Eligard (leuprolide acetate) is a prescription drug used to treat advanced prostate cancer in adults. Eligard can cause side effects that range from mild to serious. Examples include fatigue, weight gain, and hot flashes.

The active ingredient in Eligard is leuprolide acetate. The drug comes as a powder that’s mixed with liquid to make a solution for injection under the skin.

Keep reading to learn about common, mild, and serious side effects Eligard 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 Eligard treatment. Examples of the drug’s commonly reported side effects include:

Mild side effects have been reported with Eligard. These include:

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

Eligard may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

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

Serious side effects have been reported with Eligard. These include:

If you develop serious side effects during Eligard treatment, 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.

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

Allergic reaction

For some people, Eligard can cause an allergic reaction, but it isn’t known how often this occurred in the drug’s studies.

In general, symptoms of an allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

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 a treatment to manage your symptoms and can determine whether you should continue Eligard treatment.

If you have symptoms of a severe allergic reaction, such as swelling or difficulty 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’ve had a serious allergic reaction to Eligard, they may have you switch to a different treatment.

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

When do Eligard’s side effects start? Will they go away?

It depends. Some side effects may develop immediately, such as injection site reactions and dizziness. Other side effects may take longer, such as bone loss. This can vary from person to person.

How long, how often, and how severe these side effects are will also vary. Talk with your doctor if you have side effects that are ongoing and bothersome.

Does Eligard interact with alcohol?

There are no known interactions between Eligard and alcohol. But Eligard and alcohol can cause some similar side effects, such as dizziness and fatigue. So you may be more likely to have these side effects if you drink alcohol during Eligard treatment.

If you have questions about consuming alcohol during treatment with this medication, talk with your doctor or pharmacist.

Does Eligard cause long-term side effects?

It’s possible. Long-term side effects include those that may start at any time during treatment with a drug, even if you’ve taken it for a long time. It also includes side effects that may not go away, even after you stop treatment.

An example of a long-term side effect reported in Eligard studies is high blood sugar which could lead to diabetes and bone loss.

Talk with your doctor to learn more about possible side effects of Eligard and how long they may last.

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

Injection site reactions

Injection site reactions were a common side effect reported in studies of Eligard. Injection site reactions may cause symptoms in the area where the drug was injected, including:

  • burning or stinging
  • bruising
  • pain
  • itchiness

What might help

If you have any of these symptoms during or after receiving your Eligard dose, talk with your doctor. They can recommend ways to help prevent this side effect in the future. They can also rotate the area where you receive the injection (meaning they won’t inject at the same place two times in a row).

Hyperglycemia (high blood sugar)

High blood sugar was a serious side effect reported in studies of Eligard. This side effect may cause symptoms such as:

What might help

Before starting Eligard, talk with your doctor about any medical conditions you may have. They’ll help you decide whether this treatment is right for you. If they do prescribe Eligard for you, they’ll order frequent blood sugar tests throughout your treatment. But be sure to tell them if you experience any of the above symptoms.

Keeping track of side effects

During your Eligard treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start a new drug or combination of treatments.

Your side effect notes can include things such as:

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

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

Eligard can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether this drug is a good treatment option for you. Talk with your doctor about your health history before starting Eligard. Be sure to tell them if any of the following factors apply to you:

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.