Transdermal oestradiol gel in the treatment of the climacterium: a comparison with oral therapy

The effect of transdermal 17β-estradiol combined with norethisterone acetate treatment on the lipid profile in postmenopausal women: A meta-analysis and systematic review of randomized controlled trials

BACKGROUND AND AIM

The effect of transdermal 17β-estradiol and norethisterone acetate co-administration on the lipid profile in postmenopausal women remains controversial as randomized controlled trials (RCTs) conducted to investigate this research question have produced conflicting results. Consequently, to clarify this issue, we conducted a systematic review and meta-analysis of RCTs that evaluated the impact of transdermal 17β-estradiol combined with norethisterone acetate treatment on the concentrations of serum lipids in postmenopausal women.

METHODS

Relevant articles published before February 1st, 2022 were identified by searching the PubMed/Medline, Scopus, and Embase, and Web of Science electronic databases. A random-effects model, employing the method of DerSimonian and Laird, was used to evaluate effect sizes, and results were expressed as weighted mean difference (WMD) and 95% confidence intervals (CIs).

RESULTS

Pooled results from 7 RCTs with 9 intervention arms demonstrated that transdermal 17β-estradiol combined with norethisterone acetate administration significantly decreased total cholesterol (TC) (WMD: -13.43 mg/dL, 95% CI: -18.11 to -8.75, P < 0.001) and low-density lipoprotein cholesterol (LDL-C) (WMD: -13.90 mg/dL, 95% CI: -20.40 to -7.41, P < 0.001). In the subgroup analyses, a notable reduction in TC was observed in subjects with baseline TC concentrations ≥ 130 mg/dL (WMD -14.49 mg/dL), when treatment duration was ≤ 6 months (WMD: -17.21 mg/dL), and in participants with a body mass index (BMI) ≥ 25 kg/m² (WMD: -21.71 mg/dL). Moreover, in the subgroup analyses, transdermal 17β-estradiol combined with norethisterone acetate decreased triglycerides (TG) levels when the treatment duration was ≤ 6 months (WMD: -21.37 mg/dL). However, the prescription of transdermal 17β-estradiol combined with norethisterone acetate in postmenopausal women did not change high-density lipoprotein cholesterol (HDL-C) values.

CONCLUSIONS

Based on our findings, the co-administration of transdermal 17β-estradiol and norethisterone acetate in postmenopausal females can decrease TC and LDL-C levels, as well as TG values, but does not influence HDL-C concentrations.

Strategies for transdermal drug delivery against bone disorders: A preclinical and clinical update

The transdermal drug delivery system is an exceptionally safe and well-tolerable therapeutic approach that has immense potential for delivering active components against bone-related pathologies. However, its use is limited in the current clinical practices due to the low skin permeability of most active drugs in the formulation. Thus, innovations in the methodologies of skin permeation enhancement techniques are suggested to overcome this limitation. Although various transdermal drug delivery systems are studied to date, there are insufficient studies comparing the therapeutic efficacy of transdermal delivery systems to oral delivery systems. Thus, creating a decision-making dilemma between oral or transdermal therapies. Therefore, a timely review is inevitable to develop a platform for future researchers to develop next-generation transdermal drug delivery strategies against skeletal diseases that must be convenient and cost-effective for the patients with improved therapeutic efficacy. Here, we will outline the most recent strategies that can overcome the choice limitation of the drug and enhance the transdermal adsorption of various types of drugs to treat bone disorders. For the first time, in this review paper, we will highlight the preclinical and clinical studies on the different transdermal delivery methods. Thus, providing insight into the current therapeutic approaches and suggesting new directions for the advancements in transdermal drug delivery systems against bone disorders.

Transdermal hormone therapy: gels and patches

Hormone therapy (HT) in the climacteric has a number of beneficial effects including mitigation of climacteric symptoms and prevention of osteoporosis. Administration of HT via the transdermal route avoids hepatic first-pass metabolism and therefore the high plasma levels of estrogen metabolites that are associated with oral administration. Patch formulations have traditionally been the most common form of transdermal HT. However, as patches may be associated with local skin reactions, gel formulations have been developed in an attempt to improve acceptability and compliance with transdermal HT. Patch and gel formulations are equally as effective in treating climacteric symptoms and improving bone mineral density, and the effects are comparable to those achieved by oral HT.

Transdermal hormone therapy in postmenopausal women: a review of metabolic effects and drug delivery technologies

Vasomotor symptoms (VMS) associated with menopause can cause significant discomfort and decrease the quality of life for women in the peri-menopausal and post-menopausal stages of life. Hormone therapy (HT) is the mainstay of treatment for menopausal symptoms and is currently the only therapy proven effective for VMS. Numerous HT options are available to treat VMS, including estrogen-only and estrogen-progestogen combination products to meet the needs of both hysterectomized and nonhysterectomized women. In addition to selecting an appropriate estrogen or estrogen-progestogen combination, consideration should be given to the route of administration to best suit the needs of the patient. Delivery systems for hormone therapy include oral tablets, transdermal patches, transdermal topical (nonpatch) products, and intravaginal preparations. Oral is currently the most commonly utilized route of administration in the United States. However, evidence suggests that oral delivery may lead to some undesirable physiologic effects caused by significant gut and hepatic metabolism. Transdermal drug delivery may mitigate some of these effects by avoiding gut and hepatic first-pass metabolism. Advantages of transdermal delivery include the ability to administer unmetabolized estradiol directly to the blood stream, administration of lower doses compared to oral products, and minimal stimulation of hepatic protein production. Several estradiol transdermal delivery technologies are available, including various types of patches, topical gels, and a transdermal spray.

Estradiol gel

OBJECTIVE

To review the pharmacology, pharmacokinetics, safety, and efficacy of a gel containing estradiol that is applied to the skin.

DESIGN

MEDLINE and EMBASE searches were conducted from 1966 to March 2005. Additional references were identified from bibliographies from selected studies in addition to approved product information.

RESULTS

Estradiol gel is indicated for the relief of moderate to severe vasomotor symptoms in menopausal women, and moderate to severe symptoms of vulvar and vaginal atrophy. Women who are intolerant of the oral route, have had previous hypersensitivity skin reactions, or have had difficulties with adhesive patches are ideal candidates for estradiol gel.

CONCLUSIONS

Estradiol gel can effectively reduce menopause symptoms with minimal side effects. Long-term safety data of estradiol gel are required.

Delivery systems for hormone replacement therapy

The steroid hormones used for hormone replacement therapy in the menopausal transition and postmenopause can be administered by several different routes using a variety of delivery systems. The conventional approach to administration has been oral, and this is still the standard against which other routes are compared. However, there is a steadily increasing research development and popularity for alternative systems. Such systems can be geared to ultra low-dose delivery for local vaginal effect or higher dosages for systemic effect. Different delivery systems have a range of attributes with varying appeal to different individual women. Such a range of choices can be important for acceptability and compliance. One of the most important attributes of many newer delivery systems is the potential to deliver hormones in a controlled manner over prolonged periods of time, allowing constant low dosages, as well as constant blood and tissue levels. They also have the potential for reducing side effects and metabolic effects. Transdermal, subdermal, intravaginal and intrauterine systems are particularly likely to undergo refinement and further development in the foreseeable future with subsequent increases in popularity.

Overview on the effects of progestins on bone

In view of the fact that fractures are the clinically relevant events, risk factors for fractures are discussed first. Bone mineral density (BMD) appears to be a much less important risk factor for the most severe hip fractures than the risk of falling. No results of experimental studies on hormones and fractures at advanced age are available. An overview of the effects of progestins on bone is given. Effects of progestins on bone have been studied by in vitro experiments using cell lines and by more relevant clinical observations. Prospective studies have been conducted following the use of progestins contained in oral contraceptives, alone or in combination with oestrogens; long-term contraception by injection of depot preparations; so-called "add-back" hormonal therapy attempting to reverse the adverse effects of gonadotropin releasing hormone agonists on bone and after different regimens of hormone replacement therapy (HRT) in postmenopausal women. From the data there are no indications that the various progestins, used in clinical practice, have either a bone-protective or an oestrogen antagonistic activity. Progestins do not add or subtract much of the protective action of oestrogens on the bones.

Compliance with oral HRT in postmenopausal women in clinical trials--meta analysis

OBJECTIVE

To assess compliance with oral hormone replacement therapy (HRT) over time in postmenopausal women in clinical trials and to examine aspects of study conduct (e.g. randomized vs. nonrandomized design) that might be associated with observed compliance rates.

METHODS

Aggregation of data from the available published studies using meta-analysis. Eligible studies had to be clinical trials reporting compliance with oral HRT among postmenopausal women and have a sample size of at least 20. MEDLINE and EMBASE databases were used through January 1998 to find studies that assessed compliance with oral HRT in postmenopausal women in clinical trials. Summary estimates of compliance, and of associations between compliance and features of study conduct, were computed allowing for clustering of data within studies.

RESULTS

Thirty reports met the inclusion criteria. Overall compliance at about 1 year on average was 83.4%. In a multivariable model, one variable, whether compliance was the primary objective of the study or not, remained statistically significant, even after adjustment for clustering (odds ratio=0.47, 95% confidence interval: 0.22-1.00, P=0.05).

CONCLUSIONS

This study supports the importance of using appropriate methods for measuring compliance, if valid estimates of compliance are a serious objective of an investigation. There has been much discussion about the need for increased medication compliance, particularly for those medications used for prevention, but the means and methods to improve compliance remain elusive.

Pathologic and biological prognostic factors of breast cancers in short- and long-term hormone replacement therapy users

BACKGROUND

Breast cancer tumors occurring in hormone replacement therapy (HRT) users are less aggressive, but no studies have compared tumor aggressiveness among HRT users by length and mode of therapy.

METHODS

A total of 1105 consecutive postmenopausal patients treated for operable breast cancer at the European Institute of Oncology were identified. Women exposed to HRT were compared with HRT nonusers by clinical stage at presentation and pathologic and biological tumor characteristics. HRT duration and administration modality were analyzed in relation to tumor characteristics in the HRT group.

RESULTS

Better stage distribution, including smaller pathologic tumor diameter and fewer involved axillary lymph nodes, was seen in the HRT group. Estrogen receptor-positive tumors were more frequent in the control group, but this tendency was reversed with longer exposure to HRT. Histological grade III tumors were less frequent in the HRT group. More favorable prognostic factors were associated with HRT >5 years. The proliferative fraction was higher in patients with exposure <1 vs. >5 years and in oral versus transdermal users.

CONCLUSIONS

Breast cancers developing during HRT have better prognostic characteristics than those seen in HRT nonusers. A trend toward better prognostic characteristics with increasing duration of HRT was seen.

Effect of an estradiol gel with monthly or quarterly progestogen on menopausal symptoms and bleeding

OBJECTIVE

To assess the acceptability, efficacy and endometrial safety of transdermal estradiol gel (Divigel/Sandrena) combined with monthly or quarterly oral progestogen (medroxyprogesterone acetate).

METHODS

This 12-month, multicenter, open-label study was carried out at 12 study centers in Finland and Sweden. A total of 395 postmenopausal women received 1 mg estradiol in 1 g gel, daily, with oral medroxyprogesterone acetate 10 mg for the first 12 days every month (groups I and III) or every 3 months (group II). The main outcome measures were relief of climacteric symptoms, bleeding patterns and endometrial safety.

RESULTS

All regimens reduced the severity of hot flushes, sweating episodes and vaginal dryness. In groups I and III, approximately 80% and 70% of women, respectively, had regular monthly withdrawal bleeding (excepting the first cycle), with irregular bleeding in 8.3% and 5.3% of treatment months. In group II, approximately 94% of women had regular tri-monthly withdrawal bleeding, with irregular bleeding in 10.7% of the treatment months. Endometrial hyperplasia was observed in 0.3% of women. More than 87% of subjects completed the study, and 97% of these rated the gel as acceptable or convenient.

CONCLUSIONS

Both the 1- and 3-month regimens were equally effective in controlling climacteric symptoms and protecting against endometrial hyperstimulation. The bleeding patterns were comparable between groups and were similar to those reported for oral estrogens. Estradiol gel was highly acceptable to the majority of women.

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.

RB, Gomes MAS, Clapauch R. Monitorizando a terapia de reposição estrogênica (TRE) na menopausa

Acompanhamos 62 mulheres pós-menopausadas, previamente sintomáticas, mensalmente, durante 3 meses após início de terapia de reposição estrogênica (TRE) com 17-beta estradiol em gel percutâneo, na dose de 0,75 a 3,0 mg/dia (meia a duas réguas). Nas com útero, associou-se progesterone natural micronizada, 100 a 200 mg/dia cíclica ou contínua, ou acetato de medroxiprogesterona, 5 mg/dia cíclico. Durante tratamento, todas as pacientes com fogachos ou secura vaginal apresentaram níveis de E2 sérico <53 pg/ml; todas as com mastalgia, edema ou desconforto em membros inferiores apresentaram valores >193 pg/ml. Os sintomas correlacionaram-se significantemente com as dosagens plamáticas de estradiol (p=0,0001) e FSH (p=0,001) mas não de LH. As pacientes assintomáticas mostraram dosagens muito variáveis, com sobreposição de valores em relação aos grupos com hipo e hiperestrogenismo clínico; tal fato demonstra a necessidade da verificação laboratorial de suplementação estrogênica adequada em pacientes assintomáticas durante TRE. Em um subgrupo de 22 mulheres, analisaram-se também variações da relação cintura-quadril (RCQ) e do índice de massa corporal (IMC) a cada mês, correlacionando-as ao estado clínico e laboratorial das pacientes. A RCQ caiu significativamente já no primeiro mês de TRE (p=0,0008); houve flutuação no segundo mês e estabilização no terceiro. Sua variação não foi capaz de indicar o estado clínico da paciente. O IMC não variou significativamente no período.

Absorption and bioavailability of oestradiol from a gel, a patch and a tablet

OBJECTIVES

To compare oestradiol and oestrone concentrations and bioavailability after a single dose and at a steady state during oral oestradiol valerate, transdermal oestradiol gel and transdermal oestradiol patch treatments.

METHODS

Two open, randomised, cross-over studies were conducted. In the first study, 12 healthy postmenopausal women received 1.5 mg oestradiol as a transdermal gel or a 2 mg oestradiol valerate tablet daily for 14 days. In the second study, 15 postmenopausal women were treated for 18 days with 1.5 mg oestradiol gel or a transdermal patch releasing oestradiol 50 microg/24 h (replaced every 72 h). Venous blood samples for serum oestradiol and oestrone measurements with RIA were taken until 24 or 72 h after the first and last doses.

RESULTS

The tablet and the transdermal gel yielded similar serum oestradiol profiles with a peak concentration 4-5 h after administration. The patch resulted in relatively stable oestradiol levels during the mid third of the wearing time whereas much lower levels were observed in the beginning and towards the end. There was no difference in the fluctuation between the peak and trough oestradiol levels between the gel (56 or 67%) and the tablet (54%) while the fluctuation was greater with the patch (89%). The bioavailability of oestradiol from the gel was 61% as compared with the tablet and 109% as compared with the patch. The gel was not bioequivalent with the tablet or the patch.

CONCLUSIONS

The doses used of the transdermal gel and the patch roughly corresponded to each other with regard to the amount of oestradiol absorbed whereas the bioavailability from the tablet was significantly higher than from the gel. The lack of bioequivalence, the different serum oestradiol profiles and the large intersubject variability suggest that individual dose adjustments may be needed when changing administration form.

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.