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Other Names: Faslodex®

About this drug

Fulvestrant is used to treat cancer. It is given as an injection in the muscle (intramuscularly).

Possible side effects

  • Headache
  • Cough and trouble breathing
  • Tiredness and wekaness
  • Hot flashes or sudden skin flushing may happen. You may also feel warm or red. 
  • Nausea and throwing up (vomiting)
  • Constipation (not being able to move bowels)
  • Decreased appetite (decreased hunger)
  • Bone,joint and muscle pain
  • Back pain
  • Pain in your arms and/or legs
  • Tiredness and weakness
  • Pain/tenderness at the injection site
  • Changes in your liver function

Note: Each of the side effects above was reported in 5% or greater of patients treated with fulvestrant. Not all possible side effects are included above.

Warnings and Precautions

  • Risk of bleeding, especially if you have low platelets, or are taking blood-thinning medication. Ask your doctor/nurse what precautions you should take. 
  • Injection site reaction - you may get numbness/tingling and/or nerve damage at the injection site. 
  • May falsely elevate estradiol levels

Treating side effects

  • Keeping your pain under control is important to your well-being. Please tell your doctor or nurse if you are experiencing pain.
  • Manage tiredness by pacing your activities for the day.
  • Be sure to include periods of rest between energy-draining activities.
  • To help with decreased appetite, eat small, frequent meals.
  • Eat high caloric food such as pudding, ice cream, yogurt and milkshakes.
  • Drink plenty of fluids (a minimum of eight glasses per day is recommended).
  • If you throw up or have loose bowel movements, you should drink more fluids so that you do not become dehydrated (lack water in the body from losing too much fluid).
  • To help with nausea and vomiting, eat small, frequent meals instead of three large meals a day.
  • Choose foods and drinks that are at room temperature. Ask your nurse or doctor about other helpful tips and medicine that is available to help or stop lessen these symptoms.
  • Ask your doctor or nurse about medicines that are available to help stop or lessen constipation.
  • If you are not able to move your bowels, check with your doctor or nurse before you use enemas, laxatives, or suppositories.

Food and drug interactions

  • There are no known interactions of fulvestrant with food.
  • There are no known interactions of fulvestrant with other medications. Tell your doctor and pharmacist about all the prescription and over-the-counter medicines and dietary supplements (vitamins, minerals, herbs and others) that you are taking at this time. The safety and use of dietary supplements and alternative diets are often not known. Using these might affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.

When to call the doctor

Call your doctor or nurse if you have any of these symptoms and/or and new or unusual symptoms:

  • Fever of 100.5 F (38 C) or higher
  • Chills
  • Fatigue that interferes with your daily activities 
  • Headache that does not go away
  • Coughing up yellow, green, or bloody mucus
  • Wheezing or trouble breathing
  • Pain that does not go away, or is not relieved by prescribed medicines
  • Lasting loss of appetite or rapid weight loss of five pounds in a week
  • Nausea that stops you from eating or drinking and/or is not relieved by prescribed medicines
  • Throwing up more than 3 times a day
  • No bowel movement in 3 days or when you feel uncomfortable
  • Signs of possible liver problems: dark urine, pale bowel movements, bad stomach pain, feeling very tired and weak, unusual itching, or yellowing of the eyes or skin
  • Severe bleeding at the injection site
  • Numbness/tingling at the injection site
  • If you think you may be pregnant

Reproduction Warnings

  • Pregnancy warning: This drug can have harmful effects on the unborn baby. Women of childbearing potential should use effective methods of birth control during your cancer treatment and for one year after treatment. Let your doctor know right away if you think you may be pregnant.
  • Breastfeeding warning: Women should not breast feed during treatment and for one year after treatment because this drug could enter the breast milk and cause harm to a breastfeeding baby.
  • Fertility warning: In men and women both, this drug may affect your ability to have children in the future. Talk with your doctor or nurse if you plan to have children. Ask for information on sperm or egg banking.

Revised April 2018

This patient information was developed by Via Oncology, LLC © 2018. This information is not intended to be used as a substitute for professional medical advice, diagnosis, or treatment. You should not rely entirely on this information for your health care needs. Ask your own doctor or health care provider any specific medical questions that you have.

CLIENT acknowledges that the Via Pathways and Via Portal are information management tools only, and that Via Oncology, LLC has not represented the Via Pathways or Via Portal as having the ability to diagnose disease, prescribe treatment, or perform any other tasks that constitute the practice of medicine. The clinical information contained in the Via Pathways and Via Portal are intended as a supplement to, and not a substitute for, the knowledge, expertise, skill, and judgment of physicians, pharmacists and other healthcare professionals involved with patient care at CLIENT facilities.