Types of Insulin

Types of Insulin

There are three main groups of insulin: Fast-acting, Intermediate-acting and Long-acting insulin.

Fast-acting insulin

• Is absorbed quickly from fat tissue (subcutaneous) into the bloodstream.
• Is used to control the blood sugar during meal and snack and to correct high blood sugars

Includes:
Rapid Acting Insulin Analogs (Insulin Aspart, Insulin Glulisine, insulin Lyspro): This has an onset of action of 5 to 15 minute, peak effect in 1 to 2 hours and duration of action that lasts 4-6 hours. In all doses whether it is small or large, onset of action and time to peak effect is similar. The duration of insulin action is affected by the dose. For this, a few units may last 4 hours or less, where 25 or 30 units may last 5 to 6 hours. It assume that these insulins have duration of action of 4 hours.
Regular Human Insulin: This has an onset of action of 1/2 hour to 1 hour, peak effect in 2 to 4 hour, the duration of action of 6 to 8 hours. Larger the dose of regular the faster the onset of action, the longer the time to peak effect and the longer the duration of the effect.

Intermediate-acting insulin

• Is absorbed more slowly, lasts longer
• Is used to control the blood sugar overnight, both in fasting and between meals

Includes:
NPH Human Insulin which has an onset of insulin effect of 1 to 2 hour, peak effect of 4 to 6 hours, duration of action of more than 12 hours. A very small dose will have an earlier peak effect and shorter duration of action and higher doses will have a longer time to peak effect and prolonged duration.
Pre-Mixed Insulin which is NPH pre-mixed with either regular human insulin or a rapid- acting insulin analog. This insulin action profile is a combination of the short and intermediate acting insulins.

Long-acting insulin

• Is absorbed slowly and has a minimal peak effect. It has a stable plateau effect that lasts most of the day.
• Is used to control the blood sugar overnight, in fasting and between meals

Includes:
Long acting insulin analogs (Detemir, Glargine) have an onset of insulin effect in 1 1/2-2 hours. This insulin effect plateaus over the next few hours and is followed by a relatively flat duration of action that lasts 12-24 hours for insulin detemir and 24 hours for insulin glargine.

Table: Comparison of insulin action

Insulin Types	Onset	Peak Hour	Duration	Appearance
Fast-acting
Regular	½-1 hr.	2-4	6-8 hr.	clear
Lyspro/ Aspart/ Glulisine	<15 min.	1-2	4-6 hr.	clear
Intermediate-acting
NPH	1-2 hr.	6-10	12+ hr.	cloudy
Long-acting
Detemir	1 hr.	Flat, Max effect in 5	12-24 hr.	clear
Glargine	1.5 hr.	Flat, Max effect in 5	24 hr.	clear

Graph: Time action curve of different insulin