In the U.S.—

• Antineoplastic

Fulvestrant ( Fool-VES-trant) is a medicine that is used to treat breast cancer.

Many breast cancer tumors grow in response to estrogen. This medicine blocks the effects of the estrogen hormone in the body. As a result, the amount of estrogen that the tumor is exposed to is reduced, limiting the growth of the tumor.

This medicine is available only with your doctor's prescription, in the following dosage form:

Parenteral
• Injection (U.S.)

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

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to fulvestrant. Also tell your doctor and pharmacist if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Tell your doctor if you are pregnant or if you intend to become pregnant. Fulvestrant has not been studied in pregnant women. However, studies in animals have shown that fulvestrant causes serious problems with the fetus. Be sure that you have discussed this with your doctor before taking this medicine. It is best to avoid pregnancy during treatment with this medicine.

Tell your doctor right away if you think you have become pregnant while taking fulvestrant

Breast-feeding—It is not known whether fulvestrant passes into the breast milk. However, because this medicine may cause serious side effects, breast-feeding generally is not recommended while you are taking it.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people.

Other medicines—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. Tell your health care professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine. When you are taking fulvestrant, it is especially important that your doctor and pharmacist know if you are taking any of the following:

• Anticoagulants (e.g., Coumadin, Warfarin sodium)—may increase the risk of bleeding or bruising

• Bleeding problems—May be worsened by fulvestrant

• Liver disease—Effects of fulvestrant may be increased because of slower removal from the body

Fulvestrant is usually given by a health care professional. However, medicines given by injection are sometimes used at home. If you will be using fulvestrant at home, your health care professional will teach you how the injections are to be given. Be certain that you understand exactly how the medicine is to be injected. Do not reuse needles and syringes.

Put used needles and syringes in a puncture-resistant disposable container, or dispose of them as directed by your health care professional.

Dosing—

The dose of fulvestrant will be different for different patients.Follow your doctor's orders or the directions on the label. The following information includes only the average doses of fulvestrant.

• For parenteral dosage form (injection):
  • For cancer of the breast:
    • Adults—250 milligrams (mg), injected into the muscle of the buttocks on the same day of every month (e.g., the first day of every month). The dose can be given as a single 5 mL (milliliter) injection, or as two 2.5 mL (milliliter) injections, immediately following each other.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible and schedule the next dose 30 days later. Do not double doses or use more often than one dose every 30 days. If you have any questions about this, check with your doctor.

Storage—

To store this medicine:

• Store in the refrigerator.
• Protect from light, store in original container.
• Keep out of the reach of children.
• Do not keep outdated medicine or medicine no longer needed. Ask your health care professional how you should dispose of any medicine you do not use. Be sure that any discarded medicine is out of the reach of children.

Your doctor will want to check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to check for unwanted effects.

For women of childbearing age—It is very important that you do not become pregnant while taking fulvestrant.

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 immediately if any of the following side effects occur:

• More common
  • Bloating or swelling of face, arms, hands, lower legs, or feet ;  rapid weight gain;  tingling of hands or feet;  unusual weight gain or loss 
  
  

Other 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. However, check with your doctor if any of the following side effects continue or are bothersome.

• 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 ;  chest pain;  chills;  congestion;  cough, increased ;  diarrhea ;  difficult, burning, or painful urination;  difficult or labored breathing;  difficulty having a bowel movement (stool);  discouragement;  dizziness;  dryness or soreness of throat;  feeling faint, dizzy, or light-headedness;  feeling of warmth or heat;  feeling sad or empty;  fever;  flushing or redness of skin, especially on face and neck;  frequent urge to urinate;  general feeling of discomfort or illness;  headache;  hoarseness;  injection site pain;  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;  nausea;  pain ;  pelvic pain ;  runny nose ;  shivering;  shortness of breath;  skin rash ;  sleeplessness ;  sore throat;  stomach pain ;  sweating;  tender, swollen glands in neck;  tightness in chest;  trouble concentrating;  trouble in swallowing ;  trouble sleeping;  unable to sleep;  unusual tiredness or weakness;  voice changes;  vomiting;  wheezing 
  
  

• Less common
  • Difficulty in moving;  fear;  muscle pain or stiffness;  nervousness ;  pain, swelling, or redness in joints;  pale skin;  troubled breathing with exertion ;  unusual bleeding or bruising 
  
  

• Rare
  • Black, tarry stools;  feeling of constant movement of self or surroundings;  muscle aching or cramping;  muscle pains or stiffness;  pain in chest, groin, or legs, especially the calves;  sensation of spinning;  severe, sudden headache;  slurred speech;  sores, ulcers, or white spots on lips or in mouth;  sudden, unexplained shortness of breath;  sudden loss of coordination;  sudden, severe weakness or numbness in arm or leg;  swollen joints;  vaginal bleeding ;  vision changes 
  
  

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