Transdermal estradiol with oral progestin: biological and clinical effects in younger and older postmenopausal women.

The purpose of this study was to compare the biochemical and clinical effects of transdermal estrogen replacement therapy (tERT) in younger and older postmenopausal women. We treated 15 younger (less than 60 y) and 13 older (greater than or equal to 60 y) healthy postmenopausal women (45-72 y) with four successive 8-week regimens of tERT at doses of 0 to 150 micrograms/day, combined with cyclic oral medroxyprogesterone acetate (MPA). In both age groups, there were similar (p = .0001) dose-responsive increases in plasma estrogen levels and decreases in LH and FSH levels, although LH values were lower in older women both before and after tERT (p less than .02). The addition of MPA further suppressed LH and, to a lesser extent, FSH in both younger and older women. The ratio of estrogenized to nonestrogenized vaginal cells increased with tERT (p less than .007) in both age groups, but significant symptomatic improvement of vaginal irritation was noted only at the highest tERT dose. Adverse effects unrelated to age included short-term nausea in 4/28 women, and skin irritation at the patch sites in 20/28 women. Vaginal bleeding was of shorter duration, but breast tenderness was more common in older women. Further studies of long-term tERT effects in elderly women are indicated.