Learn more about usage, cautions, and possible side effects.

Common uses
This medicine is an anti-estrogen used to treat or prevent breast cancer. It may also be used to treat other conditions as determined by your doctor.
 

Before using
WARNING: Tamoxifen rarely may cause serious (possibly fatal) side effects. These include cancer of the uterus (endometrial cancer and uterine sarcoma), as well as strokes and blood clots in the lung (pulmonary emboli). Tell your doctor immediately if you develop: abnormal vaginal bleeding, irregular or abnormal menstrual periods, groin pain or pressure, chest pain, trouble breathing, one-sided weakness. If you are taking this medicine for prevention of breast cancer (those with ductal carcinoma in situ-DCIS, or those at high risk for breast cancer) you should discuss with your doctor the risks of treatment as compared to the benefits. However, if you are taking tamoxifen for treatment of breast cancer, the proven benefits clearly are greater than the risk of side effects. Consult your doctor or pharmacist for more details. Some medicines or medical conditions may interact with this medicine. INFORM YOUR DOCTOR OR PHARMACIST of all prescription and over-the-counter medicine that you are taking. DO NOT TAKE THIS MEDICINE if you are also taking letrozole. ADDITIONAL MONITORING OF YOUR DOSE OR CONDITION may be needed if you are taking fluorouracil, mitomycin or rifampin. Inform your doctor of any other medical conditions, allergies, pregnancy, or breast-feeding. Contact your doctor or pharmacist if you have any questions or concerns about taking this medicine.
 

Directions
Follow the directions for using this medicine provided by your doctor. This medicine may come with a patient information leaflet. Ask your doctor, nurse, or pharmacist any questions that you may have about this medicine. THIS MEDICINE MAY BE TAKEN on an empty stomach or with food. STORE THIS MEDICINE at room temperature in a tightly-closed container, away from heat and light. IF YOU MISS A DOSE OF THIS MEDICINE, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.
 

Cautions
A BARRIER OR NON-HORMONAL FORM OF BIRTH CONTROL is recommended for pre-menopausal women while taking this medicine. KEEP ALL DOCTOR AND LABORATORY APPOINTMENTS (e.g., yearly pelvic/gynecology exams) while you are using this medicine. THIS MEDICINE HAS BEEN SHOWN TO CAUSE HARM to the human fetus. IF YOU PLAN ON BECOMING PREGNANT, discuss with your doctor the benefits and risks of using this medicine during pregnancy. IT IS UNKNOWN IF THIS DRUG IS EXCRETED in breast milk. DO NOT BREAST-FEED while taking this medicine.
 

Possible side effects
SIDE EFFECTS, that may go away during treatment, include hot flashes, vaginal discharge, irregular or lighter menstrual cycles, weight loss, or diarrhea. If they continue or are bothersome, check with your doctor. CHECK WITH YOUR DOCTOR AS SOON AS POSSIBLE if you experience vaginal bleeding, unexplained sore throat or fever, or unusual bleeding or bruising. If you notice other effects not listed above, contact your doctor, nurse, or pharmacist.
 

Drug interactions
Drug interactions can result in unwanted side effects or prevent a medicine from doing its job. Use our drug interaction checker to find out if your medicines interact with each other. Check drug interactions
 

If you take too much
If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include shakiness, dizziness, and irregular heartbeat.
 

Additional information
DO NOT SHARE THIS MEDICINE with others for whom it was not prescribed. DO NOT USE THIS MEDICINE for other health conditions. KEEP THIS MEDICINE out of the reach of children. IF USING THIS MEDICINE FOR AN EXTENDED PERIOD OF TIME, obtain refills before your supply runs out.