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Last reviewed on RxList: 1/25/2016
Firmagon Side Effects Center

Last reviewed on RxList 01/06/2017

Firmagon (degarelix) is a gonadotropin-releasing hormone (GnRH) receptor antagonist used to treat advanced prostate cancer. Side effects of Firmagon include:

The initial dose of Firmagon is 240 mg given as two subcutaneous injections of 120 mg each. Maintenance dose is a single 80 mg injection given every 28 days. Other drugs may interact with Firmagon. Tell your doctor all medications you use. Firmagon is not for use in women, therefore, women who are pregnant, who may become pregnant, or who are nursing should not take Firmagon.

Our Firmagon (degarelix) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Firmagon Professional Information


Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

A total of 1325 patients with prostate cancer received FIRMAGON either as a monthly treatment (60-160 mg) or as a single dose (up to 320 mg). A total of 1032 patients (78%) were treated for at least 6 months and 853 patients (64%) were treated for one year or more. The most commonly observed adverse reactions during FIRMAGON therapy included injection site reactions (e.g., pain, erythema, swelling or induration), hot flashes, increased weight, fatigue, and increases in serum levels of transaminases and gamma-glutamyltransferase (GGT). The majority of the adverse reactions were Grade 1 or 2, with Grade 3/4 adverse reaction incidences of 1% or less.

FIRMAGON was studied in an active-controlled trial (N = 610) in which patients with prostate cancer were randomized to receive FIRMAGON (subcutaneous) or leuprolide (intramuscular) monthly for 12 months.Adverse reactions reported in 5% of patients or more are shown in Table 1.

Table 1: Adverse Reactions Reported in ≥ 5% of Patients in an Active Controlled Study

  FIRMAGON 240/160 mg (subcutaneous)
N = 202
FIRMAGON 240/80 mg (subcutaneous)
N = 207
Leuprolide 7.5 mg (intramuscular)
N = 201
Percentage of subjects with adverse events 83% 79% 78%
Body as a whole
Injection site adverse events 44% 35% < 1%
Weight increase 11% 9% 12%
Fatigue 6% 3% 6%
Chills 4% 5% 0%
Cardiovascular system
Hot flash 26% 26% 21%
Hypertension 7% 6% 4%
Musculoskeletal system
Back pain 6% 6% 8%
Arthralgia 4% 5% 9%
Urogenital system
Urinary tract infection 2% 5% 9%
Digestive system
Increases in Transaminases and GGT 10% 10% 5%
Constipation 3% 5% 5%

The most frequently reported adverse reactions at the injection sites were pain (28%), erythema (17%), swelling (6%), induration (4%) and nodule (3%). These adverse reactions were mostly transient, of mild to moderate intensity, occurred primarily with the starting dose and led to few discontinuations ( < 1%). Grade 3 injection site reactions occurred in 2% or less of patients receiving degarelix.

Hepatic laboratory abnormalities were primarily Grade 1 or 2 and were generally reversible. Grade 3 hepatic laboratory abnormalities occurred in less than 1% of patients.

In 1-5% of patients the following adverse reactions, not already listed, were considered related to FIRMAGON by the investigator:

Body as a whole: Asthenia, fever, night sweats; Digestive system: Nausea; Nervous system: Dizziness, headache, insomnia.

The following adverse reactions, not already listed, were reported to be drug-related by the investigator in ≥ 1% of patients: erectile dysfunction, gynecomastia, hyperhidrosis, testicular atrophy, and diarrhea.

The safety of FIRMAGON administered monthly was evaluated further in an extension study in 385 patients who completed the above active-controlled trial. Of the 385 patients, 251 patients continued treatment with FIRMAGON and 135 patients crossed over treatment from leuprolide to FIRMAGON. The median treatment duration on the extension study was approximately 43 months (range 1 to 58 months). The most common adverse reactions reported in > 10% of the patients were injection site reactions (e.g., pain, erythema, swelling, induration or inflammation), pyrexia, hot flush, weight loss or gain, fatigue, increases in serum levels of hepatic transaminases and GGT. One percent of patients had injection site infections including abscess. Hepatic laboratory abnormalities in the extension study included the following: Grade ½ elevations in hepatic transaminases occurred in 47% of patients and Grade 3 elevations occurred in 1% of patients.

Changes in bone density

Decreased bone density has been reported in the medical literature in men who have had orchiectomy or who have been treated with a GnRH agonist. It can be anticipated that long periods of medical castration in men will result in decreased bone density.

Anti-degarelix antibody development has been observed in 10% of patients after treatment with FIRMAGON for 1 year. There is no indication that the efficacy or safety of FIRMAGON treatment is affected by antibody formation.

Read the entire FDA prescribing information for Firmagon (Degarelix for Injection)

Related Resources for Firmagon

© Firmagon Patient Information is supplied by Cerner Multum, Inc. and Firmagon Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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