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. It 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).
should I take tamoxifen?
Follow all directions on your prescription
label. Do not take this medicine in larger or smaller amounts or for longer
Measure liquid medicine with the dosing
syringe provided, or with a special dose-measuring spoon or medicine cup. If
you do not have a dose-measuring device, ask your pharmacist for one.
Tamoxifen can be taken with or without
While using tamoxifen, you may need
frequent blood tests.
If you need surgery or medical tests or if
you will be on bed rest, you may need to stop using this medicine for a short
time. Any doctor or surgeon who treats you should know that you are taking
Have regular physical exams and mammograms,
and self-examine your breasts for lumps on a monthly basis while using this
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 this medication for up to 5 years.
Store at room temperature away from
moisture, heat, or cold. Do not freeze.
You should not use tamoxifen if you are
allergic to it.
You should not use tamoxifen to reduce your
risk of breast cancer if you are also taking a blood thinner such as warfarin
Do not take tamoxifen if you are pregnant.
It could harm the unborn baby. Avoid becoming pregnant while you are using this
medicine, and for at least 2 months after your treatment ends.
Hormonal contraception (such as birth
control pills, injections, implants, skin patches, and vaginal rings) may not
be effective enough to prevent pregnancy while taking tamoxifen. Use barrier or
non-hormonal birth control (examples: condom, diaphragm with spermicide, or
If 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 tamoxifen, to make sure you are not pregnant. Follow your
Taking 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 this medicine.
To make sure tamoxifen is safe for you,
tell your doctor if you have:
- a history of stroke or blood clot;
- liver disease;
- high cholesterol or triglycerides (a type of fat in the blood);
- a history of cataracts;
- if you are receiving chemotherapy or radiation.
It is not known whether tamoxifen passes
into breast milk or if it could harm a nursing baby. This medicine has been
shown to slow breast milk production. Do not breast-feed while taking
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 (especially on one
side of the body), sudden severe headache, slurred speech, problems with vision
- signs of a blood clot in the lung – chest pain, sudden cough,
wheezing, rapid breathing, coughing up blood;
- signs of a blood clot in your leg – pain, swelling, warmth, or
redness in one or both legs.
Also call your doctor at once if you have:
- blurred vision, tunnel vision, eye pain, or seeing halos around
- unusual vaginal bleeding or discharge;
- 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);
- high levels of calcium in your blood – vomiting, constipation,
increased thirst or urination, muscle weakness, bone pain, confusion, lack of
energy, or tired feeling.
Common tamoxifen side effects may include:
- hot flashes;
- menstrual changes;
- vaginal discharge;
- weight loss.
Always consult your healthcare provider to
ensure the information displayed on this page applies to your personal