What is Firmagon: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Dec 30, 2020

Firmagon overview

BRAND NAMES:

  • Firmagon

Generic Names:

  • Firmagon

Uses:

  • Treats advanced prostate cancer.

Therapeutic Classes:

  • Antiandrogen

Forms:

  • Injectable

How it’s taken:

  • By injection

What is Firmagon used for?

Firmagon is a prescription only medication that comes in subcutaneous powder for injection form. It is used by adult men to treat prostate cancer. Firmagon works by preventing the growth of testosterone which can stimulate the growth of tumors.

What form(s) does Firmagon come in

  • Injectable

What are common Firmagon doses?

  • Solution Reconstituted 80MG

Common Firmagon prescriptions

  • Firmagon
    80mg solution reconstituted

How to take Firmagon

  • Injection routeYou will receive this medicine while you are in a hospital or cancer treatment center. A nurse or other trained health professional will give you this medicine.

  • Injection routeYour doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin. This medicine is given in the stomach area.

  • Missed dose: Injection routeThis medicine needs to be given on a fixed schedule. If you miss a dose, call your doctor, home health caregiver, or treatment clinic for instructions.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Injection routeYou will receive this medicine while you are in a hospital or cancer treatment center. A nurse or other trained health professional will give you this medicine.

  • Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.

  • Injection routeYour doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin. This medicine is given in the stomach area.

  • Missed dose: Injection routeThis medicine needs to be given on a fixed schedule. If you miss a dose, call your doctor, home health caregiver, or treatment clinic for instructions.

What to do if you miss a dose of Firmagon

Firmagon contraindications

  • This medicine is not right for everyone. You should not receive it if you had an allergic reaction to degarelix.

Firmagon warnings

  • This medicine may cause the following problems: Heart rhythm problem called QT prolongationDecrease in bone density

  • Women should not use this medicine, especially women who are pregnant or able to become pregnant. This medicine can harm an unborn baby. It can also cause birth defects if the father is using it when his sexual partner becomes pregnant. If a pregnancy occurs while you are using this medicine, tell your doctor right away.

  • Tell your doctor if you have kidney disease, liver disease, heart disease, heart rhythm problems, or a problem with minerals or electrolytes in the blood (such as calcium, magnesium, potassium, or sodium).

  • Tell any doctor or dentist who treats you that you are using this medicine. This medicine may affect certain medical test results.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • Injection routeMedicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.

Firmagon interactions

  • Some medicines can affect how degarelix works. Tell your doctor if you are using medicine to treat heart rhythm problems, such as amiodarone, procainamide, quinidine, or sotalol.

  • This medicine may cause the following problems: Heart rhythm problem called QT prolongationDecrease in bone density

  • Injection routeMedicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

Firmagon side effects

Serious Side Effects

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Fast, pounding, or uneven heartbeat, dizziness, faintness

  • Weight gain

Less Serious Side Effects

  • Hot flashes

  • Pain, itching, burning, swelling, or a lump under your skin where the shot was given

  • Weight gain

  • Back pain

Subscribe to our savings newsletter

Health education, drug info, wellness & more

By clicking 'Subscribe', I agree to SingleCare's Terms & Conditions.