Tamoxifen Dosage

by on June 3, 2012

Tamoxifen acts as an antiestrogen and blocks action of estrogen. As cancer cells require estrogen in order to grow, this drug is beneficial in treatment of breast cancer. Starting dosages in breast cancer treatment is around 20mg/day. However, it may range from 20 to 40 mg/day. Dosage mainly depends on severity and stage of breast cancer. You should never change the dose unless you healthcare provider tell you to do so.

Tamoxifen dose may vary depending on factors listed below:

  1. Severity of breast cancer.
  2. If the drug is used in treatment of cancer or to prevent cancer.
  3. Other drugs taken during treatment.
  4. Medical abnormalities you already have.

Dosage for Breast Cancer Treatment

Adult Dose for Breast Cancer

  • For the treatment of breast cancer the recommended dose is 20 to 40mg daily. Dosage larger than 20mg should be taken by splitting it into two smaller doses.
  • For the treatment of Ductal Carcinoma in Situ, usually following the breast surgery and radiation the prescribed dosage is 20 mg orally daily for 5 years.
  • Dosage guidelines for women that are at high risk of developing breast cancer is 20 mg orally daily for 5 years.

Dose for Breast Cancer - Adjuvant

In the treatment of breast cancer in postmenopausal women followed by total mastectomy or segmental mastectomy, breast irradiation, axillary dissection recommended dose is 10 mg orally 2 to 3 times a day for 5 years.

Dose for Breast Cancer-Palliative

  • 10 to 20 mg orally twice a day

 Dose for McCune-Albright Syndrome

  • For the treatment of McCune-Albright Syndrome and puberty in 2 to 10 years old girls the dosage is 20 mg once a day for up to 12 months.

General Considerations about Dosage

  1. Tamoxifen is available in tablet form and can be taken orally once or twice a day.
  2. The drug can be taken with or without food. If it causes gastric symptoms then try taking it with food.
  3. Try to stick the time each day you take medicine to maintain an even level in your blood.
  4. Take the medication as per directions given by your healthcare provider to work properly. It will stop working if you stop taking it.
  5. If you are confused with the dosage of Tamoxifen then talk to your doctor.


Keep Tamoxifen in the container with tight closing and out of reach of children. Always store at room temperature and away from heat. Discard any out dated medication.