Byetta (exenatide) is a brand-name prescription medication. It’s approved by the Food and Drug Administration (FDA) to treat type 2 diabetes in adults.

Byetta is typically used as a long-term treatment for managing blood sugar levels. The drug is meant to be used along with diet and exercise.

Here are some fast facts about Byetta:

Like other drugs, Byetta can cause adverse effects. Read on to learn about potential common, mild, and serious side effects of Byetta injections. For a general overview of the medication, see this article.

Byetta can cause certain adverse reactions, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Byetta in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Byetta use. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Byetta’s prescribing information.

Mild side effects that have been reported with Byetta include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect while taking Byetta and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Byetta may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Byetta’s prescribing information.

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.

Serious side effects of Byetta that have been reported and their symptoms include:

  • Hypoglycemia (low blood sugar). Symptoms can include:
    • shaking
    • dizziness
    • weakness
    • sweating
    • confusion
  • Pancreatitis (inflammation in your pancreas). Symptoms can include:
    • severe abdominal pain
    • abdominal pain that radiates to your back
    • nausea and vomiting
  • Allergic reaction.*†

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after taking Byetta. However, this side effect wasn’t reported in clinical trials.

Byetta may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Is cancer a side effect of Byetta?

Cancer was not reported in clinical trials of Byetta.

Medications that are similar to Byetta do have boxed warnings about a risk of thyroid cancer. A boxed warning is a serious warning from the Food and Drug Administration (FDA). It alerts patients and doctors about possible dangerous effects of a drug.

Byetta doesn’t have this warning. However, it belongs to a group of drugs called glucagon-like peptide-1 (GLP-1) receptor agonists. And other GLP-1 agonists have a warning about a risk of thyroid cancer. Examples of these drugs include:

Keep in mind that the warning about thyroid cancer with GLP-1 agonists is based on animal trials. Thyroid cancer was not reported as a side effect in human trials of these medications. And it isn’t known for sure if GLP-1 agonists increase the risk of thyroid cancer in humans.

If you’re concerned about cancer and Byetta, talk with your doctor.

Should I expect weight loss during Byetta treatment?

You may lose a small amount of weight while taking Byetta.

In clinical trials, people taking Byetta lost a few pounds more than people taking a placebo. (A placebo is a treatment that does not contain an active drug.)

Byetta can also cause loss of appetite, which may result in weight loss.

In fact, certain drugs that are similar to Byetta are used for weight loss. For example, semaglutide (Wegovy) is FDA-approved for weight loss. However, Byetta is not approved for this purpose.

If you’d like to know more about the effects of Byetta on weight, talk with your doctor or pharmacist.

Does Byetta cause kidney problems?

Possibly. Kidney problems were not reported in clinical trials of Byetta. However, there have been reports of this side effect since the drug became available for use.

Kidney problems that may occur with Byetta include new or worsening kidney failure. Symptoms of kidney problems include urinating a lesser amount than usual, swelling in your ankles or feet, and fatigue.

You may have an increased risk of kidney problems with Byetta if you take other medications that affect your kidneys. Examples include:

You may also have a higher risk of kidney problems than usual if you have certain side effects with Byetta. These include vomiting, diarrhea, and nausea.* These side effects can lead to dehydration, which may cause kidney problems.

Before taking Byetta, tell your doctor if you have kidney problems. Also tell them about all other medications you take. They can advise on the risks and benefits of Byetta treatment.

* For more information about this side effect, see “Side effect specifics” below.

Learn more about some of the side effects that Byetta may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Byetta.

Nausea

Nausea was a common side effect in clinical trials of Byetta. This side effect was more common with higher doses of the drug and at the beginning of treatment with Byetta.

What you can do

Nausea due to Byetta typically goes away over time. However, if you have bothersome or long lasting nausea, talk with your doctor. They may lower your dosage to help ease your symptoms.

Dizziness

Dizziness was a less common side effect in clinical trials of Byetta.

Keep in mind that dizziness can be a symptom of hypoglycemia (low blood sugar). And hypoglycemia is a possible serious side effect of Byetta.

What you can do

If you have dizziness while taking Byetta, talk with your doctor. They can help determine if it may be due to hypoglycemia or something else. Your doctor may ask if you have other symptoms of hypoglycemia, such as shaking, sweating, or confusion.

Allergic reaction

As with most drugs, Byetta can cause an allergic reaction in some people. This side effect wasn’t reported in clinical trials. However, allergic reaction has been reported since Byetta became available for use.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep taking Byetta. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you take Byetta. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Digestive problems. Before taking Byetta, tell your doctor if you have digestive problems. This includes conditions such as gastroparesis. Byetta may cause side effects that worsen these conditions. The side effects include vomiting, diarrhea, and nausea. Due to this risk, doctors typically will not prescribe Byetta for people with digestive problems. Your doctor may recommend a different treatment option for you.

Pancreatitis. Be sure to tell your doctor if you have pancreatitis now or if you’ve had it in the past. You may have a higher risk of pancreatitis than usual as a side effect of Byetta. Doctors typically will not prescribe Byetta for people with pancreatitis or a history of the condition. Your doctor may recommend a different medication for you.

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 may be better options for you.

Kidney problems. Before taking Byetta, tell your doctor if you have kidney problems, such as kidney failure. The drug may worsen your condition. Your doctor can advise you on the risks and benefits of Byetta treatment.

Alcohol use with Byetta

The manufacturer of Byetta has not reported any interactions between alcohol and Byetta.

However, alcohol can change your blood sugar levels. This could affect how well Byetta works to manage your diabetes.

If you drink alcohol, talk with your doctor about the amount that’s safe to drink while taking Byetta.

Pregnancy and breastfeeding while taking Byetta

It isn’t known if Byetta is safe to take while pregnant or breastfeeding. There haven’t been enough clinical trials of the drug in pregnant or breastfeeding humans.

When Byetta was given to pregnant animals in animal trials, the results showed harm to their offspring. The results also showed that Byetta passes into the breast milk of lactating animals. However, animal trials don’t always predict what may happen with humans.

If you’re pregnant or planning a pregnancy, talk with your doctor. Also tell them if you’re breastfeeding or planning to breastfeed. Your doctor can discuss the risks and benefits of Byetta treatment in these situations.

Both mild and serious side effects may occur with Byetta. However, most of the drug’s side effects are mild and are expected to go away with time. Be sure to talk with your doctor if you have any bothersome or long lasting side effects during Byetta treatment.

If you’d like to learn more about Byetta, talk with your doctor or pharmacist. They can help answer any questions you have about side effects of taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Byetta. For details about other aspects of Byetta, refer to this article.
  • Byetta dosage. For information on the dosage of Byetta, see this article.
  • Drug comparison. Learn how Byetta compares with Bydureon and Victoza.
  • A look at diabetes. For details about diabetes, see our diabetes hub and list of related articles.

Disclaimer: Medical News Today 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.