Toremifene

Toremifene may cause QT prolongation (an irregular heart rhythm that can lead to fainting, loss of consciousness, seizures, or sudden death). Tell your doctor if you or anyone in your family has or has ever had long QT syndrome (an inherited condition in which a person is more likely to have QT prolongation) or you have or have ever had low levels of potassium or magnesium in your blood, an irregular heartbeat, heart failure, or liver disease. Tell your doctor and pharmacist if you are taking amitriptyline (Elavil); antifungals such as ketoconazole (Nizoral), itraconazole (Sporanox), or voriconazole (Vfend); clarithromycin (Biaxin, in Prevpac); erythromycin (E.E.S., E-Mycin, Erythrocin); granisetron (Kytril); haloperidol (Haldol); certain medications for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS) such as atazanavir (Reyataz), indinavir (Crixivan), nelfinavir (Viracept), ritonavir (Norvir, in Kaletra), and saquinavir (Invirase); certain medications for irregular heartbeat such as amiodarone (Cordarone, Pacerone), disopyramide (Norpace), dofetilide (Tikosyn), ibutilide (Corvert), procainamide (Procanbid, Pronestyl), quinidine, and sotalol (Betapace, Betapace AF); levofloxacin (Levaquin); nefazodone; ofloxacin; ondansetron (Zofran); telithromycin (Ketek); thioridazine; and venlafaxine (Effexor). If you experience any of the following symptoms, stop taking toremifene and call your doctor immediately: fast, pounding, or irregular heartbeat; fainting; loss of consciousness; or seizures.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body’s response to toremifene. Your doctor also may order electrocardiograms (EKGs, tests that record the electrical activity of the heart) before and during your treatment to be sure that it is safe for you to take toremifene.

Talk to your doctor about the risks of taking toremifene.

🔔 Why is this medication prescribed?

Toremifene is used to treat breast cancer that has spread to other parts of the body in women who have experienced menopause (‘change of life’; end of monthly menstrual periods). Toremifene is in a class of medications called nonsteroidal antiestrogens. It works by blocking the activity of estrogen (a female hormone) in the breast. This may stop the growth of some breast tumors that need estrogen to grow.

🔔 How should this medicine be used?

Toremifene comes as a tablet to take by mouth. It is usually taken with or without food once a day. Take toremifene at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take toremifene exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

🔔 Other uses for this medicine

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.