Fulvestrant (Generic Name) 

Other Names: Faslodex®

About this drug

Fulvestrant is used to treat cancer. It is given by injection in your muscle and is called an “IM injection."

Possible side effects

  • Nausea and vomiting
  • Constipation or diarrhea
  • Abdominal pain
  • Back pain
  • Headache
  • Hot flashes
  • Sore throat
  • Weakness
  • Shortness of breath
  • Redness and soreness at the injection site
  • Effects on an unborn child. This drug may have harmful effects on an unborn child. If you are pregnant, you cannot take this drug. Use effective methods of birth control during your cancer treatment. Genetic counseling is available to you to discuss the effect of this drug therapy on future pregnancies. If you are pregnant or become pregnant, talk with a genetic counselor. He or she can review the potential risks to the fetus.

Treating side effects

  • Vaginal lubricants can be used to lessen vaginal dryness, itching, and pain during sexual relations.
  • If you are constipated, ask your doctor or nurse for medicines and diet changes that may help you move your bowels regularly.
  • Ask your doctor or nurse about medicine that is available to help prevent or lessen nausea, vomiting, diarrhea, back pain, or headache.

Other instructions

If you are to receive fulvestrant by IM injection at home, you will receive guidelines for storing and injecting the drug. Store the syringes of fulvestrant in the refrigerator — never freeze them.

Food and drug interactions

There are no known interactions of this drug with food. This drug may interact with other medicine. Tell your doctor and pharmacist about all the medicines and dietary supplements (vitamins, minerals, herbs, and others) that you are currently taking. The safety and effectiveness of dietary supplements and alternative diets are often unknown. Using these might unexpectedly 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 advice.

When to call the doctor

Call your doctor or nurse immediately if you have any of the following symptoms:

  • Temperature of 100.5 F (38 C) or above
  • Chills
  • Uncontrolled nausea that prevents you from eating or drinking
  • Vomiting more than 3 times in 1 day
  • Severe headache
  • Severe stomach pain with nausea and vomiting
  • Shortness of breath
  • Rash or itching


Call your doctor or nurse as soon as possible if you have any of the following symptoms:

  • Lower belly pain or nausea that prescribed medicine doesn’t help
  • No bowel movement for 3 days or if you feel uncomfortable
  • Headache or back pain unrelieved by prescribed medicine
  • Throat pain or inability to eat or drink
  • Diarrhea of 5 or 6 stools in one day or diarrhea with weakness
  • Headache that prescribed medicine doesn’t help

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