Incretin mimetics for type 2 diabetes

Examples

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Brand Name	Chemical Name
Byetta	exenatide

Exenatide is the first of a new type of medicines 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

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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

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

How Well It Works

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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 A_1c (HbA1c) levels than they did before they added exenatide to their treatment.^{2, 3, 4} HbA_1c 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

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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. However, 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.

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

What To Think About

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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, since 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.

References

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Citations

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.

Credits

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Author	Merrill Hayden
Editor	Kathleen M. Ariss, MS
Associate Editor	Michele Cronen
Primary Medical Reviewer	Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer	Matthew I. Kim, MD - Endocrinology & Metabolism
Last Updated	July 11, 2006