Having type 1 diabetes means having daily insulin injections. Here, you can read about insulins, how they work and how they’re injected:
Up until the 1980s, all types of insulin came from the pancreas of cows and pigs. These insulins are still in use, however, science now allows the production of insulin from yeast or bacterial cells. In effect these cells act like ‘mini factories’ and produce insulin which is identical to human insulin.
Once injected, insulin is taken up by the blood and carried along with sugar to your body's cells. Insulin acts like a key to allow sugar to enter cells. By doing this, insulin lowers the level of sugar in the blood.
Different body cells, for example muscle cells, use sugar as fuel.
After a while, the effect of the insulin you injected wears off. That’s why you have to inject insulin several times a day.
There are four main types of insulin:
Rapid-acting modern insulins have been available for a few years now. Sometimes they’re also called “bolus” insulins. They have been designed to keep the benefits of short-acting insulins, but reduce some of the problems people have when taking them. The benefits of these modern insulins include the ability to inject immediately before or just after you eat, and a reduction in the risk of hypoglycaemia during early night hours when compared to short acting insulins.
Like rapid-acting modern insulins, short-acting insulin controls blood sugar after a meal, but its effects last a little longer (up to 8 hours).
Short-acting insulin is also a little slower to start working, so it needs to be injected about 15-30 minutes before the start of a meal. Like rapid-acting modern insulins, the short-acting insulins are also sometimes called “bolus” insulins.
Long-acting modern insulin is sometimes called “basal” insulin. The effects of long-acting modern insulins last longer because they’re absorbed more slowly and so one dose can last up to 24 hours.
There are different kinds of long-acting human insulins, but what they all have in common is that they all start working a bit later than the short-acting insulins. They are also active for a much longer time (8 to 24 hours). Long-acting insulins are sometimes called “basal” insulins.
If you take insulin twice a day, you may be prescribed a pre-mixed insulin. These insulins are ready-made mixtures of short and long-acting insulin, which combine the effects of both types.
An example of one such mixture is 30% short-acting insulin and 70% long-acting insulin.
These insulin mixtures may contain human or modern (analogue) insulins.
You should never mix your own insulin at home.
Everybody's different and so is each person's diabetes treatment. That’s why there are different insulin combinations, different doses and different injection frequencies available.
Your doctor may have recommended that you start your treatment by taking insulin twice a day. For example, you may be injecting pre-mixed insulin in the morning and long-acting insulin before dinner.
Over the years your body and your lifestyle may change. Your eating and exercise routines are also likely to change with time. So too will your diabetes change.
Your doctor may recommend that you start to take insulin four or more times a day. This matches the insulin pattern of people without diabetes as closely as possible.
What might this more frequent insulin treatment pattern involve? An example might be as follows:
Whenever you change your diet or your exercise routine, or if you become ill, you may need to adjust your insulins (rapid-acting modern insulin, short-acting insulin or basal). The only way to find out if you need to do this is to test your blood sugar frequently.
For example, if your blood sugar readings are high over a period of time, you may consider adding a few units to your usual pre-meal dose or evening basal insulin dose. Your doctor can explain when and how to do this.
Insulin can be injected into a number of areas on your body. Your doctor may recommend that you inject insulin in:
Insulin enters the bloodstream faster from some areas of the body than from others. Because of this, your blood sugar may be different when you inject in different areas. That’s why it’s best to have all your injections in the same part of your body.
For example, some people use the abdomen for short-acting insulin and the thigh for the long-acting type.
When you’re injecting insulin, the needle should go deep enough to reach the tissue under the skin but not into the muscle below. This is something your diabetes nurse will have explained and shown to you. If you are still not sure, ask for some more guidance, as it’s important to get it right.
Why is it important? If insulin is injected into muscle, it is taken up faster, and the effect on your blood sugar will be more difficult to predict. Using a shorter needle, for example, one that’s 6–8 mm long, may prevent this.
Always use a new needle for each injection and make sure you dispose of your needles safely in a sharps bin.
There are many different makes and types of injection devices that can be used to give insulin injections. Your diabetes care team can help you choose a device that fits your needs. They will also show you how to use it.
There are three types of injection devices:
A pre-filled insulin pen can be used several times. Once the insulin in the pen is finished, the pen can be discarded.
Durable pen injector devices can be re-filled with insulin cartridges. Each cartridge has enough insulin for several injections.
With a bottle (known as a vial) of insulin, you use a conventional syringe and needle to draw up the insulin from the bottle before taking each injection.
Store extra insulin in the fridge but not too near the freezing compartment. Never store it in the freezer.
If stored correctly, insulin will last until the expiry date. The expiry date is printed on the package. Do not use any insulin which has passed its expiry date.
Insulin in use should be kept at room temperature. This means below 25 or 30 degrees Celsius, depending on the type of insulin you use. It should NOT be kept in the fridge.
The insulin lasts for 4-6 weeks at room temperature without any problems. The exact period of time you can keep using each insulin container will be shown in the instructions in the package. Please check the patient information leaflet for your specific insulin.
Always protect your insulin from direct sunlight and high temperature.
INS/016/0809
Last updated: August 2009