Fast-and Short-Acting Bolus Insulins

Types of insulin used to support background therapy

Vials of insulin.
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When it comes to taking insulin, there are several forms of the hormone which are differentiated by the speed in which they act. This, in turn, determines when and how each form is used. Anyone with type 1 diabetes, and some with type 2 diabetes, need to take insulin to more effectively process the glucose from food.

With type 1 diabetes, this is because the pancreas can no longer make the hormone.

With type 2 diabetes, the pancreas is able to make insulin, but the body no longer responds to it as it should and will need additional insulin to compensate.

Role of Long- and Short-Acting Insulins

Insulin is given in long-acting forms to ensure more a steady regulation of insulin levels, while short-acting forms aim to lower sudden spikes in blood sugar.

  • We refer to the longer-acting form as basal insulin (basal meaning "background") since it works in the background to the keep the blood sugar stable.
  • Shorter-acting forms are called bolus insulin (bolus meaning "single dose") since it is meant to be taken specifically at meal times to keep blood sugar levels under control.

How Bolus Insulin Works

Bolus insulin refers to the extra amount of insulin the pancreas would normally produce in response to sugar (glucose) taken in through food. The level of production depends largely on the size and type of meal involved.

In persons with type 1 diabetes, the pancreas is no longer able to make insulin as the beta cells which produce the hormone have largely shut down. Because of this, bolus insulin will be used, when needed, to compensate for this loss.

To ensure the ongoing normalization of blood sugar levels, many people will often follow a basal-bolus regimen in which several shots of each are taken throughout the day for both background and mealtime maintenance purposes.

Bolus insulin is delivered by injection, while basal insulin can be delivered either by injection or a continuous, 24-hour insulin pump.

Types of Bolus Insulin

There are two types of bolus insulins: rapid-acting (also known as fast-acting) and short-acting insulins (also known as regular insulin). The four main difference between these types of insulin are:

  • How quickly they reach the bloodstream
  • When they begin to reduce the blood sugar (onset action)
  • When they begin to work their hardest (peak action)
  • How long they last for (duration)

Rapid-acting bolus insulins can start lowering your blood sugar within five to 15 minutes. Short-acting insulins, by contrast, have an onset of about 30 minutes. Both forms have a duration of up to five hours.

(In 2015, an inhaled form of rapid-acting insulin, called Afrezza, became available in the U.S. However, consumer, and provider apathy led the manufacturer to cease marketing efforts soon after the product's release.)

Types of Rapid-Acting Bolus Insulins

There are currently three rapid-acting insulins approved by the U.S. Food and Drug Administration (FDA):

  • Novolog (insulin aspart injection)
    • Onset action: five to 15 minutes
    • Peak action: one to three hours
    • Duration: three to five hours
  • Apidra (insulin namglulisine injection)
    • Onset action; five to 15 minutes
    • Peak action: 30 to 90 minutes
    • Duration: three to five hours
  • Humalog (insulin lispro injection)
    • Onset action; five to 15 minutes
    • Peak action: 30 to 90 minutes
    • Duration: three to five hours

Types of Short-Acting Bolus Insulin

There are currently two short-acting insulins approved by the FDA. Both are classified as "regular" insulin using the connotation (R).

  • Humulin (R)
    • Onset action: five 15 minutes
    • Peak action: two to four hours
    • Duration: five to eight hours
  • Novolin (R)
    • Onset action: five 15 minutes
    • Peak action: two to four hours
    • Duration: five to eight hours

    Source:

    American Diabetes Association. "7. Approaches to Glycemic Treatment." Diabetes Care. January 2016; 39(Suppl 1): S52-S59.

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