Lipids and clotting factors during low dose transdermal estradiol/norethisterone use

OBJECTIVE: To demonstrate the effects of 2-year transdermal continuous combined low-dose estradiol (0.025 mg/day) and norethisterone acetate (0.125 mg/day) on lipid/lipoprotein profile and coagulation/fibrinolysis.

METHODS: A double-blind, randomized, multicenter, parallel, 1-year trial enrolled 266 healthy women at least 2 years post menopause. Patients received either 0.025 mg estradiol and 0.125 mg norethisterone acetate daily or placebo transdermally. One hundred and thirty five women completed a second year open follow-up (96 had used Estragest TTS, 39 placebo during the first year), where all women had the estradiol/norethisterone patch. Lipid/lipoprotein profile and coagulation/fibrinolysis parameters were studied at 0, 24, 48, 72 and 96 weeks.

RESULTS: In women on estradiol/norethisterone total cholesterol, Lp(a) and VLDL cholesterol decreased significantly more than in the placebo group after 24 weeks and LDL cholesterol after 48 weeks. Women on estradiol/norethisterone had no change in HDL, triglycerides or Lp(a), an increased HDL/total cholesterol ratio and decreased LDL, VLDL and total cholesterol at 48 weeks compared to placebo. Women with active treatment also showed a significant reduction compared with the placebo group of Factor VII and antithrombin III at 24 and 48 weeks and a reduction of fibrinogen at 24 weeks. These changes persisted over the second year.

CONCLUSIONS: A continuous combined low-dose transdermal patch daily delivering 0.025 mg estradiol and 0.125 mg norethisterone acetate provided beneficial effects on lipid/lipoprotein profile and coagulation/fibrinolysis. The changes were similar to those previously described after higher dose oral and transdermal estrogen/progestogen regimens.