Insulin is always taken by injection using either a small syringe, an insulin pen or insulin pump.
Insulin must be stored in a refrigerator although the vial or pen in use can be kept at room temperature for up to 28 days and must be discarded after this time.
Insulin is described as “Rapid-acting”, “Short-acting”, “Intermediate-acting”, “Long-acting” and “Mixed”.
Rapid and short-acting insulins are described as “bolus” and are clear in appearance.
Intermediate insulins are described as “basal” and cloudy in appearance. Long acting insulins are also basal insulins but clear in appearance.
Mixed insulins are a combination of rapid or short acting insulin with an intermediate acting insulin and are cloudy in appearance.
All types of insulin have a delayed onset of their peak activity and different durations of activity.
Rapid-acting – These insulins (Novo Rapid®, Humalog®, Apidra®) acts within 10-20 mins, has a peak action between 1-3 hours and lasts for up to 5 hours.
Short-acting – These insulins (Actrapid®, Humulin R®) take effect after about half an hour and last 3 to 4 hours.
Intermediate and long-acting – These insulins (Humulin NPH®, Protaphane® and Lantus®) take effect after about an hour and are designed to last “all day” but can be taken twice a day.
Premixed – These insulins (NovoMix 30 FlexPen®, PenMix 30®, PenMix 40®, PenMix 50®, Humulin 30/70®, Mixtard 30®, Humalog Mix 25®, Humalog Mix 50®) are a mixture of short and intermediate acting insulins and act just like two injections of the separate components taken at the same time.
Some 3ml cartridges contain a mixture of both short or rapid and intermediate acting insulin, and some short and intermediate acting Insulins may be mixed in a syringe prior to injection.
The following three brands of insulin are available in New Zealand.
Each brand has several different types with different presentations and durations. Most insulins come in both 3 ml cartridges for use in Insulin pens and 10 ml vials that are administered with syringes.
Your stock of insulin must be stored in a refrigerator between 2 - 8 degrees Celsius. This is normal operating temperature for a domestic refrigerator. DO NOT STORE in the DEEP FREEZE.
All insulin has an expiry date, and any unused should be discarded after that date whether or not it has been kept in the refrigerator.
PHARMAC describes “Stat” (from the Latin word “Statin” meaning “at one time”) items where 90 days supply can be uplifted “all at once”. For other items, including insulin, only 30 days supply can be uplifted at one time unless an exception is provided.