Efficacy and safety of a seven-day, transdermal estradiol drug-delivery system: comparison with conjugated estrogens and placebo. The Transdermal Estradiol Patch Study Group.

Objective: To evaluate the efficacy and safety of a new, seven-day, transdermal estradiol system in healthy postmenopausal women with hot flushes.

Methods: Two studies are described. In the first study, subjects were randomized to treatment with a 0.05 mg/day estradiol patch, a 0.1 mg/day estradiol patch, or a placebo patch; and in the second study, to treatment with either of the two estradiol patches or oral conjugated estrogens (as Premarin) 0.625 mg/day. Efficacy was evaluated on the basis of diary entries recording hot-flush frequency and severity. Subjects' and investigators' global assessments of treatment efficacy were recorded at follow-up visits.

Results: In Study 1, both the 0.05-mg and 0.1-mg estradiol patches were significantly more effective than placebo in reducing hot flushes and were associated with higher global assessments. In Study 2, all three active treatments produced a significant reduction in the number of hot flushes compared with base-line. There were no statistically significant between-group differences, although the response to the 0.1-mg estradiol patch was greater, and to the 0.05-mg estradiol patch less, than the response to conjugated estrogens. The patches were generally well tolerated. Skin irritation from the patch was the most common adverse experience in both studies.

Conclusions: The new, seven-day, transdermal system effectively and safely treats post-menopausal vasomotor symptoms.