Insulin Pen Technology

Since the discovery of insulin in 1921, insulin injections by way of vial and syringe have been the mainstay of insulin delivery. In 1985 insulin injections were simplified when insulin pens became commercially available.1 Despite their many benefits, insulin pens are still underutilized. In the United States, only 15 % of insulin requiring patients use insulin pens.1

What is an insulin pen?

An insulin pen is a medical device used to inject insulin. Just as the name suggests, insulin pens look similar to an ink pen (an oversized ink pen).

An insulin pen contains a cartridge of insulin. Depending on the brand/type of insulin, these devices come as either a prefilled disposable pen or as a refillable pen which is non-disposable. Non-disposable insulin pens are loaded with an insulin cartridge, with the insulin cartridge being the disposable part of the pen. Insulin pens contain anywhere from 300 to 600 units of insulin, depending on the type of pen being used.

A pen needle tip is attached to the top of the insulin pen to allow for subcutaneous (beneath the skin) injection. At the bottom of the insulin pen there is a dial and a plunger. The dial allows the user to select the insulin dose and the plunger, once pressed, allows the insulin dose to be delivered.

What are the benefits of insulin pens over a vial and syringe?

  • Insulin pens are considered more convenient, easier to transport and use, all of which help improve patient satisfaction and compliance.
  • Insulin dosing is more accurate
  • Easier to use for those with impaired manual dexterity
  • May be consider more socially acceptable as insulin pens are more discreet1

Why aren’t more people using insulin pens?

  • Many health care providers are unaware of the advantages offered by insulin pens.3
  • The cost of insulin cartridges and prefilled insulin pens is often greater than the cost of insulin vials.
    • Diabetes educator, Teresa L. Pearson, brings up two important points:
      • “depending on coverage, if a patient has a copay per box of pens, the cost to the patient may actually be less per unit of insulin”
      • “most pen devices have good formulary coverage”
      • Government-sponsored health insurance plans, such as Medicaid or Medicare, may require a prior authorization for insulin pens. (Prior authorization:health care provider must contact the health plan before prescribing certain medications)

Insulin Pens Currently Available

(*This list is not all-inclusive. Please refer to manufacturer for complete details)

Steps for Proper Injection

  • Ensure insulin is at room temperature.1
  • Cleanse injection site with an alcohol swab. (Allow alcohol to air dry before injecting insulin)
  • Clean top of insulin pen with alcohol swab
  • Attach pen needle to insulin pen
    • A note about pen needle tips: “Most pen needles are between 4 and 5 millimeters long, though they can be as long as 12.7 millimeters. There’s no real benefit to using a needle longer than 8 millimeters.” 2
  • Prime insulin pen. This is also referred to an “air shot”. Dial to 2 units. Holding pen upright, push the plunger; a stream of insulin should shoot into the air.  Priming the insulin pen will help ensure that the full dose is delivered.
  • Hold insulin pen with palm and inject pen needle at a 90-degree angle
    • The pen needle is injected into the subcutaneous tissue.
    • Very lean individuals may need to pinch up the skin or inject at a 45-degree angle to prevent injecting into muscle (Injecting into muscle may increase the rate at which insulin get absorbs thus increasing the risk of hypoglycemia).
  • Press thumb on plunger
  • Hold thumb on plunger and count to 10
  • Remove pen needle
  • Remove pen needle tip from insulin pen (Pen needles tips are for single use)
  • Dispose of pen needle tip in a sharps container

Insulin Pen Storage Guidelines:

  • Insulin should be stored at room temperature. Avoid temperature extremes as such temperatures (both hot and cold) may reduce insulin strength and quality. Extra insulin pens/cartridges may be stored in the refrigerator until their expiration date.
  • On average, insulin pens are good for 28 days after initial use. Check the manufacturer packaging for information specific to the insulin pen/cartridge being using.

Do you use an insulin pen? Please share experience with the community

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