The metabolic consequences of treating postmenopausal women with non-oral hormone replacement therapy

Pharmacotherapeutic options for the treatment of menopausal symptoms

Introduction: Menopausal symptoms can be very overwhelming for women. Over the years, many pharmacotherapeutic options have been tested, and others are still being developed. Hormone therapy (HT) is the most efficient therapy for managing vasomotor symptoms and related disturbances. The term HT comprises estrogens and progestogens, androgens, tibolone, the tissue-selective estrogen complex (TSEC), a combination of bazedoxifene and conjugated estrogens, and the selective estrogen receptor modulators, such as ospemifene. Estrogens and progestogens and androgens may differ significantly for chemical structure and can be delivered through different routes, thereby displaying various pharmacological and clinical properties. Tibolone, TSEC and SERM also exhibit unique pharmacodynamics that can be exploited to obtain distinctive therapeutic effects. Non-hormonal options fall mainly into the selective serotonin reuptake inhibitor (SSRI) and selective noradrenergic reuptake inhibitor (SNRI), GABA-analogue drug classes.Areas covered: Herein, the authors describe the pharmacokinetics and pharmacodynamics of hormonal (androgens, estrogens, progestogens, tibolone, TSEC, SERMs) and non-hormonal (SSRIs, SNRIs, Gabapentin, Pregabalin, Oxybutynin, Neurokinin antagonists) treatments for menopausal symptoms and report essential clinical trial data in humans.Expert opinion: Patient tailoring of treatment is key to managing symptoms of menopause. Physicians must have in-depth knowledge of the pharmacology of compounds to tailor therapy to the individual patient's characteristics and needs.

Reprint of Are all estrogens the same?

This paper focuses on the question whether different estrogens (E) have different qualitative pharmacodynamic effects when used by women for contraception, Hormone Replacement Therapy (HRT) or prevention of osteoporosis. In this context estrogens have been defined as the estrogen agonists estradiol (E2), estrone (E1), estriol (E3), conjugated equine estrogens (CEE), diethylstilbestrol (DES) and ethinylestradiol (EE). Selective Estrogen Receptor Modulator's (SERM's) have been excluded from this analysis primarily because of lack of comparative (clinical) data with estrogen agonists. A major problem when addressing the issue of comparability of estrogen agonists is the lack of data from head-to-head estrogen-only comparative studies. Comparative studies have been performed almost exclusively with estrogen agonists combined with a series of different progestogens (P), that have been added to protect the uterus from endometrial hyperplasia. Since progestogens are known to exhibit different intrinsic pharmacodynamic properties and interactions with estrogens, it is impossible to judge which role the estrogen plays when qualitative differences between different combined E/P preparations are observed. In summary, no convincing evidence has been found that the estrogens mentioned differ qualitatively. Obviously quantitative differences are present due to differences in e.g. receptor affinity, metabolism (half life) and route of administration (transdermal/vaginal). Since DES has been discarded for human use due to teratogenicity, EE used in all combined E/P oral contraceptives is the most potent estrogen agonist available at present. In HRT, E2 and CEE are equally effective for the treatment of hot flushes and urogenital atrophy and superior to any other treatment option. For long-term treatment to prevent osteoporosis and even for short-term HRT, estrogen agonists are heavily debated recently because of a small increased risk of breast cancer, that has been known for a long time already. Well informed and individualised choice of treatment seems the appropriate solution.

Drug delivery systems for hormone therapy

Various types of formulations and delivery devices have been developed for hormone therapy (HT) and their modes of hormone action and patient responses have been evaluated. Although the Women's Health Initiative (WHI) reported the controversial results on estrogen/progestin combination therapy, HT still remains a primary therapeutic option for the treatment of menopausal symptoms and osteoporosis. As a novel alternative to HT may not be probable in clinical use for the next decade, the currently available formulations containing estrogen and progestogen should be properly optimized for HT. The extensive reviews and comparisons on the characteristics of various types of HT could lead to the development of an efficient delivery formulation which maximizes patient compliance and minimizes adverse effects for individual users.

Hormone replacement therapy and the cardiovascular system lessons learned and unanswered questions

Cardiovascular disease is the leading cause of death among women in the U.S., exceeding breast cancer mortality in women of all ages. Women present with cardiovascular disease a decade after men, and this has been attributed to the protective effect of female ovarian sex hormones that is lost after menopause. Animal and observational studies have shown beneficial effects of hormone therapy when it is initiated early in the perimenopausal period or before the development of significant atherosclerosis. However, randomized, placebo-controlled trials in older women have not shown any benefit in either primary prevention or secondary prevention of cardiovascular events, with a concerning trend toward harm. This review outlines the lessons learned from the basic science, animal, observational, and randomized trials, and then summarizes yet-unanswered questions of hormone therapy and cardiovascular risk.

Pharmacology of estrogens and progestogens: influence of different routes of administration

This review comprises the pharmacokinetics and pharmacodynamics of natural and synthetic estrogens and progestogens used in contraception and therapy, with special consideration of hormone replacement therapy. The paper describes the mechanisms of action, the relation between structure and hormonal activity, differences in hormonal pattern and potency, peculiarities in the properties of certain steroids, tissue-specific effects, and the metabolism of the available estrogens and progestogens. The influence of the route of administration on pharmacokinetics, hormonal activity and metabolism is presented, and the effects of oral and transdermal treatment with estrogens on tissues, clinical and serum parameters are compared. The effects of oral, transdermal (patch and gel), intranasal, sublingual, buccal, vaginal, subcutaneous and intramuscular administration of estrogens, as well as of oral, vaginal, transdermal, intranasal, buccal, intramuscular and intrauterine application of progestogens are discussed. The various types of progestogens, their receptor interaction, hormonal pattern and the hormonal activity of certain metabolites are described in detail. The structural formulae, serum concentrations, binding affinities to steroid receptors and serum binding globulins, and the relative potencies of the available estrogens and progestins are presented. Differences in the tissue-specific effects of the various compounds and regimens and their potential implications with the risks and benefits of hormone replacement therapy are discussed.

Hormone replacement therapy and hemostasis: Effects in Brazilian postmenopausal women

OBJECTIVE

To evaluate the impact that administration of transdermal estradiol gel combined with medroxyprogesterone acetate (MPA) has on hemostasis.

METHODS

In this open prospective longitudinal study, thirty postmenopausal women received transdermal estradiol gel (1 mg/day) continuously combined with oral MPA (5 mg/day) for 12 days/month. The following parameters were determined: prothrombin time (PT), activated partial thromboplastin time (aPTT), factors VII, X, and XII activity, fibrinogen levels, thrombin-antithrombin complex levels, protein C and S antigen, antithrombin activity, plasminogen activator inhibitor type 1 (PAI-1) antigen, tissue-type plasminogen activator (t-PA) antigen, plasminogen activity and fibrin degradation products (FbDP) antigen. They were evaluated before and after 6 months of treatment.

RESULTS

There was a significant decrease in factor VII activity (P=0.001), factor X activity (P=0.016), protein C antigen (P=0.022), antithrombin activity (P=0.025), plasminogen activity (P=0.023), t-PA antigen (P=0.043) and FbDP antigen (P=0.048) compared with baseline values.

CONCLUSION

The results suggest that the treatment with transdermal estradiol gel combined with MPA avoids any major activation of coagulation and does not produce any overall effect on fibrinolysis. Therefore, this treatment might provide interesting effects on hemostasis in postmenopausal Brazilian women.

Pharmaceutical development and clinical effectiveness of a novel gel technology for transdermal drug delivery

Transdermal gels are designed to deliver sustained drug amounts, resulting in systemically consistent levels. They represent an improvement compared with transdermal delivery by patches because they offer more dosage flexibility, less irritation potential and a better cosmetic appearance. Advanced Transdermal Delivery (ATD) gel technology was developed in order to provide enhanced passive skin permeation of various active drugs for the treatment of many conditions, including hypogonadism, female sexual dysfunction, postmenopausal symptoms, overactive bladder and anxiety. The technology consists of a combination of solvent systems and permeation enhancers enabling systemic drug delivery, and is covered by many patents. Pharmaceutical development of formulations based on the technology allowed optimisation of physicochemical parameters (rheological profile, pH) as well as skin permeation properties (type and concentration of permeation enhancers, thermodynamic activity of the drug). This gel technology has demonstrated to be efficient for many drugs, as shown in the preclinical and clinical pharmacokinetic studies presented in this technology evaluation.

Are all estrogens the same?

This paper focuses on the question whether different estrogens (E) have different qualitative pharmacodynamic effects when used by women for contraception, Hormone Replacement Therapy (HRT) or prevention of osteoporosis. In this context estrogens have been defined as the estrogen agonists estradiol (E2), estrone (E1), estriol (E3), conjugated equine estrogens (CEE), diethylstilbestrol (DES) and ethinylestradiol (EE). Selective Estrogen Receptor Modulator's (SERM's) have been excluded from this analysis primarily because of lack of comparative (clinical) data with estrogen agonists. A major problem when addressing the issue of comparability of estrogen agonists is the lack of data from head-to-head estrogen-only comparative studies. Comparative studies have been performed almost exclusively with estrogen agonists combined with a series of different progestogens (P), that have been added to protect the uterus from endometrial hyperplasia. Since progestogens are known to exhibit different intrinsic pharmacodynamic properties and interactions with estrogens, it is impossible to judge which role the estrogen plays when qualitative differences between different combined E/P preparations are observed. In summary, no convincing evidence has been found that the estrogens mentioned differ qualitatively. Obviously quantitative differences are present due to differences in e.g. receptor affinity, metabolism (half life) and route of administration (transdermal/vaginal). Since DES has been discarded for human use due to teratogenicity, EE used in all combined E/P oral contraceptives is the most potent estrogen agonist available at present. In HRT, E2 and CEE are equally effective for the treatment of hot flushes and urogenital atrophy and superior to any other treatment option. For long term treatment to prevent osteoporosis and even for short term HRT, estrogen agonists are heavily debated recently because of a small increased risk of breast cancer, that has been known for a long time already. Well informed and individualised choice of treatment seems the appropriate solution.

The effects of transdermal and oral oestrogen replacement therapy on colorectal cancer risk in postmenopausal women

The aim of this study was to examine the effects of oral and transdermal oestrogen replacement therapy on the risk of colorectal cancer. Data from a nested case–control study, designed to investigate the effect of hormone replacement therapy (HRT) on colorectal cancer were analysed. New cases of colorectal cancer, diagnosed between 1992 and mid-1998 (N=1197), were identified using the Saskatchewan Cancer Agency cancer registry. Women ⩾50 years of age, eligible for coverage by the Saskatchewan Prescription Drug Plan, were included in the study. Four controls per case were age matched to cases, using incidence density sampling. The outpatient prescription drug plan database was used to ascertain oestrogen prescriptions. Women were classified according to history of transdermal (TDE) and oral (OE) oestrogen use. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Compared with women who had never used HRT, ORs for <3 and ⩾3 years of TDE use and colorectal cancer were 0.69 (95% CI: 0.43–1.10) and 0.33 (95% CI: 0.12–0.95), and for OE use were 0.90 (95% CI: 0.73–1.01) and 0.75 (95% CI: 0.60–0.93), respectively. The risk reduction for colorectal cancer with TDE may be greater in magnitude than that which has been reported for oral HRT.

Postmenopausal estrogen therapy and serum estradiol fatty acid esters in women with and without previous intrahepatic cholestasis of pregnancy

BACKGROUND

Fatty acid esters of 17beta-estradiol (E2) are estrogen metabolites associated with lipoproteins in blood.

AIM

To study the effects of estrogen therapy on concentrations of serum E2 fatty acid esters in postmenopausal women with a history of an estrogen-related liver disorder, intrahepatic cholestasis of pregnancy (ICP), and in healthy women in a double-blind, crossover fashion.

METHOD

ICP (n = 10) and control women (n = 10) received increasing doses of E2 valerate orally 2-4 mg/day, or transdermal E2 50-100 microg/day for 6 weeks. After a 4-week wash-out period, the subjects crossed over to the alternate E2 treatment. Concentrations of serum E2 fatty acid esters were quantified after saponification by fluoroimmunoassay.

RESULTS

Oral E2 administration increased median serum E2 fatty acid ester concentrations from 57 to 73 pmol/L in the ICP and from 56 to 74 pmol/L in the control group, in association with elevations in serum E2, estrone and sex hormone-binding globulin levels. Transdermal E2 treatment did not increase serum E2 ester levels.

CONCLUSIONS

The increase in serum E2 fatty acid esters during oral E2 administration may be attributed, at least partly, to the higher estrogen dose during oral compared with transdermal therapy. A history of ICP did not affect esterification of E2 during estrogen therapy.

Haemostatic risk factors in healthy postmenopausal women taking hormone replacement therapy

OBJECTIVE

To compare changes in haemostatic parameters in healthy postmenopausal women taking either tibolone or 17beta-oestradiol/norethisterone acetate.

METHODS

Factor VIIc, antithrombin, fibrinogen, thrombin-antithrombin complex (TAT), FDP (D-Dimer), tissue plasminogen activator (tPA) and plasminogen activator inhibitor I (PAI-1) were measured in 80 healthy postmenopausal women after 3, 6 and 12 months therapy with either 17beta-oestradiol/norethisterone acetate or tibolone.

RESULTS

Both treatments significantly reduced fibrinogen, factor VIIc, antithrombin, tPA and PAI-1 antigen. Significantly lower levels of factor VIIc activity were observed on treatment with tibolone compared with 17beta-oestradiol/norethisterone acetate. TAT was unchanged with both treatments as was tPA activity. FDP (D-dimer) was increased on treatment with both preparations.

CONCLUSIONS

The enhanced fibrin turnover and reduced antithrombin activity may play a role in the increased risk of venous thromboembolism in some susceptible women taking hormone replacement therapy (HRT) and could explain the lack of benefit of HRT in the secondary prevention of cardiovascular disease. The decreased levels of fibrinogen and factor VIIc found during treatment with 17beta-oestradiol/norethisterone acetate or tibolone may offer some degree of cardioprotection in healthy woman without pre-existing disease.

Effect of hormone replacement therapy on inflammation-sensitive proteins in post-menopausal women with Type 2 diabetes

AIMS

To test the effect of oral hormone replacement therapy (HRT) on plasma C-reactive protein (CRP), soluble vascular cell adhesion molecule-1 (VCAM-1), soluble intercellular adhesion molecule-1 (ICAM-1) and IL-6 concentrations and leucocyte count in post-menopausal women with Type 2 diabetes.

METHODS

Post-menopausal women with Type 2 diabetes (n = 61) were randomized in a double-blind fashion to receive either continuous combined hormone replacement therapy (n = 29) with conjugated equine oestrogen (0.625 mg/day) plus medroxyprogesterone acetate (2.5 mg/day) or placebo (n = 32) for 6 months. Study variables were measured at baseline and at the end of the study.

RESULTS

Eight women randomized to hormone replacement therapy and four women assigned to placebo group dropped out of the study. Plasma CRP increased (2.2 mg/l, 95% confidence interval 0.3-4.1 mg/l) significantly (P = 0.02) in women treated with HRT (n = 21) compared with placebo (n = 29) taking baseline CRP, body mass index (BMI) and smoking status into account. Plasma levels of cell adhesion molecules, IL-6 and leucocyte count did not change significantly during the study.

CONCLUSIONS

These findings indicate that oral HRT with conjugated equine oestrogen plus medroxyprogesterone acetate increases plasma CRP levels but not necessarily global inflammatory activity in post-menopausal diabetic women. An increase in plasma CRP may potentially increase risk of a cardiovascular event.

Effects of progestins in different hormone replacement therapy formulations on estrogen-induced lipid changes in postmenopausal women

Hormone replacement therapy (HRT), used by many women to relieve the symptoms of menopause and for the prevention of osteoporosis, is available in an increasing number of formulations. Options include various combinations of estrogen and progestin as well as different routes of administration. For women with a uterus, who require a progestin, a convenient and commonly used option is combining the estrogen and progestin in a single pill. Such formulations have the lipid-modifying effects of estrogen, altered to specific type and dose of progestin used. The cardioprotective increases in levels of high-density lipoprotein cholesterol associated with exogenous estrogen may be blunted or even reversed with certain HRT regimens. In addition, some progestins minimize the increase in triglycerides that occurs with exogenous estrogen, whereas others do not. Because of the importance of lipid markers as risk factors for cardiovascular disease in postmenopausal women, these lipid effects should be carefully considered when selecting an HRT regimen.

Comparative absorption and variability in absorption of estradiol from a transdermal gel and a novel matrix-type transdermal patch

OBJECTIVES

To compare the absorption of estradiol from a transdermal gel and a novel matrix-type patch and to study the variability in absorption.

METHODS

Twenty-four healthy postmenopausal women were treated in an open, randomized, cross-over study for 18 days with 1.0 mg estradiol daily as a transdermal gel and a transdermal patch releasing estradiol 50 microg/24 h without a wash-out between the periods. Venous blood samples for estradiol pharmacokinetics were taken on the 15th and 18th study days of the gel period and during the 15th-18th study days during the patch period.

RESULTS

There was no significant difference in peak estradiol level or area under the estradiol time-concentration curve between the gel and the patch. However, trough estradiol concentration was significantly lower and fluctuation higher with the patch. Estradiol time-concentration curves on the 15th and 18th study days with the gel were almost superimposable. A significant difference was observed in peak estradiol levels, whereas area under the curve or trough estradiol level did not differ between the 15th and 18th study days with the gel. Inter- and intra-individual coefficients of variability were around 30% for peak estradiol level and area under the curve, except for the intra-individual coefficient of variability for area under the curve (21%) for the gel. The total coefficient of variability for area under the curve was 35% for the gel and 39% for the patch.

CONCLUSIONS

A daily 1.0 mg estradiol dose as a transdermal gel seems to correspond with a matrix-type patch releasing 50 microg estradiol daily in the extent of estradiol absorption. High variability was associated with both treatments, and both the variabilities within and between the subjects were high with the gel. Wider than generally applied confidence limits should be applied for bioequivalence testing of transdermal estradiol formulations.

Do we need clinical trials to test the ability of transdermal HRT to prevent coronary heart disease?

Postmenopausal hormone replacement therapy (HRT) with oral oestrogen was predicted to reduce coronary heart disease (CHD) risk by 50%. Randomized controlled trials show no such benefit, however, pointing instead to an initial increase in CHD events. Although the cardiovascular effects of transdermal HRT are largely unknown, improvements in arterial function are maintained when oestrogen is administered transdermally. Transdermal HRT also avoids the increased plasma levels of C-reactive protein (CRP) that are seen with oral HRT. However, the clinical significance of this general reduction in hepatic over-synthesis of plasma proteins is difficult to assess. Nevertheless, the available evidence on transdermal HRT appears to justify a formal clinical trial.

Intrauterine application of progestins in hormone replacement therapy: a review

The intrauterine application of progestins as endometrial protection against hyperstimulation by estrogen replacement therapy has been investigated in clinical trials since the early 1990s and one product has become available for this indication. This review considers the available published and presented reports on intrauterine use of progestin to date. Reports of 19 studies were reviewed. These studies included both peri- and postmenopausal women (826 in total), treated with different types of estrogens administered via various routes. Progesterone was used in two small studies, while all other studies used different doses of levonorgestrel for periods ranging from 6 months to more than 5 years. Endometrial effects, bleeding profiles, systemic effects (symptoms and metabolic), as well as clinical experience, were considered and were comparable to other forms of continuous combined hormone replacement therapy (HRT). It is concluded that the current evidence supports complete endometrial protection and a good safety profile. The observed bleeding profiles appear favorable but have not yet been directly compared with other forms of continuous combined HRT. A favorable effect on serum lipids has been observed and also awaits direct comparative confirmation. Progestin-attributable side-effects, effects on bone and breast tissues and other systemic effects have not yet been studied. Acceptance by patients has been good, while insertion did not present undue problems for the investigating physicians. Retention of the studied intrauterine systems has been very good. Intrauterine use of progestins, especially levonorgestrel, by purpose-designed systems as part of combined HRT, is a new way of administration and carries good benefits, while some aspects require more clinical evidence.

Comparison of gel and patch estradiol replacement in Brazil, a tropical country

OBJECTIVES

Compare the administering technique, local tolerance and clinical and laboratory response to hormone replacement therapy with 17-beta estradiol in gel and patch in Brazil, a tropical country.

METHODS

We carried out a transversal study by means of an outpatient interview completed by 66 menopausal women, 42 using gel, and 24 utilizing patches. We focused on the main problems with the two forms of replacement, in summer and at other times during the year.

RESULTS

The average daily dose of 17-beta estradiol administered was 150 microg in the GEL GROUP and 50 microg in the PATCH GROUP. Reports of itching (33.3%) and local skin reactions (54. 2%) occurred exclusively in the PATCH GROUP. The patches came detached in 54.2% of the patients. These problems were more frequent in the summer. There was no significant difference in the regularity of administering (P=0.38) nor in the levels of FSH (P=0.16) and LH (P=0.33) between the two groups. Problems with the application technique (P=0.002) and the blood levels of estradiol (P=0.0002) were greater in the GEL GROUP, while symptoms of hypoestrogenism predominated in the PATCH GROUP (P=0.002).

CONCLUSIONS

We concluded that, in our environment, the use of 17-beta estradiol in gel presented fewer local skin reactions, was more effective in alleviating the symptoms of hypoestrogenism and had better acceptance in hormone replacement therapy for menopausal women, as compared with the 17-beta estradiol patch.

Effect of dose on the absorption of estradiol from a transdermal gel

OBJECTIVES

To study whether dose adjustments in transdermal estradiol gel treatment would result in proportional changes in estradiol bioavailability and concentrations.

METHODS

In an open study, 23 healthy postmenopausal women were treated consecutively with 0.5, 1.0 and 1.5 mg estradiol daily as a transdermal gel. Each dose was given for 16 days. Venous blood samples for serum estradiol and estrone measurements with RIA were taken at steady state on the 16th study day. From these concentrations, pharmacokinetic parameters for estradiol were calculated and corrected to correspond to equal dose by dividing the values by the dose.

RESULTS

Area under the estradiol time-concentration curve and peak estradiol level increased linearily and dose-proportionally with daily estradiol doses of 0.5-1.5 mg. This was shown by lack of significant differences in the dose-corrected parameters. However, the 90% confidence intervals between the doses were outside the commonly accepted levels for bioequivalence. Peak estradiol level was clearer and occurred earlier with the highest 1.5 mg estradiol dose, while more stable estradiol levels were seen with the lowest 0.5 mg estradiol dose.

CONCLUSIONS

The amount of estradiol on a certain skin area seems to be the determining factor in absorption. With higher estradiol doses, the absorption will be accelerated with a clearer peak estradiol level. The linear and dose proportional absorption indicates that flexible dose adjustments within the dose range of 0.5-1.5 mg estradiol daily can be made with an anticipated effect in estradiol bioavailability and concentrations.

Indirect evidence that estrogen replacement therapy stimulates nitric oxide synthase in postmenopausal women

The aim of the study was to investigate the effects of estrogen replacement therapy (ERT) on nitric oxide (NO) activity in healthy postmenopausal women. The study group consisted of 22 postmenopausal women (last menses at least 12 months prior to study entry) who were randomized to receive treatment for 2 months with patches that delivered either 50 micrograms/day of 17 beta-estradiol or placebo in a cross-over design. Blood samples for measurements of serum citrulline and arginine were collected at the start of the study and at the end of each treatment course. Serum citrulline and arginine were measured using high-performance liquid chromatography with fluorometric detection. Arginine levels were significantly lower in the ERT group compared to the placebo group, while citrulline levels did not change. The percentage citrulline/arginine ratio was significantly higher in the ERT group (42.9 +/- 21.6) compared to the placebo group (33.9 +/- 18.5) (p < 0.01). The citrulline/arginine ratio, both at baseline and during either ERT or placebo administration demonstrated a positive linear correlation with body mass index (BMI). No correlations were found between follicle stimulating hormone, estradiol and insulin levels and BMI. No correlations were found between age, time since menopause and baseline arginine and citrulline levels or the citrulline/arginine ratio. These data indirectly demonstrate that transdermal estradiol replacement in postmenopausal women is able to stimulate NO production through the involvement of endogenous L-arginine. A positive linear correlation was found between BMI and the citrulline/arginine ratio, suggesting an additional protective cardiovascular effect in overweight women.

Debate: The potential role of estrogen in the prevention of heart disease in women after menopause

The observational studies of hormone users are compromised by systematic biases that lead to an overestimation of benefit and an underestimation of risk. Studies of mechanism could support either benefit or harm. The results of clinical trials of oral hormone therapy in women with existing coronary heart disease (CHD) have been uniformly disappointing. The largest trial found an early increased risk for CHD and for venous thromboembolism. Postmenopausal hormone therapy should not be considered for CHD prevention until methods for excluding high-risk women have been established, and until the results of the long-term trials have shown benefit. There is a need for clinical trials of nonoral estrogens.

The treatment of hypertriglyceridaemia in menopausal women with transdermal oestradiol therapy

The objective of this study was to evaluate the effect of transdermal oestradiol on serum triglycerides in menopausal women with pre-existing mild to moderate hypertriglyceridaemia. Forty-four women, who had had a hysterectomy and who had been maintained on 50 microg unopposed oestradiol for six months, were divided into two groups: those with normal baseline triglyceride concentrations (0.4-2 mmol/L) (n = 34) and those with raised baseline readings (> 2-4 mmol/L) (n = 10). There was a significant reduction in the concentrations of serum triglycerides in both groups [-9.6% (P < 0.001) and -17% (P < 0.001), respectively]. Transdermal oestradiol therapy may be a useful treatment option in menopausal women with pre-existing hypertriglyceridaemia. There is a need to conduct large, prospective, controlled trials using transdermal oestradiol to treat hypertriglyceridaemia in menopausal women.

Aortic plaque size and endometrial response in cholesterol-fed rabbits treated with estrogen plus continuous or sequential progestin

ERT is associated with a reduced incidence of coronary risk and cardiac events in postmenopausal women, but increases the risk of endometrial hyperplasia and carcinoma. Combined estrogen and progestin therapy protects the endometrium; however, its effects on heart disease risk factors are not completely known. In our study, 56 ovariectomized New Zealand White rabbits in 7 groups received a 0.5% cholesterol diet for 12 weeks. Controls were not treated with hormones. All other animals received (per kilogram body weight per week) intramuscular injections of either 0.3 mg estrogen (estradiol valerate) alone, 8.3 mg progestin (hydroxyprogesterone caproate) alone, estrogen and progestin continuously in 3 different dosages (0.3 and 8.3 mg; 1 and 8.3 mg; or 1 and 2.8 mg; estrogen and progestin, respectively), or 1 mg estrogen with 25 mg progestin sequentially in 2-week cycles. Eight non-ovariectomized animals served as further controls for endometrial analysis. Morphometric analysis of plaque size in the aortic arch showed that estrogen monotherapy, and the 3 combined therapies with 1 mg estrogen, significantly reduced intimal thickening (P<0.05). The application of progestin alone had no effect on plaque size. The endometrium was enlarged by 3-fold after estrogen treatment, and was decreased by half after progestin treatment, compared with control uteri (P<0.05). In all groups with combined hormone regimens, endometrial size was not significantly different from control uteri. However, these uteri showed more inflammatory reactions, especially when higher doses of hormones were given. In this animal model, doses of progestin that are able to successfully reduce the proliferative effect of estrogen on endometrium do not diminish the desirable antiatherosclerotic properties of estrogen.

The menopause

Menopause is diagnosed after 12 months of amenorrhoea resulting from the permanent cessation of ovarian function. The mean age at menopause is 51 years. The perimenopause, a time of changing ovarian function, precedes the final menses by several years. The physiology and clinical manifestations of this transition to menopause are not well understood; however, some symptoms, such as hot flashes, certainly begin in the perimenopause. Causal associations between menopause and several symptoms and diseases are proposed. The evidence for these associations varies and is reviewed. Hormone replacement therapy can be directed at symptom relief or at prevention or treatment of chronic diseases. Doses and routes of hormone replacement therapy vary by indication. Complications of hormone replacement therapy depend on the regimen used. Knowing the expected vaginal bleeding pattern for each hormone replacement therapy regimen is important, since unexpected bleeding may signal endometrial hyperplasia. Postmenopausal hormone therapy is a complex intervention that produces positive and negative specific health effects. Overall, based on observational studies, postmenopausal women who use hormones have a 30-50% lower all-cause mortality rate than those who do not use hormones. It is important to recognise that the value that individual women place on various health outcomes associated with hormone replacement therapy may differ. Thus, the decision to use hormone replacement therapy should be made jointly by each woman and her health-care provider, after careful consideration of possible benefits, risks, and her personal preferences.