Comparison of a triphasic oestradiol/norethisterone acetate preparation with and without an oestriol component in the treatment of climacteric complaints

A randomized, double-blind, multicentre study comparing the clinical effects of two sequential estradiol-progestin combinations containing either desogestrel or norethisterone acetate in climacteric women with estrogen deficiency symptoms

OBJECTIVES

The aim of this study was to compare a new estradiol-desogestrel (E2-DG) regimen with an E2-norethisterone acetate (NETA) combination (Trisekvens) regarding the treatment of menopausal complaints, bleeding pattern, histology of the endometrium and the occurrence of adverse experiences.

METHODS

A total of 310 peri-/postmenopausal women with climacteric symptoms were randomly allocated to oral sequential treatment with either the E2-DG combination (1.5 mg E2 for 24 days with 0.15 mg DG for the last 12 days followed by 1 placebo tablet for 4 days) or with the E2-NETA combination (Trisekvens, 2 mg E2 for 22 days with 1 mg NETA for the last 10 days followed by 1 mg E2 for 6 days). Treatments were administered double-blind for 12 cycles of 28 days.

RESULTS

One hundred and four women, 48 in the E2-DG group and 56 in the E2-NETA group, discontinued the study due to bleeding irregularities and various adverse effects. Both treatments reduced menopausal symptoms and complaints effectively and almost equally. The alleviation of perspirations and the improvement of general fitness were more apparent (P = 0.009) during cycle 1 with the E2-NETA treatment but were greater (P < 0.02) during the last 9/10-12 cycles of E2-DG treatment compared to E2-NETA. Regular withdrawal bleeding appeared in 93% and 90% of the women during treatment with E2-DG and E2-NETA, respectively. Intermenstrual bleeding occurred in 8% of women receiving E2-DG and in 13% of women treated with E2-NETA. The corresponding figures for intermenstrual bleeding-spotting were 21% and 22%. Secretory endometrium was detected in 65% and 54% of the samples taken at the end of treatment with E2-DG and E2-NETA, respectively. No hyperplasia or atypia was found. No serious adverse events related to treatment occurred.

CONCLUSIONS

Both regimens alleviated effectively menopausal complaints and did not induce hyperplasia of endometrium. The minor differences recorded between the two regimens were probably due to the differences in their composition concerning the amount of estradiol and its distribution along the cycle, the amount and type of progestin and the length of estradiol/progestin combination phase.

Clinical and endometrial effects of oestradiol and progesterone in post-menopausal women

This study reports the clinical effects in a group of post-menopausal women after 4 months of treatment with 2 mg micronized 17 beta-oestradiol (E2) in combination with different doses of micronized progesterone (50, 100 or 200 mg) for 25 days each month. The 30 participants were divided into three groups. All of the subjects tolerated the preparation well and obtained relief from their climacteric complaints. None dropped out because of side effects and no changes were observed in blood pressure, weight or Papanicolaou cytology. Breakthrough bleeding was noted in the first cycle, mainly in the group receiving the lowest dose of progesterone. Endometrial biopsies performed before and after 4 months of treatment showed an atrophic endometrium in most of the women who received 100 mg progesterone and in all of the women on 200 mg progesterone. The results showed that this new combination of 2 mg E2 and micronized progesterone in different doses was both effective and well accepted.

Pharmacokinetics of oestrogens and progestogens

There are large inter- and intra-individual variations in the serum concentrations of natural and synthetic sex steroids irrespective of the route of administration. Oral ingestion of steroids has a stronger effect on hepatic metabolism than parenteral administration, as the local concentration in liver sinusoids are 4-5 times higher during the first liver passage. Oestradiol and oestrone are interconvertible, dependent on the local concentrations in liver and target organs, and oestrone sulphate serves as a large reservoir. The oestrone/oestradiol ratio has no physiological significance, as oestrone is only a weak oestrogen. Oestrone is both a precursor and a metabolite of oestradiol. Oestriol is extensively conjugated after oral administration. Therefore, the oestriol serum levels are similar after oral intake of 10 mg and after vaginal application of 0.5 mg oestriol resulting in similar systemic effectiveness. Conjugated oestrogens can easily enter the hepatocytes but are hormonally active only after hydrolyzation into the parent steroids. Ethinylestradiol which exerts strong effects on hepatic metabolism and inhibits metabolizing enzymes, should not be used for hormone replacement therapy. Among the progestogens, the progesterone derivatives have less effects on liver metabolism than the norethisterone derivatives (13-methyl-gonanes and 13-ethyl-gonanes). The highly potent 13-ethyl-gonanes are effective at very low doses, because of a slow inactivation and elimination rate due to the ethinyl group.

Effect of oral hormone replacement therapy on liver function tests

Five oral methods of hormone replacement therapy (HRT) were prescribed to groups of healthy post-menopausal women and their effects on a group of liver function tests were examined. No evidence of deterioration in liver function was noted.

A review of the role of progestogens in hormonal replacement therapy: influence on bleeding patterns

Most post-menopausal hormone replacement regimens lead to endometrial bleeding in some women. However, the response to any one regimen varies greatly from individual to individual. With most regimens, some women will experience amenorrhoea, some will experience scheduled withdrawal bleeding and some will experience unscheduled breakthrough bleeding. The proportions of women in each case will depend on the oestrogen and progestogen dosages, the regimen and route by which these are administered and their respective 'potencies'. With appropriate counseling, many women will tolerate continued menstrual bleeding after the menopause, but most would still prefer not to have it if given the option. Much additional research needs to be done to determine which hormonal regimens are the most effective, safe and acceptable for different groups of women.