Incretin mimetics for type 2 diabetes


Generic Name Brand Name
exenatide Byetta

Exenatide is the first of a new type of medication called incretin mimetics. The U.S. Food and Drug Administration (FDA) approved exenatide to treat people with type 2 diabetes who have not been able to control their blood sugar levels with oral medicines. It is given as a shot 2 times a day, before morning and evening meals.

How It Works

Incretin mimetics act like (mimic) the natural hormones in your body that lower blood sugar. These hormones are called incretins. Exenatide:

  • Allows your pancreas to release insulin. This drug lowers blood sugar levels only when they rise too high.
  • Prevents the pancreas from giving out glucagon. Glucagon is a hormone that causes the liver to release its stored sugar into the bloodstream.
  • Helps to slow the rate at which your stomach empties after eating. This may make you feel less hungry and more satisfied after a meal.

Why It Is Used

Exenatide can be used when metformin or sulfonylurea drugs are not working to control blood sugar. You may take exenatide with these oral drugs. You most likely will not use exenatide if you are using insulin.

How Well It Works

Early studies showed that exenatide lowered blood sugar levels both before and after eating.1 Studies also showed that people who added exenatide to their treatment with some oral medicines had lower hemoglobin A1c levels than they did before they added exenatide to their treatment.2, 3, 4 A1c is a measure of how well blood sugar levels have remained within a normal or near-normal range over the previous 2 to 3 months.

Side Effects

The most common side effects of exenatide are nausea and diarrhea. Nausea is usually worse during the first few weeks of treatment and gets better over time.4, 2

Taking exenatide with a sulfonylurea drug may cause mild to moderate low blood sugar (hypoglycemia). If you take both drugs, you may need to take a lower dose of the sulfonylurea to prevent low blood sugar. But low blood sugar is not a side effect when exenatide is taken with metformin.2

Exenatide does not cause weight gain. Sometimes people who take exenatide lose weight.3

People with severe kidney disease should not take exenatide.

The U.S. Food and Drug Administration (FDA) has announced a possible link between exenatide (Byetta) and acute pancreatitis. If you have unexplained, continuous, severe stomach pain, which may or may not occur with vomiting, contact your doctor immediately.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Before injecting exenatide, talk to your doctor about other medicines you are taking. Exenatide may affect how other medicines are absorbed into your system.

If you are pregnant or want to become pregnant, talk with your doctor before you take exenatide. He or she may recommend that you take another drug because the safety of exenatide during pregnancy has not been studied in humans.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.



  1. Exenatide (Byetta) for type 2 diabetes. (2005). Medical Letter on Drugs and Therapeutics, 47(1210): 45–46.
  2. Buse JB, et al. (2004). Effects of exenatide (exendin-4) on glycemic control over 30 weeks in sulfonylurea-treated patients with type 2 diabetes. Diabetes Care, 27(11): 2628–2635.
  3. Kendall DM, et al. (2005). Effects of exenatide (exendin-4) on glycemic control over 30 weeks in patients with type 2 diabetes treated with metformin and a sulfonylurea. Diabetes Care, 28(5): 1083–1091.
  4. DeFronzo RA, et al. (2005). Effects of exenatide (exendin-4) on glycemic control and weight over 30 weeks in metformin-treated patients with type 2 diabetes. Diabetes Care, 28(5): 1092–1100.

Last Updated: June 16, 2008

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