Tamoxifen blocks the actions of estrogen, a female hormone. Certain types of breast cancer require estrogen to grow. Tamoxifen works by blocking the effect of estrogen on certain tumors. This may prevent the growth of tumors that are activated by estrogen.rnTamoxifen is used to treat and prevent some types of breast cancer. It is used in women who are at high risk for breast cancer and in women with DCIS (after surgery and radiation).rnTamoxifen may also be used for other purposes not listed in this medication guide.

The health and medical information provided here is for general purposes only and is not a substitute for the expertise and judgment of your physician, or other health care professional. It should not be understood to indicate that the use of this medicine is safe, appropriate or effective for you. Always consult your health care professional before using this, or any other, drug.

Do not use tamoxifen without telling your doctor if you are pregnant. It could cause harm to the unborn baby. Use an effective form of birth control, and tell your doctor if you become pregnant during treatment.rnBefore using tamoxifen, tell your doctor if you are allergic to any drugs, or if you have liver disease, high triglycerides (fatty acids) in your blood, a history of cataract, or a history of stroke or blood clot. Also tell your doctor if you if you are receiving chemotherapy or radiation treatment.rnIf you are taking tamoxifen to reduce your risk of breast cancer, you may need to take your first dose while you are having a menstrual period. You may also need to have a pregnancy test before you start taking this medicine, to make sure you are not pregnant. Follow your doctor`s instructions.rnTaking tamoxifen may increase your risk of uterine cancer, stroke, or a blood clot in the lung, which can be fatal. Talk with your doctor about your specific risks in taking tamoxifen.rnTo be sure this medication is not causing harmful effects, your doctor may want you to have mammograms and to perform routine breast self exams on a regular basis. Your liver function may also need to be tested. Do not miss any scheduled visits to your doctor.

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.rnStop using tamoxifen and call your doctor at once if you have any of these serious side effects:rnsudden numbness or weakness, especially on one side of the body;rnsudden headache, confusion, problems with vision, speech, or balance;rnchest pain, shortness of breath, or coughing up blood;rnpain or swelling in one or both legs;rnunusual vaginal bleeding or discharge;rnirregular menstrual periods;rnpain or pressure in your pelvic area;rnfever, chills, body aches, flu symptoms;rnpale skin, easy bruising or bleeding;rnnew breast lumps; orrnnausea, stomach pain, low fever, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes).rnLess serious tamoxifen side effects may include:rnhot flashes, warmth or tingly feeling under your skin;rnbone, joint, or tumor pain;rnredness or skin changes;rnswelling in your hands or feet;rnvaginal itching or dryness;rndepressed mood, weakness;rnweight loss;rnnausea;rncough, sore throat;rndecreased sex drive, impotence, or difficulty having an orgasm;rnheadache, dizziness; orrnthinning hair.

Take tamoxifen exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the directions on your prescription label.rnTake this medication with a full glass (8 ounces) of water.rnTamoxifen can be taken with or without food.rnIf you are taking tamoxifen to reduce your risk of breast cancer, you may need to take your first dose while you are having a menstrual period. You may also need to have a pregnancy test before you start taking this medicine, to make sure you are not pregnant. Follow your doctor`s instructions.rnIt is important to use tamoxifen regularly to get the most benefit. Get your prescription refilled before you run out of medicine completely. You may need to keep using tamoxifen for up to 5 years.rnTo be sure this medication is not causing harmful effects, your doctor may want you to have mammograms and to perform routine breast self exams on a regular basis. Your liver function may also need to be tested. Do not miss any scheduled visits to your doctor.rnStore tamoxifen at room temperature away from moisture and heat.