Insulin Analogs

An analog refers to something that is “analogous” or similar to something else. Therefore, “insulin” analogs are analogs that have been designed to mimic the body’s natural pattern of insulin release. These synthetic-made insulins are called analogs of human insulin.
 
However, they have minor structural or amino acid changes that give them special desirable characteristics when injected under the skin. Once absorbed, they act on cells like human insulin but are absorbed from fatty tissue more predictably.

Insulin analogs

Rapid-acting injected insulin analog

The fastest-working insulins are referred to as rapid-acting insulin:
  • Aspart
  • Glulisine
  • Lispro
  • Fiasp
  • Lyumjev

These insulin analogs enter the bloodstream within minutes, so it is important to inject them within 5 to 15 minutes of eating. They have a peak action period of approximately 75 minutes, and fade completely after about four hours. Higher doses may last slightly longer, but will last no more than five or six hours. Rapid acting insulin analogs are ideal for bolus insulin replacement. They are given at mealtimes and for high blood glucose correction. Faster versions of rapid-acting insulin analogs are also available. They increase the speed at which insulin is absorbed and thus have a slightly quicker onset and shorter duration of action.

Rapid-acting insulins are used in insulin pumps, also known as continuous subcutaneous insulin infusion (CSII) devices. When delivered through a CSII pump, the rapid-acting insulins provide the basal insulin replacement, as well as the mealtime and high blood glucose correction insulin replacement.

** insert time action profiles of insulin graphic**

Rapid Analog (monomer) Peak Time: 1-2 Hours

Afrezza, or inhaled insulin, is also available and has an even quicker onset and shorter duration due to its mode of administration through the lungs.

Long-acting injected insulin analogs

The insulins that work for the longest period of time are referred to as long-acting insulin. They provide relatively constant insulin levels that plateau for many hours after injection. Sometimes these insulins are called “peakless” insulins. They have an onset of action within 60-90 minutes, maximum effect in around 5 hours that gradually wanes over the next 12-36 hours:
  • Insulin detemir (Levemir®)
    • Detemir is usually injected twice a day.
  • Insulin glargine (Lantus®, Semglee®, Basaglar®)
    • Glargine is usually injected once daily but may be given twice daily if needed.
  • Insulin degludec (Tresiba®)
    • Degludec is injected once daily.

The long-acting insulin analogs are suitable for background or basal insulin replacement. It is important to take the basal insulin at the same time(s) every day to maintain the most predictable levels of basal insulin.

These long-acting insulins can't be mixed in the same syringe with other insulins – this could change how the insulin works!

Insulin glargine is a commonly used basal insulin.  It forms clusters when it is injected under the skin, as pictured below.  As the individual insulin units detach from the cluster, the insulin analog can be absorbed into the bloodstream. The slow break-up of the insulin cluster gives insulin glargine its long action.

Insulin Glargine