25 mg oestradiol implants--the dosage of first choice for subcutaneous oestrogen replacement therapy?

Oestrogen-based therapies for menopausal symptoms

PURPOSE

To summarise the dosing options, regimens, pharmacokinetics, risks and benefits of oestrogen-based therapies for the treatment of menopausal symptoms.

METHODS

A review of the literature was undertaken using multiple databases. Randomised trials, observational studies, meta-analyses and review papers were included.

RESULTS

Multiple systemic preparations of oestrogen exist and all appear comparable in terms of efficacy. They differ by pharmacokinetics and those preparations that avoid hepatic metabolism have a lower risk profile in general although their use can be limited by skin barriers or patient acceptability. All vaginal oestrogen treatments are comparable in efficacy and have not been associated with any health risks. Side-effects between all preparations differ.

CONCLUSIONS

With regards to oestrogen treatments there is not a one size fits all. Multiple treatments are available and a clinician's role is to guide and help women make evidence based, unbiased and informed choices.

Hormone replacement therapy subcutaneous implants for refractory menopause symptoms; the patient's perspective

OBJECTIVE

For women with menopause symptoms refractory to standard hormone replacement therapy (HRT) preparations, HRT implants offer an alternative. The primary objective of this study was to evaluate women's perceptions regarding efficacy, tolerability, satisfaction and safety of implant therapy.

STUDY DESIGN

A single centre service evaluation study performed at Birmingham Women's & Children's Foundation Hospital Trust. An anonymised semi-structured survey link was posted to all women (n = 397) recorded to have received HRT implant(s) at a tertiary Menopause clinic (May 1982 and Dec 2018). Women attending clinic (June 2020 to Sept 2020) were opportunistically invited to complete a written version of the survey.

MAIN OUTCOME MEASURES

Data collected included demographics, medical and surgical history, therapy duration, type, indication and complications. Climacteric symptoms were assessed using the Greene Climacteric Scale.

RESULTS

Data was obtained for 119 women. The written survey yielded higher response rates (n = 73, 61.3%). Most respondents were 51-60 years old (n = 51 42.9%) and 87.4% (n = 104) were 'White British'. 70 women used estradiol only implants. 30.1%% (n = 34) of patients reported a low Greene Climacteric Scale score (0-5). Subgroup analysis showed prevalence of sexual dysfunction and vasomotor symptoms across ages. There was a lower prevalence of psychological symptoms amongst ≥51 year olds. High satisfaction rates were reported.

CONCLUSIONS

Data from a large cohort is presented. Good symptom control, satisfaction and long-term efficacy was demonstrated. This study supports the value of HRT implants for refractory menopause symptoms. A national database of implant users would be a useful tool to record satisfaction scores and adverse events.

A double-blind placebo-controlled trial on the effects of 25 mg estradiol implants on the urge syndrome in postmenopausal women

The aim of this prospective double-blind randomized placebo-controlled trial was to determine the effect of systemic estrogen on the 'urge syndrome' in postmenopausal women. The trial took place in a tertiary referral urogynecology unit. Postmenopausal women with the 'urge syndrome' were randomly allocated to receive a 25 mg 17beta-estradiol implant or placebo implant. Serum estradiol levels and endometrial thickness were measured on entry to the trial and at 1, 3 and 6 months. The following outcome measures were employed: videocystourethrography, frequency volume chart, visual analogue score of symptoms, and King's Health Care Quality of life Questionnaire. Forty women were included. Subjectively there was a significant improvement in urgency in both groups and urge incontinence in the estradiol group, but no significant differences between the groups. Objectively no significant differences were demonstrated between the groups. Nine women in the estradiol group had vaginal bleeding, and 5 had a hysterectomy during or after the study. Despite using numerous outcome measures to examine its effect, 25 mg estradiol implants did not produce a greater improvement in the 'urge syndrome' than placebo and had a high complication rate.

The impact of subcutaneous oestradiol implants on biochemical markers of bone turnover and bone mineral density in postmenopausal women

OBJECTIVE

To evaluate the anabolic effect of oestrogen on bone by comparing the response of markers of bone formation (and resorption) and bone mineral density (BMD) to subcutaneous oestradiol implants.

DESIGN

One year double-blind placebo controlled randomised study.

SETTING

Clinical research unit within a teaching hospital.

POPULATION

Twenty-one hysterectomised postmenopausal women were randomised to 25 mg oestradiol implants at baseline and at six months or to have a sham procedure at baseline and six months.

METHODS

BMD and quantitative ultrasound (QUS) were assessed at baseline and one year. Bone alkaline phosphatase (bone ALP), procollagen type I N-terminal propeptide (PINP), osteocalcin (OC), free deoxypyridinoline (iFDPD), N-telopeptide of type I collagen (NTX), serum oestradiol and intact parathyroid hormone (PTH) were measured at baseline, 4, 8, 12 and 24 weeks.

MAIN OUTCOME MEASURES

Percentage change markers of bone turnover and PTH and change in oestradiol levels over first six months and percentage of changes in DXA and QUS over one year.

RESULTS

PINP, bone ALP and OC increased by 28%, 7% and 9%, respectively (P < 0.01) during the first four weeks of treatment and then decreased significantly. Lumbar spine (LS) and total hip (TH) BMD increased by 5.4% and 6.0% (P < 0.001), respectively, and femoral neck (FN) BMD by 3.7% (P < 0.05) during the first year of treatment compared with control subjects. The peak serum oestradiol level was achieved four weeks after implant insertion. Mean PTH levels increased significantly in subjects receiving subcutaneous oestradiol.

CONCLUSION

Subcutaneous oestrogen exerted an apparent anabolic effect on bone, which was initially reflected by an increase in bone formation markers and later by a large increase in BMD.

Pharmacokinetics and pharmacodynamics of 25-mg estradiol implants in postmenopausal Mexican women

OBJECTIVE

To assess the serum concentrations of estradiol (E2), estrone (E1), gonadotrophins, sex hormone-binding globulin, and lipids, and to determine degree of symptom relief after subcutaneous implantation of 25 mg estradiol in postmenopausal Mexican women.

DESIGN

Fifteen postmenopausal, hysterectomized women participated in an open, observational study. Blood samples were obtained before implantation and at regular intervals during a study period of 24 weeks. Climacteric symptoms were evaluated by means of the Greene climacteric scale. Wilcoxon's test was performed on the paired results of pre-and postimplantation values.

RESULTS

Serum concentrations of E2 obtained after implantation were fairly constant, remaining within the early follicular range for the entire study period of 24 weeks, and were associated with significant symptom relief. A physiological, premenopausal E2:E1 ratio was achieved. No significant metabolic changes occurred. Side effects were estrogenic in nature and no removal of implant was required.

CONCLUSIONS

Subcutaneous implantation of 25 mg estradiol results in physiological, premenopausal estrogen concentrations in most women and is associated with considerable symptom relief without inducing significant adverse metabolic effects.

A comparison of 25 mg and 50 mg oestradiol implants in the control of climacteric symptoms following hysterectomy and bilateral salpingo-oophorectomy

OBJECTIVES

1. To compare the effects of 25 mg and 50 mg oestradiol implants on serum follicle stimulating hormone and oestradiol levels; and 2. to assess the relationship of the dose of oestradiol implant and serum oestradiol on the effectiveness and duration of climacteric symptom control.

DESIGN

Randomised, double-blind investigation.

PARTICIPANTS

Forty-four women, who had undergone total abdominal hysterectomy and bilateral salpingo-oophorectomy.

METHODS

The women were randomised to receive either 25 mg (n = 20) or 50 mg (n = 24) oestradiol implants. Follow up consisted of prospective symptom enquiry and hormone assays.

MAIN OUTCOME MEASURES

Primary: climacteric symptom control: duration and effectiveness; secondary: serum oestradiol and follicle stimulating hormone levels.

RESULTS

Serum oestradiol was significantly higher and serum follicle stimulating hormone significantly lower after the fourth month of treatment in women receiving 50 mg implants. No significant difference in symptom control was noted in the two groups. The mean duration of symptom control was similar in the two groups: 5.9 months (SD 2.4) in those receiving 50 mg oestradiol and 5.6 months (SD 2.3) in those receiving 25 mg.

CONCLUSION

The higher level, 50 mg oestradiol implants does not result in better control of symptoms nor in longer periods of symptom control compared with 25 mg oestradiol implants. In order to maximise compliance, 25 mg oestradiol implants should therefore be the treatment of choice for women with normal bone density seeking relief of climacteric symptoms.

An audit of oestrogen implant hormone replacement therapy

The aim of this review was to determine the factors that impact upon oestradiol levels in patients receiving oestradiol implants and to assess the relationship between symptom scores and oestradiol levels. In addition we sought to determine the incidence of tachyphylaxis (menopausal symptoms in spite of high oestradiol levels) among our patients, and to assess the degree of menstrual cycle control in the nonhysterectomized women receiving implant treatment. We undertook an audit of the medical records of 118 women who received 673 oestradiol implants (50 or 100 mg) over an 8-year period in the menopause clinics at Royal North Shore Hospital. Data on patient age, clinical diagnosis, symptom score, previous or subsequent hysterectomy, oestradiol implant dosage (50 mg or 100 mg), number of doses, oestradiol levels and concurrent testosterone implant insertion were recorded. We found that implant dosage (p<0.001) and implant number (p<0.001) were the factors that significantly impact upon oestradiol levels. Concomitant testosterone implant usage (p=0.74), patient age (p=0.14) and hysterectomy (p=0.57) did not have a statistically significant effect upon oestradiol levels. The incidence of tachyphylaxis was 1.7% (2 patients). There was no relationship between oestradiol levels and symptom scores (p=0.69). Oestradiol implant treatment, when administered on the basis of return of symptoms, without a strict target oestradiol level, results in a steady increase in baseline oestradiol levels. The dosage used and the number of implants received are important factors influencing oestradiol levels. The incidence of tachyphylaxis is low when patients are counselled regarding the lack of agreement between symptom scores and oestradiol levels.

Effect of sustained estradiol release in the intact male rat: correlation of estradiol serum levels with actions on body weight, serum testosterone, and peripheral androgen-dependent tissues

The differential effect of increasing serum estradiol on various parameters in the intact male rat was assessed through the use of subcutaneously implanted, hormone-laden pellets. The delivery systems were designed to release drug through bioerosion at a zero-order rate over a 12-day time-course. Male Sprague-Dawley rats (190 to 220 g) were given estrogen pellets at increasing labeled strenghts (0, 0.001, 0.01, 0.1, 1.0, 10, 50, and 100 mg). Animals were weighed at various intervals before and after implantation. At Day 6, 12, and 26 after drug administration, rats were examined for 4 additional parameters, including serum estradiol and testoterone concentrations and accessory organ weights (i.e., ventral prostate and seminal vesicles). Serum estradiol levels were consistent with pellet potency and lifetime. Increases in body weight were suppressed 50% by circulating estradiol levels of approximately 200 pg/mL at Day 6,250 pg/mL at Day 12, and 285 pg/mL at Day 26. On the other hand, suppression of serum testosterone was more sensitive and was decreased 50% by peripheral estrogen levels of 36, 43, and 51 pg/mL at Days 6, 12, and 26, respectively. Accessory organ weights essentially reflected serum testosterone levels as indicated by their similar ED50 values: 50.5, 50.5, and 44.3 pg/mL for the ventral prostate at Day 6, 12, and 26, respectively, and 48, 56, and 51.5 pg/mL for the seminal vesicle regression at Day 6, 12, and 26, respectively. The data indicate the pellet used provided sustained plasma levels of hormone and these constant peripheral levels exerted potent pharmacological action. Initial body weight changes seemed to be less sensitive to the action of estradiol than serum testosterone or derivative properties, such as accessory organ weight.

Hormonal chemoprevention of cancer in women

The use of oral contraceptives in the United States during the past three decades has led to a dramatic decline in the incidence of cancers of the ovary and endometrium. The magnitude of these declines was predictable both from epidemiologic data and from the biologic effects of oral contraceptives on these tissues. Although the incidence of breast cancer has not been substantially affected by current oral contraceptives, it may be possible to develop alternative forms of contraception that provide protection against all three cancers. The major goal of hormonal chemoprevention of cancer is to reduce cell proliferation in the relevant epithelial tissue. New chemopreventive agents such as tamoxifen exemplify the application of this principle.