Easy-to-read medicine information about insulin – what it is, how to use insulin safely and possible side effects.
Insulin in our body is made by our pancreas so if the insulin-producing cells in our pancreas are damaged, (such as in type 1 diabetes and over time in type 2 diabetes) then we need to replace this insulin to help our bodies function well.
Insulin cannot be taken by mouth as a tablet because it is inactivated by our digestive enzymes.
Insulin needs to be taken as an injection, just under the skin so it can be absorbed into the bloodstream and travel around the body to help glucose get into our cells and give us the energy we need for daily life.
Types of insulin
There are different brands of insulin available in New Zealand and these are grouped by the time it takes for the insulin to work.
Type of insulin
Rapid acting insulin
Usually works straight away, so it is injected just before or with food. Its effect lasts 1 to 2 hours.
Short acting insulin
Usually works within 15 to 20 minutes, so inject each dose 15 to 20 minutes before you eat. Its effect lasts 3 to 4 hours.
Intermediate and long acting insulin
Usually works after about 1 hour. Its effect lasts all day and may be injected once or twice a day.
Levemir (not subsidized in New Zealand)
These insulins are a mixture of short and intermediate acting insulins.
These may be injected twice a day, in the morning, before breakfast and before dinner. Pre-mixed insulin must be injected before dinner, rather than before bedtime.
NovoMix 30 FlexPen
Humalog Mix 25
Humalog Mix 50
Your doctor or nurse will work with you to find the best insulin to meet your needs. This can be made up of a rapid acting insulin and an intermediate or long acting insulin, or it can be insulin and tablets.
How to use insulin
The timing of your insulin in relation to food and exercise is important. Your doctor or nurse will advise you when it is best to use your insulin.
It is best to avoid hot showers or baths within 30 minutes of an insulin dose.
Your doctor or nurse will advise what to do if you miss a dose of insulin.
Drinking alcohol can affect blood glucose and the dose of insulin may need to be changed. Avoid or limit alcohol intake.
If you are unwell and not eating as you usually do, your insulin dose may need to be changed. Contact your doctor or nurse for advice.
Insulin should be injected into the fatty tissue under the skin. The abdomen or tummy area, about 5 cm away from your belly button, is usually a good place. It is easy to reach and insulin absorbs well from this area.
Other areas such as the buttocks, thigh or outer arm are usually not preferred because they are harder to reach, insulin is absorbed slower and absorption may be affected by exercise.
Move injection sites so that the skin does not become lumpy. Lumpy skin can affect how your body absorbs insulin. You can move from one side of your abdomen to the other side each time.
Unopened insulin can be stored in the fridge until it is used.
Do not store insulin in the freezer.
Once opened, insulin vials, cartridges or pre-filled pens can be kept at room temperature but must be discarded after 28 days.
Side effects when using insulin
Sometimes insulin may lower your blood sugar too much – called hypoglycaemia. This may cause you to feel weak, faint, dizzy, drowsy or irritable. You may get a headache, tremor (shakes) or blurred vision. If this occurs, drink something sweet such as a small glass of sweetened soft drink, or fruit juice, or eat something sweet such as lollies. Make sure your family and friends know what to do too. Tell your doctor or nurse if this happens a lot. Your dose of insulin may need to be changed.
Pain or redness at the injection site – change the injection site and contact your doctor or nurse if the pain or redness continues.
Insulin interacts with some other medications and herbal supplements so check with your doctor or pharmacist.
It is important to inject insulin correctly. Ask your diabetes nurse, pharmacist or doctor for advice. The following information is a guide.
Priming your insulin pen
Priming your insulin pen means removing any air from inside the insulin cartridge, to ensure you get an accurate dose. It also ensures your pen is working correctly. It is important to prime your insulin pen with at least 2 units of insulin before every injection.
To prime your pen, use the dose selector knob to dial 2 units.
Hold your pen with the needle pointing up, into the air.
Tap the cartridge gently to collect air bubbles at the top.
Push the dose selector knob until it stops and zero is seen in the dose window. Hold this for a few seconds.
You will see drops of insulin at the tip of the needle.
If you do not see insulin drops, then repeat the process, or change the needle and repeat the priming steps.
Note: tiny air bubbles are normal and will not affect your dose.
If 2 units are used for priming each injection, this can add up to between 1-3 additional 3mL cartridges in 3 months. Tell your doctor to prescribe enough insulin to allow for priming with each injection.
Selecting your dose
Wash your hands with soap and water before injecting.
Use a new needle for every injection to minimise pain. Reusing needles can lead to bruising, bleeding and infection.
Dial the number of units you are going to inject by turning the dose selector knob.
Inject insulin into the fatty tissue just under the skin, in the abdomen or tummy area, about 5 cm away from your belly button. Read more about injection sites below.
Hold the pen in your hand with your thumb or finger on the dose selector knob at the end of the pen.
If you are using an 8 mm (or longer) needle, pinch up your skin on your stomach then slide the needle into the skin fold at a 90º angle. If your needle is less than 8 mm long, don't pinch up your skin.
Push the dose selector to inject the dose, relatively slowly, as far as it will go. The dose window should read zero.
Leave the needle in for 6 seconds.
Continue to push in the dose selector knob while you remove the needle.
Storing your insulin pen
Insulin pens that you are currently using are not kept in the fridge.
Spare pens can be kept in the fridge but once they are in use, and have a needle attached, they should be kept out of the fridge.
If they remain in the fridge, insulin can leak out. Also, pens that are frequently moved in and out of the fridge can accumulate air bubbles.
Insulin should be injected into the fatty tissue under the skin. The abdomen or tummy area, about 5 cm away from your belly button, is usually a good place. It is easy to reach and insulin absorbs well from this site.
Other areas such as the buttocks, thigh or outer arm are usually not preferred because they are harder to reach, insulin absorbs slower and absorption may be affected by exercise.
Do not inject your dose into the muscle, this can be painful and affects the absorption of insulin in the body.
If you think you are injecting into the muscle, talk to your diabetes nurse, pharmacist or doctor.
Move injection sites so that the skin at the site of injection does not become lumpy. Lumpy skin can affect how your body absorbs insulin. You can move from one side of your abdomen to the other side each time.
Do not inject insulin into any scar tissue.
Tips to minimise pain when injecting insulin
Injecting insulin can cause discomfort, but it should not be painful. Here are a few tips to minimise pain when injecting:
Make sure your stomach muscles are relaxed.
Use insulin and a needle at room temperature.
Push the needle in quickly and hold for about 10 seconds before removing the needle.
Try not to wiggle the needle as you’re injecting or removing it.
Always use a new needle for every injection.
Move the site of injection – do not inject into the same site you last used. This will help avoid scarring and reduce pain.
The following links provide more information on injecting insulin. Be aware that websites from other countries may have information that differs from New Zealand recommendations.