Medical therapy for endometriosis: a literature review.

Endometriosis is a chronic and complex disease, originated by the presence of endometrium outside uterine cavity, such as ovaries, fallopian tubes, peritoneum, vagina, intestines. The main symptoms are related to internal bleeding and chronic inflammation causing dysmenorrhea, chronic pelvic pain, dyspareunia and dysuria. Owing to adhesions, endometriosis leads to infertility. Although endometrial cells are in abnormal sites, they are influenced as well by hormonal changes and respond in a similar way to the cells developed inside the uterus. Objectives. To determine the actual role of medical therapy in the treatment of endometriosis. Search strategy. We performed a systematic review of publications from 1984 to January 2015 via PubMed search, regarding medical therapy on endometriosis. Additional relevant articles were identified from citations within these publications. Main results. Among various hormonal drugs for endometriosis the most used are: Gonadotropin Releasing Hormone (GnRH) agonists, Oral Contraceptives (OCP), danazol, aromatase inhibitors and progesterone with its derivatives. GnRH agonists (GnRHa) increase the levels of GnRH inducing a down-regulation and hypoestrogenism. Main side effects are unpleasant menopausal inducted symptoms: flushing and osteoporosis. OCP reduce the production of gonadal estrogen by means of a negative feedback mechanism. A part from reducing estrogens, they interfere with the production of prostaglandins giving a favorable effect on both inflammation and pelvic pain. Danazol is a derivative of the synthetic 17a-ethinyltestosterone. It induces a hypoestrogenic- hyperandrogenic condition, which blocks endometriotic foci and clinical symptomatology. Its oral use is limited by several side effects as the following: weight gain, muscle cramps, acne, seborrhoea, decreased breast dimension, hirsutism and tendency to the virile tone of the voice. Progestins have both a central and peripheral effect. They depress mitogenic action and estrogen production. The endometrium tends to secretory transformation, decidualization and atrophy. Several derivatives are used: medroxyprogesteron acetate (MPA), dydrogesterone, norethisterone, lynestrenol, desogestrel. In the last years, they have been used in many ways as oral, parenteral and indouterine (Levonorgestrelintrauterine device or LNG-IUD) therapy. Nevertheless, the LNGIUD is not approved for the treatment of endometriosis. The employ of progestins has been limited because of many side-effects among which breast tenderness, weight gain, acne, hirsutism and irregular bleeding. Recently dienogest, a selective progestin combining the pharmacologic properties of 19-norprogestins and progesterone derivatives gets a potent effect at the endometrium providing an efficient pain relief equivalent to GnRH agonists and reduces ectopic implants. Compared to other progestins and GnRH agonists, dienogest has been found more effective and better tolerated. Actually it remains an elective drug for medical treatment of symptomatic endometriosis. Conclusions. Endometriosis remains a chronic troublesome disease, difficult to heal completely. It interferes on the quality of life, causing pain and infertility. The use of new drugs including new progestins allows a more suitable treatment and reduces need for surgery