Skip to Content

Faslodex Side Effects

Generic Name: fulvestrant

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

For the Consumer

Applies to fulvestrant: intramuscular solution

In addition to its needed effects, some unwanted effects may be caused by fulvestrant (the active ingredient contained in Faslodex). In the event that any of these side effects do occur, they may require medical attention.

If any of the following side effects occur while taking fulvestrant, check with your doctor or nurse immediately:

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
  • sudden unexplained shortness of breath
  • swollen glands
  • unusual bleeding or bruising
  • unusual tiredness or weakness
  • vaginal bleeding
  • vision changes

Minor Side Effects

Some of the side effects that can occur with fulvestrant may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

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 (stool)
  • 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:
  • Dizziness or lightheadedness
  • 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.

Not all side effects for Faslodex may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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.