Continuous, combined hormone replacement: randomized comparison of transdermal and oral preparations

To compare two new transdermal, continuous, combined formulations and an oral regimen of hormone replacement therapy (HRT) with respect to endometrial hyperplasia, bleeding patterns, and climacteric symptoms in postmenopausal women.

This was a randomized, open, parallel-group trial during 1 year in 441 postmenopausal women who received either a 10-cm2 patch of 0.025 mg estradiol (E2) and 0.125 mg norethisterone acetate, a 20-cm2 patch of 0.05 mg E2 and 0.25 mg norethisterone acetate twice weekly, or tablets of 2 mg E2 and 1 mg norethisterone acetate once daily. The efficacy variables were frequency of endometrial hyperplasia after 1 year of treatment, number of bleeding and spotting days from the fourth to sixth treatment months, relief of climacteric symptoms, and tolerability.

The frequency of endometrial hyperplasia was no more than 2% after 1 year of treatment in all groups. One case of simple hyperplasia was detected among the women treated with 10-cm2 patches and two among those treated with oral HRT. From the fourth to sixth treatment months, amenorrhea occurred in 73%, 47%, and 66% of the women in the 10-cm2, 20-cm2, and oral HRT groups, respectively. The 10-cm2 patches and oral treatment were associated with fewer bleeding days than were the 20-cm2 patches (P<.001). During the last 3 months of the treatment year, amenorrhea was found in 100 subjects (86%) for 10-cm2 patches, 61 (65%) for 20-cm2 patches, and in 85 (79%) for oral HRT. All treatments alleviated the climacteric symptoms to a comparable extent.

In postmenopausal women, 10-cm2 patches relieved climacteric symptoms and prevented endometrial hyperplasia at least as effectively as oral HRT. Amenorrhea was induced early in a high percentage of women using 10-cm2 patches and oral HRT, and these therapies seemed to be convenient, effective, and safe for estrogen deficiency symptoms in postmenopausal women.