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Insulin is classified according to how long it works in the body. There are five different types of insulin, ranging from short to long acting. Some insulins are clear in appearance, while others are cloudy.
Often people need varying amounts of both short and longer acting insulin. However, everyone is different and will respond differently to the insulin they take in the management of diabetes.
Many different devices are available to inject insulin. Discuss the options with your doctor or diabetes educator.
Methods of taking insulin by mouth are still in development. The first inhaled insulin, which had been launched in the USA and Europe, has recently been removed from the overseas market.
Types of insulin
The five types of insulin include:
- Rapid onset–fast acting insulin
- Short acting insulin
- Intermediate acting insulin
- Mixed insulin
- Long acting insulin.
Rapid onset–fast acting insulin
Rapid onset–fast acting insulin always looks clear. It is fast acting and starts to work within one to 20 minutes. It peaks about one hour later and lasts from three to five hours. When you use this type of insulin, you must eat immediately after you inject.
The three rapid onset–fast acting insulin types currently available are:
- NovoRapid (insulin aspart)
- Humalog (insulin lispro)
- Apidta (insulin gluisine).
Short acting insulin
Short acting insulins always look clear. They begin to lower blood glucose levels within half an hour, so you need to have your injection half an hour before eating.
Short acting insulin has a peak effect at two to four hours, and lasts for between six and eight hours. Short acting insulin types currently available include:
- Actrapid
- Humulin
- Hypurin Neutral (bovine – highly purified beef insulin)
- Hypurin Neutral (porcine – highly purified pig insulin). Available only via SAS (Special Access Scheme) and not PBS listed.
Intermediate acting insulin
Intermediate acting insulins always look cloudy. They have either protamine or zinc added to delay their action. These insulins begin to work about 90 minutes after you inject, peak at four to 12 hours and last for 16 to 24 hours.
Intermediate acting insulins currently available include:
With protamine added – Protaphane, Humulin NPH, Hypurin Isophane (bovine), Hypurin Isophane (porcine) via SAS.
Mixed insulin
Mixed insulin always looks cloudy. It contains a pre-mixed combination of either a rapid onset–fast acting or a short acting insulin and intermediate acting insulin. This makes it easier because two types of insulin can be given in one injection.
If the insulin is ‘30/70’ then it contains 30 per cent of quick acting and 70 per cent of intermediate acting insulin. ‘50/50’ means 50 per cent of each.
Before injecting a mixed or other cloudy insulin, you must gently roll the vial or pen between the palms of your hands and/or rock it slowly to make sure the different strengths of insulin are evenly distributed.
The mixed insulins currently available include:
- With rapid acting insulin – NovoMix 30 (30% Rapid, 70% Intermediate), Humalog Mix 25 (25% Rapid, 75% Intermediate NPH), Humalog Mix 50 (50% Rapid, 50% Intermediate NPH)
- Other mixed insulins – Mixtard 30/70, Mixtard 20/80 (discontinued from 01/09/07), Mixtard 50/50 and Humulin 30/70.
Long acting insulin
There are two kinds of long acting insulin, which both have a clear appearance.
They are:
- Lantus (glargine insulin) – has no pronounced peak action, which means the insulin is released into your bloodstream at a relatively constant rate. One injection can last 24 hours.
- Levemir (detemir insulin) – has a relatively flat action, can last up to 24 hours and may be given once or twice during the day.
Insulin injection devices
There are many different devices available to inject insulin. The main choices include:
- Insulin syringes
- Insulin delivery pens
- Insulin pumps.
Insulin syringes
Points to consider include:
- Insulin syringes are to be used with 10ml insulin vials.
- Syringes are manufactured in 30 unit (0.3ml), 50 unit (0.5ml) and 100 unit (1.0ml) measures. The size of syringe will depend on the insulin dose; for example, it is easier to measure a 10 unit dose in a 30 unit syringe and 55 units in a 100 unit syringe.
- Needles on the syringes are available in different lengths, ranging from 8mm to 12mm. Your doctor or diabetes educator will help you decide which syringe is right for you.
- Use each syringe once only.
- Syringes are free for people registered with the National Diabetes Service Scheme (NDSS).
Insulin delivery devices
Points to consider include:
- ‘Pen’ devices come in all shapes and sizes. An insulin cartridge (3ml, containing 300 units of insulin) fits into the device. When finished, a new cartridge is inserted. However, some pen devices are pre-filled with insulin and the whole device is disposable. Your doctor or diabetes educator will advise the right type for your needs.
- Durable devices include NovoPen 3, NovoPen Demi, HumaPen, HumaPen Luxura, Autopen 24 and HemaPen Demi.
- Pre-filled disposable devices include Innolet, FlexPen, Novolet and Solarstar.
- Many people find pen devices easier and more convenient than syringes.
- Those who have difficulties with their sight or arthritis may find the Innolet pre-filled device easier to use. Discuss this with your doctor or diabetes educator.
- Pen needles vary in length (5mm, 6mm, 8mm or 12mm). They also vary in thickness or gauge (28G, 29G, 30G or 31G). The higher the number, the finer the needle.
- It is recommended that the pen needle be changed with each injection.
- Pen needles are free for people registered with the National Diabetes Service Scheme (NDSS).
Insulin pumps
Points to consider include:
- The insulin pump is a small programmable device, about the size of a pager, that holds a reservoir of insulin. The pump is programmed to deliver insulin into the body through thin plastic tubing known as the infusion set or giving set.
- The pump is worn outside the body – in a pouch, on your belt or in your bra. The infusion set has a fine needle or flexible cannula that is inserted just below the skin (usually on the abdomen) where it stays in place for two to three days.
- Only short or rapid acting insulin can be used in the pump. Whenever food is eaten, the pump is manually programmed to deliver an amount of insulin into the body, similar to the way the pancreas does in people without diabetes. Between meals, a small and steady rate of insulin is delivered.
- The insulin pump isn’t suitable for everyone. If you’re considering using one, you must discuss it first with your diabetes health care team.
- The cost of insulin pumps is generally covered by private health insurance. The consumables required for use (such as cannulas, lines and reservoirs) are subsidised by the NDSS and cost approximately $20–$50 per month.
Storage of insulin
Unopened insulin vials or pen cartridges should be kept on their side in the refrigerator (between 2°C and 8°C), and away from the freezer or freezing coils. Once opened, insulin should be kept below either 25°C or 30°C (please refer to specific product information for the insulin that you use) and thrown away after 30 days, even if there is some insulin left.
Always check the expiry date and appearance of insulin before use. Insulin is destroyed when it has been exposed to direct sunlight, heat or allowed to freeze. In this case, it should not be used. Avoid leaving insulin in a car or any other place where the maximum recommended storage temperature will be exceeded.
Disposal of used syringes
Used syringes, pen needles and lancets must be disposed of in a sharps container that meets the Australian Safety Standards, is puncture proof and has a secure lid. These containers are usually yellow in colour and are available through pharmacies, councils and Diabetes Australia – Vic.
Procedures to dispose of sharps containers vary between the states and territories. Contact Diabetes Australia – Vic, your state government department of health or your local council for information.
Where to get help
- Your doctor
- Diabetes educator
- An accredited practising dietitian, contact the Dietitians Association of Australia
- Diabetes specialist
- Diabetes Australia – Vic Tel. (03) 9667 1777 or 1300 136 588
- International Diabetes Institute Tel. (03) 9258 5050
Things to remember
- There are five different types of insulin, ranging from short to long acting.
- Insulin injection devices include insulin syringes, insulin delivery pens and the insulin pump.
- Syringes and pen needles are free for people registered with the National Diabetes Service Scheme (NDSS).
You might also be interested in:
Diabetes.
Diabetes and healthy eating.
Diabetes insipidus.
Diabetes type 1 - juvenile diabetes.
Diabetes type 2.
Want to know more?
Go to More information for support groups, related links and references.
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