Endometriosis - Medications

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GnRH Agonists

Gonadotropin releasing hormone (GnRH) agonists are effective hormone treatments for endometriosis. They are able to block the release of the reproductive hormones LH (luteinizing hormone) and FSH (follicular-stimulating hormone). As a result, the ovaries stop ovulating and no longer produce estrogen. Ovulation and menstruation resume around 4 to 10 weeks after stopping the drug. The specific length of time depends on the type of GnRH agonist used.

Women with endometriosis often have a difficult time getting pregnant. A 2006 review suggested that GnRH agonists may help women with endometriosis become pregnant when the drug is given along with in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). (IVF and ICSI are standard infertility treatments.) The review found that 3 to 6 months of GnRH therapy in combination with infertility treatment quadrupled the pregnancy rate. However, the study did not supply data on how many women actually gave birth. In addition, there is not enough information on whether these drugs may adversely affect a woman or her fetus.

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Specific GnRH Agonists. GnRH agonists include goserelin (Zoladex), buserelin, a monthly injection of leuprolide (depot Lupron), and a nasal spray, Nafarelin (Synarel). Studies have reported that nafarelin shrank all implants and significantly relieved symptoms in 85% of patients, delayed recurrence of endometriosis after surgery, and in comparison with leuprolide, was less expensive, had fewer side effects, and a provided better quality of life.

Side Effects and Complications. Commonly reported side effects (which can be severe in some women) include menopause-like symptoms that include hot flashes, night sweat, and changes in the vagina, weight change, and depression. The side effects vary in intensity depending on the GnRH agonist. They may be more intense with leuprolide and persist after the drug has been stopped.

The most important concern is possible osteoporosis from estrogen loss. Women ordinarily should not take GnRH agonists for more than 6 months. Certain approaches may preserve enough estrogen to protect bones and still effectively relieve endometriosis symptoms: