Pharmacodynamic assessment of dihydroxyprogesterone acetophenide plus estradiol enanthate as a monthly injectable contraceptive.

ABSTRACT

PIP: The pharmacodynamics of the combination of dihyroxyprogesterone acetophenide (DHPA) and estradiol enanthate (E2-EN) following its intramuscular administration at 2 doses were studied in 16 healthy women of reproductive age attending the Family Planning Clinic at General Hospital in Mexico City. Subjects were randomly allocated in 2 groups: group I (n=9) received the combination DHPA 150 milligrams and E2-EN 10 milligrams on 3 consecutive monthly injections, while group II (n=7) received 1/2 dose of the same formulation. Ovarian function and endometrial bleeding patterns were investigated in all participants for 1 pretreatment cycle, 3 treatment intervals and 2 post-treatment cycles. The results disclosed that ovulation was inhibited for at least 30 days following DHPA/E2-EN administration in all participants from both groups. The circulating estradiol levels 30 days after last injection were slightly elevated as compared with those observed in normal early follicular phase. Return to ovulatory cycles was documented within 90 days after treatment. The length of the bleeding-free intervals during treatment was shortened in both groups, particularly group II. No significant changes in HDL-cholesterol levels were observed throughout the study. It is envisaged however, that large modification of the formulation and additional long-term safety studies will be required prior to its recommendation.