Clinical Overview

Tamoxifen citrate – Proven Efficacy and Established Safety Profile.

Over 40 years’ experience in the US (first approved in 1977 for metastatic breast cancer).

Adjuvant Treatment of Breast Cancer

In women with ER-positive or ER-unknown breast cancer:

  • With positive nodes who received about 5 years of treatment, overall survival at 10 years was 61.4% for tamoxifen vs. 50.5% for control (log-rank 2p <0.00001). The recurrence-free rate at 10 years was 59.7% for tamoxifen vs. 44.5% for control (log-rank 2p <0.00001).
  • With negative nodes who received about 5 years of treatment, overall survival at 10 years was 78.9% for tamoxifen vs. 73.3% for control (log-rank 2p <0.00001). The recurrence-free rate at 10 years was 79.2% for tamoxifen vs. 64.3% for control (log-rank 2p <0.00001).
  • Who received 1 year or less, 2 years, or about 5 years of tamoxifen, the proportional reductions in mortality were 12%, 17%, and 26%, respectively (2p <0.003). The corresponding reductions in breast cancer recurrence were 21%, 29%, and 47% (2p <0.00001).


Although results of the NSABP B-14 study suggest that continuation of therapy beyond five years does not provide additional benefit, a subsequent report of the ATLAS trial suggest that continuing tamoxifen to 10 years further reduced recurrence and mortality.

Ductal Carcinoma in Situ

The incidence of invasive breast cancer was reduced by 43% among women assigned to tamoxifen (44 cases on tamoxifen, 74 cases on placebo; p = 0.004; RR = 0.57, 95% CI: 0.39 to 0.84).

Reduction in Breast Cancer Incidence in Women at High Risk

After a median follow-up of 4.2 years, the incidence of invasive breast cancer was reduced by 44% among women assigned to tamoxifen (86 cases on tamoxifen, 156 cases on placebo; p <0.00001; RR = 0.56, 95% CI: 0.43 to 0.72).

Metastatic Breast Cancer

<h2>SOLTAMOX® Important Safety Information - WARNING: UTERINE MALIGNANCIES and THROMBOEMBOLIC EVENTS</h2><span >See more</span>


  • Serious, life-threatening, and fatal events from use of tamoxifen include uterine malignancies, stroke, and pulmonary embolism. (5.1, 5.2)
  • Discuss risks and benefits of tamoxifen with women at high risk for breast cancer and women with ductal carcinoma in situ (DCIS) when considering tamoxifen use to reduce the risk of developing breast cancer. (5.1, 5.2)
  • For most patients already diagnosed with breast cancer, the benefits of tamoxifen outweigh its risks. (5.1, 5.2)

See full prescribing information for complete boxed warning.

SOLTAMOX® Important Safety Information

  • Tamoxifen citrate is contraindicated in patients who require concomitant warfarin therapy, or a history of deep vein thrombosis or pulmonary embolus, and in patients with known hypersensitivity to the drug or any of its ingredients.
  • Uterine malignancies: Promptly evaluate abnormal vaginal bleeding in a woman with current or past tamoxifen use.
  • Thromboembolic events: Risk increases with coadministered chemotherapy. For treatment of breast cancer, consider risks and benefits in patients with a history of thromboembolic events.
  • Embryo-fetal toxicity: Can cause fetal harm. Advise females of reproductive potential of the potential risk to a fetus and to use effective contraception.
  • Effects on the liver: Liver cancer and liver abnormalities, some fatal, have occurred. Perform periodic liver function testing.
  • The most common adverse reactions (≥20% incidence) associated with tamoxifen are hot flashes, mood disturbances, vaginal discharge, vaginal bleeding, nausea, and fluid retention.
  • Anastrozole and letrozole: Should not be used in combination with tamoxifen.
  • Warfarin: Do not use in patients taking tamoxifen for DCIS and for reduction in breast cancer incidence in women at high risk. Closely monitor coagulation indices for increased anticoagulant effect when used with tamoxifen for metastatic breast cancer or as adjuvant therapy.
  • Do not use tamoxifen in lactating women.
  • Verify pregnancy status of females prior to initiation of tamoxifen.
  • Advise females and males to use effective contraception.

Please see full Prescribing Information for SOLTAMOX®.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit, or call 1-800-FDA-1088.