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Faslodex Side Effects

Generic name: fulvestrant

Medically reviewed by Philip Thornton, DipPharm. Last updated on Jul 31, 2023.

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

Applies to fulvestrant: intramuscular solution.

Serious side effects of Faslodex

Along with its needed effects, fulvestrant (the active ingredient contained in Faslodex) 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 fulvestrant:

More common

Less common

Incidence not known

Other side effects of Faslodex

Some side effects of fulvestrant 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

Incidence not known

For Healthcare Professionals

Applies to fulvestrant: intramuscular solution.


Very common (10% or more): Nausea (up to 34%), stomatitis (up to 28%), diarrhea (up to 24%), vomiting (up to 19%), abdominal pain (up to 12%)

Common (1% to 10%): Constipation[Ref]


Very common (10% or more): Neutropenia (up to 83%), leukopenia (up to 53%), anemia (up to 30%), thrombocytopenia (up to 23%)

Common (1% to 10%): Reduced platelet count

Uncommon (0.1% to 1%): Leukorrhea, febrile neutropenia[Ref]


Very common (10% or more): Vasodilation(up to 18%), hot flushes

Common (1% to 10%): Venous thromboembolism[Ref]


Very common (10% or more): Bone pain (up to 16%), muscle pain, joint pain

Common (1% to 10%): Back pain, pain in extremity[Ref]

Nervous system

Very common (10% or more): Headache (up to 15%)

Common (1% to 10%): Sciatica, peripheral neuropathy, dysgeusia, dizziness, paresthesia

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


Very common (10% or more): Pharyngitis (up to 16%), dyspnea (up to 15%)

Common (1% to 10%): Epistaxis, cough, chest pain[Ref]


Very common (10% or more): Pelvic Pain (up to 10%)

Common (1% to 10%): Urinary tract infection, vaginal hemorrhage

Uncommon (0.1% to 1%): Vaginal moniliasis[Ref]


Very common (10% or more): Alopecia (up to 18%), rash (up to 17%)

Common (1% to 10%): Dry skin, sweating, pruritus[Ref]


Very common (10% or more): Hypersensitivity reactions

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


Very common (10% or more): Elevated hepatic enzymes (ALT, AST, ALP)

Common (1% to 10%): Elevated bilirubin

Uncommon (0.1% to 1%): Hepatic failure, hepatitis, elevated gamma-GT[Ref]


Very common (10% or more): Infections (up to 47%)

Common (1% to 10%): Influenza syndrome[Ref]


Very common (10% or more): Injection site pain (up to 12%), injection site reaction

Common (1% to 10%):

Uncommon (0.1% to 1%): Injection site hemorrhage, injection site hematoma[Ref]


Common (1% to 10%): Increased lacrimation, blurred vision, dry eye[Ref]


Very common (10% or more): Anorexia (up to 16%)

Common (1% to 10%): Peripheral edema[Ref]


Common (1% to 10%): Insomnia, depression, anxiety[Ref]


Very common (10% or more): Fatigue (up to 41%), pain (up to 19%), pyrexia (up to 13%)

Common (1% to 10%): Asthenia[Ref]

Frequently asked questions


1. (2002) "Product Information. Faslodex (fulvestrant)." Astra-Zeneca Pharmaceuticals

2. Cerner Multum, Inc. "UK Summary of Product Characteristics."

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.