Gonadotrophin-releasing hormone analogues for pain associated with endometriosis

Diagnosis and recommended management of endometriosis

“…The choice of which medical treatment -the combined oral contraceptive (COC), progestogens, danazol, gestrinone (Dimetriose) or a gonadotrophinreleasing hormone (GnRH) agonist -depends principally upon their side-effect profile (see Table 2) as they all relieve pain associated with endometriosis equally well. 4 GnRH agonist therapy given for three months may be as effective as six months' treatment in relieving endometriosis-associated pain. If longer treatment is required, GnRH agonist use can be extended safely with 'add-back' HRT, usually a low-dose continuous combined preparation, or tibolone (unlicensed use).…”

Treatment of pelvic pain associated with endometriosis

“…The underlying theory of addback treatment is the ''estrogen threshold hypothesis,'' which holds that the amount of estrogen and/or progestogen necessary to prevent hot flushes, bone loss and other hypoestrogenic symptoms and side effects is less than that which would stimulate endometriosis (61). Although norethindrone acetate is the only hormone approved by the FDA for addback therapy, other combinations of conjugated estrogens and progestogens also have been shown effective for decreasing hypoestrogenic side effects and maintaining bone density, while not adversely affecting the extent of pain relief achieved with GnRH agonist treatment (62,63).…”

“…Few randomized, controlled trials have evaluated the individual medical options (62,64,66,67). Randomized trials comparing different agents are confounded by the side effects associated with the medications.…”

Treatment of pelvic pain associated with endometriosis

“…The underlying theory of add-back treatment is the "estrogen threshold hypothesis," which holds that the amount of estrogen and/or progestogen necessary to prevent hot flushes, bone loss and other hypoestrogenic symptoms and side effects is less than that which would stimulate endometriosis (61). Although norethindrone acetate is the only hormone approved by the FDA for addback therapy, other combinations of conjugated estrogens and progestogens also have been shown effective for decreasing hypoestrogenic side effects and maintaining bone density, while not adversely affecting the extent of pain relief achieved with GnRH agonist treatment (62,63). …”