GnRH agonists
By inducing a state of hypoestrogenism and temporary menopause
with amenorrhea, GnRH agonists have been used to shrink fibroids
and restore hemoglobin levels in symptomatic women (Donnez et al.,
1989, 1990; Carr et al., 1993; Lethaby et al., 2001) (Fig. 5). They cannot
be used for long periods of time because of their side effects, such
as hot flushes and bone loss. A very recent review demonstrated that
there is modest evidence that add-back therapy (tibolone, raloxifene,
estriol and ipriflavone) can help reduce bone loss and that medroxyprogesterone acetate (MPA) and tibolone may moderate
vasomotor symptoms (Moroni et al., 2015).
The future of medical therapy
Evidence of the crucial role of progesterone
pathways in the pathophysiology of uterine
fibroids by use of selective progesterone
receptor modulators.
The mechanism of action by which SPRMs reduce menstrual blood
loss in women with fibroids remains unknown (Wilkens et al., 2013),
although a number of possible factors have been proposed by
Williams et al. (2007, 2012). Wilkens et al. (2013) reported that uterine
NK cells regulate endometrial bleeding and were suppressed by
asoprisnil.
Long-term intermittent administration
of SPRMs, opening up new treatment
perspectives