[Effectiveness of bisphosphonate administration during Gn-RH agonist therapy for endometriosis].

Gn-RH agonist therapy is widely used for treatment of endometriosis. However, it is well known that there are some side effects due to too much suppress of plasma sex steroid hormone levels. The decrease of the BMD (bone mineral density) is a serious side effect, and the BMD values are decreasing significantly even in the short period during Gn-RH agonist therapy. In this review, the author shows the effect of bisphosphonate administration on the prevention of the bone loss during Gn-RH agonist therapy for the endometriosis. By the administration of EP (estrogen-progestogen) preparations, the decreasing of the BMD can prevent (so called add-back therapy), however, there are some patients who could not be administrated these drugs because of their previous diseases. Bisphosphonate administration is much effective for the prevention of the bone loss compared with EP preparations. From these results, it is concluded that bisphosphonate administration has a beneficial effect for the prevention of the bone loss during Gn-RH agonist treatment.