Estrace

Estrogens occur in nature in several forms. In women with active menstrual cycles, the ovaries produce between 70 and 500 micrograms of estradiol daily. This is converted to estrone and to a lesser extent estriol. After menopause, estrone is the most active circulating estrogen. (After menopause estrone is made in the adrenal glands.) Estrogens cause growth and development of female sex organs and maintain sex characteristics, including underarm and pubic hair and the shape of body contours and skeleton. Estrogens also increase secretions from the cervix and growth of the inner lining of the uterus (endometrium). Estrogens reduce LDL-cholesterol ("bad" cholesterol) and increase HDL-cholesterol ("good" cholesterol) concentrations in the blood. Estrogens, when taken alone or in combination with a progestin, have been shown to reduce the risk for hip fracture due to osteoporosis by 25%.

Estradiol tablets are generally prescribed once daily. In some patients, a so-called cyclic regimen is used, wherein estradiol is given daily for 23 consecutive days, followed by 5 days of no medication, after which the cycle resumes.

The adhesive part of the patch should be applied to a dry, hairless, clean part of the trunk, but not on the breasts. It should not be placed onto irritated or damaged skin. Sites of application should be rotated, with at least one week between repeated applications to any one site. The patch should be applied immediately after removing the protective layer, and pressure should be applied to the patch when it is attached for about 10 seconds.

Among the most common endocrine side effects are break-through bleeding or spotting, loss of periods or excessively prolonged periods, breast pain, breast enlargement, and changes in sexuality (increase or decrease in libido). Abdominal pain may indicate the development of gallstones or occasionally hepatitis. Migraine headaches have been associated with estrogen therapy. Estrogens can cause sodium and fluid retention. Melasma, tan or brown patches, may develop on the forehead, cheeks, or temples. These may persist even after the estrogen is stopped. Conjugated estrogens may cause an increase in the curvature of the cornea. Patients with contact lenses may develop intolerance to their lenses.

Blood clots are an occasional but serious adverse effect and are dose-related. (The higher the dose, the more likely the clots.) Cigarette smokers are at a higher risk for clots, and, therefore, patients requiring estrogen therapy are strongly encouraged to quit smoking.

Estrogens can promote a buildup of the uterine lining (endometrial hyperplasia) and increase the risk of endometrial carcinoma. At diagnosis, endometrial cancers in estrogen recipients are generally of an earlier stage and a lower grade. Survival is also is better in women exposed to estrogens than in those not exposed to estrogens. The addition of a progestin to estrogen therapy prevents endometrial carcinoma.

Conflicting data exists on the association between estrogens and breast cancer. There may be a small increase in risk. The effect of concomitant progestin therapy on the risk of estrogen-induced breast carcinoma is unclear.

Estrogens can inhibit the metabolism of cyclosporine, resulting in increased cyclosporine blood levels. Such increased blood levels can result in kidney and/or liver damage. If this combination cannot be avoided, cyclosporine concentrations can be monitored, and the dose of cyclosporine can be adjusted to assure that its blood levels are not elevated.

Estrogens appear to increase the risk of liver disease in patients receiving dantrolene through an unknown mechanism. Women over 35 years of age and those with a history of liver disease are especially at risk.

Estrogens increase the liver's ability to manufacture clotting factors. Because of this, patients receiving warfarin (Coumadin) need to be monitored for loss of anticoagulant (blood thinning) effect if an estrogen is added when warfarin is already being taken.

Rifampin, barbiturates, carbamazepine (Tegretol), griseofulvin, phenytoin (Dilantin) and primidone, can all increase the elimination of estrogen by enhancing the liver's ability to metabolize it. Concurrent use may result in reduction of the beneficial effects of estrogens.

Estradiol is prescribed for symptomatic treatment of the usual symptoms associated with menopause (hot flashes, vaginal dryness, etc.), prevention of bone fractures associated with osteoporosis, reduction of the risk of heart attacks and strokes, and dysfunctional (excessive and painful) uterine bleeding. The vaginal cream is prescribed for vaginal or vulvar atrophy associated with menopause.

All forms should be stored between 15° (59°F) and 30°C (86°F).