Firmagon (degarelix) is a brand-name drug that’s prescribed to treat advanced prostate cancer in adults. As with other drugs, Firmagon can cause side effects, such as hot flashes and injection site reactions.

Firmagon 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.

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

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

Mild side effects that have been reported with Firmagon include:

  • back pain
  • unintentional weight gain
  • erectile dysfunction
  • fatigue (tiredness)
  • chills
  • constipation
  • joint pain
  • hot flashes (feelings of intense heat)
  • injection site reactions (see “Side effect specifics”)
  • increase in certain liver enzyme levels

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 Firmagon and want to tell the FDA about it, visit MedWatch.

Firmagon 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 Firmagon’s prescribing information.

If you develop serious side effects while taking Firmagon, 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:

  • gynecomastia, which may include symptoms such as:
    • swollen breasts
    • breast tenderness or pain
    • nipple discharge
  • high blood pressure, which, in severe cases, may cause symptoms such as:
    • sweating
    • dizziness
    • flushing
  • testicular atrophy, which may include symptoms such as:
  • urinary tract infections, which may include symptoms such as:
    • cloudy urine
    • bloody urine
    • burning sensation when urinating
    • increased urgency and frequency of urination
  • abnormal heart rhythms (see “Side effect specifics”)
ALLERGIC REACTION

For some people, Firmagon can cause an allergic reaction.

This side effect wasn’t reported in the drug’s studies. But, it has occurred since the drug has been on the market.

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 Firmagon, your doctor may recommend taking a different medication instead.

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

How long do Firmagon’s side effects last?

It depends. The length of time that Firmagon’s side effects last can vary. Certain side effects may go away within a few days. For example, injection site reactions, including pain and swelling, may last for only a few days. Others, such as high blood pressure and testicular atrophy may last throughout your treatment. In some cases, they can continue even though you’ve stopped Firmagon treatment.

Talk with your doctor or pharmacist if you experience any ongoing side effects

Does Firmagon cause weight loss?

It’s not likely. Unintentional weight loss wasn’t reported as a side effect in Firmagon’s clinical trials. However, Firmagon may cause unintentional weight gain.

Talk with your doctor if you’re concerned about weight loss during treatment with Firmagon.

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

Injection site reactions

Injection site reactions were a common side effect reported in clinical trials of Firmagon. These reactions mainly occurred with the starting dose. They were typically described as temporary and mild to moderate in intensity. These reactions may cause symptoms at the injection site, including:

  • pain
  • skin discoloration
  • swelling
  • skin hardening

What you can do

These symptoms are typically mild and should lessen within a few days. Talk with your doctor if the above symptoms last longer than a few days, bother you, or become severe. They can recommend ways to manage these symptoms or an alternative medication to manage your prostate cancer.

Abnormal heart rhythms

Abnormal heart rhythms were reported in Firmagon’s clinical trials. Although rare, this is a serious side effect that can include QT prolongation. When this occurs, your heart’s electrical activity changes and is no longer normal. This can affect your heart rhythm and lead to potentially life threatening outcomes, including sudden cardiac arrest. You may not experience any symptoms with QT prolongation. if you do have symptoms, they may include:

  • dizziness
  • seizures
  • sudden fainting
  • a fluttering feeling in the chest

What you can do

Talk with your doctor about any medical conditions you have and medications you take. Certain medications are known to also cause QT prolongation. Medical conditions, including long QT syndrome, congested heart failure, and certain electrolyte level abnormalities, can affect your heart rhythm.

Your doctor may have you complete an electrocardiogram (EKG) before and during treatment. This will allow your doctor to monitor your heart’s electrical activity. They may also order tests to check your blood electrolytes before and during treatment. They will need to treat any electrolyte abnormalities you have before starting treatment.

Talk with your doctor if you experience any of the above symptoms while using Firmagon. They may recommend an alternative medication to treat your prostate cancer.

Below is important information you should consider before taking Firmagon.

Precautions

Before taking Firmagon, discuss your health history with your doctor. Firmagon 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:

  • kidney or liver problems
  • heart problems, including long QT syndrome
  • electrolyte levels problems, including changes in levels of sodium, potassium, and calcium
  • previous allergic reaction to this or a similar drug
  • pregnancy
  • breastfeeding
  • alcohol consumption

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.