Zoladex (goserelin) is a brand-name implant prescribed for certain types of cancer, endometriosis, and more. As with other drugs, Zoladex can cause side effects, such as hot flashes and headache.

Zoladex can cause certain side effects, 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.

The following lists include a few of the more common side effects reported by people who took Zoladex in studies. These side effects can vary depending on the condition the drug is used to treat.

More common side effects in people taking Zoladex for prostate cancer include:

More common side effects in people taking Zoladex for endometriosis, dysfunctional uterine bleeding, and breast cancer include:

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

Here are some of the mild side effects that have been reported with Zoladex. These side effects can vary depending on the condition the drug is used to treat.

Mild side effects in people taking Zoladex for prostate cancer include:

Mild side effects in people taking Zoladex for endometriosis, dysfunctional uterine bleeding, and breast cancer 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 and reviews side effects of the medication. If you develop a side effect while taking Zoladex and want to tell the FDA about it, visit MedWatch.

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Zoladex may cause serious side effects. Some are more common, while others are rare. The following list may not include all possible serious side effects of the drug. For more details, you can refer to Zoladex’s prescribing information.

If you develop serious side effects while taking Zoladex, 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 that have been reported and their symptoms include:

  • depression*
  • tumor flare*
  • high blood sugar levels, which may cause symptoms such as:
    • extreme thirst or hunger
    • frequent urination
    • headaches
    • blurry vision
    • irritability
  • cardiovascular (heart and blood pressure) conditions, such as heart attack or stroke. Symptoms may include:
    • shortness of breath
    • chest pain
    • fainting
    • slurred speech
    • sudden weakness on one side of your body
    • facial drooping
  • hypercalcemia (high blood calcium levels), which may cause symptoms such as:
    • extreme thirst
    • frequent urination
  • long QT syndrome (a condition that affects your heart rhythm), which may cause symptoms such as:
  • injury at the injection site, which may cause symptoms such as:
    • bruising
    • bleeding
    • pain

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

ALLERGIC REACTION

For some people, Zoladex implant can cause an allergic reaction.

In general, symptoms of allergic reaction can be mild or serious.

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Zoladex, your doctor may recommend taking a different medication instead.

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

Does Zoladex cause long-term side effects?

Possibly, but long-term side effects weren’t common in clinical trials of the drug. Long-term side effects include those that may start at any time you’re taking 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 taking the drug.

Examples of long-term side effects reported in Zoladex’s clinical trials include:

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

Will I have side effects while coming off Zoladex?

It’s possible. Additionally, the side effects that may occur depend on the condition you’re taking Zoladex for.

If you’re taking Zoladex for prostate or breast cancer, stopping the drug can cause the symptoms of your condition to come back.

In most cases, if you’re a female* who hasn’t gone through menopause, Zoladex treatment will make your period stop. Once you stop (or “come off”) Zoladex, your period will likely return within 12 weeks.

If you have more questions about potential side effects after coming off Zoladex, talk with your doctor.

* Use of the term “female” in this article refers to a person’s sex assigned at birth.

Do the side effects of Zoladex differ when used for prostate cancer compared to when it’s used for endometriosis?

Yes. In clinical trials of Zoladex, the more common side effects varied depending on the condition being treated.

For example, people taking Zoladex for prostate cancer commonly experienced ED and difficulty passing urine. For people taking Zoladex for endometriosis, headache, sweating, acne, and mood changes were more common.

To learn more about the side effects of Zoladex when used for prostate cancer or endometriosis, talk with your doctor.

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

Tumor flare

Tumor flare is a sudden but temporary worsening or development of new tumor symptoms. This may occur during the first few weeks of Zoladex treatment. Symptoms may include:

  • bone pain
  • other cancer-related pain
  • kidney problems
  • spinal cord compression (pressure in the spinal cord)

What you can do

If you suddenly have new or worsening cancer symptoms, talk with your doctor. They may ask questions and order tests to determine the cause of your symptoms. If needed, they may also prescribe medications to manage your symptoms.

Depression

Depression was commonly reported in clinical trials of Zoladex. It was common in people who took Zoladex for breast cancer, dysfunctional uterine bleeding, and endometriosis.

Depression is a mood disorder that is characterized by feelings of sadness and emptiness. It can last several weeks, months, or years. Symptoms may include:

  • loss of interest in hobbies
  • decreased energy
  • feelings of guilt or worthlessness
  • depressed mood
  • changes in sleep patterns
  • thoughts of suicide

What you can do

If you, your loved ones, or caregivers notice any changes in your mood, thoughts, or behavior, talk with your doctor. They will likely ask questions to determine whether you have depression. If so, they can discuss potential treatment options for you.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

Before taking Zoladex, discuss your health history with your doctor. Zoladex may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

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.