What is the most important information I should know about tamoxifen?
Taking tamoxifen may increase your risk of uterine cancer, liver cancer, stroke, or a blood clot in the lung, which can be fatal.
What is tamoxifen?
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).
Tamoxifen may also be used for purposes not listed in this medication guide.
What should I discuss with my healthcare provider before taking tamoxifen?
You should not use tamoxifen if you are allergic to it.
May harm an unborn baby. You may need a pregnancy test to make sure you are not pregnant. Use birth control while using tamoxifen and for at least 2 months after your last dose. Tell your doctor if you become pregnant.
To prevent pregnancy while using tamoxifen, use a barrier form of birth control: condom, diaphragm, cervical cap, or contraceptive sponge. Avoid using hormonal birth control, including birth control pills, injections, implants, skin patches, and vaginal rings.
You should not use tamoxifen to reduce your risk of breast cancer if you also take warfarin (Coumadin, Jantoven).
Tell your doctor if you have ever had:
- a stroke or blood clot;
- liver disease;
- high cholesterol or triglycerides (a type of fat in the blood);
- 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, which can be fatal. Talk with your doctor about your own risks.
Do not breastfeed while using this medicine, and for at least 3 months after your last dose.
Not approved for use by anyone younger than 18 years old.
How should I take tamoxifen?
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
Measure liquid medicine with the supplied syringe or a dose-measuring device (not a kitchen spoon).
Take with or without food.
You may need to keep using this medicine for 5 to 10 years.
Have regular physical exams and mammograms, and self-examine your breasts for lumps on a monthly basis while using tamoxifen.
This medicine can affect the results of certain medical tests. Tell any doctor who treats you that you are using tamoxifen.
Store at room temperature away from moisture, heat, and light. Do not refrigerate or freeze. Throw away any leftover liquid medicine 3 months after you first opened the bottle.
What happens if I miss a 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.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking tamoxifen?
Follow your doctor's instructions about any restrictions on food, beverages, or activity.
What are the possible side effects of tamoxifen?
Get emergency medical help if you have signs of an allergic reaction: 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.
Also call your doctor at once if you have:
- unusual vaginal bleeding or discharge;
- blurred vision, eye pain or redness, seeing halos around lights;
- changes in your menstrual periods;
- pain or pressure in your pelvic area;
- a new breast lump;
liver problems --nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
high blood calcium --confusion, tiredness, nausea, vomiting, loss of appetite, constipation, increased thirst or urination, weight loss.
Common side effects may include:
- vaginal bleeding or discharge;
- hot flashes;
- swelling, weight gain;
- nausea; or
- mood changes.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
What other drugs will affect tamoxifen?
Many drugs can affect tamoxifen, and some drugs should not be used at the same time. Tell your doctor about all other medicines you use. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.
Where can I get more information?
Your doctor or pharmacist can provide more information about tamoxifen.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
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