estrogens conjugated, Premarin (cont.)

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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.

PREGNANCY: Estrogens should not be given to pregnant women due to the risk of harm to the fetus.

NURSING MOTHERS: Estrogens are secreted in breast milk and may cause unpredictable effects in the infant. Estrogens may also reduce the quality of breast milk. They should not be taken by women who are breastfeeding.

SIDE EFFECTS: Common side effects of conjugated estrogens include headache, abdominal pain, nervousness, nausea, back pain, joint pain and vaginal bleeding. Patients also may experience vaginal spotting, loss of periods or excessively prolonged periods, breast pain, breast enlargement and an increase or decrease in sexual drive.

Effects of estrogen on the skin include rash, and melasma (tan or brown patches) that may develop on the forehead, cheeks, or temples and may persist even after estrogens are stopped.

In the eyes, conjugated estrogens may cause an increase in the curvature of the cornea, and, as a result, patients with contact lenses may develop intolerance to their lenses.

Estrogens may increase calcium levels in the blood (hypercalcemia) in patients with breast and bone cancer.

Some patients may experience increased blood pressure and triglyceride levels.

There is an increased risk of cholesterol gallstones among men and women taking estrogens.

Estrogens also may inhibit the flow of bile from the liver (cholestasis) and uncommonly cause jaundice.

Estrogens can cause salt (sodium) and water retention (edema). Therefore, patients with heart failure or reduced function of their kidneys who are taking estrogens should be carefully observed for retention of water and its complications.

Blood clots in the legs or lungs occasionally occur in women taking conjugated estrogens. This potentially serious complication of estrogen therapy is dose-related, that is, it occurs more commonly with higher doses. Therefore, the lowest effective doses that relieve symptoms should be used.

Cigarette smokers are at a higher risk for blood clots. Therefore, patients requiring estrogen therapy should quit smoking.

Estrogens can promote a build up of the lining of the uterus (endometrial hyperplasia) and increase the risk of endometrial cancer. (Women who have undergone surgical removal of the uterus--hysterectomy--are not susceptible to endometrial hyperplasia.) The addition of a progestin to estrogen therapy prevents the development of endometrial cancer.

The Women's Health Initiative found that postmenopausal women (50-79 years old) taking conjugated estrogens, 0.625 mg daily, in combination with medroxyprogesterone, 2.5 mg daily, for five years, had an increased risk of heart attacks, stroke, breast cancer, and blood clots, while postmenopausal women taking conjugated estrogens without progesterone experienced only increased strokes but not increased blood clots, heart disease, or breast cancer.

There was an increased risk of impaired cognition and/or dementia among women over age 65 treated with either estrogens or estrogens and medroxyprogesterone.

Reference: FDA Prescribing Information


Last Editorial Review: 2/2/2012



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