MIRENA^® is an approved intrauterine delivery system (IUS), containing 52mg levonorgestrel (LNG), and is indicated for: Contraception; Idiopathic menorrhagia and protection from endometrial hyperplasia during estrogen replacement therapy. One administration is effective for five years.
MIRENA^® releases LNG into the uterine cavity following insertion. The in vivo dissolution rate is about 20ug/ 24 hours initially and is reduced to about 11ug/ 24 hours after five years. The mean dissolution rate of LNG is about 14ug/ 24 hours over the time up to five years.
In women under hormone replacement therapy, MIRENA^®  can be used in combination with oral or transdermal estrogen preparations without progestogens.
MIRENA^®, when inserted according to the insertion instructions, has a failure rate of approximately 0.1 % per year. The failure rate may increase in case of expulsion or perforation.
Upon removal of MIRENA®,  women return to their normal level of fertility.