Twenty two weeks of transdermal estradiol increases sex hormone-binding globulin in surgical menopausal women

The effect of estrone on thrombin generation may explain the different thrombotic risk between oral and transdermal hormone replacement therapy

BACKGROUND

The metabolism of estrogen contained within hormone replacement therapy (HRT) is influenced by the route of administration, and this may affect the risk of venous thromboembolism. Thrombin generation, a global coagulation assay, is a marker of hypercoagulability and is of potential use in determining the thrombotic risk associated with particular HRT administration routes.

OBJECTIVES

To determine whether any effect of oral and transdermal HRT on thrombin generation is related to the plasma estrogen profile.

METHODS

We investigated the effects of oral, transdermal and no HRT (controls) in 52, 39 and 52 postmenopausal women, respectively, on thrombin generation, standard markers of thrombophilia, estradiol level and estrone level.

RESULTS

All parameters of thrombin generation were altered in women using oral HRT as compared with controls (P<0.001 for all comparisons). No such differences were found in women using transdermal HRT. Estrone levels correlated with peak thrombin generation (R=0.451, P<0.001) in women using oral HRT, but there was no correlation in women using the transdermal route.

CONCLUSIONS

Thrombin generation is significantly increased in women who use HRT administered by the oral route. This is probably mediated by the hepatic first-pass metabolism of estrone, the main metabolite of oral estradiol, which is avoided by the transdermal route. The effect of estrone on thrombin generation may provide the explanation for the higher thrombotic risk seen in women using oral rather than transdermal HRT.

Effect of oral versus transdermal steroidal contraceptives on androgenic markers

OBJECTIVE

The purpose of this study was to compare biochemical androgen profiles in women treated with the contraceptive patch versus an oral contraceptive (OC).

STUDY DESIGN

Twenty-four healthy women were randomly assigned to receive 3 cycles of either the contraceptive patch (ethinyl estradiol [EE] 20 microg/d and norelgestromin 150 microg/d) or OC (EE 35 mug and norgestimate 250 microg). Blood samples were taken at baseline and end of treatment. Serum levels of sex hormone-binding globulin (SHBG), total testosterone (T), androstenedione (A), dehydroepiandrosterone sulfate (DHEAS), dihydrotestosterone (DHT), and 3alpha-androstanediol glucuronide (3alpha-diol G) were quantified by immunoassay methods; free T was calculated. The paired t and Student t tests were used for statistical analysis.

RESULTS

Nineteen women completed the study (patch, n = 10; OC, n = 9). Despite a 1.6-fold relative increase in SHBG levels with the patch versus OC (449% vs 274%, P = .03), free T decreased equally in both groups (patch 60%, P < .0001; OC 59%, P < .0001). DHEAS decreased by 26% in the patch group (P < .01) and 32% in the OC group (P < .001). 3alpha-diol G was reduced by 52% in the patch group (P < .0001) and 51% in the OC group (P < .0001). In addition, the OC was associated with significant decreases in A and DHT.

CONCLUSION

The contraceptive patch had an effect comparable to the OC on several key androgenic markers. Given these biochemical findings, the contraceptive patch has significant potential as a therapeutic agent for disorders of androgen excess.

Tools for making correct decisions regarding hormone therapy. part I: background and drugs

OBJECTIVE

To review existing scientific data related to the biology of estrogen in the aging process of women, and to understand the pharmacology, physiology, and diversity of sex hormones.

DESIGN

A MEDLINE computer search was performed to identify relevant articles.

RESULT(S)

Estrogen and progesterone have been prescribed for postmenopausal women over the last 60 years. Various formulations have had divergent properties, which are related to dissimilarities in the molecule structure, metabolism, plasma carrier, distribution, receptor binding, and the specific localizations of the different receptors in the various organs.

CONCLUSION(S)

Extensive data are available on the various characteristics of sex-hormone formulations, which are related to clinical consequences. The drugs and means of application have resulted in fundamental differences in activity, such as variance between oral and transdermal applications resulting in different forms of liver involvement. This information could assist in understanding why certain formulations may either prove harmful or beneficial to specific women.

Pharmacokinetics of oral micronized beta-estradiol in postmenopausal women receiving maintenance hemodialysis

BACKGROUND

Although 11% of postmenopausal women with end-stage renal disease (ESRD) are prescribed hormone replacement therapy (HRT), the appropriate use remains poorly explored. Although there remains controversy surrounding the benefits of HRT, it may be of particular interest in this population, which has a high risk of bone loss and a fourfold increase in fracture risk compared to the general population. However, the appropriate dose of estrogen for use in postmenopausal women with ESRD is not known. The objective of this study was to evaluate the steady-state pharmacokinetics of oral micronized beta-estradiol in postmenopausal women with ESRD compared with postmenopausal women with normal renal function in order to determine equivalent dosing.

METHODS

Six postmenopausal women with ESRD receiving maintenance hemodialysis and 6 healthy postmenopausal controls received 14 days of micronized beta-estradiol (1.0 mg for control, 0.5 mg for ESRD). Blood, urine, and dialysate samples were obtained during a dosage interval on day 14. Estradiol, estrone, albumin, and sex-hormone binding globulin (SHBG) concentrations were determined. Free estradiol concentrations were calculated using a previously described method.

RESULTS

Women with ESRD had significantly lower serum albumin (610 +/- 31 micromol/L vs. 684 +/- 83 micromol/L) and SHBG (78 +/- 17 vs. 118 +/- 13 nmol/L) than control subjects. Total clearance of estradiol was not significantly different. Due to difference in binding, free estradiol concentrations were significant higher in ESRD women (53.2 +/- 17.7 pg/mL) than control women (43.5 +/- 8.7 pg/mL), despite receiving 50% of the dose. There was no significant difference in estrone concentrations. Clearance of both estradiol and estrone in the dialysate was minimal.

CONCLUSION

Women with ESRD should receive approximately 50% of the dose typically prescribed to women without ESRD.

Positive effects on cardiovascular and breast metabolic markers of oral estradiol and dydrogesterone in comparison with transdermal estradiol and norethisterone acetate

OBJECTIVES

To assess differences in two sequential combined hormone replacement therapy (HRT) products on selected cardiovascular and breast metabolic markers. The products were different concerning the route of administration of estradiol and its combined progestin, either oral or transdermal, and the androgenic properties of progestogens, respectively, dydrogesterone and norethisterone acetate.

METHODS

One hundred and nineteen healthy non-hysterectomized postmenopausal women were included in this open, multi-center, two parallel group trial. They were randomized to a treatment of six 28-day cycles with oral estradiol sequentially combined with dydrogesterone (oE2/D10) or a sequential combination patch of estradiol plus norethisterone acetate (tdE/NETA). At baseline and after six cycles the high-density lipoprotein cholesterol (HDL-C), the sex hormone binding globulin (SHBG) and the total insulin-like growth factor-I (IGF-I) blood levels were determined by a central laboratory. A total of 89 women were compliant to the protocol.

RESULTS

After six cycles, a statistically significant difference (P<0.001) concerning HDL-C, SHBG and IGF-I levels was found between the two treatment groups. The HDL-C levels were increased in the oE2/D10 group and decreased in the tdE/NETA group, with a final difference of about 0.3 mmol/l. The oE2/D10 treatment induced a sharp increase (about 57 mmol/l) in SHBG levels. IGF-I levels decreased with both the products, but the difference in favor of the oE2/D10 treatment was of about 30 ng/ml. Moreover, patients on tdE/NETA with an IGF-I baseline value below the median showed an increase.

CONCLUSION

Oral estradiol sequentially combined with dydrogesterone, a non-androgenic progestogen, induced positive changes of some cardiovascular (HDL-C) and breast (SHBG and IGF-I) metabolic markers. These effects were significantly different from those obtained with a transdermal estradiol associated to an androgenic progestogen.

Long-term effects of continuous oral and transdermal estrogen replacement therapy on sex hormone binding globulin and free testosterone levels

OBJECTIVE

To determine the long-term effects of estrogen replacement therapy on sex hormone binding globuline (SHBG) and free testosterone (fT) levels in surgical postmenopausal women.

STUDY DESIGN

Forty patients with surgical menopause were enrolled in this prospective study. The women were randomly divided into two groups. The first group received oral therapy (continuous conjugated equine estrogens (CEE) - 0.625mg per day) and the second group received transdermal therapy (patches delivering continuous 17beta-estradiol (E2)--0.05mg per day). Serum SHBG and fT levels were determined at baseline and after first and second years of treatment. Two-way repeated measures analysis of variance with Bonferroni adjusted post-hoc test and unpaired-t-test were performed for statistical analysis with SPSS program.

RESULTS

Serum SHBG levels increased significantly with oral CEE after first year of treatment (P<0.05) and remained at this level for the next year. Transdermal therapy did not affect SHBG levels after first and second years (P<0.05). Serum fT levels did not change significantly in either group at the end of the first or second years (P<0.05) although there was a significant difference between the groups after 2 years (P<0.05).

CONCLUSION

Oral conjugated estrogens increased SHBG levels during therapy. This effect may balance the increased estrogen and androgen stimulation on breast tissue and may be more beneficial to the cardiovascular system in postmenopausal women.

The pharmacokinetics and efficacy of different estrogens are not equivalent

In the next decade many women will turn to the medical community for advice on maintaining or improving health after menopause. Estrogen replacement therapy, with or without progestins, alleviates menopausal symptoms, prevents or manages osteoporosis, and reduces the increased cardiovascular disease risk that results from estrogen deficiency caused by ovarian decline. Although several estrogen replacement products are available, the pharmacokinetics and efficacy of these products may vary depending on either the estrogen formulation or the route of administration, or both. For example, oral estrogens, which elicit a marked hepatic response, induce greater beneficial effects on serum lipoproteins than transdermal estrogens, which circumvent first-pass liver metabolism. Oral conjugated estrogens and transdermal estradiol increase bone density and prevent bone loss. This article summarizes the studies comparing estrogen formulations and discusses the differential effects of various estrogen products that promote postmenopausal health.