OVESTIN TABLETS

Indications

• Hormone replacement therapy in postmenopausal women
• Management of atrophic vaginitis
• Treatment of vulvar and vaginal atrophy
• Symptomatic relief in menopausal symptoms
• Monitoring fetal well-being during pregnancy

Dosage

Children: Oestriol is not typically indicated for paediatric use. For any paediatric dosing considerations, consult the BNF for Children.

Adults: The dosage of oestriol for adults should be determined based on the specific clinical situation and patient response. Refer to the BNF for specific dosing recommendations.

Mechanism of action

Oestriol exerts its effects by binding to estrogen receptors in target cells. Upon binding, the estrogen receptor-ligand complex translocates to the nucleus, where it regulates gene transcription leading to the production of messenger RNA. This mRNA then directs the synthesis of specific proteins, which mediate the physiological effects of oestriol. Additionally, oestriol increases the hepatic synthesis of sex hormone binding globulin (SHBG) and thyroid-binding globulin (TBG), while also suppressing follicle-stimulating hormone (FSH) levels from the anterior pituitary.

Pharmacodynamics

Oestriol is a weak estrogen that plays a significant role during pregnancy, where it is produced in substantial quantities. Its estrogenic activity helps in the maintenance of the female reproductive system and has been shown to alleviate symptoms of multiple sclerosis in pregnant women. It is particularly effective in treating atrophic changes in the vaginal epithelium due to estrogen deficiency.

Pharmacokinetics

Oestriol is absorbed after oral administration and undergoes hepatic metabolism. It has a relatively short half-life and is excreted primarily in urine as conjugated metabolites. Its pharmacokinetic profile allows for effective management in estrogen-deficient states, such as menopause.

Adverse effects

• Nausea
• Headache
• Breast tenderness
• Vaginal discharge
• Dizziness
• Mood changes

Interactions

• Anticoagulants may have altered effects
• Some anticonvulsants may affect estrogen levels
• Corticosteroids may have increased effects

Precautions

• Use cautiously in patients with a history of hormone-sensitive cancers
• Monitor for signs of thromboembolic events
• Assess liver function prior to therapy

Pregnancy

Estriol is produced in significant amounts during pregnancy, particularly by the placenta, and is used as an indicator of fetal health.

Breast-feeding

Estriol is generally considered safe during breastfeeding, but consultation with a healthcare provider is recommended.

Storage

Store at room temperature, away from moisture and heat.

Formulations

• Oral tablets
• Vaginal cream
• Intravaginal suppositories

Mechanism of action

Estriol levels can be measured to give an indication of the general health of the fetus. DHEA-S is produced by the adrenal cortex of the fetus. This is converted to estriol by the placenta. If levels of "unconjugated estriol" are abnormally low in a pregnant woman, this may indicate a problem with the development of the child. The drug interacts with a target cell receptor. When the estrogen receptor has bound its ligand it can enter the nucleus of the target cell, and regulate gene transcription which leads to formation of messenger RNA. The mRNA interacts with ribosomes to produce specific proteins that express the effect of estriol upon the target cell. Estrogens increase the hepatic synthesis of sex hormone binding globulin (SHBG), thyroid-binding globulin (TBG), and other serum proteins and suppress follicle-stimulating hormone (FSH) from the anterior pituitary. ... Synthetic estriol, is chemically and biologically identical to endogenous human estriol. Estriol, a weak estrogen, is a natural metabolite of estradiol, the predominant estrogen. Estriol exerts estrogenicity by binding to estrogen receptors, present in the female genital tract. Estriol, oral or vaginal, similar to estradiol, corrects lowered proliferation and abnormal physiology in the atrophic vaginal epithelium seen in estrogen deficient states, such as after natural or surgical menopause. In contrast, the histology of the endometrium after using Gynest Cream rarely shows minor signs of proliferation in previously atrophic endometria. Estrogens have an important role in the reproductive, skeletal, cardiovascular, and central nervous systems in women, and act principally by regulating gene expression. Biologic response is initiated when estrogen binds to a ligand-binding domain of the estrogen receptor resulting in a conformational change that leads to gene transcription through specific estrogen response elements (ERE) of target gene promoters; subsequent activation or repression of the target gene is mediated through 2 distinct transactivation domains (ie, AF-1 and AF-2) of the receptor. The estrogen receptor also mediates gene transcription using different response elements (ie, AP-1) and other signal pathways. Recent advances in the molecular pharmacology of estrogen and estrogen receptors have resulted in the development of selective estrogen receptor modulators (eg, clomiphene, raloxifene, tamoxifen, toremifene), agents that bind and activate the estrogen receptor but that exhibit tissue-specific effects distinct from estrogen. Tissue-specific estrogen-agonist or -antagonist activity of these drugs appears to be related to structural differences in their estrogen receptor complex (eg, specifically the surface topography of AF-2 for raloxifene) compared with the estrogen (estradiol)-estrogen receptor complex. A second estrogen receptor also has been identified, and existence of at least 2 estrogen receptors (ER-alpha, ER-beta) may contribute to the tissue-specific activity of selective modulators. While the role of the estrogen receptor in bone, cardiovascular tissue, and the CNS continues to be studied, emerging evidence indicates that the mechanism of action of estrogen receptors in these tissues differs from the manner in which estrogen receptors function in reproductive tissue. /Estrogen General Statement/ Intracellular cytosol-binding proteins for estrogens have been identified in estrogen-responsive tissues including the female genital organs, breasts, pituitary, and hypothalamus. The estrogen-binding protein complex (ie, cytosol-binding protein and estrogen) distributes into the cell nucleus where it stimulates DNA, RNA, and protein synthesis. The presence of these receptor proteins is responsible for the palliative response to estrogen therapy in women with metastatic carcinoma of the breast. /Estrogen General Statement/ Estrogens have generally favorable effects on blood cholesterol and phospholipid concentrations. Estrogens reduce LDL-cholester

Pharmacodynamics

Estriol (also oestriol) is one of the three main estrogens produced by the human body. It is only produced in significant amounts during pregnancy as it is made by the placenta. In pregnant women with multiple sclerosis (MS), estriol reduces the disease's symptoms noticeably, according to researchers at UCLA's Geffen Medical School.