Estriol
Indications
Estriol is used for:
Infertility due to cervical hostility, Menopausal atrophic vaginitis, Menopausal hormone replacement therapy, Dyspareunia, Dryness and itching of vagina due to Oestrogen deficiency, Prevention of recurrent infections of the vagina and lower urinary tract, Micturition complaints (such as frequency and dysuria), Urinary incontinence.
Pre- and postoperative therapy in postmenopausal women undergoing vaginal surgery, Climacteric complaints such as hot flushes and night sweating, a diagnostic aid in case of a doubtful atrophic cervical smear.
Adult Dose
Oral
Menopausal hormone replacement therapy
Adult: 0.5-3 mg daily for 1 mth followed by 0.5-1 mg daily; or 0.25-2 mg daily in combination with other natural oestrogens. A progestogen is required if administered to women with a uterus.
Infertility due to cervical hostility
Adult: 0.25-1 mg/day on days 6-15 of the menstrual cycle. Increase dose each mth until an optimal effect is obtained.
Vaginal
Menopausal atrophic vaginitis
Adult: As cream: Apply 500 mcg once daily, reduce to twice wkly subsequently.
Child Dose
Renal Dose
Administration
Tablet: May be taken with or without food.
Contra Indications
• Pregnancy • Known, past or suspected breast cancer • Known or suspected oestrogen-dependent malignant tumours (e.g. endometrial cancer) • Undiagnosed genital bleeding • Untreated endometrial hyperplasia • Previous idiopathic or current venous thromboembolism (deep venous thrombosis, pulmonary embolism) • Active or recent arterial thromboembolic disease (e.g. angina, myocardial infarction) • Acute liver disease, or a history of liver disease as long as liver function tests failed to return to normal
Precautions
In order to prevent endometrial stimulation, the daily dose should not exceed 8 mg nor should this maximum dose be used for longer than several weeks. As for all hormone replacement therapies, yearly medical examination is advisable. With vaginal infections, a concomitant specific treatment is recommended. Patients with any of the following conditions should be monitored; thrombosis, severe liver disorders; porphyria; a history during pregnancy or previous use of steroids of severe pruritus, cholestatic jaundice, herpes gestationis, or otosclerosis.
Pregnancy-Lactation
Interactions
Reduced efficacy may occur when used with activated charcoal, barbiturates, carbamazepine, griseofulvin, hydantoin and rifampicin. May possibly change efficacy of oral anticoagulants and increase pharmacologic effects of succinylcholine, theophyllines and troleandromycin.
Adverse Effects
Side effects of Estriol :
Breast tension or pain, nausea, spotting. Fluid retention, cervical hypersecretion.
Mechanism of Action
Estriol is a naturally occurring oestrogen. It induces normalization of vag epithelium. It is claimed to have only a mild proliferative effect on the endometrium. It only has a short retention time in the nuclei of endometrial cells.