Fluoxymesterone is a synthetic androgen steroid hormone available by prescription. It may be given to men who have medical conditions that lower or inhibit the body’s natural production of testosterone or to women with certain forms of breast cancer. Health-care providers generally warn the drug can cause a variety of possible side effects and may not recommend its use in certain patients due to potentially serious side effects.
The primary uses of fluoxymesterone are in men with lower levels of androgen hormones, which may be seen in conditions such as hypogonadism or delayed puberty. Androgen hormones are also often called male hormones, and are primarily responsible for male sexual development. Testosterone, which begins forming in males in the womb and promotes the development of a penis, testes and a scrotum, is the most known androgen hormone.
In puberty, testosterone levels usually surge again, promoting further growth of the sex organs, as well as development of secondary sexual features, including facial and genital hair growth and a deepening of the voice. Even after puberty, testosterone is generally responsible for maintaining secondary male sexual features, as well as libido. Fluoxymesterone, usually given by mouth in the form of a pill, can help mimic the body’s own testosterone when the body can’t produce enough, to help support the growth and maintenance of these male sexual characteristics.
Another use of fluoxymesterone is in women with certain forms of breast cancer. In some women, the production of estrogen and other female hormones can promote the growth of breast cancer cells. Fluoxymesterone can help offset the effects of natural estrogen in the body, thereby potentially helping to prevent cancer growth in women with estrogen-sensitive breast cancer.
Health-care providers generally warn patients taking fluoxymesterone about many possible side effects. In men, these side effects may include acne, growth of breast tissue, fluid build-up in the extremities, depression, anxiety and decreased sperm production. For women, side effects may include deepening of the voice, increase in body hair, growth of the clitoris, absence of a menstrual period and fluid retention.
Fluoxymesterone may also increase calcium levels in the blood, raise cholesterol and/or cause liver damage in both sexes, so health-care providers generally recommend regular blood tests to check for problems. Due to possible side effects and the potential to worsen certain underlying conditions, fluoxymesterone may not be recommended for some people, including those with heart or liver problems and women who are pregnant.