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Minerva Ginecologica 2006 December;58(6):553-60

Copyright © 2006 EDIZIONI MINERVA MEDICA

language: Italian

GnRH agonists and antagonists in the preoperative therapy of uterine fibroids: literature review

De Falco M., Pollio F., Pontillo M., Ambrosino E., Busiello A., Carbone I. F., Ciociola F., Di Nardo M. A., Landi L., Di Lieto A.

Dipartimento di Scienze Ostetrico-Ginecologiche e Urologiche e Medicina della Riproduzione Università Federico II di Napoli, Napoli

Uterine leiomyomas are the most frequent gynecological benign tumors. Their growth is regulated by ovarian steroids, therefore a hypoestrogenic state, like menopause or pharmacologically induced pseudo-menopause by GnRH-agonists or GnRH-antagonists, is associated with the decrease of their volume. This volume reduction allows a less invasive surgical procedure and may reduce the amount of blood loss during surgery. Therefore, GnRH-agonists and antagonists are used in presurgical treatment of uterine fibromatosis. This review analyses the effects of GnRH-agonists and GnRH-antagonists therapies. GnRH-agonists produce a down-regulation of GnRH receptor, while GnRH-antagonists compete with endogenous GnRH for pituitary binding sites. Due to the lack of any intrinsic activity of GnRH-antagonists, the characteristic initial flare-up observed with GnRH-agonist treatment is absent. So, GnRH-antagonists rapidly suppress gonadotropin release within 4-8 h, while GnRH-agonists show clinical effects after 2 or 3 weeks of treatment. GnRH-antagonist activity is dose-dependent so it is possible to adjust the dose to obtain the proper levels of inhibition. The GnRH-agonist presurgical treatment usually is a short-term therapy (3-6 months), because it causes side-effects like menopause symptoms. GnRH-antagonist clinical effects can be achieved with a short-time therapy too. Their side-effects include flushes and head-ache. After stopping therapy with both drugs, leiomyomas rapidly achieve their original size while side-effects disappear. Further studies are necessary to establish the use of GnRH-antagonists in leiomyomas therapy, but in Italy this is not possible because their use is not approved.