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Generic name: fluoxymesterone (floo OX i MES te rone)
Brand name: Androxy, Halotestin
Drug class: Androgens and anabolic steroids, Hormones / antineoplastics

What is fluoxymesterone?

Fluoxymesterone is a man-made form of testosterone, a naturally occurring sex hormone that is produced in a man's testicles. Small amounts of testosterone are also produced in a woman's ovaries and adrenal system.

Fluoxymesterone is used in men and boys to treat conditions caused by a lack of this hormone, such as delayed puberty or other hormonal imbalances.

Fluoxymesterone is also used in women to treat breast cancer that has spread to other parts of the body. Fluoxymesterone treats only the symptoms of metastatic breast cancer but does not treat the cancer itself.

Fluoxymesterone may also be used for purposes not listed in this medication guide.

What is the most important information I should know about fluoxymesterone?

This medicine can cause birth defects. Do not use fluoxymesterone if you are pregnant.

You should not use fluoxymesterone if you have prostate cancer or male breast cancer.

Fluoxymesterone will not enhance athletic performance and should not be used for that purpose or shared with another person.

What should I discuss with my healthcare provider before taking fluoxymesterone?

You should not use fluoxymesterone if you are allergic to it, or if you have:

  • prostate cancer;

  • male breast cancer; or

  • if you are pregnant.

Fluoxymesterone will not enhance athletic performance and should not be used for that purpose or shared with another person.

To make sure fluoxymesterone is safe for you, tell your doctor if you have:

  • benign prostatic hypertrophy (BPH);

  • breast cancer;

  • delayed puberty (unless you are taking fluoxymesterone to treat it);

  • liver or kidney disease;

  • diabetes;

  • any debilitating condition; or

  • heart disease, coronary artery disease (hardened arteries), congestive heart failure, or a history of heart attack.

This medication can harm an unborn baby or cause birth defects. Do not use fluoxymesterone if you are pregnant. Use effective birth control to avoid pregnancy during your treatment with fluoxymesterone. Follow your doctor's instructions about how long to prevent pregnancy after your treatment ends.

It is not known whether fluoxymesterone passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are taking fluoxymesterone.

Fluoxymesterone can affect bone growth in boys who are treated for delayed puberty. Bone development may need to be checked with X-rays every 6 months during treatment.

How should I take fluoxymesterone?

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended.

While using fluoxymesterone, you may need frequent blood tests.

Store at room temperature away from moisture, heat, and light.

Read all patient information, medication guides, and instruction sheets provided to you. Ask your doctor or pharmacist if you have any questions.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking fluoxymesterone?

This medicine can pass into body fluids (urine, feces, vomit). Caregivers should wear rubber gloves while cleaning up a patient's body fluids, handling contaminated trash or laundry or changing diapers. Wash hands before and after removing gloves. Wash soiled clothing and linens separately from other laundry.

Fluoxymesterone will not enhance athletic performance and should not be used for that purpose or shared with another person.

Fluoxymesterone side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop using fluoxymesterone and call your doctor at once if you have:

  • shortness of breath (even with mild exertion), swelling, rapid weight gain;

  • increased or ongoing erection of the penis;

  • nausea, vomiting, loss of appetite, increased thirst, muscle weakness, confusion, and feeling tired or restless; or

  • upper stomach pain, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).

Women receiving fluoxymesterone may develop male characteristics, which could be irreversible if testosterone treatment is continued. Stop taking this medication and call your doctor at once if you notice any of these signs of excess testosterone:

  • changes in menstrual periods;

  • male-pattern hair growth (such as on the chin or chest);

  • hoarse voice; or

  • enlarged clitoris.

Common side effects (in men or women) may include:

  • acne, changes in skin color;

  • increased hair growth;

  • male pattern baldness;

  • increased or decreased interest in sex;

  • breast swelling;

  • headache, anxiety, depression; or

  • numbness, burning, pain, or tingly feeling.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Fluoxymesterone dosing information

Usual Adult Dose for Hypogonadism -- Male:

-5 to 20 mg orally per day
-Usually preferable to start therapy at a higher level within the range (e.g., 10 mg) with subsequent adjustment as required.

-This drug may be given as a single dose or in divided doses.
-Dosage and duration of therapy will depend on age, sex, diagnosis, patient response to treatment, and appearance of adverse effects.

Uses: This drug is indicated for replacement therapy in conditions associated with a deficiency or absence of endogenous testosterone.

-Primary hypogonadism (congenital or acquired)
-Hypogonadotropic hypogonadism (congenital or acquired)
-Testicular failure due to cryptorchidism, bilateral torsion, orchitis, vanishing testis syndrome, or orchidectomy
-Idiopathic gonadotropin or luteinizing hormone-releasing hormone (LHRH) deficiency, or pituitary-hypothalamic injury from tumors, trauma, or radiation

Usual Adult Dose for Breast Cancer--Palliative:

Palliation of Inoperable Mammary Cancer:
-10 to 40 mg orally per day in divided doses for 3 months or more

Palliation of Advanced Mammary Carcinoma:
-Hormone therapy is adjunctive to and not a replacement for conventional therapy; therapy duration will depend on the response of the condition and the appearance of adverse reactions.

-Androgen therapy appears to occasionally accelerate the disease; patients should be followed closely.
-This treatment has been used in premenopausal women with breast cancer who have benefited from oophorectomy and are considered to have a hormone-responsive tumor.

Use: Secondary treatment in women with advancing inoperable metastatic (skeletal) mammary cancer who are 1 to 5 years postmenopausal.

Usual Pediatric Dose for Delayed Puberty -- Male:

2.5 to 20 mg orally per day; generally in the lower range of 2.5 to 10 mg orally per day, taken in one single dose or in divided doses for a limited duration (e.g., 4 to 6 months).

-Various dosage regimens have been used: some call for lower dosages initially with gradual increases as puberty progresses, with or without a decrease to maintenance level; other regimens call for higher dosage to induce pubertal changes and lower dosage for maintenance after puberty.
-The chronological and skeletal ages should be taken into consideration in determining the initial dose and when adjusting the dose.
-Brief treatment with conservative doses may occasionally be justified in these male patients if they do not respond to psychological support.
-Patients and parents should be advised of the potential adverse effect on bone maturation prior to treatment.
-Hand and wrist x-rays to determine bone age should be obtained every 6 months to assess the effect of treatment on the epiphyseal centers.

Use: Stimulate puberty in adolescent males with clearly delayed puberty

What other drugs will affect fluoxymesterone?

Other drugs may interact with fluoxymesterone, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Date modified: October 13, 2017
Last reviewed: October 20, 2015

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.