Johns Hopkins Health Alert
Insulin: Youve Got Choices
Approximately 40% of people with type 2 diabetes eventually require some type of insulin treatment to control their blood glucose, either because their diabetes gets worse or it no longer responds to oral drugs. Many people with type 2 diabetes take insulin in combination with metformin, a thiazolidinedione, or a sulfonylurea.
Insulin was once obtained exclusively from pig or cow pancreas. Today, regular and intermediate-acting insulins are referred to as human insulins, because they are manufactured to be identical to the insulin produced by the human pancreas. Rapid- and long-acting insulins are chemically modified forms of human insulin.
There are four main types of insulin:
- Rapid-acting insulin.
Insulin aspart (Novolog), insulin lispro (Humalog), and insulin glulisine (Apidra) are called insulin analogues, because their chemical structure is a modified form of human insulin that is designed to work more quickly and peak faster than regular insulin. These manufactured insulins work with time-actions that are close to the natural insulin functions in the body. Consequently, they may be effective in preventing high blood glucose (hyperglycemia) after meals and are less likely to produce hypoglycemia later on.
- Regular or short-acting insulin.
This type of insulin is manufactured to be the same as the insulin produced in the human body. Popular brands have an "R" (for regular) in their names, for example, Humulin R and Novolin R.
Regular insulin is typically injected 30 to 60 minutes before meals and usually reaches the bloodstream within 30 minutes, in time to cover the rise in blood glucose that begins after food is eaten. Insulin action peaks two to three hours after injection and the effects generally last about three to six hours.
- Intermediate-acting insulin.
This type of human insulin called NPH insulin contains protamine, which makes the solution cloudy and slows the absorption of insulin. NPH insulins have an "N" in their names, for example, Humulin N and Novolin N.
After injection, intermediate-acting insulins reach the bloodstream within two to four hours and show peak action in four to 10 hours. Duration of action is from 10 to 16 hours. Intermediate-acting insulin is often used in combination with regular or rapid-acting insulin.
- Long-acting insulin.
Both insulin glargine (Lantus) and insulin detemir (Levemir) are long-acting insulin analogues. They are often used alone in people with type 2 diabetes, or in combination with a more quick-acting insulin. Lantus is a clear solution in the vial, but it precipitates in the skin after injection, which greatly slows absorption and makes it very long acting, usually 20 to 24 hours. Levemir also is absorbed slowly, because it binds to the protein albumin in the skin. Its effects last about 14 to 18 hours.
Posted in Diabetes on September 2, 2010
Medical Disclaimer: This information is not intended to substitute for the advice of a physician. Click here for additional information: Johns Hopkins Health Alerts Disclaimer
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