The levonorgestrel-releasing intrauterine system 52 mg as a contraceptive versus a therapeutic: essential differences and perspectives.

Background: It is 100 years since the discovery of oestrogen and nearly that since the discovery of progesterone. It is over 50 years since the concept of using intrauterine progesterone. Ten years after its synthesis, the research using levonorgestrel as an intrauterine agent was introduced.

Areas covered: The pharmacodynamics and pharmacokinetics of LNG-IUSs and the LNG-IUS 52 mg in particular explain why intrauterine LNG is so highly effective for contraception. When intrauterine LNG is used therapeutically it should ideally be based on clinical monitoring of the pathology being treated rather than a fixed time period While the LNG-IUS 52 mg is probably required for most medical conditions, consideration should be given for using the LNG-IUS 13.5 mg for hyperplasia and endometrial protection during oestrogen therapy and for older women who appear more prone to a low rate of LNG induced breast cancer, although there is not yet an official indication for this.

Conclusion: The desire for fertility control, therapy for various genital pathological conditions and reduction of repeated endometrial decidualization and inflammatory breakdown and its consequences, and menopausal problems can be aided by intrauterine LNG. This review explains how a contraceptive also became a WHO listed essential medicine.