Insulin is a hormone produced by certain cells called beta cells in the pancreas.
All tissues in the body will require glucose for normal functioning. Insulin drives the glucose in the blood to the tissues, so that they can continue to function well. Some organs like the brain does not require insulin for taking up glucose into them.
In patients with type1 diabetes, the cells of the pancreas are destroyed by the body’s immune cells. There is lack of insulin the body and insulin needs to be given from outside.
In patients with type 2 diabetes, there is failure of insulin to act (insulin resistance) as well as a reduction in the production of insulin. As the duration of diabetes progresses, patients will have progressive reduction in the production of insulin.
People with type 2 diabetes mellitus diagnosed for the first time with high sugars are preferably managed with insulin. When people with T2DM on oral glucose lowering drugs fail to maintain good blood sugar control, they should be considered for injectable treatments. Insulin is the commonest form of injection used in people with diabetes. There is no reason to believe that insulin is the last resort, and can be started at any stage of type 2 DM. People with T2DM planned for surgery, developing an acute infection or a heart attack should also be managed with insulin.
Insulin is broadly divided into 2 types: human insulin and insulin analogs. Human insulin is made by recombinant DNA technology and resembles the structure of human natural insulin. Analogs differ in their chemical pattern from human insulin by 2 or 3 aminoacids and this gives them a better duration of action and timing of the peak. Insulin analogs have specific features that make them resemble normal secretion of insulin in the human body.
Insulin is a very safe drug. If you don’t match insulin for food and activity, you may have low sugars (hypoglycemia). There can be various other reasons why low blood sugars can occur in a person with diabetes. This can be due to missing of food, insulin dosing mistakes, excessive or unplanned exercise or additional medicines that are taken with insulin. Insulin seldom causes allergy. If the needles are not used with sterile precautions, they can cause infections. The fatty tissue at the site of injection can become bulged out (lipohypertrophy) or thinned out (lipoatrophy)
Insulin injections should be delivered to the fatty tissue under the skin. You can take insulin on the abdomen or on the thigh. Other sites are shown in figure. Keep rotating the sites to prevent lipohypertrophy or lipoatrophy.
You may store insulin for a period of time until the expiry date has been reached. You should not use insulin past the expiry date. The effective way for you to store insulin is on its side in the refrigerator. The refrigerator should be between 2- and 8-degrees C.
Never freeze insulin. The bottle of insulin that is being used may be kept out of the refrigerator but must not be exposed to extreme temperatures. Insulin kept out of the refrigerator must be discarded after one month. If your room temperatures are below 30 degree C, opened bottles of insulin and insulin pens can be stored outside. If you need to carry insulin during travel, you can use stuff like FRIO valets.
Insulin is conventionally delivered by insulin syringes. A pen is an insulin delivery device that can accurately deliver insulin. They can be disposable or reusable. The disposable ones are used till the insulin in the cartridge gets over. The reusable pens have cartridges which can be replaced once they are over. Insulin can be delivered with a pump also.