Oral Progestins in Hormonal Contraception: Importance and Future Perspectives of a New Progestin Only-Pill Containing 4 mg Drospirenone

Hormonal contraceptives are an effective and safe method for preventing pregnancy. Progestins used in contraception are either components of combined hormonal contraceptives (tablets, patches or vaginal rings) or are used as a single active ingredient in progestin mono-preparations (the progestin-only pill (POP), implants, intrauterine systems or depot preparations). Progestins are highly effective in long-term contraception when used properly, and have a very good safety profile with very few contraindications. A new oestrogen-free ovulation inhibitor (POP) has recently been authorised in the USA and the EU. This progestin mono-preparation contains 4 mg of drospirenone (DRSP), which has anti-gonadotropic, anti-mineralocorticoidic and anti-androgenic properties. The hormone administration regimen of 24 days followed by a 4-day hormone-free period was chosen to improve bleeding control and to maintain oestradiol concentrations at early follicular-phase levels, preventing oestrogen deficiency. Clinical trials have demonstrated a high contraceptive effectiveness, a very low risk of cardiovascular side effects and a favourable menstrual bleeding pattern. Due to the long half-life of DRSP (30 - 34 hours), the effectiveness of the preparation is maintained even if a woman forgets to take a pill on a single occasion. Studies involving deliberate 24-hour delays in taking a pill have demonstrated that ovulation inhibition is maintained if a single pill is missed. Following a summary of the current status of oestrogen-free contraception, this review article will describe the clinical development programme of the 4 mg DRSP mono-preparation and the resulting data on the effectiveness and safety of this new oestrogen-free oral hormonal contraceptive.