About tamoxifen
Selective estrogen receptor modulator
Used for
- Treats hormone receptor-positive breast cancer.
- Reduces breast cancer risk in some people at high risk.
- Treats ductal carcinoma in situ after breast surgery.
Usual adult dose
Usually 20 mg by mouth once daily; some advanced cancers require 20–40 mg daily.
Common side effects
- Hot flashes and sweating
- Nausea or vaginal discharge
- Menstrual changes
- Fatigue or leg cramps
Important warnings
- Raises risk of blood clots, stroke, and uterine cancer.
- Seek urgent care for chest pain, sudden breathlessness, or one-sided leg swelling.
- Avoid during pregnancy; use effective contraception during treatment and for two months afterward.
- Liver problems and changes in vision can occur.
Pregnancy
Avoid; may harm an unborn baby. Effective contraception is needed during treatment and for two months afterward.
Breastfeeding
Breastfeeding is not recommended during treatment or for about three months after the last dose.
Interactions
- Warfarin and other blood thinners may increase bleeding risk.
- Paroxetine, fluoxetine, and other strong CYP2D6 inhibitors may reduce effectiveness.
- Rifampin and some other enzyme-inducing medicines can reduce tamoxifen levels.
- Other cancer treatments may increase blood-clot risk.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.