Precautions

Before taking tamoxifen,

* tell your doctor and pharmacist if you are allergic to tamoxifen or any other drugs.
* tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking. Be sure to mention any of the following: aminoglutethimide (Cytadren); anticoagulants ('blood thinners') such as warfarin (Coumadin); bromocriptine (Parlodel); cancer chemotherapy drugs; letrozole (Aromasin); phenobarbital (Luminal, Solfoton); and rifampin (Rifadin, Rimactane). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
* in addition to the conditions listed in the IMPORTANT WARNING section, tell your doctor if you have or have ever had liver disease or high blood levels of cholesterol.
* tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. You should not plan to have children while taking tamoxifen or for 2 months after treatments. (Talk to your doctor for further details.) Use a reliable nonhormonal method of birth control to prevent pregnancy. Tamoxifen may harm the fetus.

Side effects

Tamoxifen may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

* increased bone or tumor pain
* hot flashes
* upset stomach
* swelling of the hands, feet, ankles, or lower legs
* vaginal discharge
* excessive tiredness
* dizziness
* depression
* headache
* thinning of hair
* loss of appetite
* stomach cramps
* constipation
* loss of sexual desire or ability (in men)

Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them or those listed in the IMPORTANT WARNING section, call your doctor immediately:

* persistent pain or reddening around the tumor site
* vision problems
* pain or swelling of the legs
* shortness of breath

Tamoxifen may cause other side effects. Call your doctor if you have any unusual problems while taking this drug.

Special instructions

* Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to tamoxifen. You should visit your gynecologist regularly. Follow your doctor's directions for examining your breasts; report any lumps immediately.
* Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking tamoxifen.

About your treatment Your doctor has ordered the drug tamoxifen to help treat your illness. Tamoxifen comes as tablet to take by mouth. This medication is used to: * treat breast cancer * reduce the risk of breast cancer in women at high risk for the disease Tamoxifen is in a class of drugs known as antiestrogens; it blocks the activity of estrogen, a female hormone produced by the body in the breast. The length of treatment depends on the types of drugs you are taking, how well your body responds to them, and the type of cancer you have. Other uses for this medicine Tamoxifen is also used sometimes to induce ovulation (egg production) in women who do not produce ova (eggs) but wish to become pregnant, to treat breast pain, and to decrease the size and pain of gynecomastia (swelling and tenderness of the breast). Tamoxifen may be useful in in treating carcinoid tumors. Talk to your doctor about the possible risks of using this drug for your condition. This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.