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Fluoxymesterone is a synthetic male hormone used to treat women with hormone-dependent breast cancer , and may also be used as a testosterone replacement for men. Fluoxymesterone is sold as Halotestin, Android-F, and Ora-Testryl.


Fluoxymesterone is used to manage metastatic breast cancer in menopausal women who have hormone receptor-positive tumors. It may also be used as a supplement to chemotherapy for metastatic breast cancer, or as a hormone replacement for men. Additionally, it is sometimes used to treat anemia .


Fluoxymesterone is a synthetic androgen, or male hormone, similar in action to testosterone. Fluoxymesterone works by attaching itself to androgen receptors; this causes it to interact with the parts of the cell involved in the making of proteins. It may cause an increase in the synthesis of some proteins or a decrease in the synthesis of others. These proteins have a variety of effects, including blocking the growth of some types of breast cancer cells, stimulating cells that cause male sexual characteristics, and stimulating the production of red blood cells.

When used as a breast cancer treatment, this drug blocks the growth of tumor cells that are dependent on female hormones to grow. It can only be used on female breast cancer patients who have reached menopause one to five years earlier, or as a result of surgery. It may be used in addition to other chemotherapeutic drugs, such as tamoxifen or cyclophosphamide , doxorubicin , and fluorouracil .

Fluoxymesterone may be used to treat men; it replaces male hormones which are not being released in the body as a result of tumors, radiation, or surgery affecting the pituitary or hypothalamus.

Recommended dosage

The recommended dosage will depend on the age, sex, and diagnosis of the patient, as well as the response to treatment and occurrence of side effects. Treatment is usually with a full therapeutic dose initially, then adjusted to the individual needs of the patient.

Women being treated for breast cancer usually take 10 to 40 mg per day orally, divided into several doses. Up to three months may be required for a response to treatment.

Androgen replacement therapy for men is usually started at 5 to 20 mg per day, taken orally in divided doses.

If a dose is missed, it should be taken as soon as it is remembered, unless it is more than two hours late. If it is more than two hours late, the patient should skip that dose and continue to follow the normal dosing schedule.


Fluoxymesterone may be taken with food if it causes stomach upset. Patients taking this medication should ensure that they see their physician regularly during treatment and receive appropriate laboratory tests. Liver function should be monitored and cholesterol and red blood cell levels may need to be examined during treatment. Female breast cancer patients should have their serum and urine calcium levels checked. Prepubescent males will require x rays to determine the rate of their bone maturation. Diabetics should be aware that this medication may affect blood sugar levels.

Fluoxymesterone should not be taken by pregnant women as it will affect the sexual development of the fetus. The hormone may also pass into the milk of nursing mothers, affecting sexual development of the infant. Fluoxymesterone should not be taken by people with liver, kidney, heart or blood vessel disease, prostate problems, or sensitivity to the dye tartrazine. Patients with migraines or epilepsy should discuss these conditions with their physician before using the drug. Elderly male patients using fluoxymesterone have an increased risk of prostate enlargement.

Patients should consult their physician before discontinuing the drug.

Side effects

Patients who use fluoxymesterone have an increased risk of developing liver disease, and should report symptoms such as yellowing of the eyes and skin to their physicians immediately. Women being treated for breast cancer and patients who are immobilized may develop hypercalcemia . Other side effects which may occur include the following:

  • fluid retention
  • nausea and vomiting
  • diarrhea
  • anxiety
  • depression
  • changes in sex drive
  • dizziness
  • suppression of blood clotting factors II, V, VII, and X
  • headache
  • itching
  • reduction in number of white blood cells
  • increase in number of red blood cells

Women who take this medication may also experience menstrual irregularities, acne, enlarged clitoris, and masculine characteristics such as deepening of the voice, increased hair growth, and male pattern baldness. Some of these changes may go away if the medication is stopped, while others may remain.

Men taking fluoxymesterone may experience breast growth, erections of excessive frequency and duration, impotence, decreased ejaculatory volume, and bladder irritation.


A large number of medications may cause interactions with fluoxymesterone, including acetaminophen, anabolic steroids, anticoagulants, antidiabetic agents, and many others. Patients should notify their physicians of any medications they are taking before using fluoxymesterone.

Racquel Baert, M.Sc.



a male hormone


high levels of calcium in the blood