Diabetes Forecast

Insulin (and other injected drugs)

Diabetes is a disease affecting the body's production of insulin (type 1) or both the body's use and its production of insulin (type 2). Injectable insulin is a lifesaver for people who can no longer produce it on their own


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Choosing the insulin that's most appropriate for you is a collaboration between you and your health care provider. Still, it's important to understand the basics of how insulin works. Here, we've broken it down into key terms:

The amount of time after injection it takes an insulin to reach your bloodstream and start lowering your blood glucose levels.

Duration: The length of time an insulin acts to keep blood glucose levels lowered.

Peak Time: The time when your insulin dose is at its strongest.

Basal Insulin: A long-lasting background insulin dose that controls blood glucose levels when you're not eating, including during sleep.

Bolus Insulin: A dose of rapid-acting or regular insulin taken to cover mealtime blood glucose spikes.

Rapid-Acting Insulin:
Insulin that starts working quickly: in about 15 minutes. The effect will peak about 1 or 2 hours after injection and last between 3 and 4 hours. Thanks to its quick onset, this type of insulin is ideal for before-meal doses. Inject it within 15 minutes before mealtime, and it'll start working at about the same time you start eating. When your food is being digested, the insulin hits its peak. Since this insulin leaves the bloodstream quickly, it decreases your risk for low blood glucose (hypoglycemia) hours after your meal. Types: Insulin glulisine (Apidra), insulin lispro (Humalog), and insulin aspart (NovoLog)

Regular Insulin: This insulin is short acting as opposed to rapid-acting because it takes a longer time to work than rapid-acting insulin. Within 30 minutes of injecting a dose, the insulin begins to act. It peaks between 2 and 4 hours later. The effect can last up to 8 hours, and a higher dose typically results in a longer duration of action. Types: Humulin R, Novolin R, ReliOn Regular

Intermediate-Acting Insulin: Currently, the only intermediate-acting insulin on the market is NPH. Unlike other insulins, NPH appears cloudy because it is a suspension of insulin crystals that needs to be resuspended according to package instructions before use. It takes between 2 and 4 hours for this type of insulin to start working in the body. It usually peaks between 6 and 12 hours after injection, and it lasts for about 12 to 18 hours. You may need to take a combination dose of intermediate-acting and regular or rapid-acting insulin. Types: NPH (Humulin N, Novolin N, and ReliOn N)

Long-Acting Insulin: There are two types of long-acting insulin--insulin glargine and insulin detemir--both of which last up to 24 hours. Insulin glargine, sold under the brand name Lantus, and insulin detemir, marketed as Levemir, start to work about 2 to 4 hours after injection. Once these insulins reach the bloodstream, they may last up to 24 hours (with less of a peak in action compared to NPH insulin), so a single daily dose may provide enough basal insulin for the entire day. Some people, however, require twice-daily dosing; your doctor will determine which option is best for you. Many people supplement their long-acting insulin with a bolus of rapid- or short-acting insulin to cover post-meal blood glucose surges. Others with type 2 diabetes may accomplish this by taking pills in conjunction with insulin. Types: Insulin detemir (Levemir) and insulin glargine (Lantus)

Mixtures: For convenience you may mix NPH insulin with rapid-acting or regular insulin instead of injecting each separately. If mixing insulin is part of your treatment plan, your doctor will give you instructions about which insulin to mix to obtain optimal blood glucose control. But keep in mind: You should never mix long-acting insulin (insulin glargine or insulin detemir) with any other insulin. For people with poor eyesight or trouble mixing--or those who find self-mixing of insulin an inconvenience--premixed insulin such as 70/30 insulin may be a benefit. Types: 70 percent NPH, 30 percent regular (Humulin 70/30, Novolin 70/30, and ReliOn 70/30), 50 percent lispro protamine, 50 percent insulin lispro (Humalog Mix 50/50), 75 percent lispro protamine (NPL), 25 percent lispro (Humalog Mix 75/25), and 70 percent aspart protamine and 30 percent aspart (NovoLog Mix 70/30)

Insulin Pens: Some insulins are available in "pen" form. A lightweight device resembling a pen is filled with an insulin cartridge for easy use. A few cautions: Follow instructions on how to mix your premixed insulin pens. It's also crucial that you remove your pen needles between injections. The needle is an open pathway for air to enter the pen, it may allow insulin to leak out, and it's also a prime portal for bacteria and other contaminants. People with poor vision or dexterity problems may benefit from the ease of injecting insulin from a pen.

Here are a few tips that might also help you when you are purchasing insulin:

  • Know your prescription. Yes, it goes without saying. Still, you should be familiar with the brand name and type of insulin you are taking, as well as your prescribed dose. It's also important to identify whether you've been prescribed U-100 or the less common U-500.
  • Select your pharmacy with care. A good pharmacist will answer your questions, alert you to potential problems, and take an overall interest in your medical needs. A pharmacy that offers home delivery can help if you have trouble getting around. Many people get their presciptions by mail order, 3 months' worth at a time.
  • Plan the delivery. Orders purchased by mail order or online may be shipped across the country and therefore be subject to sweltering or freezing temperatures. Find out how the vials will be stored in transit (for example, your insulin should be kept cool during warmer months), then examine them upon arrival. When your delivery is scheduled to arrive, make sure you're home to accept the shipment and prevent the package from sitting outside in the cold, rain, or heat.


While your medical insurance may dictate which brands you can use, you should still understand the various aspects of insulin syringes so you can better discuss your options with your doctor. Syringes differ with respect to needle length, needle thickness, and how much insulin the barrel holds. These features allow you and your health care provider to pick a syringe that works best for you.

Before you choose, you may want to consider these points:

  • Barrel: How much insulin your syringe can hold is important for accuracy. With a barrel that's too big you'll have trouble measuring out a small dosage. Though all syringes have markings on the barrel that indicate dosage, different brands may mark these lines differently. For example, on one syringe, each line may indicate a single unit; another syringe may indicate two units with each line; others may have smaller, half-unit markings for people (children in particular) who require extra-small doses.
  • Gauge: A syringe's gauge indicates how thick the needle is. The higher the number, the thinner the needle. Knowing which gauge is best for you may be a matter of trial and error, so discuss your options with your doctor or diabetes educator.
  • Needle length: Apart from the perception of pain a needle causes, there is no difference in needle lengths in terms of comfort. However, some very thin people may need a shorter needle to avoid injecting into their muscles. Talk with your doctor about what's right for you.
  • Design: A syringe is a syringe is a syringe, right? Wrong. People with vision impairment may find the markings on one syringe barrel easier to read than those on another. Some also find that a colorful plunger--the portion of the syringe that you press to release the insulin--makes measuring and administering a dose easier.
  • Cost: Finding on-sale syringes isn't hard, and shopping around could save you small amounts that, in the long run, add up. But consider convenience. If the cheaper syringes are out of your way, it may be worth paying extra.
  • Disposal: You may be tempted to reuse your syringes, but manufacturers say doing so could dull the needle (ouch!) or lead to infection or tissue damage. When disposing of your used syringes and lancets, there are a couple of things you need to be aware of. First, check to see if your state has a specific law stating how these items should be trashed. Whether or not you're legally obligated to dispose of your used syringes and lancets in a specific way, it's important to respect others who may come in contact with them. For this reason, it's key that you place the used items in a solid container that can be sealed shut. When you're ready to trash the container, use a magic marker to label it "Used Sharps," then place in the trash. Another option is to purchase a device that will clip your needles and store them safely.

Injection Aids and Alternatives

Advances in insulin injections over the past few decades have made it easier than ever to find an injection method that works best for you. If you're looking for an alternative to syringe injection or need help inserting the needle, speak with your doctor about your options. Many times doctors or diabetes educators have sample products on hand that you can test before buying. Your doctor will also be able to determine which product works best with your type of syringe and needle length. But, as with all diabetes products, check with your insurance company to make sure it will be covered.

Insertion aids: If you fear needles or have trouble inserting one into your skin, an insertion aid may be a smart purchase. The devices, many of which are spring loaded and release insulin at the touch of a button, help the needle get into your skin faster, so you spend less time injecting the insulin. Plus, most shield the needle from your view, so you can inject without anxiety if seeing the needle bothers you.

Infusers: These stick-on devices serve as a gateway for needles, allowing you to reduce the number of needle sticks you do in a day. Here's how it works: A needle or catheter is inserted under the skin, staying in place for up to 72 hours. When you're ready for an insulin dose, you inject directly into the infuser--not your skin. Since the catheter rests under your skin, infections are possible, and learning how to properly care for the device is essential. Getting properly trained in using your infuser is crucial.

Jet injectors: This needle-free injection method uses a thin, forceful stream of insulin to penetrate through the skin. While you won't have to use a needle, the pressure may cause bruising. You and your doctor can work to ensure good glucose control as you transition to using the injector.



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