Insulin is classified based on how quickly it takes effect, when it has maximal effect and how long it last. There are four categories:
- Rapid acting should be taken just before or just after eating. It begins to lower blood glucose in less than 15 minutes. It continues to work for about 2 to 5 hours. Common rapid acting insulins include Insulin glulisine (ApidraÒ), insulin lispro (HumalogÒ), and insulin aspart (NovoLogÒ). FiaspÒ is a new rapid acting insulin aspart with a 2.5 minute onset.
- Insulin human inhaled powder (AfrezzaÒ) mealtime insulin has a 3-7 minute onset and 1.5 to 3 hour duration.
- Short acting should be taken 30 minutes before a meal. It begins to lower blood glucose within 30 minutes to 1 hour. It lasts for about 5 to 8 hours. Common types are Humulin RÒ and Novolin RÒ.
- Intermediate acting has an effect for 10-24 hours, depending on the type, so it is typically only taken once per day. Common types are NPH such as Humulin NÒ with a duration of 12-16 hours and Novolin NÒ with a duration up to 24 hours.
- Long acting has an effect for 24 hours, depending on the type, so it is only taken once per day. This basal insulin has no peak. It is taken once per day. Common types include insulin detemir (LevemirÒ) and insulin glargine (LantusÒ) or (BasaglarÒ).
- Ultra-long-acting is taken once a day. Insulin degludec (TrisebaÒ) has an onset of 1 hour and a duration of at least 42 hours. Insulin glarnine (ToujeoÒ) has an onset of 6 hours and duration of 36 hours.
Insulin can be packaged in vials, pens/cartridges, or inhaled. There are also pre-mixed insulins that contain a combination of insulin types described above. Hypoglycemia is a potential side effect of insulin. Education to prevent and treat hypoglycemia is necessary for individuals taking insulin.
Characteristics to consider with your insulin include
- Onset- how quickly it will start working
- Peak- the time when the insulin is most effective in lowering blood glucose. Note that basal insulin has no peak so is always the same in terms of effectiveness.
- Duration- how long it continues to have an effect on your blood glucose
- Strength- the most common strength is U-100, which means it has 100 units of insulin per 1 milliliter of fluid. Insulin at U-500 and U-40 are available in some countries.