Tamoxifen

Common use

Tamoxifen blocks the actions of estrogen, a female hormone. Certain types of breast cancer require estrogen to grow. Tamoxifen is used to treat some types of breast cancer in men and women. Tamoxifen is also used to lower a woman's chance of developing breast cancer if she has a high risk (such as a family history of breast cancer).

Dosage and direction

Take tamoxifen exactly as prescribed by your doctor. Take with or without food. You may need to keep using this medicine for 5 to 10 years.

Precautions

To make sure tamoxifen is safe for you, tell your doctor if you have: a stroke or blood clot; liver disease; high cholesterol or triglycerides (a type of fat in the blood); cataracts; chemotherapy; or if you also use anastrozole or letrozole.
Taking tamoxifen may increase your risk of uterine cancer, liver cancer, stroke, or a blood clot in the lung. Talk with your doctor about your own risks.

Contraindications

You should not use tamoxifen if you are allergic to it.
Tamoxifen may harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant. Tell your doctor if you become pregnant.
Do not breastfeed while using tamoxifen, and for at least 3 months after your last dose.
This medicine is not approved for use by anyone younger than 18 years old.
To make 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.

Possible side effect

Get emergency medical help if you have signs of an allergic reaction to tamoxifen: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Tamoxifen can increase your risk of stroke or blood clots. Call your doctor at once if you have: signs of a stroke - sudden numbness or weakness, severe headache, slurred speech, problems with vision or balance; signs of a blood clot in the lung - chest pain, sudden cough or shortness of breath, dizziness, coughing up blood; or signs of a blood clot deep in the body - pain, swelling, or warmth in one leg.
Common tamoxifen side effects may include: vaginal bleeding or discharge; hot flashes; swelling, weight gain; nausea; or mood changes.

Drug interaction

You should not use tamoxifen to reduce your risk of breast cancer if you also take warfarin (Coumadin, Jantoven).

Missed dose

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Overdose

Seek emergency medical attention.

Storage

Store at room temperature away from moisture, heat, and light. Do not refrigerate or freeze. Keep away from children and pets.