• How to Inject Insulin with Syringes and Pens
• Future Prospects for Insulin Delivery
Insulin has come a long way since a young scientist named Frederick Banting first discovered it in the 1920s. Banting had a breakthrough idea to isolate pancreas cells with an odd name—the islets of Langerhans. These oddly named cells are powerhouses for making insulin in the body. Working with several scientists, Banting treated a dog and then a boy with diabetes using extracts from these cells. Medical insulin had arrived.
In 1923, Banting and his mentor J.J.R. Macleod were awarded the Nobel Prize in Medicine—and they shared their prize money with their scientific collaborators. Their discovery paved the way for the first treatments for diabetes and the foundation for technology in development today.
For many years, scientists made insulin by purifying extracts from the pancreases of pigs and cows. Now, almost all insulin is made in laboratories by inserting the human gene for insulin into bacteria, which are rapidly grown and harvested for their insulin. Although it doesn’t come directly from people, it is known as human insulin.
Types of Insulin
Each type of insulin has a different action time, a term that describes the length of time it takes to begin acting and how long its effect lasts. The action times of insulin are due to the following three features: onset, peak time, and duration.
Terms for Insulin Action Time
• Onset: the length of time it takes for insulin to reach the blood and begin lowering blood glucose levels
• Peak time: the time during which insulin is at its maximum strength in lowering blood glucose levels
• Duration: the length of time in which insulin continues to lower blood glucose
Your insulin doses should mimic how insulin works naturally in the body. In people without diabetes, the pancreas makes and releases small amounts of insulin throughout the day and night. This is called the basal insulin. The pancreas also releases a short burst of insulin when people without diabetes eat and their blood glucose begins to rise. This is called a bolus of insulin.
Long-acting insulins are basal insulins. Rapid-acting and regular insulins are bolus insulins. Intermediate-acting insulin may provide both basal and some bolus effect or, if taken at bedtime, provide mostly a basal effect. Most people with diabetes take both basal and bolus insulin.
Types of Insulin
Long-Acting Insulin Analogs
The two types of long-acting insulin analogs are insulin glargine (brand name Lantus) and insulin detemir (brand name Levemir). They both start to work 2–4 hours after injection and last up to 24 hours.
Intermediate-Acting Insulin
The one type of intermediate-acting insulin is called NPH, sometimes referred to as isophane insulin (brand names Humulin N, Novolin N). It starts to work 2–4 hours after injection, peaks 4–10 hours after injection, and lasts 10–16 hours. It contains a molecule known as protamine, which slows down how fast the body absorbs insulin. It is also cloudy, rather than clear like other insulin, because it contains suspended insulin crystals.
Regular Insulin
Regular insulin is short acting and must be injected several times throughout the day. It is sold under the brand names Humulin R and Novolin R. It starts to work 30–60 minutes after injection, peaks 2–3 hours after injection, and lasts for 3–6 hours.
Rapid-Acting Insulin Analogs
Rapid-acting insulin analogs go to work almost as fast as naturally produced insulin, so it’s easy to use when timing insulin with food. It gives you a lot more flexibility. For example, you can count the carbohydrates in a meal and use rapid-acting insulin to cover the exact amount. The three types of rapid-acting insulin analogs are insulin lispro (brand name Humalog), insulin glulisine (brand name Apidra), and insulin aspart (brand name Novolog). They go to work within 15 minutes, peak 1–2 hours after injection, and last for 3–5 hours.
Premixed (Biphasic) Insulin
You might be advised to mix your NPH insulin and regular or rapid-acting insulins in one injection. You can mix them yourself (discussed later in this chapter). You can also buy premixed insulins. Mixtures of intermediate and regular insulins and intermediate- and rapid-acting insulins come in various combinations that make them more convenient and easier to handle. The intermediate-acting component is sometimes referred to as “protamine.”
Premixed insulins can be useful for people with eyesight or dexterity problems that make drawing different amounts of insulin from two different bottles difficult. Common mixtures of insulin are 70% NPH/30% regular, available only in vials (Humalin 70/30 or Novolin 70/30); 50% lispro protamine/50% insulin lispro (Humalog Mix 50/50); 75% lispro protamine/25% lispro (Humalog Mix 75/25); and 70% aspart protamine/30% aspart (Novolog Mix 70/30).
All insulins used for injections have added ingredients that help prevent bacteria and molds from growing in the vial. Intermediate- and long-acting insulins also contain ingredients that prolong their action times. Some people may experience allergic reactions to these ingredients. Talk to your provider if you suspect you might have an allergic reaction to your insulin.
Signs of Allergies to Insulin
• Dents under the skin at injection sites
• Redness at injection sites
• Groups of small bumps, similar to hives
• Swelling at injection sites
Buying and Storing Insulin
Insulin is sold at retail pharmacies in your neighborhood and big-box stores, mail-order pharmacies, and online pharmacies. The National Association of Boards of Pharmacy recommends buying from Internet pharmacies accredited through the Verified Internet Pharmacy Practice Sites program (VIPPS).
Your choice of pharmacy will depend on factors such as convenience, price, and insurance coverage. Don’t assume that most pharmacies will charge the same price for insulin. Shop around, and keep these tips in mind.
Insulin Strength
Insulin strength is now standardized in the United States. In the past, insulin came in different strengths, which made it confusing for consumers. The most common strength is U-100, which means it has 100 units of insulin per milliliter of fluid. Some people may take U-500 if they are insulin resistant or insulin may be diluted for smaller amounts. Keep in mind that some other countries do carry insulin in different strengths, so when you travel you’ll always want to bring your own insulin and syringes.
Tips for Buying Insulin
• Ask about discounts you might receive for buying in larger quantities. Check the expiration dates if you decide to buy in bulk.
• Check with your insurance company or managed-care provider to see whether they offer insulin at a reduced price for preferred pharmacies.
• Consider the convenience of the pharmacy—whether it is close by or delivers. This can be a lifesaver if you are busy, ill, or housebound.
• Consider the manner of your pharmacist. You may put a high priority on having a pharmacist who is easy to talk to or who takes the extra time to answer your questions.
• Ask questions. Check to make sure you have the desired brand and type of insulin. You may want to bring along an empty bottle to make sure you get exactly the same thing each time. Ask the pharmacist if something doesn’t look quite right or if you are uncertain.
Ordering your insulin by mail may appeal to you. It is convenient and could save you money if you buy your insulin and other supplies in bulk.
Tips for Mail-Ordering Insulin
• If you live in a warm climate or order during the summer, ask how perishable items such as insulin will ship. Insulin is sensitive to heat, so overnight shipping might be best.
• When you start a new drug, such as insulin, buy it from a pharmacy. You may need a different dose or type—or you may stop taking it altogether.
• Inspect insulin vials carefully for signs of damage or crystallization on the inside vial. Call the mail-order firm immediately to report spoiled insulin.
• Check the expiration date on each item that arrives. If you’ll need the item in 6 months, make sure it doesn’t expire in 2 months. Send back all items with expiration dates that are just around the corner.
• Check out other mail order and shopping tips for all your diabetes supplies in chapter 7.
Storing Insulin
The basic rule in storing insulin is to keep unopened bottles in the refrigerator and opened bottles at room temperature. Insulin kept at room temperature will be more comfortable to inject than cold insulin. The expiration date on a bottle of insulin applies to bottles that have not been opened and have been stored in the refrigerator.
Tips for Opened Bottles of Insulin
• Throw away bottles that have been opened for a month and kept at room temperature, as the insulin may lose its strength.
• If you go through bottles slowly, write the date you first open the vial on the label, so you know when to toss it.
• Storage guidelines vary from 10 to 28 days for different types of insulin cartridges and pens. Read the label or package or ask your pharmacist if special storage requirements are necessary.
Avoid extreme hot or cold temperatures when storing your insulin. Generally, your insulin should be okay if the temperature is comfortable for you. Storing insulin at temperatures colder than 36°F can cause it to lose potency and clump. Make sure that your insulin doesn’t come in contact with ice or become too cold if you carry your insulin in a cooler when travelling. Avoid getting insulin too hot or leaving it in direct sunlight for too long. Insulin can spoil if it gets hotter than 86°F.
Avoid Prefilling Syringes
In general, you should draw up your insulin as close as possible to the time you want to take it. For some people, including those with vision problems, it may be helpful to have someone else prefill syringes and store them in the refrigerator for later use. If you feel that you could benefit from prefilling and storing syringes, be sure to consult with a pharmacist or your diabetes educator beforehand.
Signs of Insulin Defects
• If your blood glucose values are rising, you might consider whether your insulin is working properly.
• Never use insulin if it looks abnormal.
• Regular, lispro (Humalog), aspart (Novolog), and glargine (Lantus) insulins are clear. If you use clear insulin, always check for any floating particles, cloudiness, or changes in color. This could be a sign that your insulin is contaminated or has lost its strength.
• Other types of insulin come as suspensions. This means that the material is not completely dissolved, and you might be able to see solid material floating in liquid. However, it should look uniformly cloudy. If you are using NPH, check that your insulin is free of any large clumps of material.
• Do not use any insulin if you see chunks of material floating around. These changes could mean that crystals or aggregates are forming and the insulin is spoiled or denatured. This can be caused if the insulin bottle is shaken too much or if it is stored at temperatures that are either too hot or too cold.
• If you have been instructed to dilute your insulin, use only the dilutent recommended by the manufacturer. Properly diluted insulin is good for 2–6 weeks when stored in the refrigerator.
• If you find anything wrong with your insulin right after you buy it, return it immediately.
• If the insulin looks different later, try to figure out whether you have handled or stored the insulin the wrong way. If not, talk to your pharmacist about a refund or exchange.
How to Inject Insulin with Syringes and Pens
Some people with diabetes use a needle and syringe or an insulin pen to take their insulin. Once you learn how, this will be a quick and relatively painless task. Injecting insulin today is a lot less painful than it used to be. You can choose micro-fine needles and helpful devices that make injecting with syringes possible for almost anyone. Whether you use an insulin syringe or pen, the goal is to deliver insulin into the fat that lies just beneath your skin.
Syringes
A syringe consists of a needle, barrel, and plunger. You want to consider the needle length and gauge, as well as the barrel size when selecting a syringe.
Syringe needles come in different lengths and gauges. Some people prefer a shorter length needle, particularly if you are thin and want to avoid injecting into your muscle. Syringe lengths are: 1/2”, 5/16”, and 3/16”. Some people also prefer a thinner or higher gauge needle. Thinner needles have higher gauges. For example, a 31-gauge needle is thinner than a 29-gauge needle. You may have to try different needles to see which length and gauge you prefer.
Syringe barrels also come in different sizes. It is important to match the size of the syringe to the dose you’ll take with it. You want a syringe that will hold your entire dose of insulin. For example, you would want to use a 50-unit syringe to hold your entire dose of 45 units of insulin. Make sure that you can see the markings on your syringe. There are devices that make it easier to read the markings on the syringe, so ask your pharmacist or diabetes educator if such a product will be helpful for you.
Tips for Selecting Syringe Size
|
If your dose is |
Use this syringe |
|
30 units or less, measured in 1/2 units |
3/10 ml/cc (30 units) with 1/2-unit markings |
|
30 units or less, measured in whole units |
3/10 ml/cc (30 units) with 1-unit markings |
|
31–50 units |
1/2 ml/cc (50 units) |
|
51–100 units |
1 ml/cc (100 units) |
Reusing Syringes
Some people have had success reusing syringes. It’s up to you whether you want to reuse your syringes. The most important advice is to never share or borrow a used syringe. Most manufacturers of disposable syringes recommend that they be used only once. This is because syringes cannot be guaranteed to be sterile if they are reused. If you have poor personal hygiene, are ill, have open wounds on your hands, or have a low resistance to infection for any reason, you should not reuse syringes. Needles also can become chipped or dull after use. Most needles can be used several times before the tip becomes dull. Using a dull tip is more painful than using a new, sharp needle.
Reusing syringes can save you money and create less medical waste to litter the environment. There is no evidence that you are more likely to become infected with something, as long as you follow some simple guidelines.
How to Reuse a Syringe
1. Carefully recap the syringe when you are finished using it.
2. Don’t let the needle touch anything but clean skin and your insulin bottle stopper. If it touches anything else, don’t reuse it.
3. Store the used syringe at room temperature.
4. There will always be a tiny, even invisible, amount of insulin left in the syringe. If you use glargine insulin (Lantus), be careful not to use the glargine (Lantus) syringe for other insulins.
5. Do not reuse a needle that is bent or dull because this can make the injection more painful. However, just because an injection is painful doesn’t mean the needle is dull. You may have hit a nerve ending.
6. Do not clean the needle with alcohol. This removes some of the coating that makes the needle go more smoothly into your skin.
7. When you’re finished with a syringe, dispose of it properly according to the laws in your area. Contact the city or county sanitation department for information.
Syringe Disposal
How you get rid of your syringe can affect anyone who might come in contact with your trash. This includes the members of your family, neighbors, your trash collector, and people using beaches and other public areas. So it’s important that you do it safely.
Never toss a used syringe directly into a trashcan. Syringes and lancets and any other material that touches human blood is considered medical waste and must be handled carefully. Before deciding what you will do, you might want to check with your local health department. Some towns and counties have special laws or rules for getting rid of medical waste and may offer safe alternatives.
When traveling, if possible, bring your unused syringes home. Pack them in a heavy-duty container, such as a hard plastic pencil box. There are products specifically designed to clip and hold syringes for disposal. Check Diabetes Forecast’s annual Consumer Guide for these products.
Insulin Pens
An insulin pen looks like an ink pen. Instead of a writing tip, it has a disposable needle, and instead of an ink cartridge, there is an insulin cartridge. Always use a new needle with an insulin pen.
Insulin pens are popular because they are convenient and deliver accurate doses. You don’t have to worry about filling syringes or carrying them with you when you are away from home. However, although premixed insulin is available in pens, you cannot mix insulin in pens yourself.
You can buy a prefilled pen that you throw away once the insulin cartridge is empty. A variety of insulins are available in pens. You decide the number of units you want, set the injector for that dose, stick the needle in your skin, and inject the insulin. This makes them useful for multiple-dose schedules. Pen injectors are conveniently portable because you don’t have to carry around a bottle of insulin. Some are designed to make it easier for people with visual or dexterity problems to give injections.
How to Prepare Insulin Injections
Your diabetes educator or provider will explain and show you how to prepare insulin for injection. You can use a syringe or insulin pen, whichever you prefer.
Equipment
• Syringe and needle, or insulin pen
• Insulin bottle
• Alcohol swab
Instructions
1. Wash your hands.
2. Choose injection site and cleanse with alcohol swab. Do not inject insulin into a callused or hard, lumpy site. Rotate sites as instructed by your health care professional.
3. Check the bottle of insulin to make sure you are using the right kind. For an insulin pen, screw on the needle. Use a new needle every time with insulin pens.
4. For cloudy insulin, gently roll the bottle of insulin between your palms or rotate the pen slowly from end to end to mix. Make sure it is mixed thoroughly. Shaking the bottle can cause air bubbles. Do not use if it has clumps or particles in it.
5. Clean insulin syringe with alcohol swab. For an insulin syringe, hold the syringe with the needle pointing up and draw air into it by pulling down on the plunger to the amount that matches the dose to be given.
6. For an insulin pen, perform an “air shot” by pushing 1–2 drops of insulin through the needle. Set the insulin dose according to manufacturer’s directions. Proceed to instructions on injecting insulin.
7. Remove the cap from the needle. Hold the insulin bottle steady on a tabletop and push the needle straight down into the rubber top on the bottle. Push down on the plunger to inject the air into the insulin bottle.
8. Keep the needle in and turn the bottle and syringe upside down so that the insulin is on top. Pull the correct amount of insulin into the syringe by pulling back on the plunger.
9. Check for air bubbles on the inside of the syringe. If you see air bubbles, keep the bottle upside down and push the plunger up so the insulin goes back into the bottle.
10. Pull down on the plunger to refill the syringe. If necessary, empty and refill until all air bubbles in the syringe are gone.
11. Remove the needle from the bottle after checking again that you have the correct dose.
12. If you need to set the syringe down before giving your injection, recap the needle, and lay it on its side. Make sure the needle doesn’t touch anything.
How to Inject Insulin
Your diabetes educator or health care provider will explain how to inject insulin. Whether it’s your first time or you’re a seasoned pro, it’s always a good idea to review the basics. It often helps to go over your injection technique with your health care team. Trying to relax before injections can help ease the discomfort because tense muscles can make the injection hurt.
Keeping your injection site clean will reduce the risk of developing an infection. You don’t have to use alcohol to clean your skin before injecting the needle. Soap and water works fine. If you use alcohol before injections, make sure the alcohol dries first or the injection may sting.
Equipment
• Prepared syringe or insulin pen.
• Cotton ball or tissue, if desired, to cover the injection site for a few seconds after the injection.
• Alcohol or soap and water to clean injection site.
Instructions
1. Choose an injection site with fatty tissue, such as the abdomen (except for a 2-inch circle around the belly button), the back of the arm, the top and outside of the thigh, or the buttocks. Make sure the site and your hands are clean and dry.
2. Gently pinch a fold of skin between your thumb and forefinger, and inject straight in if you have a normal amount of fatty tissue. For a thin adult or a small child, you may need to inject at a 45-degree angle. With smaller needles, this may not be necessary.
3. Push the needle through the skin as quickly as you can.
4. Relax the pinch and push the plunger in to inject the insulin.
5. Pull the needle straight out.
6. Cover the injection site with your finger, a cotton ball, or gauze, and apply slight pressure for 5–8 seconds. Do not rub. Rubbing may spread the insulin too quickly or irritate your skin.
7. Write down how much insulin you injected and the time of day.
Mixing Insulins
If you’re mixing insulins on your own, you’ll mix them in a syringe. Never mix insulins without approval from your provider. Usually, only mix insulins made by the same company. For instance, don’t mix regular insulin made by Lilly with NPH made by Novo Nordisk. Never mix long-acting insulin with regular insulin, which can lead to unpredictable results. Insulin glargine (Lantus) insulin has a lower pH level and cannot be mixed in the same syringe with any other insulin. Insulin detemir (Levemir) should not be mixed as well.
How to Mix Insulin
Equipment
• Syringe, the correct size for the total units of insulin
• Bottles of insulin
• Alcohol swab
Instructions
1. Be clear on the amounts of each insulin and the total units you want. To find the total units, add the number of units of rapid-acting or regular insulin to the number of units of intermediate- or long-acting insulin.
2. Wash your hands.
3. Clean vial tops with alcohol swab.
4. For cloudy insulin, gently roll the bottle of insulin slowly between your palms to mix. Make sure it is mixed thoroughly. Do not use if it has clumps or particles in it. Shaking the bottle can cause air bubbles.
5. Draw air into the syringe equal to the intermediate dose.
6. Hold the bottle steady on the table and put the needle through the rubber stopper. Inject the air into that bottle. Take out the needle without drawing up any insulin.
7. Draw air into the syringe equal to the dose of rapid-acting or regular insulin and inject the air into the bottle of rapid-acting or regular insulin.
8. With the needle still in the rapid-acting or regular insulin bottle, turn it upside down so that insulin covers the tip of the needle.
9. Pull the correct amount of insulin into the syringe by pulling back on the plunger. Check for air bubbles in the syringe. If you see air bubbles, keep the bottle upside down and push the plunger up so the insulin goes back into the bottle. If necessary, empty and refill until all air bubbles in the syringe are gone. Remove the syringe.
10. Insert the syringe into the bottle of intermediate-acting insulin. (You have already injected the right amount of air into this bottle.) Turn the bottle upside down, so that the insulin covers the tip of the needle.
11. Slowly pull the plunger down to draw in the right dosage of intermediate-acting insulin. This will be the total units of the regular or rapid-acting and intermediate-acting insulins.
12. Do not return any extra insulin back to this bottle. The insulin in the syringe is now a mixture. Double check for the correct total amount of insulin. If incorrect, discard the insulin in the syringe and start over.
13. Take the needle out of the bottle, recap the needle, and lay the syringe carefully on a table without letting it touch anything.
14. Choose site for injection, cleanse site. (See illustration below.)
Injection Aids
Talk to your doctor or your diabetes educator if you are having problems with any aspect of insulin injections. Be sure to let them know if the injections are causing you a great deal of stress or anxiety, too. Products are available to make injections easier, such as insertion aids, insulin infusers, and jet injectors. Ask your educator if you can try out some of these insulin-injection aids before you buy anything so that you don’t waste your money.
An insertion aid is an automatic injector that inserts a needle into your skin. Some automatically release the insulin when the needle hits your skin. With others, you have to press the plunger on the syringe. An automatic injector can be useful if you have arthritis or other problems that make it difficult to hold a syringe steadily. If you cringe at the thought of injecting yourself or don’t like the sight of needles, an automatic injector may be for you.
An insulin infuser reduces the number of needle sticks per day. You insert a needle, called a catheter, under your skin that stays in place for 3 days. Then you inject insulin into the catheter rather than your skin. You’ll need to ask your provider for training in using an insulin infuser because these devices increase the risk of infections.
Jet injectors push the insulin out so fast that it acts like a liquid needle, passing insulin directly through the skin. If you fear needles or take several injections each day, a jet injector may be an option for you.
Several products are available that make it easier for people who are visually impaired to inject insulin. Some of these aids only fit certain brands of syringes. Make sure that any aids you purchase will fit the equipment you already have.
Examples of Visual Aids for Injecting
• Dose gauges help you measure your insulin accurately—even mixed doses. Some are designed to click with every 1 or 2 units of insulin you measure. Others have Braille or raised numbers.
• Needle guides and vial stabilizers help you insert the needle into the insulin vial correctly. Some of these will also let you set a desired dose level.
• Syringe magnifiers can enlarge the measure marks on a syringe barrel. One model combines a magnifier with the needle guide and vial stabilizer. Another clips around the syringe and magnifies the scale.
Injection Sites
It is usually recommended that you rotate your injection site in order to avoid developing problems in and under your skin. You can inject insulin into your abdomen, but you can use other sites as well. Insulin works best when injected into a layer of fat under the skin, above the muscle tissue. Several areas of the body have enough fat tissue under the skin for insulin injection.
Typical Injection Sites
• The abdomen, except for a 2-inch circle around the belly button, is the most common site.
• The top and outer thighs are also common. This is best for when you are sitting.
• The backs of the upper arms, the hips, and the buttocks also work well.
• Some people, especially those with a large body size, have other options. For example, the lower back can also be a good injection site, as long as there is enough fat under the skin.
Rotating Injection Sites
Wherever you choose to inject, you will want to inject at different sites within that area so you don’t develop problems in and under the skin. You may find that it works best to rotate injection sites within one general area, such as the abdomen, rather than to rotate randomly among sites in different areas of the body. However, some people achieve consistent results by doing all morning injections at one site, such as the buttocks, and all evening injections at a second site, such as the abdomen. Injecting in the same general area makes your response to insulin more predictable because insulin is absorbed at different rates in different body areas. Rotating among random sites could lead to large fluctuations in blood glucose levels.
Once you have used each injection site within a body area, you can start over in the same body area. There are many opinions on the best way to rotate injection sites. Talk to your diabetes educator about the best method for you.
Tips for Selecting Insulin Sites
• Divide the body area into injection sites about the size of a quarter. Try to make each new injection at least a finger-width away from your last shot.
• You may need to create a way to remember where that last site was. For example, you might inject all of your morning shots on the right side and all of your evening shots on the left.
• When injecting into the arm, use the outer back area of the upper arm, where there is fatty tissue. Avoid the deltoid muscle, the large triangular muscle that covers the shoulder joint. Don’t inject into muscle tissue anywhere in the body.
• When injecting in the thighs, use the top and outside areas. If you inject in the inner thighs, rubbing between the legs may make the injection site sore. Also avoid the bony area above the knees, where there isn’t much fat.
• Inject anywhere there is fat on the abdomen, except for the 2-inch space around the belly button. This area has tough tissue that causes erratic insulin absorption.
• Avoid injecting too close to moles or scar tissue anywhere on the body.
Differences in Insulin Absorption
Most insulins are absorbed most quickly (and at the most consistent speed) when injected into the abdomen, more slowly when injected into the arms, and slower still when injected into the thighs and buttocks. After you have been injecting insulin into your abdomen for several weeks, you probably know how long it will take for the insulin to take effect. This predictability can help you better manage your blood glucose.
If you were to suddenly switch to injecting insulin into your thigh, you might experience a different response. You might find that it takes longer for your insulin to take effect. Then it would be more difficult to meet your target blood glucose levels without adjusting when you inject.
Other factors, such as body temperature, food, physical activity, and level of stress, affect your body’s response to insulin. Your response to insulin might even be the opposite of what you might expect, based on where you inject. For example, playing soccer for 2 hours may cause your insulin to be absorbed more quickly than usual so that your blood glucose level isn’t where you expect it to be.
So what can you do? Routinely check your blood glucose level. It is the only way to make sure you are having the response you had planned. Then you’ll know if your site rotation plan is working for you.
A General Rule for Insulin Absorption
In general, anything that increases the blood flow to an area increases insulin absorption.
Physical Activity and Insulin Absorption
• Strenuous use of muscles near an injection site can make the insulin act more rapidly than normal because of the increased flow of blood to the exercising muscles.
• You might want to think about the insulin absorption rate if you notice that your insulin is peaking faster than expected when you exercise.
• In general, it’s a good idea to avoid strenuous activity during the peak action times of your insulin. Insulin plus exercise can lead to hypoglycemia.
• When you work out, you have to decide whether to eat more or take less insulin because both physical activity and insulin decrease the amount of glucose in the blood.
• Frequent blood glucose monitoring will help you figure out these ups and downs in blood glucose and how to keep things in balance.
Skin Problems and Injection Sites
The main skin problems that can occur at insulin injection sites are lipoatrophy and lipohypertrophy. By rotating injection sites, you can avoid some of these problems.
Lipoatrophy is probably caused by an immune reaction, although its exact cause is not known. When lipoatrophy occurs, your body is responding to insulin as a “foreign” substance. This problem is not as common with human insulin or insulin analogs. Make sure you use highly purified insulin, preferably human. Injection site rotation may also help.
Lipohypertrophy is not an immune reaction, but you will need to change injection sites to avoid this. When the same sites are used over and over again, fat deposits can accumulate in the area. You may be reluctant to make changes to your insulin regimen because the injections are less painful in these areas. If you have lipohypertrophy, this may be because it can numb the affected area. On the other hand, injections can sometimes be more painful in these areas. The abnormal cell growth can limit the absorption of your insulin. Do not inject into the lumps. Insulin action can be affected because it is unable to move through the tissue. Inject away from the lumps, and remember to rotate injection sites. Ask a member of your health care team to check your injection sites periodically.
Insulin Pumps
Insulin pumps are small, programmable devices that deliver a steady, measured amount of insulin under your skin. They are smaller and better than ever. They can be a great choice for people who want an alternative to multiple daily injections of insulin.
Parts of the Insulin Pump
• Most pumps consist of a refillable cartridge, which holds the insulin, and a miniature computer that allows the user to program the release of insulin. Wireless, disposable pumps contain insulin but are not refillable.
• Some pumps use an infusion set to deliver insulin. The infusion set includes a cannula (a needle or small tube) that is inserted beneath your skin. It has an adhesive to keep the
infusion set in place for a few days. It also has small, flexible tubing to connect the infusion set to the pump.
• Several insulin pump systems don’t have tubing. Instead, they are made up of two items—a small, plastic insulin holder (pod) that attaches directly to the skin and a wireless, handheld device that you use to manage the release of insulin.
Monitoring and Insulin Pumps
Pumps cannot automatically sense your body’s need for insulin. They don’t adjust
by themselves. You still need to take blood glucose readings throughout the day.
Basics of Insulin Pumps
The Device
This is the insulin pump itself and is like a small computer. The device beeps if the tubing or cannula becomes clogged. It lets you know when the batteries are low. It has dosage limits to stop an accidental overdose. You can program it to change the amount of insulin to deliver in order to match your needs.
Insulin Reservoir
For most pumps, insulin is pumped from a filled syringe or cartridge inside the pump through thin plastic tubing to a needle or catheter inserted under the skin. Depending on your insulin needs, the reservoir can hold up to a 3-day supply of insulin.
Infusion Sets
The tubing comes in different lengths, but it is long enough to allow plenty of slack for normal body movement.
Basal Insulin
The insulin pump sends a continuous flow of insulin that trickles through the tube into the infusion set site at a slow, steady (basal) rate, day and night. The basal rate for pumps can be adjusted from 0.1 to 10 units per hour, depending on your needs.
Bolus Insulin
Before you eat, you push a button to deliver a desired amount of insulin, called a bolus. You can adjust the size of the bolus, depending on how much carbohydrate is in your meal. At the same time, you can deliver an extra amount of insulin to correct for higher-than-normal glucose levels, if they are present. Some new pumps ask how much carbohydrate you will eat and what your current blood glucose level is to help you calculate how much bolus insulin you’ll need. Delivering a bolus of insulin is just like injecting your premeal shot of insulin when you take multiple injections—without the shot! Usually, you won’t have to take an extra bolus when you eat between meals, unless the snack is large.
Choosing an Insulin Pump
A major advantage of a pump is that you don’t have to stop what you’re doing to fill a syringe or to prepare an insulin pen. Your insulin is delivered at the push of a button. You can do this anywhere and at any time. Pumps are also precise. You can set them to pump out as little as one-tenth of a unit (0.1 unit) of insulin per hour.
Pumps Take Commitment
One of the most important factors is your level of commitment to this therapy. Using an insulin pump does take work—especially when you first begin using one—but many people find that the added flexibility and improved control are worth the extra effort.
Some Reasons for Choosing an Insulin Pump
• You’re planning a pregnancy and want the tightest blood glucose control possible.
• You work odd hours at your job or don’t have a regular shift, and it’s difficult to adjust to a new injection schedule every weekend.
• You have had unwanted swings in blood glucose when injecting intermediate- or long-acting glucose, and you’d like to keep your blood glucose in check.
• You want an insulin plan that adapts to day-to-day changes in your lifestyle. Making a list of personal advantages and disadvantages may help you decide.
Features of Insulin Pumps
There are several insulin pumps on the market today. You can find a list of the available insulin pumps in Diabetes Forecast’s annual Consumer Guide. Your doctor or diabetes educator may prefer one brand over another. Ask for his or her thoughts on each model. Your best bet may be to talk to other people who use pumps. Find out what they like and don’t like about each model.
Features of Insulin Pumps
• Is it waterproof? Some models are waterproof and can be submerged for up to 30 minutes. Other models are splash proof or water resistant. Check to see if your pump meets your personal needs.
• Can you adjust the basal rate for different times of day? Your pump can alter the rate dozens of times a day. For example, your basal needs might be greater from 3 a.m. to 7 a.m. than your needs during the rest of the day.
• All pump manufacturers offer a 24-hour toll-free support number. You will want to talk to service people about problems when you suspect the pump isn’t working correctly.
• What kind of warranty does the manufacturer offer?
• How often do you have to change the batteries? How easy are the batteries to find, and how expensive are they? Batteries usually last 2–4 months.
• Do you want a pump that will help you calculate doses based on your blood glucose level and carbohydrate intake?
• Some insulin pumps have multiple, programmable features, including alerts. Some also have larger memories than others to store boluses, insulin totals, and alerts.
• Does your pump include software that charts your progress or that you can download to your computer?
• Do you want a pump that uses dual-wave or square-wave bolus, which helps manage meals spread out over time or higher-fat meals.
• Some pumps are designed to work together with blood glucose monitors or continuous glucose monitors. For example, you may be able to program targets for correction, insulin action time, and insulin sensitivity factors. If used correctly, these features can help users do the math so they do not provide too much or too little insulin. You’ll want to research your options.
Cost of Insulin Pumps
Insulin pumps can be expensive. But with a prescription and some persistence, most insurance companies can be convinced to pay for all or part of it. Monthly maintenance can run $300 or more, including insulin, infusion sets, and blood testing supplies. If your insurance company will cover them, you’re all set. But some insurance companies won’t pay the start-up or maintenance costs of the pump.
Getting Your Insurance to Pay for an Insulin Pump
• Pump companies have billing departments that have relationships with most insurance companies. A pump company can contact your insurance company to help you get coverage.
• Your provider can be your most convincing advocate if he or she has made an evaluation that you would do well with an insulin pump. Your health care provider may have to write a letter to your insurer. Pump companies can help prepare standardized letters to prepare for a provider’s signature.
• Ask your diabetes educator to write to your insurance company as well.
• Work on writing effective, informative letters. All letters should stress how lower glucose levels can mean fewer and less severe diabetes complications in the long run, which is also less expensive for the insurance company in the long run.
• Keep asking! Keep in mind that it took many years, much research, and lots of people asking to convince insurance companies to pay for other therapeutic measures, such as prescription footwear, that have long-term health benefits.
Using an Insulin Pump
Once you’ve decided to go ahead with an insulin pump, your pump company will provide you with an experienced pump trainer who will teach you how to use the device properly. This will include both selecting an insertion site for the pump and programming the pump to deliver the proper amount of insulin. You will also learn what to do in an emergency and how to obtain supplies.
Insertion Sites
Insertion sites are any sites you normally use for injection. Some people choose the abdomen for insulin delivery. This area is convenient to use and gives a reliable, uniform absorption of insulin.
How you insert the insulin needle will be different for different brands of infusion sets. With some infusion sets, you use a needle to insert a catheter and then remove the needle, leaving the soft catheter under your skin. With other sets, you insert a short needle. With the pod, you insert a catheter under the skin.
You don’t have to worry that it will hurt when you exercise or if someone bumps into your pump, infusion area, or pod. The needle or catheter should be comfortable at all times. If you see any redness or swelling at the infusion site, remove the needle or catheter right away and find a new infusion site. Discuss persistent problems (lasting longer than 24 hours) with your health care team.
Pumps Are Easy to Remove
Some pumps are easy to remove temporarily because, after connecting the tubing, you can leave part of the infusion set (the needle or flexible catheter) in place. You reattach only the pump and the tubing. Some infusion sets even have a quick-release feature.
Changing the Insertion Site
• Every 1–3 days, you’ll need to replace the infusion set and move to a new insertion site. This helps you avoid infection at the insertion site or a clog in the infusion set.
• Place the new insertion site at least 1 inch away from the last insertion site on the abdomen. Just like with syringes, you need to avoid inserting the needle into scar tissue or moles and use a site-rotation schedule.
• Using the same insertion site too often or for too long can cause the same skin problems (lipoatrophy, lipohypertrophy) that develop when you don’t rotate your syringe injection sites. Scarring can occur.
• Check your injection site every day to make sure insulin is not leaking out.
Programming and Wearing a Pump
A big advantage to using a pump is that you will have flexible insulin coverage for meals and snacks. You will have to spend some time at the beginning finding the best basal rates for you. You may need to adjust the basal rate during different times of the day. You will also need to figure out how big a bolus you will need for each meal.
Most people learn how to estimate the number of grams of carbohydrate in meals so they can take the needed number of insulin units. This may help you even out your after-meal blood glucose levels. You’ll avoid having big changes in blood glucose levels throughout the day. Eventually, this will lead to a more flexible eating schedule.
Calculating Basal and Bolus Insulin
• Your diabetes care provider or educator will help you calculate your basal and bolus insulin doses.
• Most people learn a matching rule for giving a bolus according to the amount of carbohydrate that they would like to eat, which may be different at each meal, according to time of day.
• The total basal dose over a day is some percentage of the total daily insulin dose that you’ve been injecting, perhaps 40–50%.
• The other 50–60% of your daily insulin dose is divided into the before-meal bolus doses, most of it at breakfast and dinner and the remainder at lunch and bedtime.
• You will need to know how these doses were chosen, so you can learn to adjust them for fine-tuning.
People wear the pump almost all the time. If you take the pump off, you’ll need to go back to injecting insulin with either an insulin pen or a syringe and needle. However, it is possible for you to take the pump off temporarily, but not for more than 1–2 hours. Your blood glucose levels will rise quickly because you don’t have any insulin. Through experience and testing, you will figure out how long you can keep the pump off before you need to put it back on or take an insulin injection.
Like all things that are worthwhile, using a pump successfully takes practice. You will most likely have problems here and there.
Unhooking the Pump
You may want to set a temporary basal level or unhook your pump during sex or other physical activities that can lower blood glucose level. How long you can keep the pump off without an injection depends on how active you are when the pump is off. Keep in mind that removing or suspending your pump for long periods can lead to clogs in the cannula when you try to start up again.
Unexplained High Blood Glucose on the Insulin Pump
Mysterious high blood glucose levels are some of the most common problems for people on an insulin pump. Consider these possibilities when troubleshooting your pump.
• Insulin: Is it expired? Has it been exposed to extreme heat or cold? Does it look clumped or is it filled with particles? Is the vial nearly empty? Have you used it for more than 1 month?
• Insertion site: ave you placed the catheter in or near a scar or mole or near your beltline or any other area where there’s friction from clothing? Does the site hurt? Is it red or swollen? An infection could delay the absorption of insulin.
• Infusion set or pod: Did the needle come out? Is insulin leaking around the infusion site? Is there blood or air in the infusion line? Is there a kink in the line? Did the line come loose from the pump? Has the infusion set been in place for more than 2 days? Think about changing the infusion line.
• Insulin pump: Is the basal rate set correctly? Has the battery run down? Was the insulin cartridge placed correctly? Is it empty? Was the pump primed with insulin when a fresh cartridge was put in? Is the pump working correctly?
• Alarms: High blood glucose occurs quickly when clogged or kinked tubing or dislodged pods stop the flow of insulin and pressure builds up in the infusion line. Your pump will sound an alarm if this happens.
Insulin Plans
How often should you use insulin? There is no answer that is right for all people at all times. Different plans suit different people, depending on how easily managed your blood glucose levels are and how well you understand the way different foods, physical activity, and stress affect your blood glucose levels.
Most people with type 1 diabetes will have to start with multiple daily injections of insulin. This section begins by describing multiple daily injection plans that are appropriate for people with type 1 diabetes and some people with type 2 diabetes. Toward the end of this section, you will find less intensified insulin plans that are appropriate for some people with type 2 diabetes. First, let’s review some of the basics.
Insulin and Type 1 Diabetes
• Most people with type 1 diabetes require multiple daily injections of insulin or an insulin pump and frequent blood glucose monitoring.
• The pancreas no longer secretes insulin, so the goal of insulin therapy is to mimic a normal pancreas as closely as possible.
Insulin and Type 2 Diabetes
• In some people, not enough insulin is produced in relation to how much is needed by the body. Insulin is often needed along with meal planning and exercise.
• In addition, the cells in the body resist the action of the insulin that is produced. Diet and exercise and oral diabetes medications alone or with insulin may be needed.
• Therapies for type 2 diabetes may have to take into account both lack of insulin and resistance to insulin. Some people may be able to manage blood glucose by changing their eating and exercise habits. Others will need oral diabetes medication, and still others will need insulin in addition to diet and exercise.
When and How to Start Insulin?
If you have type 2 diabetes, when and how you start taking insulin is up to you and your health care provider. For example, you may take a once-daily insulin injection in addition to other medications or you may take multiple daily injections. There are many factors to consider when discussing insulin, including your current medication regimen and blood glucose goals. You’ll discuss several considerations with your health care provider to develop the best insulin plan for you. Don’t be afraid to ask questions.
Insulin and Gestational Diabetes
Some women manage the high blood glucose levels caused by insulin resistance without insulin therapy. Others need the help of insulin.
Most insulin plans try to mimic a normal pancreas. A pancreas puts out a steady stream of insulin (a basal dose) day and night. It also secretes an extra dose of insulin (a bolus) in response to food intake (see the graph above).
If you use an insulin pump, you’ll set up your basal and bolus doses of insulin to mimic this rhythm. If you choose to inject insulin, you’ll use longer-acting insulin to mimic basal insulin and rapid-acting or regular insulin to mimic bolus insulin.
The type, dose, and schedule of these insulins will be up to you and your provider. You might want to refer back to “Insulins Used in the United States” table) to review when different insulins take action.
Work with your provider to come up with a plan to suit your life and schedule. If your plan is not working out for you, talk to your provider. There are usually many other plans you can try.
Multiple Daily Injections
People with type 1 diabetes must use multiple daily injections of insulin or pumps to manage their diabetes. Some people with type 2 diabetes also find that multiple daily injections of insulin or pumps work best for them.
Taking multiple daily injections is sometimes called intensive diabetes management or tight control. The goal is to mimic the natural secretion of insulin from the pancreas as much as possible. The goals, advantages, and disadvantages of tight control are discussed in detail in chapter 9.
The more often you inject insulin, the more opportunities you have to fine-tune your control. You also have more freedom and flexibility with your schedule and food choices.
With this plan, long-acting insulin analogs, such as insulin glargine (Lantus) or detemir (Levemir), provide your basal dose of insulin. You then take rapid-acting insulin before a meal based on the carbohydrates you eat at that meal. The injections of rapid-acting insulin analogs provide the bolus for the three meals (see graph above).
To make this plan work for you, you need to monitor your blood glucose frequently. You will need to adjust the amounts of rapid-acting insulin given before each meal in order to cover the carbohydrates in your meal, lower a high blood glucose level not sufficiently lowered by the previous rapid-acting insulin injection, or anticipate the rise in blood glucose caused by the next meal.
You will also have the opportunity to make adjustments during the day. If you are exercising after lunch, you might want to reduce the amount of your noon insulin dose. If you are going out to a fancy dinner where you know you’ll be eating more than usual, you may want to take more insulin. Your diabetes educator can help you learn how to adjust your insulin doses.
One Unit of Insulin
• Generally, 1 unit of insulin will lower blood glucose levels by about 25–100 mg/dl. You need to find out how it affects your blood glucose levels.
• In general, 1 unit of insulin will cover up to 20 grams of carbohydrate. You also need to find out how this applies to you.
Insulin Pump or Multiple Daily Injections
If you are injecting insulin multiple times a day, you may want to consider an insulin pump.
Daily Insulin Dose
• Your starting insulin dose for either injections or the pump will be based on your weight and current insulin program. For example, for people with type 1 diabetes who are within 20% of their ideal body weight, the total daily insulin dose needed for intensive therapy is 0.5–1.0 units of insulin per kilogram of body weight. That means that if you weigh 127 pounds (1 kilogram equals 2.2 pounds), you would take about 29–57 units of insulin each day.
• Your total daily insulin dose would be at the high end of the range if you were resistant to insulin (57 units) or at the lower end of the range, if you were very sensitive to insulin (29 units).
• About one-third to one-half of your total daily dose would provide your basal insulin level, and the rest would be used to cover meals.
• Most people start out with lower doses and gradually increase the amount of insulin until they reach their blood glucose target.
• If you are pregnant, your total daily insulin dose will go up as you gain weight and develop more insulin resistance. Your insulin dose may even triple during the course of pregnancy.
Whichever formula or calculation you use, you will most likely have to make adjustments as you find the program that best suits you. You will probably have a plan for how to adjust your dose, but you will also need to be in close contact with your health care team.
You will be able to make small adjustments throughout the day to accommodate your meals and activities. If monitoring shows that your blood glucose levels are too high, you need to take extra insulin or reduce the amount of carbohydrate in your next meal.
Insulin Distribution
Here is one formula that some people find helpful as a starting point for deciding how to distribute insulin throughout the day.
• 40–50% total insulin as the basal dose
• 15–25% before breakfast
• 15% before lunch
• 15–20% before supper
• 0–10%, as needed, to cover a bedtime snack
Rapid-Acting Insulin Analogs and Meals
Knowing when and how much insulin to take at meals can be confusing. Here are some tips to get you started.
• Rapid-acting insulin is taken before meals or very big snacks to counteract the increase in blood glucose that will occur as food is digested.
• You can take your injection just before you eat.
• Rapid-acting insulin analogs begin to work in about 5–15 minutes. Taking your injection more than 15 minutes before meals may result in hypoglycemia.
One Shot a Day
A single shot of insulin can sometimes be enough to bring your blood glucose into the target range. You might be able to inject long-acting insulin, such as insulin glargine (Lantus) or detemir (Levemir), or intermediate-acting insulin, such as NPH, to provide a basal level of insulin (see graph below).
Which Type of Insulin Is Right for Me?
• Long-acting insulin provides a steady level of insulin throughout the day and night.
• Intermediate-acting insulin that is taken at bedtime might help lower fasting blood glucose levels.
• Intermediate-acting insulin that is taken in the morning will provide some coverage for the food you eat as well as provide a basal insulin level.
At mealtimes, there isn’t always enough insulin available from one injection to lower your blood glucose. Taking one shot a day can also mean that you are locked into a schedule for your meals.
Some people with type 2 diabetes may be able to make enough insulin to cover the post-meal increase in blood glucose. For these people, providing the basal insulin helps their pancreas to do its job better. Usually, however, one shot of basal insulin does not result in optimal control because glucose rises after meals.
Another option is to take oral diabetes medications or other injectable medications along with the one injection of basal insulin. These medications can provide the coverage needed for meals.
More Than One Shot
You may get better coverage by splitting your one shot of insulin into two shots. These can be given in the morning and in the evening. Usually, for twice-daily injections, you’ll use intermediate-acting or premixed insulin instead of long-acting insulin. The morning shot will be a bigger dose than the evening shot (see graph below).
However, even with this plan, you may have a period in the early morning, between 3 and 10 a.m., when your insulin level may be low.
Another possibility is to take a combination of insulins. You can take rapid-acting or regular insulin along with your morning shot of intermediate-acting NPH insulin. This gives you a bolus of insulin to cover your breakfast meal. Additional insulin can be taken later in the day. You can either use premixed insulins or mix two types of insulin in one injection (see graphs above).
Some people choose to take a basal, long-acting insulin analog once daily and a mealtime rapid-acting insulin analog up to three times a day, rather than NPH and rapid-acting insulin.
It may take a little experimenting and consulting with your health care team to figure out how to best mix rapid-acting or regular and intermediate-acting insulins. You may have to change the ratio many times before you get the results that best suit you.
You may find it convenient to buy premixed insulin, such as a 70/30 or 75/25 mixture, or you may prefer to split and mix the doses yourself. Mixing the doses yourself gives you the flexibility to match your insulin dose to your insulin needs. This may be helpful when you are trying to account for your physical activity and meals.
With this plan, you will still need to monitor your blood glucose closely. You need to monitor your blood glucose levels before and after meals. You may need to monitor at other times as well.
Fine-Tuning Your Insulin Plan
A two-shot program gives you better insulin coverage than a single-shot plan but still keeps you closely tied to a regular meal schedule and a regular pattern of activity. Usually the three major meals have to be about 5 hours apart for optimal coverage. This is because you cannot make short-term adjustments with longer-acting insulins. Only rapid-acting or regular insulin can be adjusted to immediately respond to a blood glucose level or change in schedule.
Highs in the Morning
• You may want to move your evening insulin shot from dinnertime to bedtime so your body will have a little more insulin to cover rising blood glucose levels overnight. Make sure that your glucose levels are on target during the evening hours if you try this adjustment.
• You may find that you have low blood glucose in the early morning (around 2 or 3 a.m.) with the two-shot plan. If this is the case, think about a three-shot plan.
• With a three-shot plan (see graph below), you would give yourself a mixture of rapid-acting or regular insulin and intermediate-acting insulin at breakfast, rapid-acting or regular insulin at dinner, and intermediate-acting insulin at bedtime.
Future Prospects for Insulin Delivery
People with diabetes have more options than ever for delivering insulin. However, people are continually working toward developing better technology that will improve life for people with diabetes.
The so-called artificial pancreas (or “closed-loop system”) is closer to becoming a reality every year. A closed-loop system would work as close to a real pancreas as possible—responding to glucose and delivering insulin appropriately. A truly successful closed-loop system would need to incorporate a continuous glucose monitor, a pump or other insulin delivery device, and a computer to manage the system. There may still be a role for the patient, such as confirming recommended doses.
Currently, this technology is still in the planning and development stages. However, there are several continuous glucose monitors on the market, and one company makes a continuous glucose monitor and insulin pump that specifically work together.
In Conclusion
In addition to insulin, some people with type 1 or type 2 diabetes take an injectable medication called pramlintide acetate. It is taken with meals to help reduce blood glucose levels. It can also suppress your appetite, so you feel fuller and eat less at meals. Pramlintide acetate cannot be mixed with insulin and is available in a separate, prefilled pen or vial and syringe.
Taking insulin is a big step. When you’re first discussing starting insulin with your health care team, don’t be afraid to take notes or ask lots of questions about anything that’s not clear. Even if you have taken insulin before, you might want to review your insulin schedule on a return visit to your care provider, especially if you are experiencing any difficulties. You might also want to go over any changes in your schedule. Make sure you understand how to time injections with meals. Go step by step through a typical day. Also discuss how to adjust your insulin doses and timing for an unusual day—what happens if you oversleep, get sick, travel across time zones, or plan to be unusually active?
Before you leave your diabetes care provider’s office, be sure you understand the following:
• What type of insulin you will be taking and the name of the insulin.
• Symptoms of high and low blood glucose that may indicate a problem with your insulin doses and how to appropriately treat and prevent these incidents.
• Where you should inject it.
• Whether you need to prepare any mixtures.
• How often you will take injections.
• The best times of the day to take insulin.
• How to store your insulin.