types of insulin are categorized according to how fast
they start to work (onset) and how long they continue to work (duration). The
types now available include rapid-, short-, intermediate-, and long-acting
Humulin R, Novolin R, Humulin R U-500
Humulin N, Novolin N
70% NPH and 30%
Humulin 70/30, Novolin 70/30
lispro protamine and 50% lispro
Humalog Mix 50/50
75% lispro protamine and 25% lispro
Humalog Mix 75/25
70% aspart protamine and 30% aspart
NovoLog Mix 70/30
50% NPH and 50% regular
Injectable insulin is packaged in small
vials (bottles) and cartridges that hold more than one
dose and are sealed with rubber lids. The cartridges are used in pen-shaped
devices called insulin pens.
How insulin is taken
Insulin usually is given as
an injection into the tissues under the skin (subcutaneous). It can also be
given through an
insulin pump, an
insulin pen, or jet injector, a device that sprays the
medicine into the skin. Some insulins can be given through a vein (only in a
Research is ongoing to develop not only new forms of
insulin but also insulin that can be taken in other ways, such as by mouth.
How It Works
Insulin lets sugar (glucose) in the
blood enter cells, where it is used for energy. Without insulin, the blood
sugar level rises above what is safe for the body. If the cells don't get sugar to use for energy, they try to use other nutrients in the body. When this happens, acids can build up. Too much acid production (ketoacidosis) can be serious or even life-threatening.
Your body uses
insulin in different ways. Sometimes you need insulin to work quickly to reduce
blood sugar. Your body also needs insulin on a regular basis to keep your blood
sugar in a target range.
Rapid-acting and short-acting insulins reduce
blood sugar levels quickly and then wear off.
When you use
intermediate- or long-acting insulin with rapid- or short-acting insulins, the longer acting
insulin starts taking effect when the shorter acting insulin begins to wear
Usually people who take insulin use a combination of a
rapid- or short-acting and an intermediate- or long-acting insulin. This can help to
keep blood sugar levels within a range that is safe for the body throughout the
type 2 diabetes whose
pancreas produces little or no insulin or whose other diabetes
medicines do not control their blood sugar. These people may take insulin
either by itself or along with other diabetes medicine.
People with type 2
diabetes whose blood sugar levels are high because of a severe illness or major
surgery. After blood sugar levels return to a target range, these people may be
able to stop taking insulin.
Women with type 2 diabetes who are
pregnant or breast-feeding and who cannot keep their blood sugar levels in a
target range with diet and exercise. Only one oral
diabetes medicine (glyburide) has been studied for use during pregnancy. Until
further research is done, the American Diabetes Association recommends that
pregnant women and women who are breast-feeding not take oral diabetes
How Well It Works
Insulin is effective in reducing
blood sugar levels by helping sugar (glucose) enter the cells to be used for
Some things that affect
how fast and how well an insulin dose works are:
Where the dose is given. If you give insulin
into your abdomen (especially above and to the side of your belly button), the
medicine will get into your system more consistently from day to day. If the
medicine is given into a muscle or a small blood vessel instead of fatty
tissue, the medicine will get into your system faster.
insulin is given. Higher doses of insulin reduce the blood sugar level more
than lower doses.
Whether you have exercised before or just after taking insulin.
If you have just exercised the muscles in the area where you give your insulin
injection, the medicine will get into your system faster.
apply heat to the area. The medicine will get into your system faster if you
take a hot bath or shower, put on a heat pack, or massage the area where you
have just given your insulin injection.
If you do not have enough
fluid in your body (you are dehydrated). You will not have as much blood flow
to your skin, so insulin will not be absorbed as well.
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
Usually the benefits of the medicine are more important than any minor side effects.
Side effects may go away after you take the medicine for a while.
If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.
Call 911 or other emergency services right away if you have:
Swelling of your face, lips, tongue, or throat.
Passed out (lost consciousness), or you suddenly become very sleepy or confused. You may have low blood sugar, called hypoglycemia.
Call your doctor if you have:
Problems with frequent high or low blood sugar levels.
Common side effects of this medicine include:
Low blood sugar.
See Drug Reference for
a full list of side effects. (Drug Reference is not available in all
What To Think About
insulin pump provides a way to give insulin with less
frequent injections, and it is as effective as multiple daily injections at keeping
blood sugar levels in a target range.
Don't share insulin pens with anyone else who uses insulin. Even when the needle is changed, an insulin pen can carry bacteria or blood that can make another person sick.
The long-acting insulin
glargine (Lantus) may help prevent some people from having frequent nighttime
low blood sugar levels. It may also help people who have had
difficulty keeping their blood sugar levels in their target range with
When you buy insulin, check the generic or brand names
to make sure you are buying the correct type. For example, if you have been
using Humulin R (insulin regular), make sure you buy Humulin R instead of
Humulin N (insulin NPH).
Know when your prescribed types of insulin start working
(onset), when they work most (peak), and how long they work
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Advice for women
If you are pregnant, breast-feeding, or planning to get pregnant, do not use any medicines unless your doctor tells you to. Some medicines can harm your baby. This includes prescription and over-the-counter medicines, vitamins, herbs, and supplements. And make sure that all your doctors know that you are pregnant, breast-feeding, or planning to get pregnant.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Centers for Disease Control and Prevention (2007). Guideline for isolation precautions: Preventing transmission of infectious agents in healthcare settings 2007. Available online: http://www.cdc.gov/hicpac/2007IP/2007isolationPrecautions.html.
How this information was developed to help you make better health decisions.