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Firmagon Side Effects

Generic name: degarelix

Medically reviewed by Last updated on Oct 6, 2023.

Note: This document contains side effect information about degarelix. Some dosage forms listed on this page may not apply to the brand name Firmagon.

Applies to degarelix: subcutaneous powder for solution.

Serious side effects of Firmagon

Along with its needed effects, degarelix (the active ingredient contained in Firmagon) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking degarelix:

More common

Less common


Incidence not known

Other side effects of Firmagon

Some side effects of degarelix may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Less common

For Healthcare Professionals

Applies to degarelix: subcutaneous powder for injection.


Very common (10% or more): Increased liver transaminases (47%), increased gamma-glutamyltransferase (10%)

Uncommon (0.1% to 1%): Increased bilirubin, increased alkaline phosphatase[Ref]


Very common (10% or more): Injection site reaction (including pain, erythema, swelling, induration, nodule; 44%), pyrexia (10%), fatigue (10%)

Common (1% to 10%): Chills, asthenia, influenza-like illness[Ref]


Very common (10% or more): Decreased hematocrit (40%), decreased hemoglobin (15%)

Common (1% to 10%): Anemia

Rare (less than 0.1%): Neutropenic fever[Ref]


Very common (10% or more): Hot flush (26%), QT/QTc interval prolongation (20%)

Common (1% to 10%): Hypertension

Uncommon (0.1% to 1%): Cardiac arrhythmia (including atrial fibrillation), palpitations, vasovagal reaction (including hypotension)

Rare (less than 0.1%): Myocardial infarction, cardiac failure[Ref]


Very common (10% or more): Abnormal BUN (15%)

Common (1% to 10%): Abnormal creatinine level

Uncommon (0.1% to 1%): Renal impairment[Ref]


Very common (10% or more): Increased weight (11%), decreased weight (10%)

Common (1% to 10%): Abnormal potassium level

Uncommon (0.1% to 1%): Hyperglycemia/diabetes mellitus, increased cholesterol, decreased appetite, blood calcium changes[Ref]


Very common (10% or more): Antibody formation (10%)[Ref]


Common (1% to 10%): Hyperhidrosis (including night sweats), rash

Uncommon (0.1% to 1%): Urticaria, skin hyperpigmentation, skin nodule, alopecia, pruritus, erythema[Ref]


Common (1% to 10%): Nausea, constipation, diarrhea

Uncommon (0.1% to 1%): Vomiting, abdominal pain, abdominal discomfort, dry mouth[Ref]


Common (1% to 10%): Urinary tract infection, gynecomastia, testicular atrophy, erectile dysfunction

Uncommon (0.1% to 1%): Pollakiuria, micturition urgency, dysuria, nocturia, incontinence, testicular pain, breast pain, pelvic pain, genital irritation, ejaculation failure[Ref]


Common (1% to 10%): Back pain, arthralgia, musculoskeletal pain and discomfort

Uncommon (0.1% to 1%): Osteoporosis/osteopenia, arthralgia, muscular weakness, muscle spasms, joint swelling/stiffness[Ref]

Nervous system

Common (1% to 10%): Dizziness, headache

Uncommon (0.1% to 1%): Mental impairment, hypoesthesia[Ref]


Common (1% to 10%): Insomnia

Uncommon (0.1% to 1%): Loss of/decreased libido, depression[Ref]


Uncommon (0.1% to 1%): Hypersensitivity reaction

Postmarketing reports: Anaphylaxis, angioedema[Ref]


Uncommon (0.1% to 1%): Blurred vision[Ref]


Uncommon (0.1% to 1%): Dyspnea[Ref]

Frequently asked questions


1. Cerner Multum, Inc. UK Summary of Product Characteristics.

2. Cerner Multum, Inc. Australian Product Information.

3. Product Information. Firmagon (degarelix). Ferring Pharmaceuticals Inc. 2013.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.