Firmagon treats prostate cancer. May cause hot flashes. It is injected under the skin in the stomach area.

Firmagon Overview


Firmagon is a prescription medication used to treat advanced prostate cancer. Firmagon belongs to a group of drugs called gonadotropin-releasing hormone (GnRH) blockers. It works by reducing the amount of testosterone in the body, which prostate cancer cells need to grow.

This medication comes in an injectable form to be injected under the skin in the area of the stomach once every 28 days.

Some common side effects are hot flashes, injection site pain, weight gain, and tiredness.

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Uses of Firmagon

Firmagon is a prescription medication used in the treatment of advanced prostate cancer.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information. 



Firmagon Drug Class

Firmagon is part of the drug class:

Side Effects of Firmagon

The common side effects include:

  • hot flashes
  • injection site pain, redness, and swelling, especially with the first dose
  • weight gain
  • increase in some liver enzymes
  • tiredness
  • hypertension
  • back and joint pain
  • chills
  • urinary tract infection
  • decreased sex drive and trouble with erectile function (impotence)
These are not all the possible side effects. For more information, ask your doctor or pharmacist.

Firmagon Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take medicines for your heart. Firmagon can cause a change in the heart rhythm known as QT prolongation. Be sure to mention any of the following medicines:

  • amiodarone (Cordarone)
  • disopyramide (Norpace)
  • quinidine
  • procainamide
  • sotalol 

This is not a complete list of Firmagon drug interactions. Ask your doctor or pharmacist for more information.

Firmagon Precautions

Firmagon can cause a serious heart rhythm problem known as QT prolongation. Tell your doctor if you have heart disease.

You should not receive Firmagon if you are allergic to any ingredient in Firmagon. Signs of an allergic reaction are:

  • Hives
  • Itching
  • Unexplained swelling of the mouth or throat
  • Wheezing
  • Difficulty breathing or swallowing.
Women who are pregnant or may become pregnant should not receive Firmagon.

Firmagon Food Interactions

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of Firmagon there are no specific foods that you must exclude from your diet when receiving Firmagon.

Inform MD

Before receiving Firmagon, tell your doctor about all your medical conditions, including if you:

  • have any heart problems
  • have problems with balance of your body salts or electrolytes, such as sodium, potassium, calcium, and magnesium
  • have kidney or liver problems
  • are pregnant or plan to become pregnant
  • are breastfeeding or plan to breastfeed
  • have any allergies to medications, foods, dyes, or perservatives

Tell your doctor about all the medicines you take, including prescription and nonprescription medicines, vitamins, and herbal supplements. 

Firmagon and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant. The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy. This medication falls into category X.

This medication is not intended for use in women and should especially be avoided by pregnant women. Tell your doctor if you are pregnant or plan to become pregnant. Women who are pregnant or may become pregnant should not receive Firmagon. This medication may harm the unborn baby.

Firmagon and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if Firmagon is excreted in human breast milk or if it will harm your nursing baby.

Firmagon Usage

Firmagon comes as a liquid to be injected under the skin (subcutaneously) of the stomach area, usually once every 28 days. The area where the medication is injection should change with each dosage. It should not be injected in the area of the ribs or waistline as these areas could be easily rubbed against or receive pressure.

This medication is usually given by a doctor or nurse in a medical facility, such as the doctor's office, clinic, or hospital.

  • The injected medicine gives you a continuous release of Firmagon over one month.
  • Two injections are given as a first dose and the following monthly doses are one injection.
  • Always set up an appointment for your next injection.
  • If you miss a dose of Firmagon, or if you think you forgot to get your monthly dose of Firmagon, talk to your healthcare provider about how to get your next dose.

Firmagon Dosage

Take this medication exactly as prescribed by your doctor. Follow the directions on your prescription label carefully. The dose your doctor recommends may be based on the following:

  • the condition being treated
  • other medical conditions you have
  • other medications you are taking
  • how you respond to this medication
  • your weight
  • your height
  • your age
  • your gender

The starting dose of Firmagon is two 120 mg injections (240 mg) on the first day of treatment. The mainanence dose of one 80 mg injection is given 28 days after the first dose. The 80 mg maintenance dose will be given every 28 days until treatment ends.


Firmagon Overdose

Firmagon is usually administered by a healthcare provider in a medical setting making it unlikely for an overdose to occur. However, if overdose is suspected, seek emergency medical attention.

Other Requirements

Keep all medical and laboratory appointments while receiving this medication. To get the most benefit from this medication you should not skip doses. If you are unable to make an appointment, reschedule as soon as possible.