Selecting the Insulin Delivery Device
Insulin must be injected into the subcutaneous layer of fat. As of early 2008, the only available devices for administering insulin were syringes, insulin pens, and air-propelled “jet” injection devices. The type of delivery device you choose will depend on your insulin prescription, budget, insurance coverage, and comfort level.
Choosing a Syringe
Syringes are probably the least expensive option, are readily available at virtually any pharmacy, and are easy to operate. If your insulin regimen requires mixing two types of insulins that aren't commonly available in a premixed pen, a syringe is your only choice.
Syringes come in a variety of sizes, from 30 to 100 units (from 1/33 of a cc to 1 cc). Some come with half-unit markings. When you're shopping for syringes, make sure you choose a type with markings that are easy for you to read and that accommodate your regular dosage.
Insulin Pens
Pens cost more but have the benefit of eliminating the step of drawing insulin from the vial. Instead, a pen uses a premeasured insulin cartridge, which usually contains 300 units of insulin. Pens are either disposable, one-use models or reusable. The reusable ones allows you to insert and dispose of insulin cartridges, which you buy separately. Both types require the use of disposable pen needles, also purchased separately.
Alert
Overseas, insulin dilutions and measurements are a little different, with U-40 being the standard instead of U-100. Syringes are also marked in these units. If you're traveling abroad, be aware of this important difference and bring along plenty of supplies.
An insulin pen resembles just that, a pen. You uncap it to reveal the pen needle, then “dial up” your dose by turning the barrel until the correct number of units is displayed. After priming, you put the pen against the injection site and press a button to administer the insulin.
Today's pens are fairly discreet, and some models are designed to resemble a regular writing pen. Some newer pen models feature a display and memory module that allows you to “remember” the time of your last injection and amount of insulin taken.
Other Injection Devices
Fact
People who have problems with daily injections may benefit from a device called the I-Port (Patton Medical), a medication delivery system that is inserted into the skin. After the initial insertion, the port can be left in place for up to three days, and features a flexible cannula that you can inject insulin into without penetrating the skin again.
Jet injection devices use air pressure to force insulin through the skin without actually puncturing it. They are more expensive than both pens and syringes, and can require more training to use effectively. The air pressure must be adjusted to propel the insulin strongly enough to penetrate the skin but lightly enough not to bruise. Finding a balance can take a little time.
For those people who are afraid of needles, a jet injector may be a good choice. However, at a cost of several hundred dollars, they require a significant initial investment (although eventually they will pay for themselves). Some people find them bulky to carry conveniently, as they are bigger than both syringes and pens.
Insulins by Type, Onset, Peak, and Duration
Compiled from Eli Lilly and Company, Novo Nordisk A/S, and Sanofi-Aventis U.S. product labeling information. These are general guidelines only. A number of factors can affect insulin action, including dosage, the injection site, time of day, and exercise.
* Novolin N is also sold as ReliOn at Wal-Mart in the United States.
