Premarin is a mixture of over ten different estrogens -- including estrone (which we make in our own bodies), and equilin and equilenin (horse estrogen -- which, of course, we don’t make in our own bodies). In fact, the name Premarin comes from "pregnant mare’s urine". . . which is its source. Because it comes from horse urine, the pharmaceutical company that makes Premarin (Wyeth-Ayerst Laboratories) considers it a natural estrogen. They are technically right; after all, horse urine is definitely natural! But by most standard definitions of natural as it applies to HRT, Premarin isn’t considered one of the naturals" since isn’t identical to the estrogen we produce in our own bodies.

When you take conjugated estrogens, your body converts them into active estrogens -- and uses them as it would estrogen your ovaries have produced. About 10 to 15% of the estrogens, however, can’t be used.

Some people have a bias against Premarin because of its source, but, in all fairness, because conjugated estrogen is similar to our own estrogen, Premarin has been shown to eliminate the symptoms of menopause, to prevent bone loss and appears to protect against cardiovascular disease.

Standard dosage: .625 mg -- this is the amount most studied and usually has been shown to be the lowest amount required to protect against osteoporosis and heart disease, although recent studies also indicated that .3 milligram will also eliminate symptoms and prevent osteoporosis. The lower dosages’ effect on heart disease isn’t known yet.

Premarin® (conjugated estrogens tablets, USP) is indicated for the prevention and management of osteoporosis, and for the treatment of moderate to severe vasomotor symptoms and vaginal dryness associated with menopause.

There can be side effects with Premarin. One is the possibility of developing cancer of the uterus. Your doctor or other health care provider may prescribe a progestin along with Premarin to reduce this risk. If you have had a hysterectomy, you do not have this risk. Side effects of Premarin include blood clots, nausea, vomiting, and breast tenderness.

Premarin may not be right for every woman.

When you discuss taking Premarin with your doctor or other health care provider, be sure to discuss your personal and family medical history, including any breast cancer, uterine cancer, abnormal vaginal bleeding, or abnormal blood clotting. You should not take Premarin if you have had any of these conditions. Pregnant women should not take Premarin because of possible risk to the fetus.