Antiandrogen

An antiandrogen, androgen-receptor antagonist, or androgen antagonist, is any of a group of hormone receptor antagonist compounds capable of preventing or inhibiting the biologic effects of androgens, or male sex hormones, on normally responsive tissues in the body. Antiandrogens usually work by blocking the appropriate receptors, competing for binding sites on the cell's surface, obstructing the androgens' pathway.

Indications
Antiandrogens are often indicated to treat severe male sexual disorders, such as hypersexuality (excessive sexual desire) and sexual deviation such as paraphilias. They are also useful as antineoplastic agents and in palliative, adjuvant or neoadjuvant hormonal therapy in prostate cancer.

Antiandrogens can also be used for treatment of benign prostatic hyperplasia (prostate enlargement), acne vulgaris, androgenetic alopecia (male pattern baldness), and hirsutism (excessive hairiness). On occasion, they are also used as a male contraceptive agent, to purposefully prevent or counteract masculinisation in the case of transsexual women undergoing sex reassignment therapy, and to prevent the symptoms associated with reduced testosterone, such as hot flashes, following castration. They can also be used for the treatment of polycystic ovarian syndrome (PCOS).

The administration of antiandrogens in males can result in slowed or halted development or reversal of male secondary sex characteristics, reduced activity or function of the accessory male sex organs, and hyposexuality (diminished sexual desire or libido).

Sometimes as a part of a program for registered sex offenders recently released from prisons, the offender is administered antiandrogen drugs to reduce the likelihood of repeat offending by reducing sexual drive, etc.

Examples
Currently available antiandrogen drugs (brand names, which may include other active ingredients, in parentheses) include:


 * Spironolactone (Aldactone, Spirotone), a synthetic 17-spirolactone corticosteroid, which is a renal competitive aldosterone antagonist in a class of pharmaceuticals called potassium-sparing diuretics, used primarily to treat low-renin hypertension, hypokalemia, and Conn's syndrome.
 * Cyproterone acetate (Androcur, Climen, Diane 35, Ginette 35), a synthetic steroid, a potent antiandrogen that also possesses progestational properties.
 * Flutamide (Eulexin), nilutamide (Anandron, Nilandron) and bicalutamide (Casodex), nonsteroidal, pure antiandrogens. Flutamide is the oldest and has more unwanted side-effects than the others. Bicalutamide is the newest and has the least side-effects.
 * Ketoconazole (Nizoral), an imidazole derivative used as a broad-spectrum antifungal agent effective against a variety of fungal infections; side-effects include serious liver damage and reduced levels of androgen from both the testicles and adrenal glands. Ketoconazole is a relatively weak antiandrogen.
 * Finasteride (Proscar, Propecia) and dutasteride (Avodart), inhibitors of the 5-α-reductase enzyme that prevent the conversion of testosterone into dihydrotestosterone (DHT). Finasteride blocks only 5-α-reductase type II, dutasteride also blocks type I. They are not general antiandrogens in that they do not counteract the effects or production of other androgens other than DHT; however, DHT is 3-5 times more potent than testosterone or other androgens (except in skeletal muscle tissue, where testosterone is the main androgen).There are a number of in vivo and in vitro plant/herbal inhibitors of the 5-alpha reductase
 * DDE The metabolite of DDT is DDE, which acts as a weak antiandrogen.
 * Bexlosteride
 * Izonsteride
 * Epristeride
 * Turosteride
 * RU58841, a non-steroidal antiandrogen

Antiandrogen herbs
The best known plant-derived anti-androgen is 3,3'-Diindolylmethane(DIM)

Spearmint tea has antiandrogenic properties in females with hirsutism. ,

Scutellaria baicalensis may also have antiandrogenic properties.

The compound N-butylbenzene-sulfonamide (NBBS) isolated from Pygeum africanum is a specific androgen antagonist. ,

Glycyrrhiza glabra has shown antiandrogenic activity in male rats

A herbal formula (termed KMKKT) containing Korean Angelica gigas Nakai (AGN) root and nine other oriental herbs has shown in vitro anti-androgen activity.

Pygeum africanum contains an antiandrogenic compound atraric acid.

Duke's database lists several more herbs that have antiandrogenic properties.