Postmenopausal women who suffer from breast cancer that has spread to other parts of the body might take toremifene. This medication blocks the effects of estrogen in the body. This stops some tumors from growing that require estrogen in order to grow so that cancer can be controlled.
This medication can cause a potentially life-threatening irregular heartbeat. Call your doctor if you experience a pounding heartbeat, lightheadness, fainting or seizures. Patients who have had heart disease or heart failure are at greater risk for this serious side effect, as are patients who have a history of low potassium or magnesium levels.