Imvaggis (Estriol)

Estriol is used in hormone replacement therapy to address estrogen‑deficiency conditions affecting the urogenital tract, particularly in postmenopausal women.

• Vaginal atrophy: Improves thinning of the vaginal epithelium and reduces dryness.
• Menopausal symptoms related to estrogen deficiency: Alleviates burning, itching and discomfort during menopause.
• Urogenital symptoms in postmenopausal women: Restores lubrication and reduces urinary irritation.
• Genitourinary syndrome of menopause (GSM): Improves overall genital health and comfort.

• Estriol binds to estrogen receptors ERα and ERβ in vaginal and urinary tract tissues. This receptor activation modulates transcription of estrogen‑responsive genes, leading to increased synthesis of epithelial proteins, enhanced vascularization, and restoration of normal mucosal thickness. The selective activity of estriol provides estrogenic effects with a lower proliferative impact compared with stronger estrogens, consequently improving tissue elasticity and lubrication and alleviating atrophic symptoms.

Estriol administered vaginally may be associated with a range of adverse reactions, varying in frequency and severity.

Common Side Effects

• Vaginal irritation or burning: mild discomfort at the application site.
• Discharge or spotting: transient vaginal bleeding or increased secretions.
• Headache: mild to moderate headache episodes.
• Nausea: occasional feeling of nausea.

Serious or Rare Side Effects

• Endometrial hyperplasia: abnormal thickening of the uterine lining.
• Breast tenderness or enlargement: persistent swelling or pain.
• Thromboembolic events: rare clot formation in veins or arteries.
• Allergic reaction: rash, itching, swelling, or anaphylaxis.

When prescribing vaginal estriol, clinicians should consider several precautionary measures to ensure safe use.

• Indication verification: Confirm estrogen‑deficiency symptoms before initiating therapy.
• Duration of use: Limit continuous treatment to the shortest effective period, typically up to 12 weeks, unless reassessed.
• Concomitant estrogen therapy: Avoid using with other systemic estrogen products to prevent excess exposure.
• History of hormone‑sensitive cancers: Use with caution or avoid in patients with breast or endometrial cancer.
• Monitoring: Assess vaginal health and symptom relief regularly; discontinue if adverse effects arise.
• Store at ambient temperature: Keep the product below 25 °C in the original packaging, protected from moisture and direct sunlight.

Estriol may interact with other medicines, altering its efficacy or safety profile.

Major Interactions (Avoid)

• Anticoagulants (e.g., warfarin): Increased risk of bleeding.
• Hormonal contraceptives: Potential additive estrogen effects.
• Tamoxifen or aromatase inhibitors: May reduce therapeutic benefit.

Moderate Interactions (Monitor Closely)

• Antihypertensives: Estriol can affect blood pressure control.
• Thyroid hormone replacement: May require dose adjustment.
• Certain antifungal agents (e.g., ketoconazole): May influence estriol metabolism.