Tamoxifen
The original targeted cancer drug (1977): a pill that blocks oestrogen's effect on breast cancer and halves recurrence, still essential for premenopausal women.
Selective oestrogen receptor modulator: antagonist in breast, partial agonist in bone and endometrium. Five years reduces 15-year breast cancer mortality by about a third (EBCTCG); ten years is better than five (ATLAS, aTTom). Standard for premenopausal women (alone or with OFS), for men, and for chemoprevention. Endometrial cancer and thromboembolism are the serious rare harms; CYP2D6 activation to endoxifen.
1.Tamoxifen is converted by CYP2D6 to endoxifen
- Route
- Oral
- Schedule
- 20 mg once daily for 5-10 years
- Dose modifications
- Low-dose 5 mg for DCIS/prevention (TAM-01)
- Monitoring
- Gynaecologic symptoms; avoid strong CYP2D6 inhibitors
- Medicare
- Part D (self-administered)
Oral, self-administered, so it is a Part D drug: covered through a stand-alone Part D plan or Medicare Advantage drug benefit, usually on the specialty tier with 25 to 33% coinsurance until the annual cap ($2,000 in 2025, $2,100 in 2026). Generic, on the lowest tiers; often a few dollars a month.
- Commercial insurance
- covered on label
Multi-source generic on low-cost tiers; usually no prior authorisation. Cash prices without insurance are modest.
Sources: Medicare.gov: Drug coverage (Part D) · Medicare.gov: Costs for Medicare drug coverage (annual out-of-pocket cap). Not medical or financial advice; verify with your plan.
- Notes
- Generic; recommended in NICE NG101 for ER-positive breast cancer and for risk reduction in high-risk women (CG164). Funded routinely.
- NHS England
- Routinely funded for the appraised indication (or via managed access)
Sources: NICE search: tamoxifen. Funding decisions are indication-specific and change monthly; verify with NICE and your treating team.
Approvals
| Region | Year | Indication |
|---|---|---|
| US | 1977 | Advanced breast cancer |
| US | 1998 | Risk reduction in high-risk women |
| Adverse event | Any grade | Grade 3+ |
|---|---|---|
| Hot flushes | 41% | — |
| Endometrial cancer (10-year cumulative) | 3% | — |
| Venous thromboembolism | 2% | — |
| Cataract | 5% | — |
Events listed without rates were not read from a primary source; see the label. Blank cells mean the figure was not sourced, not that it is zero.
Trials
topRecruiting now (live from ClinicalTrials.gov)
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Landmark trials in OnCo
Latest papers
topQuery for this drug: (TITLE:"Tamoxifen" OR ABSTRACT:"Tamoxifen" OR TITLE:"Nolvadex" OR ABSTRACT:"Nolvadex") AND (cancer OR tumor OR tumour OR oncology OR carcinoma OR lymphoma OR leukemia OR leukaemia OR myeloma OR sarcoma OR melanoma OR glioma). Results are unfiltered search hits about Tamoxifen, not a curated reading list.
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