A multicentered pharmacokinetic, pharmacodynamic study of once-a-month injectable contraceptives. I. Different doses of HRP112 and of DepoProvera. World Health Organization Task Force on Long-acting Systemic Agents for Fertility Regulation

Abstract

A multicentered study was undertaken at three institutions in Hungary, Mexico and Thailand in women of reproductive age to evaluate the effects of full and half doses of HRP112 (depot-medroxyprogesterone acetate (DMPA) plus estradiol cypionate) and DMPA alone on ovarian function, bleeding patterns and HDL-cholesterol levels. Full dose HRP112 contained 25mg DMPA plus 5mg, of estradiol cypionate and the half dose, 12.5mg DMPA plus 2.5mg of estradiol cypionate. The full and half dose DMPA were 25 and 12.5mg respectively. In all, 88 women were recruited in the study and randomized within each centre, to the four treatment groups. Subjects were studied for a control cycle, three one-month injection intervals and followed-up for a further two months. Serum concentrations of estradiol, progesterone and medroxyprogesterone acetate were determined three times a week during the third injection interval and during the two months of follow-up. While the results from all centres indicated that the four preparations were all effective in inhibiting ovulation for at least one month, there were marked between centre differences in pharmacokinetic profiles. More regular bleeding patterns were observed in women who received the estrogen-progestogen combination preparations than in those who received DMPA alone.