Byetta (exenatide) is a prescription drug that’s used to treat type 2 diabetes. Byetta can cause side effects that range from mild to serious. Examples include nausea and vomiting.

Specifically, Byetta is prescribed to adults with type 2 diabetes to help manage blood sugar levels. It should be used along with diet and exercise. Byetta is not prescribed to treat type 1 diabetes.

The active ingredient in Byetta is exenatide. (An active ingredient is what makes a drug work.) The drug comes as a liquid solution that’s given as an injection under your skin.

Keep reading to learn about the common, mild, and serious side effects that Byetta can cause. For a general overview of the drug, including details about its uses, see this article.

Some people may experience mild to serious side effects during their Byetta treatment. Examples of Byetta’s most commonly reported side effects include:

* To learn more about this side effect, see the “Side effects explained” section below.

Byetta can cause you to experience mild side effects. Examples of mild side effects that have been reported with Byetta include:

* To learn more about this side effect, see the “Side effects explained” section below.

In most cases, these side effects should be temporary. And some may be managed. If you have symptoms that are ongoing or that bother you, talk with your doctor or pharmacist. Do not stop Byetta treatment unless your doctor recommends it.

Byetta may cause mild side effects other than those listed above. See the Byetta prescribing information for details.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Byetta, visit MedWatch.

Though many side effects from Byetta are mild, serious side effects are possible as well. Serious side effects that have been reported with Byetta include:

If you develop serious side effects while taking Byetta, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

* To learn more about this side effect, see the “Side effects explained” section below.

Get answers to some frequently asked questions about Byetta’s side effects.

Will I have a higher risk of side effects if I take the 10-microgram (mcg) strength of Byetta compared with the 5-mcg strength of the drug?

It’s possible that you may have more side effects from Byetta if you take a higher dose. For example, you may be at an increased risk of low blood sugar when taking a higher dose of Byetta. This is because a higher dose means there’s more of the drug working in your body to lower your blood sugar.

If you have side effects that are bothersome during your Byetta treatment, talk with your doctor. They may recommend decreasing your dose to determine whether the side effects ease.

Can Byetta cause long-term side effects?

It’s possible for Byetta to cause long-term side effects. But in many cases, side effects from this medication are short term.

Kidney problems are an example of a long-term side effect that can result from taking Byetta. In rare cases, Byetta can cause serious kidney injury. And you may still have kidney problems even after stopping Byetta.

If you develop any side effects that don’t go away or that concern you, talk with your doctor. They can help you determine if it’s safe for you to continue treatment with Byetta.

Is it possible for Byetta to cause cancer?

Byetta isn’t known to cause cancer, and this wasn’t a side effect reported in people taking the drug in studies.

But drugs similar to Byetta, including the long-acting form of exenatide (the active drug in Byetta), do have warnings for thyroid cancer. Although it’s rare, these medications may increase your risk of developing this form of cancer. In fact, medications similar to Byetta have boxed warnings for the possibility of thyroid cancer, particularly certain thyroid tumors. Boxed warnings are the most serious warnings issued by the FDA. They alert doctors and patients about possible drug effects that may be dangerous.

Examples of drugs that are similar to Byetta that have warnings for thyroid cancer include:

If you’re concerned about your risk of cancer while taking Byetta, talk with your doctor. They may want to monitor your thyroid throughout your treatment. Or they may recommend a different treatment altogether.

Does Byetta cause weight loss?

You may lose weight from taking Byetta. This medication is not a weight loss drug, but it may cause nausea and a decrease in appetite. These symptoms may cause you to eat less, which can lead to weight loss. Many people taking Byetta in studies lost about 2.7 kilograms, which is about 6 pounds, on average.

If you have weight loss that’s bothersome to you, talk with your doctor. They can recommend ways to gain weight or manage your weight loss.

Learn more about some of the side effects Byetta may cause.

Nausea

You may experience nausea from taking Byetta. This was one of the most common side effects reported by people taking this medication. This side effect happened most often at the beginning of Byetta treatment. For many people, this went away after they’d been taking Byetta for some time.

What might help

Nausea is a common side effect that occurs with Byetta. In many cases, it goes away over time. Your doctor may recommend ways to decrease the nausea, such as having you take another medication temporarily. Once your body gets used to Byetta, you may not experience nausea anymore.

If you have nausea that is severe or bothersome to you, talk with your doctor. They may be able to recommend ways to relieve this side effect.

Low blood sugar

You may develop low blood sugar from taking Byetta. This medication works to treat type 2 diabetes by helping to lower blood sugar. But in some cases, your blood sugar may become too low. Your risk of this side effect increases if you take Byetta with another drug that also lowers blood sugar, including insulin.

You should be aware of the symptoms of low blood sugar so you can be treated right away if you have them. Left untreated, low blood sugar can be serious and may lead to confusion, fainting, or even seizures or coma.

Some symptoms of low blood sugar to watch for include:

What might help

Before starting Byetta, talk with your doctor about monitoring and treating low blood sugar. If you have symptoms, your doctor will likely recommend that you check your blood sugar levels immediately. If it’s below 70 milligrams per deciliter (mg/dL), the American Diabetes Association recommends:

If your level is still below 70 mg/dL, repeat this process again.

Examples of some foods that have 15 g of carbohydrates include:

  • glucose tablets
  • a tablespoon of sugar or honey
  • 4 ounces of juice or (non-diet) soda

Talk with your doctor if you have frequent low blood sugar. You should also tell them if you have any changes in your diet, exercise level, or other medications. In some cases, they may have you adjust your dose of Byetta to prevent low blood sugar.

Dizziness

You may have dizziness from taking Byetta. This was a common side effect reported in studies of people taking this medication.

What might help

If you have dizziness often, talk with your doctor. In some cases, this can be a sign of low blood sugar, which can be serious. Your doctor may suggest you check your blood sugar when you feel dizzy. They may also be able to recommend ways to decrease dizziness.

Allergic reaction

Like most drugs, Byetta can cause an allergic reaction in some people.

Symptoms can be mild or serious and can include:

  • rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away.

They may suggest the following to help you manage your symptoms:

  • an antihistamine you swallow, such as Benadryl (diphenhydramine)
  • a product you apply to your skin, such as hydrocortisone cream

If your doctor confirms you had a mild allergic reaction to Byetta, they’ll decide if you should continue taking it.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you had a serious allergic reaction to Byetta, they may have you switch to a different medication.

Keeping track of side effects

Consider keeping notes on any side effects you have during your Byetta treatment. You can then share this information with your doctor. This is especially helpful to do when you first start taking new drugs or using a combination of treatments.

Your notes can include things such as:

  • what dose of drug you were taking when you had the side effect
  • how soon after starting that dose you had the side effect
  • what your symptoms were
  • how it affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Byetta affects you. They can then use this information to adjust your treatment plan if needed.

Byetta may not be right for you if you have certain medical conditions or other factors that affect your health. Talk with your doctor about your health history before you take Byetta. The list below includes factors to consider.

Kidney problems. If you have kidney problems, talk with your doctor before starting Byetta. This medication can increase your risk of kidney problems and may make existing kidney problems worse. Your doctor may monitor your kidneys more often during your treatment or they may recommend a different medication.

Allergic reaction. If you’ve had an allergic reaction to Byetta or any of its ingredients, your doctor will likely not prescribe Byetta. Ask your doctor what other medications are better options for you.

Stomach or gastrointestinal disease. Byetta can cause stomach problems to occur. If you already have stomach or gastrointestinal (digestive) problems, Byetta may make your condition worse. Tell your doctor about any stomach or digestive issues you have. They may recommend a different medication for you.

Low platelet levels. Tell your doctor if you have low platelet levels. (Platelets are a type of blood cell that help your blood to clot.) Byetta can cause low platelet levels, which can increase your risk of bleeding. If you already have low platelet levels, Byetta can make your condition worse. Your doctor may monitor your blood levels or recommend a different treatment option for you.

Pancreatitis. Tell your doctor if you’ve ever had pancreatitis (swelling of your pancreas). Byetta can cause pancreatitis to occur. If you have a history of this condition, taking this medication can increase your risk of getting it again. Your doctor will likely recommend a different treatment option for you.

Alcohol and Byetta

There are no known interactions between Byetta and alcohol. But alcohol can affect your blood sugar levels, which can affect your diabetes.

If you drink alcohol, talk with your doctor about how much, if any, is safe during Byetta treatment.

Pregnancy and breastfeeding while taking Byetta

It’s not known whether Byetta is safe to use while pregnant or breastfeeding. But unmanaged blood sugar levels can be harmful to a fetus. Byetta is prescribed to help manage blood sugar levels.

If you’re pregnant, breastfeeding, or planning either, talk with your doctor before starting Byetta.

In many cases, side effects from Byetta are mild. But some side effects may be serious. Talk with your doctor about any questions you have before starting Byetta treatment. A few questions to consider include:

  • Are there any ways to prevent side effects from this medication?
  • If I experience side effects, can my dose be changed to reduce them?
  • What should I do if I become pregnant during my Byetta treatment?

To learn more about Byetta, see these articles:

To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

Q:

If I’m taking Byetta with other medications for my diabetes, am I at an increased risk of side effects?

Anonymous

A:

Yes, you may have an increased risk of side effects if you take Byetta with other medications for diabetes treatment. For example, your risk of having low blood sugar is higher if you’re taking Byetta with another diabetes medication. These include insulin or a medication from the drug group sulfonylureas. The dose of these medications may need to be decreased during your Byetta treatment.

It is important to know the signs and symptoms of low blood sugar so you can be treated appropriately. (Please see the “Side effects explained” section above.) If you’re concerned about side effects from the medications you’re taking for diabetes, talk with your doctor or pharmacist. They can help adjust your treatment plan if necessary.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.
Was this helpful?

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.