Posted on April 28th, 2009 by

Class: Hormonal therapy

Generic Name: Fluoxymesterone (floo-ocks-ee-MESS-ter-own)
Trade Name: Halotestin®

For which conditions is this drug approved? Fluoxymesterone is used for the treatment of hormone-positive breast cancer that has recurred following previous therapy. It is important for patients to remember that physicians have the ability to prescribe medication for conditions other than those for which the drug has been approved by the FDA. Patients who have received a prescription of this drug for a condition other than which it is approved may wish to discuss this issue with their physician.

What is the mechanism of action? Fluoxymesterone is classified as an androgen. Androgens are naturally occurring hormones that tend to be found in higher levels in males than females. The presence of androgens aids in the suppression of estrogen, a common female hormone. A significant portion of breast cancer is stimulated to grow from the presence of estrogen, and is referred to as hormone-positive breast cancer. Treatment with fluoxymesterone results in a lowered levels of estrogen, thereby reducing the growth stimulatory effects caused by normal estrogen levels..

How is fluoxymesterone typically given (administered)? Fluoxymesterone is given orally, as a tablet.

How are patients typically monitored? Patients will usually have scheduled meetings with their healthcare provider while they are being treated with fluoxymesterone.  Typically, blood will be drawn to check levels of blood cells and to monitor functions of some organ systems, such as the kidneys or liver.  Patients may also undergo physical examinations, scans or other measures to assess side effects and response to therapy.  In addition, patients will be monitored for liver problems, including hepatitis and liver damage. This is an uncommon, but serious, side effect of treatment with fluoxymesterone, with the risk increasing with long-term use.

What are the common side effects of treatment with fluoxymesterone?

• Cessation of menstruation in women
• Deepening of voice
• Swelling of hands, feet or face (edema)
• Acne
• Enlargement of the clitoris

What are the less common side effects of treatment with fluoxymesterone?

• Weight gain
• Nausea
• Growth of facial hair
• Changes in sex drive

What are the possible late side effects of treatment with fluoxymesterone? Liver abnormalities, including hepatitis and liver damage, may develop in patients who have used fluoxymesterone as long-term treatment.

This is not a complete list of side effects. Some patients may experience other side effects that are not listed here. Patients may wish to discuss with their physician the other less common side effects of this drug, some of which may be serious.

Some side effects may require medical attention. Other side effects do not require medical attention and may go away during treatment. Patients should check with their physician about any side effects that continue or are bothersome.

What can patients do to help alleviate or prevent discomfort and side effects?

• Pay careful attention to the physician’s instructions and inform the physician of any side effects.
• Maintain adequate rest and nutrition.
• Wear sunscreen and protective clothing and try to minimize sun exposure.
• Drink plenty of fluids. (Patients should ask their physician about the amount of liquid to consume during a day.)
• Eat small meals frequently to help alleviate nausea.
• Patients who experience hot flashes may wish to wear light clothing, stay in a cool environment, and place cool cloths on their body or head to relieve their symptoms.

Are there any special precautions patients should be aware of before starting treatment?

• Patients should inform their physician if they are pregnant, breastfeeding or planning a family in the near future. This drug may cause birth defects. It is important to use some kind of birth control while undergoing treatment. Also, patients may want to talk to their physician if they are considering having children in the future, since some drugs may cause fertility problems.
• It is important that patients inform their physician of any pre-existing conditions (chicken pox, heart disease, kidney disease, liver disease, lung disease, etc.) as they may worsen with this drug.
• Patients should inform their physician of any other medication they are taking (whether prescription or over-the-counter, including vitamins, herbs, etc.) as they may interfere with treatment.
• Patients should check with their physician before starting any new drug or nutritional supplement.
• Patients should inform their physician of any known drug or food allergies or any reactions to medications they have experienced in the past.
• Diabetic patients should monitor their blood glucose closely and notify their physician of any changes. Fluoxymesterone may affect blood glucose levels and insulin/diabetic medication requirements.
• If an oral dose is missed, do not double up on doses.  Patients should contact their physician in this event.
• Keep tablets out of reach of children and return to the pharmacy for safe disposal if treatment is terminated.

When should patients notify their physician?

• Persistent and severe nausea
• Swelling, redness and/or pain in only one extremity
• Yellowing of the skin or eyes
• Swelling of the feet or ankles
• Sudden weight gain
• Difficulty breathing
• Change in menstrual cycle

What is a package insert?
A package insert is required by the FDA and contains a summary of the essential scientific information needed for the safe and effective use of the drug for healthcare providers and consumers.  A package insert typically includes information regarding specific indications, administration schedules, dosing, side effects, contraindications, results from some clinical trials, chemical structure, pharmacokinetics and metabolism of the specific drug. By carefully reviewing the package insert, you will get the most complete and current information about how to safely use this drug. If you do not have the package insert for the drug you are using, your pharmacist or physician may be able to provide you with a copy.

Copyright © 2016 CancerConnect Last updated 07/10.

Important Limitations of Use

The information provided above on the drug you have selected is provided for your information only and is not a substitute for consultation with an appropriate medical doctor. We are providing this information solely as a courtesy and, as such, it is in no way a recommendation as to the safety, efficacy or appropriateness of any particular drug, regimen, dosing schedule for any particular cancer, condition or patient nor is it in any way to be considered medical advice. Patients should discuss the appropriateness of a particular drug or chemotherapy regimen with their physician.

As with any printed reference, the use of particular drugs, regimens and drug dosages may become out-of-date over time, since new information may have been published and become generally accepted after the latest update to this printed information. Please keep in mind that health care professionals are fully responsible for practicing within current standards, avoiding use of outdated regimens, employing good clinical judgment in selecting drugs and/or regimens, in calculating doses for individual patients, and verifying all dosage calculations.



The prescribing physician is solely responsible for making all decisions relating to appropriate patient care including, but not limited to, drugs, regimens, dose, schedule, and any supportive care.

Tags: F, Hormonal Therapy

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