Two landmark studies, the Diabetes Control and Complications Trial and the United Kingdom Prospective Diabetes Study, have shown the importance of glycemic control in patients with type 1 or type 2 diabetes to help minimize macrovascular and microvascular complications.1 Insulin is the drug of choice in many patients with diabetes used to help achieve glycemic control. However, insulin use in the United States is often underutilized because of the stigma and other barriers associated with the use of vials and syringes.
Throughout the years, insulin delivery systems have been ever-changing as new technology is developed. Insulin was first discovered in the 1920s and the delivery system utilized glass vials and reusable needles (sharpened with a pumice stone).1 Sterilization by boiling both the needles and syringes was required before use. Insulin vials and syringes were used for more than 60 years before the introduction of the insulin pen in 1985.1
The first insulin pen, NovoPen, was a metal reusable pen that was loaded with insulin cartridges.1 This allowed patients with diabetes to have the freedom to continue with their active lifestyles. Although there are a few reusable insulin pens still available, advancements in technology have since replaced the insulin reusable pen with disposable plastic prefilled pens (Table).2
Insulin pens are an option for many patients and can be simpler to administer compared with a vial and syringe. As insulin pen delivery devices are becoming more popular in the community, what do pharmacists need to know to tell their patients who are new to insulin pens?
Supplies Needed for Insulin Injection
If patients have previously been using the insulin vial and syringe method, then they are used to injecting themselves several times a day. But what if they are new to injection? First, patients need to understand what supplies they will need for self-injection before they are ready for the injection, including:
- Insulin pen (checking the label if prescribed more than 1 insulin pen)
- Pen needle
- Alcohol swabs
- Sharps container.
For patients using mixed insulin, remind them that their insulin will be cloudy and the insulin pen should be rolled 10 times between their hands and then flipped 10 times to make sure it is mixed thoroughly.3
Attaching the Pen Needle
There are several companies that manufacture pen needles. Pen needles are chosen by the healthcare provider based on their compatibility to the insulin pen, the gauge and length desired, and the cost. Newer recommendations have suggested that initial insulin therapy should begin with shorter needles. There is no clinical reason to recommend pen needles longer than 6 mm.4 (Remember: the bigger the gauge number, the thinner the needle.) The pen needle has several components: the outer shield, the inner shield, the pen needle, and the paper tab. The directions for installing the pen needle onto the insulin pen are5:
- Wash hands
- Pull cap off insulin pen
- Wipe rubber stopper with alcohol swab
- Remove the paper tab from the outer shield
- Push the needle onto the pen and twist until it is tight
- Pull the outer shield off and put it aside (it will be needed later to remove the needle from the pen)
- Pull the inner shield off. Remind your patient that a new pen needle should be used for each injection to help minimize the risk of infection and pain.
Priming the Pen
The pen needs to be primed prior to each use, because it ensures that the pen is working properly and removes any trapped air bubbles.4 The patient should dial 2 units on the pen and then press the button to shoot some insulin into the air (this is often referred to as an “air shot”). If the 2 drops of insulin are not seen after repeated priming and ensuring proper placement of the pen needle, the pen should not be used because this indicates that there may be a problem with the pen.
Sometimes when the pen needle is added to the pen some insulin drops may be seen, but this does not mean that the pen has been primed; priming still needs to be performed before the injection. Once the pen has been primed, the patient is ready to self-inject.
Steps for Injecting
1. Pick an injection site. The following sites are recommended for insulin injection because of the amount of subcutaneous tissue under the skin and the minimal number of nerve endings in these areas: the abdomen, the back of the arms, the outer thighs, and the upper buttocks or hips. Insulin absorption does differ depending on where it is injected. The fastest absorption occurs in the abdomen, followed by the back of the arms, the outer thighs, and the upper buttocks or hips. It is important to recommend that your patients rotate the injection sites daily. This will minimize the risk of hard lumps or extra fat deposits in the area forming as a result of repeated injection in the same area.5
2. Dial the dose. Using the dose knob, patients should dial the desired number of units to inject and view it in the dosing window. If the wrong dose is dialed, the dial can be turned in either direction until the correct number of insulin units are showing in the dosing window.5
3. Sterilize. Patients should wipe the injection area with an alcohol swab and allow the site to dry.5
4. To pinch or not to pinch? If the pen needle is 5 mm or less, then no pinching of the skin is required and the injection can go into the skin at a 90-degree angle. If the pen needle is longer than 5 mm, pinching the skin to avoid injecting insulin into the muscle is recommended. Remind your patients to make sure that the skin is pulled up and not the muscle. The injection can be at a 90-degree angle or a 45-degree angle to avoid going into the muscle.4,5
5. Press the injection button. Patients should press the injection button in all the way. Patients should slowly count to 5 before the insulin pen is removed to ensure that the entire insulin dose is delivered.5
6. Remove the needle from the insulin pen. Removing the pen needle from the insulin pen after the injection can prevent air from entering the insulin pen, infection resulting from bacteria entering the pen, and any leakage of insulin. To remove the pen needle, patients should place the outer needle cap onto the pen needle, use it to unscrew the needle from the pen, and then replace the insulin cap on the pen. If needed, the outside of the pen can be wiped with a damp cloth only.5
7. Dispose of the needle. Patients should dispose of pen needles properly in an approved sharps container. Local regulations should be followed for the proper disposal of used sharps containers.5
Injecting cold insulin can be painful. Therefore, storing the insulin pen that is currently being used at room temperature (cooler than 86°F) is recommended. If opened insulin is stored at room temperature, it will last about 1 month (some insulin will have different expiration dates—always check the package insert).6
It is a good idea for patients to date the insulin pen once it is opened and review it each time an injection is to occur to ensure that the expiration date has not passed. Once the insulin pen has been opened and stored at room temperature, it should not be put back in the refrigerator, as this can cause the insulin to shrink and air to enter the reservoir, resulting in the possibility that a proper dose may not be administered. Unopened insulin pens should be stored in the refrigerator (36°F to 46°F) until they are ready to use. Instruct your patients to take the new insulin pen out of the refrigerator well ahead of the first use to allow it to warm to room temperature.
As pharmacists, our role is to educate and encourage our patients. Insulin pens can be a great alternative for patients who are skeptical of insulin therapy. Knowing the proper injection technique will help patients minimize their fear of injecting and obtain greater glycemic control.
- Selam JL. Evolution of diabetes insulin delivery devices. J Diabetes Sci Technol. 2010;4:505-513.
- Consumer Guide 2014. Diabetes Forecast. January 2014. www.diabetesforecast.org/2014/Jan/images/insulin-pen-chart-2.pdf.
- University of Pittsburgh Medical Center. Insulin Pens: How to Give a Shot. www.upmc.com/patients-visitors/education/diabetes/pages/insulin-pens-how-to-give-a-shot.aspx. Accessed September 23, 2013.
- BD Diabetes Professional Resources. www.bd.com/us/diabetes/hcp/main.aspx. Accessed September 23, 2013.
- Becton, Dickinson and Company. BD Getting Started: Using Insulin Pens and Pen Needles. 2009.
- American Diabetes Association. Insulin Storage and Safety. www.diabetes.org/
syringe.html. Accessed September 23, 2013.