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People with diabetes use insulin pens to inject insulin, a vital hormone for people who have diabetes. They contain a cartridge, a dial to measure dosage, and a disposable needle.
The pens allow more simple, accurate, and convenient delivery than using a vial and syringe.
Not every person with diabetes will need to take insulin. However, those that do sometimes find that sticking to an insulin schedule can be demanding, disruptive, and draining.
Some people prefer insulin pens as a way to make taking insulin less intrusive and inconvenient.
In this article, we look at the types of insulin pen, how to use them, and the benefits and disadvantages of choosing an insulin pen over a vial and syringe.
Different brands and models of insulin pen are available. Most fall into two distinct categories: disposable and reusable.
- A disposable pen: This contains a prefilled insulin cartridge. Once used, the entire pen unit is thrown away.
- A reusable pen: This contains a replaceable insulin cartridge. Once empty, a person discards the cartridge and installs a new one.
A person must replace the disposable needle after each injection of insulin. With proper care, reusable insulin pens can last for several years.
Follow the instructions for using an insulin pen closely, as they vary slightly in use between manufacturers.
People who have never used an insulin pen before may need to seek advice from their doctor before first use.
Here is a general guide for insulin pen use. However, you may find that some steps are different on purchasing a particular brand. Clarify how to use any specific insulin pen with a doctor.
The overall steps are as follows:
- If using a new pen, remove it from the refrigerator 30 minutes before use.
- Check the expiration date and that the insulin is the correct type and strength.
- If necessary, insert a new cartridge into a reusable pen.
- Mix the insulin by gently rolling the pen between the palms of the hands.
- Tilt the pen up and down, until the insulin is clear and smooth.
- Wash hands thoroughly.
- Remove the pen cap, and clean the top with alcohol.
- Firmly attach a new needle to the pen.
- Remove the needle caps while retaining the outer cap.
- Turn the dial to the correct dose.
- Double-check the dose before injecting.
- Clean the chosen injection site with alcohol, and allow the area to dry.
- Do not inject into areas that have wounds or bruising.
- If possible, vary the injection site to avoid lumps or swelling.
- Hold the pen to the injection site, being sure to following any instructions on the packaging.
- Press the injection button.
- Wait for 10 seconds before removing the needle from the skin.
- Press on the injection site for 5 to 10 seconds, but do not rub the skin.
- Remove and safely dispose of the needle.
- Replace the cap on the pen.
Unopened insulin and new insulin pens require storage in the refrigerator.
However, once a person has opened insulin, they must keep the hormone at room temperature and out of direct sunlight.
According to the American Diabetes Association, when a person stores insulin at room temperature, it lasts for around 28 days.
Expiry date depends on the type of insulin that the pen contains. It is always important to check the date and follow any instructions for storage and use.
Expired or improperly stored insulin may not be as effective as it should be.
Insulin pens should never be stored with the needle attached, even if it is a new needle. This can affect the cleanliness and sterility of the needle, interfere with the insulin dose given, and increase the risk of infection.
Choosing a brand, model, and category of pen will depend on several factors. Discuss this with a doctor before making any purchase.
Some general considerations about the pen include:
- the type and brand of insulin available
- the size of insulin dose it can hold
- the increments by which a person can increase the dose of insulin
- material and durability, if choosing a reusable pen
- how it indicates remaining insulin levels
- ability to correct dose levels that are put in wrong
- size of the numbers on the dose dial
- level of dexterity required to use the pen
Needle length and thickness are other considerations for choosing an insulin delivery product. Manufacturers measure the thickness of a needle using “gauge”. The higher the gauge, the thinner the needle.
Thicker gauges might cause more pain but also deliver insulin more quickly.
Needles can be between 4 and 12.7 millimeters (mm) in length. A shorter needle might reduce the risk of accidentally injecting insulin into the muscle instead of the fat just under the skin, or subcutaneous fat.
Research has highlighted the benefits of using insulin pens, particularly prefilled, disposable pens.
People with diabetes are happier using insulin pens than the vial and syringe technique, according to the ADA’s current standards of care.
One reason for this is that insulin pens have many features that make them safe and convenient. For example, one randomized, open label, crossover study that compared pen use with a vial and syringe regimen found that
In the vial and syringe group, only 19 percent were as confident that they were getting the right dose.
Other advantages include:
- ease of use, particularly for older adults and children
- the ability of a person with diabetes to fine-tune and deliver highly accurate doses using an insulin pen
- the portable, discreet, and convenient nature of the pens
- small and thin needle sizes that reduce fear and pain
- the ability to accurately pre-set doses using a dial
- time-saving benefits, due to prefilled and pre-set insulin levels
- memory features that recall the timing and amount of the previous dose
- a range of accessories to allow for easier storage and use
The ADA advises doctors to prescribe an insulin pen for people who have issues with finger dexterity problems and reduced vision. An insulin pen can support a more accurate dose of insulin than a vial and syringe.
“Smart” pens also exist that can calculate appropriate doses of insulin and provide a report on insulin usage for the user to download.
Although insulin pens provide many benefits, they also have some drawbacks, including:
- a restriction on using all types of insulin through a pen, for example on using mixtures of different types in one injection
- being available for self-injection only
- a higher cost than the vial and syringe method
- the wasting of some insulin with each use
- a lack of universal coverage by some insurance providers
While insulin pens might be more expensive than a vial and syringe, they are more convenient, less painful, and easily storable and transportable.
They essentially combine the vial and syringe, allowing greater dose accuracy and easier administration of doses.
Be sure to closely follow the instructions on the packaging and store insulin in a cool dry place once open.
Insulin alone can help manage diabetes, but maintaining a balanced diet and exercise regimen alongside any prescribed medications is an effective route to controlling blood sugar.
What other ways are there to take insulin?
Insulin is also available as an inhaled powder marketed under the brand name Afrezza.
It begins working about 15 minutes after inhaling a dose, with peak action in about 1 hour, then its effect continues for 2 to 4 hours, making it a convenient option for after-meal insulin dosing.