Fluoxymesterone

Absorption

Oral absorption is less than 44%.

Toxicity

Side effects include virilization (masculine traits in women), acne, fluid retention, and hypercalcemia.

Description

Fluoxymesterone(Halotestin) is a steroid with an androgenic property that is used in primary hypogonadism and testicular failure due to cryptorchidism, vanishing testes syndrome, or orchidectomy; and in hypogonadotrophic hypogonadism and luteinizing hormone-releasing hormone (LHRH) deficiency or pituitary hypothalamic injury from tumors, trauma, or radiation. It mimics the actions of testosterone, which is responsible for normal growth and development of the male sex organs and for the maintenance of secondary sex characteristics. In female postmenopausal patients, fluoxymesterone may be indicated in the palliation of recurrent mammary cancer.

Chemical properties

white to light yellow crystal powder

Originator

Halotestin, Upjohn, US,1957

The Uses of Fluoxymesterone

Fluoxymesterone is an anabolic steroid with androgenic activity. It is used in the treatment of male hypogonadism. It showed antitumor effects on pregnancy-dependent mammary tumors TPDMT-4.

Indications

In males, used as replacement therapy in conditions associated with symptoms of deficiency or absence of endogenous testosterone. In females, for palliation of androgenresponsive recurrent mammary cancer in women who are more than one year but less than five years postmenopausal.

Background

An anabolic steroid that has been used in the treatment of male hypogonadism, delayed puberty in males, and in the treatment of breast neoplasms in women.

Indications

Fluoxymesterone promotes growth and development of male reproductive organs, maintains secondary sex characteristics, increases protein anabolism, and decreases protein catabolism. It is used to treat symptoms of low testosterone in adult men who have hypogonadism (a condition in which the body does not produce enough natural testosterone). It is also used for palliation of androgen-responsive recurrent mammary cancer in women who are more than 1 year but less than 5 years postmenopausal (women).

Definition

ChEBI: Fluoxymesterone is an anabolic androgenic steroid, a 17beta-hydroxy steroid, an 11beta-hydroxy steroid, a fluorinated steroid and a 3-oxo-Delta(4) steroid. It has a role as an antineoplastic agent and an anabolic agent.

brand name

Android (Valeant); Halotestin (Pharmacia & Upjohn); Ora-Testryl (Bristol-Myers Squibb).

Therapeutic Function

Androgen

General Description

Fluoxymesterone, 9α-fluoro-11β,17β-dihydroxy-17-methylandrost-4-en-3-one, is ahighly potent, orally active androgen, about 5 to 10 timesmore potent than testosterone. It can be used for all theindications discussed previously, but its great androgenicactivity has made it useful primarily for treatment of theandrogen-deficient male.

Pharmacokinetics

Fluoxymesterone is a synthetic androgen, or male hormone, similar 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.

Pharmacokinetics

By substituting a 9α-fluoro group onto an analog of 17α-methyltestosterone, fluoxymesterone has 20 times the anabolic and 10 times the androgenic activity of 17α-methyltestosterone. It has a mean half-life of 9 hours, and less than 5% of the drug is excreted unchanged. An adverse effect of fluoxymesterone is sodium and water retention that could lead to edema.

Side Effects

Fluoxymesterone is used as an androgen hormonal supplement. An adverse effect of fluoxymesterone is sodium and water retention that could lead to edema. Side effects associated with this agent include closing of the epiphyseal closures, hypercalcemia, and edema. This product should not be given to boys who are in puberty because of its effect on the epiphyseal closures.

Safety Profile

Fluoxymesterone is contraindicated in male subjects with known or suspected carcinoma of the prostate gland. Prolonged use of high-dosage 17-alpha-alkyl androgens is known to have caused hypercalcemia, hepatic adenoma, hepatocellular carcinoma, and hepatitis. Fluoxymesterone, which accelerates bone maturation without producing linear growth, should be used cautiously in males with delayed puberty. Edema and CHF may occur in patients with preexisting cardiovascular problems. Androgens cause virilization in female subjects.

Synthesis

Fluoxymesterone, 9-fluoro-11|?,17|?-dihydroxy-17|á-methylandrost- 4-en-3-one (29.3.8), is made from 11|?-hydroxy-4-androsten-3,17-dione, which is reacted with pyrrolidine to give a dieneamine (29.3.4). This undergoes a reaction with methylmagnesiumiodide, which after hydrolysis forms 11|?,17|?-dihydroxy-17|á-methylandrost- 4-en-3-one (29.3.5). Dehydration of this compound by selective tosylation of the secondary hydroxyl group at C11 using p-toluenesulfonyl chloride and subsequent reaction with a base gives the diene (29.3.6), and the double bond at C9¨CC11 is transformed to an epoxide (29.3.7) by subsequent reaction with N-bromoacetamide in a wet solvent (source of HOBr), and a base. Further reaction with hydrogen fluoride results in an opening of the epoxide ring and the formation of the desired fluoxymesterone (29.3.8).

Metabolism

Presence of 17-alpha alkyl group reduces susceptibility to hepatic enzyme degradation, which slows metabolism and allows oral administration. Inactivation of testosterone occurs primarily in the liver

Mode of action

Fluoxymesterone binds to androgen receptors, suppressing GnRH, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) through a negative feedback mechanism involving the hypothalamus and anterior pituitary. It antagonizes the estrogenic effects in estrogendependent target cells.