Insulin pens and insulin pumps: tools for scientific blood sugar management

What is an insulin pen?

What are the commonly used types? An insulin pen is an insulin injection device, slightly larger than a fountain pen. Insulin is contained in the pen vial, making it portable. To use, simply remove the cap for injection, making it convenient. It uses a special cartridge-type insulin with a concentration different from regular insulin: U-100 (100 U/ml) (regular insulin has a concentration of U-40, or 40 U/ml, with each vial containing 400 U). Commonly used types include:

① Disposable insulin pens: These are for single use only. After use, the pen and cartridge are discarded and replaced with a new one. These pens are simple and hygienic. Currently, NovoRapid refillable, NovoRapid 30 refillable, and Lantus pre-filled pens are used in my country.

② Reusable insulin pens: After the cartridge is used up, it is replaced for reuse. Insulin pens can be used for many years, even a lifetime. Currently, the main type of insulin pen available in my country, either for purchase or with a prescription from a hospital, is the insulin pen. Different brands of insulin pens vary in appearance and operation. When purchasing, you should refer to the instructions and learn how to use it with the help of a doctor, pharmacist, or nurse.

How to use an insulin pen?

The correct steps and precautions for using an insulin pen are as follows:

① Matching the pen and cartridge: Currently, insulin pens sold in the domestic market include Novo Nordisk, U-Band, Dexter, and Dongbao pens. First, you need to know which manufacturer's product you are using, and then you must use the matching insulin cartridge produced by that manufacturer. Before injection, prepare the cartridge, needle, insulin pen, 75% medical alcohol, and medical cotton swabs.

② Checking the expiration date and installing the cartridge and needle: Check the properties of the medication in the cartridge, looking for crystals, flocculent matter, etc., and whether it has exceeded its expiration date. In principle, the needle should only be used once. Reusing the needle can cause burrs and barbs, which can lead to skin bleeding, pain, and an increased chance of skin infection. The needle may even break off inside the skin. ③ Air Expulsion: Hold the pen vertically, turn the dose selection knob to "2" and then push it to "0" to expel one drop of insulin. If no insulin is expelled, repeat this procedure until one drop is expelled. If using intermediate-acting insulin or premixed insulin, invert the pen to mix the medication before expelling air. Air expulsion must be performed each time a new cartridge and needle are inserted.

④ Injection Method: Before each injection, check that there is a sufficient dose of insulin. If the insulin to be injected is a suspension, invert the insulin pen approximately 9 times until the medication becomes a uniform white suspension before injection. During injection, gently pinch the skin with your left hand, hold the insulin pen in your right hand, and inject the medication. After injection, leave the needle under the skin for at least 5 seconds, continue holding the injector, and after removing the needle, press the injection site with a dry cotton swab for at least 3 minutes.

⑤ Post-Injection Handling: After injection, replace the inner needle cap, unscrew the needle, discard the used needle, and replace the pen cap. ⑥ Insulin Storage: Unopened insulin cartridges can be stored at 2-8℃ (in a refrigerator). Once opened, cartridges inserted into an insulin pen can be stored at room temperature (<25℃) for one month. Insulin cartridges should not be frozen, as frozen insulin easily loses its biological activity. Insulin pens should also not be exposed to sunlight. Generally, the shelf life of various insulin pens is 1-2 years after manufacture.

What is an insulin pump?

An insulin pump is about the size of a pager. It contains a reservoir for short-acting insulin, an external display screen, and buttons for setting the pump program. A sensitive drive motor slowly pushes insulin from the reservoir through the infusion catheter into the subcutaneous tissue. The insulin pump mimics the secretion of insulin by pancreatic beta cells and can be used year-round, releasing insulin 24 hours a day. It has two release rhythms: basal release and pre-meal bolus (advanced release). Patients simply need to set the release program according to their own needs. The timed release of small doses of insulin is called the "basal release rate." In this way, between meals and at night, insulin can control blood sugar within the required range. At each meal, patients can also receive a "pill-sized dose" of insulin, a large pre-meal dose, to match the amount of food consumed. Insulin pumps are typically clipped to a belt or carried in a pocket. Various clips and accessories make insulin pumps easy to carry and use in different situations.

How to Choose Insulin? Different types of insulin have different onset times and durations of action. Long-acting insulin, while having a slower onset, has a longer duration of action, providing prolonged blood sugar control. Short-acting insulin, while having a faster onset, has a very short duration of action, controlling blood sugar only for a short time. Intermediate-acting insulin falls in between. Therefore, each patient should choose the appropriate insulin type based on their condition. Initially used patients who have never used insulin before generally prefer short-acting insulin. Patients with postprandial hyperglycemia and those in the acute phase of infection should also use short-acting insulin. For patients taking oral hypoglycemic agents, injecting intermediate-acting insulin before bedtime can further control blood sugar. In addition, to reduce the frequency of insulin use, intermediate-acting insulin can be used in combination with short-acting insulin or premixed insulin preparations can be used, while long-acting insulin is often used in combination with short-acting insulin because it is not effective when used alone.