While alternative delivery methods continue to be researched, currently the only way to take insulin outside a medical setting in the United States is to inject it into the fatty tissue just below the skin. [Editor's note: Inhaled insulin was approved by the Food and Drug Administration in January 2006, but the only inhaled insulin to reach the market so far was discontinued in October 2007.] There are a few device options for doing this. The body areas used most commonly for insulin injections or to insert an insulin pump infusion set are the abdomen, buttocks, and thighs. (See “Insulin Injection Sites.”)
Insulin vial and syringe. The traditional way of taking insulin, using a syringe to draw insulin from a vial and inject it, is widely used in the United States. Technique is important when administering insulin with a syringe and is best learned with guidance from a health-care provider. Insulin syringes come in a variety of sizes to accommodate larger or smaller doses. Different lengths and gauges of needles are available, too. Your diabetes care team can help determine the right size syringe and needle for you.
Insulin pens and dosing devices. Insulin pens are usually the size of a large fountain pen, with other dosing devices about the size of a cell phone. Some are reusable, and some are disposable. Reusable insulin pens and devices use cartridges of insulin that are replaced as they are emptied. Disposable pens and devices are prefilled with insulin and discarded when empty. However, there is a limited time an insulin pen or device can be stored at room temperature. Check package inserts for specifics, and discard any cartridge or disposable pen or device that has been kept at room temperature longer than specified by the manufacturer.
The general procedure for injecting insulin with a pen or dosing device is as follows: A disposable pen needle is attached, the dose is dialed in, the needle is inserted into the skin, and a button on the pen is pressed to deliver the insulin. However, because the steps for using a pen are somewhat different from those for using a syringe, and because each device may work a little differently, it’s important to read the manufacturer’s package insert for specific instructions for each pen or dosing device.
Insulin pump. Insulin pumps are small, computerized, mechanical devices about the size of a pager. Insulin pumps deliver insulin by pumping rapid- or short-acting insulin through plastic tubing to a small catheter or needle that is inserted into the fat layer under the skin and taped in place. Pumps are generally programmed to deliver a steady, small dose insulin (basal insulin), and the user delivers larger amounts of insulin (bolus doses) based on the amount of carbohydrate in meals and snacks. To learn more, consultation with a physician and a diabetes educator with expertise in insulin pump therapy is recommended.
Insulin jet injectors. Jet injectors send a fine spray of insulin through the skin using a high-pressure air mechanism instead of a needle. If used incorrectly, injectors can be painful, injure the skin, and result in inaccurate dosing, so education and training on use of the injector device is important.
When insulin is prescribed, it is important that the method of delivery be individualized. Expense and insurance coverage may influence your choice, as may issues such as convenience and level of manual dexterity. Work with your diabetes care team to choose and learn to use the best method for you.
How am I doing?
Blood glucose self-monitoring lets you know how well your treatment is working. Your diabetes care team can help you decide when and how often to monitor and also how to interpret your monitoring results. Most insulin users should check their blood glucose level at least three times daily. Checking both before meals and after meals (one to two hours after eating) can be useful for fine-tuning bolus, or premeal, doses. Checking first thing in the morning, before meals, at bedtime, and in the middle of the night can assist with determining basal insulin needs. Any changes in insulin dosing should be made cautiously and with the direction of your diabetes care team.