Medical Health Encyclopedia

Danazol (Danocrine) is a synthetic substance that resembles a male hormone (androgen). It suppresses the pathway leading to ovulation. Studies have shown symptomatic improvement in 90% of women, although in one study, only about 58% of women expressed satisfaction with this therapy. A high drop-out rate occurs, most often because of adverse side effects, particularly male characteristics, such as growth of facial hair, acne, weight gain, dandruff and deepening of the voice. Danazol may increase the risk for unhealthy cholesterol levels. A few cases of blood clots and strokes have also been reported, as well as rare cases of liver damage. One study reported that taking a low dose may relieve endometrial symptoms and reduce the risk for these side effects. Exercise may help reduce side effects. As with GnRH agents, pregnant women or those trying to become pregnant should not take this drug because it may cause birth defects.

Antiprogestins

Antiprogestins are promising agents for endometriosis because they reduce both estrogen and progesterone receptors.

Gestrinone. Gestrinone is the most studied antiprogestin and may be comparable to GnRH agonists in reducing pain and have fewer menopausal symptoms. In one study bone density even increased slightly. Adverse effects of gestrinone include male hormone symptoms, such as acne, and possibly the development of unhealthy cholesterol levels.

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Mifepristone. Mifepristone (Mifeprex) is another antiprogestin that is effective for treating endometriosis. In one six-month study, mifepristone improved symptoms and reduced endometrial implants without causing menopausal side effects. Long-term use, however, may cause changes in the uterine tissue and cell proliferation.

Investigative Drugs

GnRH Antagonists. GnRH antagonists include ganirelix (Antagon) and cetrorelix (Cetrotide). These are newer agents differ from GnRH agonists in that they have a direct effect on the pituitary gland. The result is quicker action. They also pose a lower risk for complications and side effects.