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 or balance;
signs of a blood clot in the lung - chest pain, sudden cough, wheezing, rapid breathing, coughing up blood; or
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 lights;
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); or
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;
flushing;
nausea/vomiting;
vaginal discharge; or
weight loss.
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.
 Tamoxifen side effects (more detail)
