Examples
The different 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 insulin.
Rapid-acting
| Generic Name | Brand Name |
|---|---|
| insulin aspart | NovoLog |
| insulin glulisine | Apidra |
| insulin lispro | Humalog |
| Generic Name | Brand Name |
|---|---|
| insulin regular | Humulin-R |
| Generic Name | Brand Name |
|---|---|
| insulin NPH | Humulin-N |
| Generic Name | Brand Name |
|---|---|
| insulin detemir | Levemir |
| insulin glargine | Lantus |
There are premixed rapid- and intermediate-acting insulins available, including:
- 70% intermediate-acting (NPH) and 30% short-acting regular insulin, called 70/30 insulin
- 50% intermediate-acting (NPH) and 50% short-acting regular insulin, called 50/50 insulin
- 75% intermediate-acting and 25% rapid-acting Humalog (lispro), called 75/25 insulin
- 70% intermediate-acting and 30% rapid-acting NovoLog (insulin aspart), called NovoLog Mix 70/30
Packaging
Injectable insulin is packaged in small glass 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 medication into the skin. Some insulins can be given through a vein (only in a hospital).
Research is ongoing to develop new forms of insulin, as well as insulin that can be taken in other ways, such as by mouth or nasal spray.
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.
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 within a normal or near normal range.
- Rapid-acting and short-acting insulins reduce blood sugar levels quickly and then wear off.
- When you use long-acting insulin with rapid- or short-acting insulins, the long-acting insulin starts taking effect when rapid- or short-acting insulins begin to wear off. The long-acting insulin glargine (Lantus) starts to work within an hour after it is given and continues to work at the same rate for about 24 hours. Lantus cannot be mixed in the same syringe with other types of insulin.
- Usually people who take insulin use a combination of a rapid- or short-acting and an intermediate- or long-acting insulin. This helps keep blood sugar levels within a range that is safe for the body throughout the day.
Why it is used
Insulin is used to treat:
- People with type 1 diabetes.
- People with type 2 diabetes whose pancreas produces little or no insulin or whose oral medications do not control their blood sugar. These people may take insulin either alone or along with oral medication.
- 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 who cannot keep their blood sugar levels within a target range with diet and exercise. Only one oral diabetes medication (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 medications.
How well it works
Insulin is effective in reducing blood sugar levels by helping sugar (glucose) enter the cells to be used for energy.
For people with type 1 diabetes
Results of the 10-year Diabetes Control and Complications Trial (DCCT) and the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study showed that people with type 1 diabetes who kept their blood sugar levels tightly within a normal or near-normal range (tightly controlled therapy) had fewer incidences of eye, kidney, and nerve damage from diabetes than people who were on standard therapy. Tightly controlled therapy also lowered the risk of heart attacks and deaths from heart disease.
One study shows that insulin glargine (Lantus) is as effective as NPH insulin in controlling blood sugar in people with type 1 diabetes. Lantus causes fewer low blood sugar episodes than NPH.
For people with type 2 diabetes
Results of the United Kingdom Prospective Diabetes Study (UKPDS) showed that insulin decreased the risk of diabetic retinopathy, diabetic nephropathy, and diabetic neuropathy in people with type 2 diabetes.
Side effects
The major side effect of insulin can be a dangerously low blood sugar level (severe hypoglycemia). A very low blood sugar level can develop within 10 to 15 minutes with rapid-acting insulins.
Insulin can contribute to weight gain, especially in people with type 2 diabetes who already are overweight.
Other possible side effects of long-term insulin use include the loss of fatty tissue (lipodystrophy) where the insulin is injected and, rarely, allergic reactions that include swelling, or edema.