust the dose of the insulin based on the glucose levels, the food to be eaten and the activity levels. In MDI, a person injects insulin several times during the day, but may not be able to make proper adjustments. They are given fixed doses prescribed by the doctor before each meal.
Is Insulin Therapy Painful?
Most people are concerned about taking insulin. They remember the large needles that were used to administer flu shots or for the immunizations! Today's needles are very thin and fine and are relatively pain free. The best way to help people overcome their fears is to have them try to inject themselves once. They will often be surprised that they can do it and that the pain is much less than what they originally expected.
Injecting Insulin
Insulin is presently available in strengths of U-40 and U-100. The syringes used by the patient should be compatible with the strength of insulin used. For example, if insulin which has strength of U-40 (which means that 1 ml contains 40 units of insulin) is used, a syringe where 1 ml is divided into 40 parts should be used. It is important to take care of these small details as using a wrong combination can lead to serious problems.
Injection Sites
It is very important for people with diabetes to learn about the correct injection sites. The sites for injection include:
- Any four quadrants of abdomen, always at least an inch away from the umbilicus (belly button or navel).
- Front or outer aspect of both the thighs.
- Upper outer area of buttocks.
- Outer and rear surfaces of upper arms
Rotation of the injection sites is a must for the patients. For instance, the morning injection is always given at the abdomen, but in different places, and the evening injection is rotated around the leg. This will prevent the development of hardened areas or lumps that can slow down the rate of absorption.
What are the Different Insulin Delivery Devices?
There are mainly three devices used to deliver insulin - the insulin syringe, the insulin pen and the insulin pump.
- Insulin Syringes: Syringes have been in use since insulin was discovered in 1921. At that time they were bigger, made of glass and more painful to use. Today, they are disposable with needles attached to them. The needles are thin, very fine and lubricated. All these features minimize the pain. Syringes should be disposed off after a single use.
- Insulin Pens: An insulin pen looks like a fountain pen. They are convenient and easy to use. There are two basic types - disposable and reusable. A disposable pen comes already filled with insulin. When a pen is empty, expired or has been open for a month, it is simply discarded. Reusable pens have replaceable cartridges of insulin. Pen needles are disposable and should only be used once.
- Insulin Pumps: An insulin pump is a small computerized device which appears in the size of a pager. The pump continuously delivers rapid-acting insulin through a catheter (small tube). It is inserted into the fat under the skin via a needle. The needle is removed and the catheter remains in place. The catheter is attached to tubing, which is then connected to the pump. The catheter is placed in the stomach, leg or in the hip area. Each pump holds up to 300 units of insulin. The pump has to be worn all the time. These pumps are extremely expensive, and therefore, can only be afforded by a small population.
What are the Guidelines for Storage of Insulin?
- Check for the expiry date. Once the vial or the cartridge is opened, it should be discarded after one month, even if some insulin remains. You should note that the potency of insulin gets lost over time.
- It should not be frozen or stored in direct sunlight or in heated areas.
- In places where refrigeration is not possible, store in earthen pots, which are used to store drinking water, in cooling jars or wrap a cool wet cloth around the insulin container to keep it in a cool atmosphere.
The new insulin analogs and the newer insulin delivery devices such as the insulin pen and the insulin pumps have contributed to the convenience and the flexibility of insulin therapy. The action of the insulin is more consistent and reliable and their delivery modes are even more convenient and easy for people from all walks of life.
