Source: Medicines & Healthcare Products Regulatory Agency (GB) Revision Year: 2020 Publisher: Gedeon Richter Plc., Gyรถmrลi รบt 19-21., 1103 Budapest, Hungary
Pharmacotherapeutic group: Natural and semisynthetic oestrogens, plain
ATC code: G03CA03
The active ingredient, synthetic 17-beta-estradiol, is chemically and biologically identical to endogenous human estradiol.
Endogenous 17-beta-estradiol induces and maintains the primary and secondary female sexual characteristics. The biological effect of 17-beta-estradiol is carried out through a number of specific oestrogen receptors. The steroid receptor complex is bound to the cells' DNA and induces synthesis of specific proteins.
Maturation of the vaginal epithelium is dependent upon oestrogens. Oestrogens increase the number of superficial and intermediate cells and decrease the number of basal cells in vaginal smear.
Oestrogens maintain vaginal pH around normal range (4.5) which enhances normal bacterial flora.
Treatment of vaginal oestrogen deficiency symptoms: vaginally applied oestrogen alleviates the symptoms of vaginal atrophy due to oestrogen deficiency in postmenopausal women.
A 12-months, double-blind, randomised, parallel group, placebo-controlled, multicentre study was conducted to evaluate the efficacy and safety of estradiol 10 micrograms vaginal tablets in the treatment of postmenopausal vaginal atrophy symptoms.
After 12 weeks of treatment with estradiol 10 micrograms vaginal tablets, the change from baseline, in comparison with placebo treatment, demonstrated significant improvements in the three primary endpoints: Vaginal Maturation Index and Value, normalisation of vaginal pH and relief of the moderate/severe urogenital symptoms considered most bothersome by the subjects.
Endometrial safety of estradiol 10 micrograms vaginal tablets was evaluated in the above mentioned trial and a second, open-label, multicentre trial. In total, 386 women underwent endometrial biopsy at the beginning and at the end of 52 weeks treatment. Incidence rate of hyperplasia and/or carcinoma was 0.52% (95% CI 0.06%, 1.86%), indicating no increased risk.
A 6 week placebo-controlled trial with estradiol 10 micrograms vaginal tablets confirmed significant improvements in Vaginal Maturation Value and normalisation of pH value.
Oestrogens are well absorbed through the skin, mucous membranes and the gastrointestinal tract. After vaginal administration, estradiol is absorbed circumventing first-pass metabolism.
A 12-weeks, single-centre, randomised, open-label, multiple dose, parallel-group trial was conducted to evaluate the extent of systemic absorption of estradiol from a 10 micrograms vaginal tablet. Subjects were randomised 1:1 to receive either 10 micrograms or 25 micrograms estradiol vaginal tablet. Plasma levels of estradiol (E2), oestrone (E1) and oestrone sulfate (E1S) were determined. The AUC(0-24) for plasma E2 levels increased almost proportionally after the administration of 10 micrograms and 25 micrograms estradiol vaginal tablet. The AUC(0-24) indicated higher systemic estradiol levels for the 10 micrograms E2 tablet as compared to baseline on treatment days 1, 14 and 83, being statistically significant at days 1 and 14 (Table 1). However, average plasma E2 concentrations (Cave(0-24)) at all evaluated days remained within the normal postmenopausal range in all subjects. The data from days 82 and 83 as compared to baseline indicate that there is no cumulative effect during twice-weekly maintenance therapy.
Table 1. Values of PK parameters from plasma Estradiol (E2) concentrations: estradiol 10 micrograms vaginal tablet:
| AUC(0-24) pg h/mL (geom. mean) | Cave(0-24) pg/mL (geom. mean) | |
|---|---|---|
| Day -1 | 75.65 | 3.15 |
| Day 1 | 225.35 | 9.39 |
| Day 14 | 157.47 | 6.56 |
| Day 82 | 44.95 | 1.87 |
| Day 83 | 111.41 | 4.64 |
The levels of oestrone and oestrone sulfate seen after 12 weeks of estradiol 10 micrograms vaginal tablet administration did not exceed baseline levels, i.e. no accumulation of oestrone or oestrone sulfate was observed.
A further 14 day pharmacokinetic study with Vagirux confirmed these results.
The distribution of exogenous oestrogens is similar to that of endogenous oestrogens. Oestrogens are widely distributed in the body and are generally found in higher concentrations in the sex hormone target organs. Oestrogens circulate in the blood largely bound to sex hormone binding globulin (SHBG) and albumin.
Exogenous oestrogens are metabolized in the same manner as endogenous oestrogens. The metabolic transformations take place mainly in the liver. Estradiol is converted reversibly to oestrone and both can be converted to oestriol which is the major urinary metabolite. In postmenopausal women, a significant portion of the circulating oestrogens exists as sulfate conjugates, especially oestrone sulfate, which serves as a circulating reservoir for the formation of more active oestrogens.
Estradiol, oestrone and oestriol are excreted in the urine along with glucuronide and sulfate conjugates.
The extent of systemic absorption of estradiol during treatment with estradiol 10 micrograms vaginal tablets has been evaluated in postmenopausal women aged 49-78 only.
17-beta-estradiol is a well-known substance. Non-clinical studies provided no additional data of relevance to clinical safety beyond those already included in other sections of the SmPC.
ยฉ All content on this website, including data entry, data processing, decision support tools, "RxReasoner" logo and graphics, is the intellectual property of RxReasoner and is protected by copyright laws. Unauthorized reproduction or distribution of any part of this content without explicit written permission from RxReasoner is strictly prohibited. Any third-party content used on this site is acknowledged and utilized under fair use principles.
