Tamoxifen is a drug that blocks the action of the hormone estrogen.
It is used in the treatment of breast cancer in women. Take it exactly as prescribed. Do not stop taking this medication, even if you feel nauseated or experience vomiting. If you vomit shortly after a dose, or if you miss a dose, contact your doctor. Nausea, vomiting, hot flashes, weight gain, headache, menstrual changes, genital itching, rash or dry skin are common side effects.