A single-arm study to evaluate the transfer of drospirenone to breast milk after reaching steady state, following oral administration of 4 mg drospirenone in healthy lactating female volunteers.

The primary objective of this trial was to assess the transfer of drospirenone to breast milk after daily administration of an oral test preparation containing 4 mg of drospirenone at the steady state. The secondary objective of the trial was to assess safety based on clinical and laboratory measurements and reporting of adverse events and/or adverse drug reactions. This was an open label, non-comparative single-center study. Drospirenone 4 mg per day was the first postpartum contraceptive for the study participants who were no longer breastfeeding yet were still lactating. It was administered for 7 days to achieve steady-state concentration. All participants were volunteers who planned to use oral contraceptives as their family planning method in the future. Twelve volunteers completed the trial according to the protocol, and the samples of all 12 study completers were analyzed. The average concentration-time curve of drospirenone in plasma 24 h after the administration of the last dose (area under the curve (0-24 h)) was 635.33 ng h/mL and 120 h after the single repeated dose administration (area under the curve (0-120 h)) was 1180.57 ng h/mL, respectively. The average C On average, 18.13% of plasma drospirenone made it to breast milk and the highest concentration of drospirenone in breast milk was 17.55% of that in plasma. The total quantity of drospirenone passing to breast milk is on average 4478 ng during a 24-h period representing 0.11% of the maternal daily dose. Thus, at the recommended doses, no effects on breastfed newborns/infants are anticipated with drospirenone 4 mg.