Search

This article is focused on the use of norethisterone acetate as progestogen in hormone replacement therapy. Emphasis is made on the fact that the primary reason for adding a progestogen to hormone replacement therapy is to protect the endometrium against hyperplasia. In this paper we review data that demonstrate that hormone replacement therapy that includes norethisterone acetate has positive effects on the postmenopausal bone metabolism and that it increases bone mass more than expected and more than treatment with alendronate. All available evidence is reviewed to show that norethisterone acetate, if given in the correct dosage, does not influence serum lipids and lipoproteins in any negative way. It is furthermore shown that norethisterone acetate seems to be superior compared to other progestogens to provide optimum bleeding control and endometrial protection. Also, hormone replacement therapy combinations with norethisterone acetate efficiently alleviate hot flushes. Hormone replacement therapy and the risk of breast cancer and the role of progestogens are discussed.

Bleeding and climacteric symptoms were recorded in two groups of postmenopausal women receiving either continuous combined estradiol and norethisterone acetate or estradiol and cyproterone acetate. Out of a sample of 99 postmenopausal women aged 45 to 54 years, 86 completed a 2-year, double-blind, placebo-controlled study. Comparison of the bleeding patterns in the two groups revealed a statistically significant difference: More women in the estradiol-cyproterone acetate group experienced bleeding and for a longer duration. Thirteen women in the estradiol-norethisterone acetate group were amenorrheic, compared with two in the other group. The Kupperman index score in both groups declined to about 30% to 40% of initial values (p less than 0.001). The hot flushes in both treatment groups decreased to a highly significant degree (p less than 0.001), to a value below 20% of baseline values. We conclude that a continuous combination of estrogen and progestogen can produce amenorrhea and symptomatic relief. However, the progestogen components seem to differ in their ability to control bleeding.

Serum lipids and lipoproteins were examined in a group of 45 healthy postmenopausal women who were treated for 2 years with either 3 mg of percutaneous estradiol (n = 20) or placebo (n = 25). Percutaneous estradiol was given alone during the first year of treatment and in combination with oral micronized progesterone (200 mg) for 12 days of each cycle during the second year. The women were examined every 3 months throughout the 2 years. Percutaneous estrogen therapy significantly reduced total serum cholesterol and low-density lipoprotein cholesterol, whereas no significant differences were observed in serum triglycerides and high-density lipoprotein cholesterol. Addition of oral progesterone during the second year of treatment did not produce any significant alterations in serum total cholesterol or low-density lipoprotein cholesterol, both of which remained significantly reduced. Serum triglycerides remained virtually unchanged, whereas a slight but significant increase (p less than 0.05) was observed in high-density lipoprotein cholesterol levels at the end of the study period. We conclude that percutaneous estrogen administration produces changes in total serum cholesterol and low-density lipoprotein cholesterol levels similar to those observed after oral estrogen administration. However, the magnitude and time course of the response seem to be modulated by the route of administration. Addition of oral micronized progesterone does not influence the beneficial estrogenic actions on serum lipids and lipoproteins and seems to be a proper "progestogen" in percutaneous estrogen therapy.

The effect of percutaneous estradiol alone and combined with natural progesterone on postmenopausal bone loss was studied. A total of 57 women who had experienced a natural menopause 6 months to 3 years previously entered the study. After an initial examination the women were allocated in a blinded pattern to treatment with 3 mg of percutaneous estradiol or placebo. The code was broken after 1 year of treatment, and the women receiving estradiol continued with a cyclic addition of progesterone, whereas those receiving placebo continued with placebo. The women were examined every 3 months during the 2 years of treatment. Measurement of the bone mineral content in the forearms (single photon absorptiometry) and the spine and total skeleton (dual photon absorptiometry) showed a significant decrease of 5% to 7% in the placebo group during the 2 years of treatment, whereas it remained constant in all bone compartments in the estradiol group. Addition of progesterone did not influence the results. Biochemical estimates of calcium metabolism changed toward a premenopausal level in the estradiol group but remained unchanged in the placebo group. We conclude that percutaneous estradiol is effective as preventive therapy of postmenopausal bone loss and that addition of progesterone does not influence bone or calcium metabolism.