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Nolvadex (tamoxifen)
Selective estrogen receptor modulator (SERM) that blocks estrogen signaling in breast tissue while preserving bone density.
Tamoxifen (Nolvadex) was the first targeted cancer therapy and first SERM, developed by ICI (now AstraZeneca) and approved in 1977. It remains a cornerstone of ER-positive breast cancer treatment. Available generically worldwide. WHO Essential Medicine.
At a glance
| Generic name | tamoxifen |
|---|---|
| Also known as | Nolvadex, Soltamox |
| Sponsor | AstraZeneca (originally ICI) |
| Drug class | SERM (Selective estrogen receptor modulator) |
| Target | Aldehyde oxidase, 3-beta-hydroxysteroid-Delta(8),Delta(7)-isomerase, 5-hydroxytryptamine receptor 6 |
| Modality | Small molecule |
| Therapeutic area | Oncology |
| Phase | FDA-approved |
| First approval | 1977-12-30 (United States) |
Mechanism of action
Tamoxifen revolutionized breast cancer treatment as the first targeted therapy in oncology. It competitively blocks estrogen binding to the estrogen receptor in breast tissue, while acting as an estrogen agonist in bone and endometrium. Five years of adjuvant tamoxifen reduces breast cancer recurrence by approximately 50% and mortality by 30%. It also reduces breast cancer risk in high-risk women.
Approved indications
- Carcinoma of female breast
- Infiltrating duct carcinoma of breast
- Prevention of Breast Carcinoma
Boxed warnings
- WARNING: UTERINE MALIGNANCIES and THROMBOEMBOLIC EVENTS Serious and life-threatening events from the use of SOLTAMOX include uterine malignancies, stroke, and pulmonary embolism [see Warnings and Precautions (5.1 , 5.2) ] . Fatal cases of each type of event have occurred. Incidence rates per 1000 women-years for these events were estimated from the National Surgical Adjuvant Breast and Bowel Project (NSABP) P-1 trial in women at high risk for breast cancer [see Clinical Studies (14.4) ] : Endometrial adenocarcinoma: 2.20 for tamoxifen vs. 0.71 for placebo Uterine sarcoma: 0.17 for tamoxifen vs. 0.04 for placebo Stroke: 1.43 for tamoxifen vs. 1.00 for placebo. Pulmonary embolism: 0.75 for tamoxifen versus 0.25 for placebo. Discuss the potential benefits of tamoxifen versus the potential risks of these serious events with women at high risk for breast cancer and women with ductal carcinoma in situ (DCIS) considering tamoxifen to reduce the risk of developing breast cancer [see Warnings and Precautions (5) ]. For most patients already diagnosed with breast cancer, the benefits of tamoxifen outweigh its risks. WARNING: UTERINE MALIGNANCIES and THROMBOEMBOLIC EVENTS See full prescribing information for complete boxed warning . 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 )
Common side effects
- Hot Flashes
- Fluid Retention
- Vaginal Discharge
- Nausea
- Irregular Menses
- Weight Loss (>5%)
- Skin Changes
- Flush
- Amenorrhea
- Altered Menses
- Oligomenorrhea
- Bone Pain
Serious adverse events
- Thrombotic Events
- Deep Vein Thrombosis
- Pulmonary Embolism
- Superficial Phlebitis
- Thrombocytopenia
- Increased SGOT
- Increased Bilirubin
- Increased Creatinine
- Loss of Libido
- Impotence
Key clinical trials
- A Multicenter, Open-label, Phase 2 Basket Study of MK-5684 in Participants With Selected Solid Tumors (OMAHA-015) (Phase 2)
- A Neoadjuvant Phase II Trial of ZD1839 (Iressa) and Tamoxifen in Inoperable Locally Advanced HER2-Overexpressing, ER-Positive Breast Cancer Patients: Biologic Correlative Study (AZ #1839US/0303) (Phase 2)
- Modulation of Visceral Fat by Estrogens After Menopause (Phase 2)
- Preoperative Window of Opportunity Study With Giredestrant (GDC-9545) or Tamoxifen in Premenopausal Women With Estrogen Receptor-Positive/Human Epidermal Growth Factor Receptor 2-Negative & Ki67≥10% E (Phase 2)
- A Prospective, Randomized, Multicentre, Comparative and Open-label Study on Hepatotoxicity of ARIMIDEX Compared With Tamoxifen in Adjuvant Therapy in Postmenopausal Women With Hormone Receptor+ Early (Phase 4)
- The Effects of Short-term Preoperative Treatment With Hormonal Therapy on Gene Profiles in Breast Cancer (Phase 2)
- Evaluation of Endometrial Changes in Breast Cancer Women With or Without Hormonal Therapies (N/A)
- A Randomized Phase II Study to Evaluate the Efficacy of Fezolinetant in Reducing Vasomotor Symptoms in Women With Breast Cancer on Endocrine Therapy (Phase 2)
Primary sources
Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.
| Source | Used for |
|---|---|
| FDA label | Mechanism, indications, dosing, boxed warnings, drug interactions |
| ClinicalTrials.gov | Trial enrolment, design, endpoints, results |
Competitive intelligence
For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:
- Nolvadex CI brief — competitive landscape report
- Nolvadex updates RSS · CI watch RSS
- AstraZeneca (originally ICI) portfolio CI