Premarin side effects

List of side effects
Coronary heart disease and stroke Venous thromboembolism (VTE) Breast cancer Endometrial cancer Gallbladder Disease Hypercalcemia Visual Abnormalities

Coronary heart disease and stroke
In the Premarin substudy of the Women’s Health Initiative study (WHI), an increased risk of coronary heart disease (CHD) events (defined as non-fatal myocardial infarction and CHD death) was observed in women receiving Premarin compared to women receiving placebo (37 vs 30 per 10,000 person-years). The increase in risk was observed in year one and persisted. Return to top

Venous thromboembolism (VTE)
In the Premarin substudy of WHI, a 2-fold greater rate of VTE, including deep venous thrombosis and pulmonary embolism, was observed in women receiving Premarin compared to women receiving placebo. The rate of VTE was 34 per 10,000 woman-years in the Premarin group compared to 16 per 10,000 woman-years in the placebo group. The increase in VTE risk was observed during the first year and persisted. Return to top

Breast cancer
Estrogen/progestin therapy in postmenopausal women has been associated with an increased risk of breast cancer. In the PREMPRO substudy of the Women’s Health Initiative study, a 26% increase of invasive breast cancer (38 vs 30 per 10,000 woman-years) after an average of 5.2 years of treatment was observed in women receiving Premarin compared to women receiving placebo. The increased risk of breast cancer became apparent after 4 years on Premarin. The women reporting prior postmenopausal use of estrogen and/or estrogen with progestin had a higher relative risk for breast cancer associated with Premarin than those who had never used these hormones. Return to top

Endometrial cancer
The reported endometrial cancer risk among unopposed estrogen users is about 2- to 12-fold greater than in nonusers, and appears dependent on duration of treatment and on estrogen dose. Most studies show no significant increased risk associated with the use of estrogens for less than one year. The greatest risk appears associated with prolonged use, with increased risks of 15- to 24-fold for five to ten years or more, and this risk has been shown to persist for at least 8 to 15 years after estrogen therapy is discontinued. Return to top

Gallbladder Disease
A 2- to 4-fold increase in the risk of gallbladder disease requiring surgery in postmenopausal women receiving estrogens has been reported. Return to top

Hypercalcemia
Estrogen administration may lead to severe hypercalcemia in patients with breast cancer and bone metastases. If hypercalcemia occurs, use of the drug should be stopped and appropriate measures taken to reduce the serum calcium level.Return to top

Visual Abnormalities
Retinal vascular thrombosis has been reported in patients receiving estrogens. Discontinue medication pending examination if there is sudden partial or complete loss of vision, or a sudden onset of proptosis, diplopia, or migraine. If examination reveals papilledema or retinal vascular lesions, estrogens should be discontinued. Return to top