Description and Brand Names

Drug information provided by: IBM Micromedex

US Brand Name

  1. Faslodex


Fulvestrant injection is used to treat hormone-receptor (HR) positive, human epidermal growth factor receptor 2 (HER2)-negative advanced breast cancer in postmenopausal women who have not been previously treated with other medicines. It is also used to treat HR positive breast cancer that has progressed or worsened after hormonal therapy.

Fulvestrant injection is also used together with ribociclib to treat HR-positive, HER2-negative advanced or metastatic breast cancer in postmenopausal women who have not been previously treated with other medicines or whose cancer has progressed or worsened after hormonal therapy.

Fulvestrant injection is also used in combination with palbociclib or abemaciclib to treat HR positive, HER2-negative advanced or metastatic (cancer that has spread) breast cancer in women who have received hormonal therapy.

Many of the breast cancer tumors will grow when estrogen is available in the body. This medicine blocks the effects of estrogen in the body. As a result, the amount of estrogen that the tumor is exposed to, is reduced, which will limit the growth of the tumor.

This medicine is to be given only by or under the direct supervision of your doctor.

This product is available in the following dosage forms:

  • Solution

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of fulvestrant injection in the pediatric population. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of fulvestrant injection in the elderly.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Fluoroestradiol F 18

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Bleeding problems or
  • Thrombocytopenia (low platelets in the blood)—Use with caution. May make these conditions worse.
  • Liver disease, moderate—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
  • Liver disease, severe—Use has not been studied in patients with this condition.

Proper Use

Medicines used to treat cancer are very strong and can have many side effects. Before receiving this medicine, make sure you understand all the risks and benefits. It is important for you to work closely with your doctor during your treatment.

A nurse or other trained health professional will give you this medicine in a medical facility. It is given as a shot into the buttocks slowly on days 1, 15, 29, and once every month thereafter.

This medicine comes with a patient information leaflet. Read and follow the instructions carefully. Ask your doctor if you have any questions.

Your doctor may also give you other medicines (eg, luteinizing hormone-releasing hormone agonist) while being treated with fulvestrant and palbociclib, abemaciclib, or ribociclib, before your menopause.

Cancer medicines can cause nausea or vomiting, even after receiving medicines to prevent it. If you have nausea and vomiting after receiving this medicine, talk to your doctor or nurse about ways to control these effects.

Missed Dose

This medicine needs to be given on a fixed schedule. If you miss a dose, call your doctor, home health caregiver, or treatment clinic for instructions.


It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Receiving this medicine while you are pregnant can harm your unborn baby. If you are a woman who can bear children, your doctor may give you a pregnancy test 7 days before you start receiving this medicine to make sure you are not pregnant. Use a highly effective form of birth control to keep from getting pregnant during treatment and for 1 year after your last dose. If you think you have become pregnant while receiving the medicine, tell your doctor right away.

Talk with your doctor before receiving this medicine if you plan to have children. Some men and women who receive this medicine have become infertile (unable to have children).

This medicine may increase your risk of bleeding. This is more likely to occur if you have bleeding problems or if you are taking a blood thinner (eg, warfarin). Tell your doctor right away if you have unusual bleeding or bruising after receiving this medicine.

This medicine may cause you to have bleeding from the vagina, especially when you first start receiving it. If the bleeding continues or is bothersome, check with your doctor right away.

Tell your doctor if you have numbness, tingling, or weakness in your legs after receiving this medicine.

Before you have any medical tests, tell the medical doctor in charge that you are using this medicine. The results of some tests (eg, serum estradiol) may be affected by this medicine.

Side Effects

Along with its needed effects, a medicine 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:

More common

  1. Black, tarry stools
  2. bleeding gums
  3. bloating or swelling of the face, arms, hands, lower legs, or feet
  4. blood in the urine or stools
  5. burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  6. chest pain or tightness
  7. chills
  8. cloudy urine
  9. cough
  10. difficulty breathing
  11. fainting
  12. fever
  13. hoarseness
  14. irregular heartbeat, recurrent
  15. lower back or side pain
  16. painful or difficult urination
  17. pale skin
  18. pinpoint red spots on the skin
  19. rapid weight gain
  20. sore throat
  21. sores, ulcers, or white spots on the lips or in the mouth
  22. tender, swollen glands in the neck
  23. tingling of the hands or feet
  24. trouble with swallowing
  25. troubled breathing with exertion
  26. unusual bleeding or bruising
  27. unusual tiredness or weakness
  28. unusual weight gain or loss

Less common

  1. Anxiety
  2. confusion
  3. dizziness or lightheadedness
  4. fast heartbeat
  5. mood or mental changes
  6. muscle cramps in the hands, arms, feet, legs, or face
  7. numbness and tingling around the mouth, fingertips, or feet
  8. pain in the chest, groin, or legs, especially the calves
  9. pain, redness, or swelling in the arm or leg
  10. seizures
  11. severe, sudden headache
  12. slurred speech
  13. stomach cramps
  14. sudden loss of coordination
  15. sudden, severe weakness or numbness in the arm or leg
  16. tremor
  17. vision changes

Incidence not known

  1. Dark urine
  2. flushing or redness of the skin
  3. general feeling of tiredness or weakness
  4. headache
  5. hives or welts, itching, skin rash
  6. large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  7. light-colored stools
  8. nausea
  9. stomach pain, continuing
  10. upper right abdominal pain
  11. vaginal bleeding
  12. vomiting
  13. yellow eyes or skin

Some side effects 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

  1. Back pain
  2. bladder pain
  3. body aches or pain
  4. bone pain
  5. change in or loss of taste
  6. constipation
  7. decreased appetite
  8. depression
  9. diarrhea
  10. difficulty having a bowel movement
  11. difficulty with moving
  12. dry skin
  13. dryness or soreness of the throat
  14. feeling of warmth or heat
  15. feeling sad or empty
  16. frequent urge to urinate
  17. general feeling of discomfort or illness
  18. hair loss or thinning of hair
  19. irritability
  20. joint pain
  21. lack or loss of appetite
  22. lack or loss of strength
  23. loss of interest or pleasure
  24. muscle aches and pains
  25. muscle stiffness
  26. pain at the injection site
  27. pain in the arms or legs
  28. pelvic pain
  29. shivering
  30. stomach pain
  31. sudden sweating
  32. trouble concentrating
  33. voice changes
  34. weight loss

Less common

  1. Dry eye
  2. dry mouth
  3. increased tearing
  4. nervousness
  5. swelling or redness in the joints

Incidence not known

  1. Feeling of constant movement of self or surroundings
  2. sensation of spinning

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.