Types of Injectable Insulin

Injectable insulins come in four different types. The different classifications indicate both how quickly an insulin gets absorbed into the blood stream, and how long an insulin exerts a measurable effect in the body. The American Diabetes Association advises patients that they will probably have to use more than one type of injectable insulin to control their blood sugar. To meet this need for more than one type of insulin, some drug makers market premixed insulin products.

Rapid-Acting

Rapid-acting insulins begin exerting an effect within 15 minutes of injection and begin losing their effectiveness after 30 minutes. Designed to be injected shortly before a patient eats a meal, rapid-acting insulins get completely metabolized within five hours. The U.S. Food and Drug Administration has approved three forms of rapid-acting insulin: Humalog (insulin lispro) from Lilly, NovoLog (insulin aspart) from Novo Nordisk, and Apidra (insulin glulisine) from Sanofi-aventis.

Short-Acting

Also known as "regular insulin," short-acting insulins start working about 30 minutes after injection and continue working for between three and eight hours. Like rapid-acting insulins, short-acting insulins get injected shortly before meals. Humulin R (recombinant human insulin) from Lilly and Novolin R (recombinant human insulin) from Novo Nordisk are the FDA-approved forms of short-acting insulin.

Intermediate-Acting

Humulin N (insulin lente isophane) from Lilly and Novolin N (NPH insulin isophane) from Novo Nordisk are classified as intermediate-acting insulins because they take effect an average of two hours after injection and work to regulate a patient's blood sugar for up to 18 hours. Patients administer intermediate-acting insulin after dinner and before going to sleep.

Long-Acting

The FDA has approved the long-acting insulins Lantus (insulin glargine) from Sanofi-aventis and Levemir (insulin detemir) from Novo Nordisk. These insulins exert an effect for a full 24 hours, and patients should inject them once each day. The long-acting insulins can take as much as 10 hours to start working.

Premixed

Depending on their needs, patients may receive prescriptions for premixed insulin injections. Products such as Lilly's Humulin 70/30 and Novo Nordisk's Novolin 70/30, for instance, contain carefully balanced mixtures of regular-acting---the first number of the ratio---and intermediate-acting insulin. Patients need to following their doctors' instructions on when to administer injections of premixed insulins and on how much to inject carefully to avoid dangerous drops or spikes in blood sugar.

References

• Types of Insulin from the American Diabetes Association
• Insulin information from MayoClinic.com
• Insulin injection information from Medline Plus

Resources

• American Diabetes Association
• Diabetes overview for the National Institute of Diabetes and Digestive and Kidney Diseases