What is esterified estrogens, and how does it work (mechanism of action)?
Esterified estrogens are a mixture of
several estrogens, a type of female hormone. Estrogens cause growth and
development of female sex organs and the maintenance of sex characteristics,
including growth of underarm and pubic hair and shaping of body contours and
skeleton. Estrogens also increase secretions from the cervix and promote growth
of the inner lining of the uterus (endometrium).
What brand names are available for esterified estrogens?
Estratab (Discontinued in the USA), Menest
Is esterified estrogens available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for esterified estrogens?
What are the side effects of esterified estrogens?
The most common endocrine side effects are
- bleeding or spotting,
- loss of periods, or
- excessively prolonged periods,
- breast pain,
- breast enlargement, and
- changes in sexuality (increase or decrease in libido).
Other important side effects include:
Melasma (tan or brown patches) may
develop on the forehead, cheeks, or temples. These may persist even after the
estrogen is stopped. Estrogens may cause an increase in the curvature of the
cornea, and, therefore, patients with contact lenses may develop intolerance to
What is the dosage for esterified estrogens?
The dose for menopause and related conditions is 0.3 to 1.25
mg daily for 3 weeks then 1 week off. Female hypogonadism is treated with 2.5 to
7.5 mg daily for 20 days then 10 days off. Breast cancer is treated with 10 mg
three times daily for at least 3 months and the dose for prostate cancer is 1.25
to 2.5 mg 3 times daily.
Which drugs or supplements interact with esterified estrogens?
Estrogens increase the
liver's ability to
manufacture proteins that are required for blood to clot. Therefore, patients
receiving warfarin (Coumadin), which reduces clotting ("thins" the blood) by
inhibiting the production of proteins required for clotting, should receive
clotting tests if an estrogen is added to their treatment. If blood clots too
easily, the dose of warfarin may need to be increased.
carbamazepine (Tegretol), griseofulvin, phenytoin (Dilantin) and primidone can
increase the elimination of estrogen by enhancing the liver's ability to
metabolize (destroy) it. Use of these drugs may result in a reduction of the
beneficial effects of estrogens. Conversely, drugs such as erythromycin,
ketoconazole (Nizoral), itraconazole (Sporanox), and ritonavir (Norvir) may
reduce the elimination of estrogens by the liver and lead to increased levels of
estrogens in the blood. Grapefruit juice also may increase levels of estrogen by
increasing the absorption of estrogens from the intestine. Increased levels of
estrogens in the blood may result in more estrogen-related side effects.
Is esterified estrogens safe to take if I’m pregnant or breastfeeding?
Estrogens should not be used
during pregnancy because of an
increased risk of fetal abnormalities.
Estrogens are secreted in milk and cause
unpredictable effects in the infant. Therefore, they generally should not be
used during breastfeeding.
What else should I know about esterified estrogens?
What preparations of esterified estrogens are available?
Tablets: 0.3, 0.625, 1.25, and 2.5 mg.
How should I keep esterified estrogens stored?
Tablets should be stored between 2 C (36 F) and 30 C (86 F).