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Faslodex Side Effects

Generic Name: fulvestrant

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

For the Consumer

Applies to fulvestrant: intramuscular solution

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
  • Bloating or swelling of the face, arms, hands, lower legs, or feet
  • rapid weight gain
  • tingling of the hands or feet
  • unusual weight gain or loss
Less common
  • Difficult or labored breathing
  • tightness in the chest
Incidence not known
  • Black, tarry stools
  • chest pain
  • chills
  • cough
  • fever
  • flushing or redness of the skin
  • hives or welts, itching, or rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • pain in the chest, groin, or legs, especially the calves
  • painful or difficult urination
  • severe and sudden headache
  • slurred speech
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sudden and severe weakness or numbness in the arm or leg
  • sudden loss of coordination
  • swollen glands
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vaginal bleeding
  • vision changes

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
  • Back pain
  • bladder pain
  • bloody or cloudy urine
  • body aches or pain
  • bone pain
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • depression
  • diarrhea
  • difficulty having a bowel movement
  • difficulty with moving
  • dizziness
  • dryness or soreness of the throat
  • feeling faint, dizzy, or lightheaded
  • feeling of warmth or heat
  • feeling sad or empty
  • frequent urge to urinate
  • general feeling of discomfort or illness
  • headache
  • hoarseness
  • irritability
  • joint pain
  • lack or loss of appetite
  • lack or loss of strength
  • loss of interest or pleasure
  • lower back or side pain
  • muscle aches and pains
  • muscle stiffness
  • nausea
  • pain at the injection site
  • pain in the arms or legs
  • pelvic pain
  • shivering
  • stomach pain
  • sudden sweating
  • tender, swollen glands in the neck
  • trouble concentrating
  • trouble with swallowing
  • unable to sleep
  • voice changes
  • vomiting
  • weight loss
Less common
  • Nervousness
  • pain, swelling, or redness in the joints
  • pale skin
Incidence not known
  • Feeling of constant movement of self or surroundings
  • sensation of spinning

For Healthcare Professionals

Applies to fulvestrant: intramuscular solution


Gastrointestinal side effects have included nausea (26%), vomiting (13%), constipation (12.5%), diarrhea (12.3%), abdominal pain (11.8%), and anorexia (9%).[Ref]


Hematologic side effects have included anemia (4.5%) and postmarketing reports of leukopenia.[Ref]


Cardiovascular side effects have included vasodilation (17.7%), and peripheral edema (9%). Postmarketing reports have included thromboembolic phenomena.[Ref]


Musculoskeletal side effects have included bone pain (15.8%), and arthritis (2.8%). Postmarketing reports have included myalgia.[Ref]

Nervous system

Nervous system side effects have included dizziness (6.9%), insomnia (6.9%), paresthesia (6.4%), depression (5.7%), and anxiety (5%). Postmarketing reports have included vertigo.[Ref]


Respiratory side effects have included pharyngitis (16.1%), dyspnea (14.9%), and cough increased (10.4%).[Ref]


Genitourinary side effects have included urinary tract infection (6.1%). Postmarketing reports have included vaginal bleeding.[Ref]


Dermatologic side effects have included rash (7.3%).[Ref]


Endocrine side effects have included sweating (5%).[Ref]


General side effects have included asthenia (22.7%), pain (18.9%), headache (15.4%), back pain (14.4%), pain at injection site (10.9%), pelvic pain (9.9%), chest pain (7.1%), flu syndrome (7.1%), fever (6.4%), and accidental injury (4.5%).[Ref]


Hypersensitivity side effects including angioedema and urticaria have been reported.[Ref]


Hepatic side effects have included postmarketing reports of elevated bilirubin, elevated gamma GT, hepatitis, and liver failure.


1. "Product Information. Faslodex (fulvestrant)." Astra-Zeneca Pharmaceuticals, Wilmington, DE.

Some side effects of Faslodex may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.