Estriol (Oral)

Estriol induces the normalization of the vaginal epithelium and thus helps to restore the normal microflora and the physiological pH in the vagina. As a result, it increases the resistance of the vaginal epithelial cells to infection and inflammation. In comparison to other estrogens, estriol is short acting. In the years just before and after the menopause (which can be natural or surgically induced) estriol can be used in the treatment of symptoms and complaints related to estrogen deficiency. Estriol is particularly used in the treatment of urogenital symptoms.

After oral administration, estriol is rapidly and almost completely absorbed from the gastrointestinal tract. Peak plasma levels of unconjugated estriol are reached within 1 hr of administration. Nearly all (90%) estriol is bound to albumin in the plasma and unlike other estrogens; estriol is hardly bound to sex hormone-binding globulin. The metabolism of estriol consists mainly of conjugation and deconjugation during enterohepatic circulation. Estriol, a metabolic end product, is mainly excreted via the urine in the conjugated form. Only a small fraction is excreted via the feces, mainly as unconjugated estriol.

It is important that the total daily dose is taken at one time. It may be taken with or without food.

• Atropy of the lower urogenital tract: 4-8 mg/day for the first weeks, followed by a gradual reduction, based on relief of symptoms, until a maintenance dosage (e.g. 1-2 mg/day) is reached.
• Pre and postoperative therapy in postmenopausal women undergoing vaginal surgery: 4-8 mg/day in the 2 weeks before surgery; 1-2 mg/day in the 2 weeks after surgery.
• Climacteric complaints such as hot flushes and night sweating: 4-8 mg/day during the first weeks, followed by a gradual reduction. For maintenance therapy the lowest effective dosage should be used.
• A diagnostic aid in case of a doubtful atrophic cervical smear: 2-4 mg/day for 7 days before taking the next smear.
• Infertility due to cervical hostility: In general 1-2 mg/day on days 6-15 of the menstrual cycle. However, for some patients dosages as low as 1 mg/day are sufficient, whereas others may need up to 8 mg/day. Therefore, the dosage should be increased each month until an optimal effect on the cervical mucus is obtained.

There are strong indications that estrogens, estriol included, can increase the pharmacologic effects of certain corticosteroids. If necessary, the dosage of the corticosteroid should be reduced. There are also some indications, mainly obtained with other estrogens or oral contraceptives, that concurrent use of estriol with activated charcoal, barbiturates, hydantoins and rifampicin may possibly decrease the effectiveness of estriol.

Contraindicated in pregnancy, known or suspected estrogen-dependent tumours, undiagnosed vaginal bleeding, untreated endometrial hyperplasia, known or suspected breast cancer.

Breast tension or pain, nausea, spotting, fluid retention and cervical hypersecretion may occasionally occur and be indicative of too high dosage. Headache, hypertension, leg cramps and vision disturbances are seldom observed. In general, most of these adverse reactions disappear after the 1 st week of treatment.

Breast enlargement, vaginal candidiasis, change in vaginal bleeding pattern, vomiting, stomach cramps, cholestatic jaundice, chloasma or melasma, erythema multiforme, erythema nodosum, hemorrhagic eruption, mental depression, chorea, increasing or decreasing body weight, edema, changes in libido.

Estriol is contraindicated during pregnancy. Use Estriol in breastfeeding women only if really needed, as estriol is excreted in the milk and it may decrease the quality and quantity of the milk production.

During prolonged treatment with estrogens, periodic medical examinations are advisable. With vaginal infections, a concomitant specific treatment is recommended. 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. Patients with any of the following conditions should be monitored: A history of latent or overt cardiac failure, fluid retention due to renal dysfunction, hypertension, epilepsy or migraine (or a history of these conditions), severe liver disorders, endometriosis, fibrocystic mastopathy, porphyria, hyperlipoproteinaemia, a history during pregnancy or previous use of steroids of severe pruritus, cholestatic jaundice or herpes gestationis. Estrogen is reported to increase the risk of endometrial carcinoma in postmenopausal women. Use with precaution in gallbladder disorders, hypercalcemia, additional progestin, hypercoagulability, urethral bleeding and mastodynia.

Drugs for Infertility, Drugs for menopausal symptoms: Hormone replacement therapy, Female Sex hormones

Symptoms that may occur in the case of an acute overdosage are nausea, vomiting and possibly withdrawal bleeding in females. No specific antidote is known. If necessary, a symptomatic treatment should be instituted.

Keep below 30°C temperature, away from light & moisture. Keep out of the reach of children.