Insulin Pens: Features and How they Work

Today, insulin pens are one of the fastest, easiest, and most accurate methods of injecting insulin in diabetic patients.
Insulin Pens: Features and How they Work

Last update: 14 August, 2021

Insulin pens are the most widely used method of administering insulin to diabetic patients. They’re easy to use as well as accurate. What should you know about them? How do they work? To understand better, let’s first take a brief look at what insulin does and what happens in the body when someone has diabetes.

What is insulin?

The location of the pancreas in the body.

Insulin is a hormone that the pancreas produces. Its job is to regulate the amount of blood glucose, or sugar, in the body. Insulin can either be missing or unusable in diabetes patients. In fact, diabetes can be due to two different causes:

  • Your body doesn’t produce insulin (type 1 diabetes).
  • Your body doesn’t use the insulin you have even if you produce enough (type 2 diabetes).

Using artificial insulin is the main way to treat type 1 diabetes. How does artificial insulin work in the body? Note the following three aspects that are involved in how it works:

  • Onset time. The time that elapses before insulin reaches your bloodstream and begins to lower your blood sugar levels.
  • The maximum peak effect. This is the point when the insulin is at its most powerful to be able to reduce blood glucose.
  • Effect duration. This is how long the insulin does its job of lowering blood sugar levels.

Types of insulin

Insulin types are classified according to how long they’re effective and how long they take to start working. Therefore, you’ll find the following types:

  • Rapid-acting insulin. This type takes effect within 15 minutes after injection. It reaches its maximum effectiveness at one hour and lasts for two to four hours.
  • Regular or short-acting insulin. This reaches the bloodstream within 30 minutes after injection. Its maximum effect is achieved after two or three hours and is effective for between three and six hours.
  • Intermediate-acting insulin. It reaches the bloodstream between two and four hours after injection. It reaches its maximum effect four to 12 hours after injection. Intermediate-acting insulin is effective for approximately 12 to 18 hours.

Types of insulin pens

There are two types of insulin pens.

  • Disposable pens. You can only use them until the insulin in the cartridge runs out, then you have to throw them away.
  • Reusable pens. These allow you to change the cartridge when the insulin runs out.

You can adjust the amount of insulin you inject by moving a dial on the pen. That way you can adjust your dose according to your current needs. For safety, you should change the needle each time you use the pen.

Advantages and disadvantages of insulin pens

What are some of the advantages of using insulin pens? Well, they’re faster and easier to use than traditional syringes because the dose is already prepared. In addition, you can inject insulin with more precision thanks to the dosing system. The size and shape of the pens are also advantageous because the pens are easy to use and transport.

However, insulin pens also have disadvantages. For instance, you can’t mix different types of insulin. Another disadvantage is that you need to prime and test them before each new dose, which means you’re wasting a small amount of insulin.

How does an insulin pen work?

Insulin pens, both disposable and reusable, have a needle that you use to inject yourself. If you’re using reusable pens, you’ll need to change the needle after each use.

Steps to follow

Before injecting yourself, make sure you wash your hands. Adjust the dial to the number of insulin units you require. Then point the pen with the needle upwards, and press until you see a drop come out. This drop is to check it’s working correctly.

Clean the skin where you’re going to inject and double-check the dial is at the right dosage. Next, squeeze the skin where you’re going to inject and push the needle in quickly and firmly. Then squeeze the pen with your thumb to inject the dose. When you’ve injected it, discard the needle safely.

How to store insulin pens

To properly store insulin pens, you should take into account two things: the temperature and the time you’re storing them. Since they should be kept at between 36 and 46°F, the refrigerator would be a good place. Also, keep in mind that insulin shouldn’t be exposed to sources of intense light or heat.

Make sure you don’t keep insulin below 35°F as that’s when it can start to lose its effectiveness. However, if you keep it in the fridge it should be fine to use until the expiration date on the package.

As we’ve seen, insulin pens are the easiest, quickest, and most accurate method of administering insulin to diabetic patients. Remember that you can use insulin pens for up to 30 days after the first use.

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  • Cohen, M. R. (2015). PLUMAS DE INSULINA ¡No las reutilicen! Nursing (Ed. Española). https://doi.org/10.1016/j.nursi.2015.06.007

  • Sacylite. (2005). Insulinas : clasificación y usos. Informacion Terapeutica.

  • Pereira, L. O., Francischi, R. P. de, & Lancha Jr., A. H. (2005). Obesidade: hábitos nutricionais, sedentarismo e resistência à insulina. Arquivos Brasileiros de Endocrinologia & Metabologia. https://doi.org/10.1590/s0004-27302003000200003