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Generic name: exenatideex-EN-a-tide ]
Brand name: Byetta Prefilled Pen
Drug class: Incretin Mimetics (GLP-1 Agonists)

Medically reviewed by Philip Thornton, DipPharm. Last updated on May 18, 2023.

What is Byetta?

Byetta is an injectable diabetes medicine that helps control blood sugar levels. This medication helps your pancreas produce insulin more efficiently. Byetta is a short-acting form of exenatide.

Byetta is used together with diet and exercise to improve blood sugar control in adults with type 2 diabetes. Byetta is not for treating type 1 diabetes.

This medication guide provides information about the Byetta, an immediate-release brand of exenatide. Bydureon is an extended-release brand of exenatide that is not covered in this medication guide.


You should not use Byetta if you have severe kidney disease (or you are on dialysis), or if you have slowed digestion or diabetic ketoacidosis.

You should not use this medicine if Byetta has ever caused you to have low platelet levels in your blood.

Stop using this medicine and call your doctor at once if you have nausea and vomiting with severe pain in your upper stomach spreading to your back.

You should not use Byetta together with fast-acting or short-acting insulins. Do not use this medicine together with Bydureon.

Before taking this medicine

You should not use Byetta if you are allergic to exenatide, or if you have:

To make sure Byetta is safe for you, tell your doctor if you have ever had:

Follow your doctor's instructions about using this medicine if you are pregnant or you become pregnant. Controlling diabetes is very important during pregnancy, and having high blood sugar may cause complications in both the mother and the baby.

Exenatide can make birth control pills less effective. If you take birth control pills, take your pill at least 1 hour before your Byetta injection.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk.

Byetta is not approved for use by anyone younger than 18 years old.

How should I use Byetta?

Use Byetta exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Byetta is injected under the skin. A healthcare provider may teach you how to properly use the medication by yourself.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Prepare your injection only when you are ready to give it. You must give the injection right away after mixing.

Byetta is usually injected twice a day, before the morning and evening meals. Do not use after eating a meal. You must use Byetta within 60 minutes (1 hour) before eating. Your injections should be given at least 6 hours apart.

You may have low blood sugar (hypoglycemia) and feel very hungry, dizzy, irritable, confused, anxious, or shaky. To quickly treat hypoglycemia, eat or drink a fast-acting source of sugar (fruit juice, hard candy, crackers, raisins, or non-diet soda).

Your doctor may prescribe a glucagon injection kit in case you have severe hypoglycemia. Be sure your family or close friends know how to give you this injection in an emergency.

Also watch for signs of high blood sugar (hyperglycemia) such as increased thirst or urination.

Blood sugar levels can be affected by stress, illness, surgery, exercise, alcohol use, or skipping meals. Ask your doctor before changing your dose or medication schedule.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

Never share an injection pen or syringe with another person, even if the needle has been changed. Sharing these devices can allow infections or disease to pass from one person to another.

Exenatide can lower your platelet counts for up to 10 weeks after you stop using Byetta. You may need frequent medical tests while using this medicine and for a short time after you stop.

Byetta is only part of a complete treatment program that may also include diet, exercise, weight control, regular blood sugar testing, and special medical care. Follow your doctor's instructions very closely.

Storing unopened (not in use) pens: Keep the medicine in its original container. Refrigerate and use until expiration date. Protect from light.

Do not freeze. Throw away the medicine if it has been frozen.

Storing opened (in use) pens: Store at room temperature and use within 30 days. Protect from heat and bright light. Do not store the injection pen with a needle attached.

Dosing information

Usual Adult Dose for Diabetes Type 2:

Immediate-release (Byetta):
Initial dose: 5 mcg subcutaneously twice a day within the 60-minute period before the morning and evening meals
-Maintenance dose: After 1 month, may increase dose to 10 mcg subcutaneously twice a day based on clinical response
-Maximum dose: 10 mcg twice a day
-Alternatively, may give before the two main meals of the day provided dosing is 6 hours or more apart

-This drug has not been studied in patients with a history of pancreatitis and therefore, other therapies should be considered in these patients.
-Extended-release exenatide is not recommended as first-line therapy because of the uncertainty of the risk of thyroid C-cell tumors.
-Patients may experience transient (approximately 2 to 4 weeks) elevation in blood sugar when switching from immediate-release exenatide to extended-release.

Use: As an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose can cause severe nausea and vomiting, or signs of low blood sugar (headache, hunger, irritability, dizziness, feeling shaky).

What should I avoid while using Byetta?

You should not mix Byetta with insulin in the same syringe. Do not use Byetta together with Bydureon.

Avoid drinking alcohol. It can lower your blood sugar.

Byetta side effects

Get emergency medical help if you have signs of an allergic reaction to Byetta: hives, itching; rapid heartbeats; difficult breathing; feeling light-headed; swelling of your face, lips, tongue, or throat.

Some people using exenatide have had serious or fatal bleeding caused by low levels of platelets (blood cells that help your blood to clot). Stop using Byetta and call your doctor right away if you have unusual bleeding or bruising.

Stop using Byetta and call your doctor at once if you have:

Common Byetta side effects include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Byetta?

If you take the following medicines, take them at least 1 hour before you use Byetta:

If you take these medicines with food, take them with a meal or snack separate from the meal times when you use Byetta.

Exenatide can make it harder for your body to absorb other medicines you take by mouth. Tell your doctor about all your current medicines and any you start or stop using, especially:

This list is not complete. Other drugs may interact with exenatide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Popular FAQ

Bydureon Bcise starts working as soon as you inject the first dose but it may take two or more weeks before it has a noticeable effect on your blood sugar, and longer before it decreases your HbA1c levels. Bydureon Bcise builds up gradually in your body with each weekly dose and reaches its optimal level after 10 weeks of dosing. The extended-release delivery system keeps a consistent level of medicine in your body. Continue reading

Bydureon can be left unrefrigerated at room temperature for up to 4 weeks (28 days) as long as the temperature in the room does not exceed 86°F (30°C). This will allow you to take your weekly dose with you, especially if you are traveling. Never leave your Bydureon pen in the sun or a hot place, like your car's jockey box, because it will become too hot. And do not put it back in the refrigerator if it has been out of the refrigerator for longer than an hour. Continue reading

Bydureon works by mimicking the effects of a naturally occurring human incretin, called GLP-1. Incretins are gut-derived hormones, similar to glucagon, that are released in response to food ingestion, mainly when we eat glucose or fat. When GLP-1 binds to the GLP-1 receptor it causes an increase in our body’s production of insulin in response to food. When Bydureon is given by injection into the upper thigh once a week, it binds to the GLP-1 receptor, stimulating insulin release from the beta cells of the pancreas whenever we eat. Continue reading

The Bydureon pen was discontinued in March 2021 and has been replaced by Bydureon Bcise Autoinjector. The Bydureon Bcise Autoinjector has been designed to be easy to use. There is no need to attach a needle (the hidden needle is already attached) or turn a dial. Always store your Bydureon Bcise autoinjector flat in the refrigerator. It can be self-injected at home once a week and it is easy to learn how to administer it yourself. If you have difficulty injecting it, a family member, friend, caregiver, or healthcare provider may be able to do it for you. Instructions for injecting the Bydureon Bcise autoinjector are given below. Continue reading

The Bydureon Bcise Autoinjector has been designed to be easy to use. There is no need to attach a needle (the hidden needle is already attached) or turn a dial. Always store your Bydureon Bcise autoinjector flat in the refrigerator. Continue reading

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Byetta only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.