Tamoxifen (NOLVADEX)

Breast cancer, early stage

Breast cancer, advanced or metastatic

Breast cancer, early stage

• Dose – Oral: 20 mg once daily continuously for up to 5-10 years
• Given as monotherapy or in combination with abemaciclib
• Patients can also be switched from tamoxifen to an aromatase inhibitor for a total duration of 5-10 years of treatment

Breast cancer, advanced or metastatic

• Dose – Oral: 20 mg once daily continuously until disease progression or unacceptable toxicity

Available as 10 mg or 20 mg tablets. Tablets should NOT be broken or crushed. Store at room temperature.

Selective Estrogen Receptor Modulator (SERM)

Take with or without food

If a dose is missed, patients should be instructed to take it as soon as they can if it is within 12 hours of the missed dose. If it is over 12 hours since the missed dose, patients should skip the missed dose and resume with the next scheduled dose.

Common: Hot flashes, Vaginal bleeding, Arthralgia/Myalgia.

Less Common: Thromboembolic events, Sweating, Hypercalcemia, Altered lipid profile, Hepatotoxicity, Myelosuppression, Depression, Cataracts, Ocular changes, Endometrial cancer, Tumor flare.

The adverse effects listed above are not exhaustive. Please refer to the relevant product monograph for full details.

Baseline before treatment: gynecological exam (postmenopausal patients with an intact uterus), GGT, ALT, LDH, alkaline phosphatase and bilirubin; calcium and albumin in those with known bone metastases.

During treatment: gynecological exam (postmenopausal patients with an intact uterus).

If clinically indicated: CBC & differential, platelets, serum cholesterol and triglycerides, bilirubin, alkaline phosphatase, ALT, GGT, ophthalmologic exam , corrected calcium.

• This drug can impact or be impacted by metabolic enzymes for absorption and excretion. Many drugs can also affect or be affected by these enzymes, so please consult with pharmacy to assess for interactions.
• Avoid grapefruit, grapefruit juice, Seville oranges, or Seville orange juice.
• Avoid estrogen-containing or estrogenic agents if possible as they can decrease the effect of tamoxifen.
• Current drug interaction databases should be consulted for more information.

• Avoid in pregnancy and lactation.
• Tamoxifen is associated with an increased risk of thromboembolism.
• Hot flashes are one of the most common adverse events reported in women taking tamoxifen, but are rarely severe. They may be controlled in some patients by a decreased or divided dose, and patients who have their sleep interrupted by drenching night sweats may benefit by taking their tamoxifen in the morning. Several medication options are available to decrease the frequency and severity of hot flashes.
• Tamoxifen use has been associated with an increased incidence of endometrial changes, including hyperplasia, polyps, uterine fibroids, and endometriosis.
• If estrogen use is required for patient, the lowest dose and shortest duration to relieve symptoms should be prescribed, and patient should be monitored carefully. For vaginal complaints such as dyspareunia, dryness and sexual dysfunction, topical estrogen may be considered.

BC Cancer. BC Cancer Drug Manual. Tamoxifen. Vancouver, British Columbia: BC Cancer Agency. Available at:  http://www.bccancer.bc.ca/drug-database-site/Drug%20Index/Tamoxifen_monograph.pdf. Updated August 1, 2020. Accessed January 22, 2024.

Lexicomp. Tamoxifen Monograph. In: Lexi-Drugs. Hudson, Ohio: Lexi-Comp, Inc. Available at: https://online.lexi.com/lco/action/doc/retrieve/docid/patch_f/7724?cesid=2BHGDdhxwET&searchUrl=%2Flco%2Faction%2Fsearch%3Fq%3Dtamoxifen%26t%3Dname%26acs%3Dfalse%26acq%3Dtamoxifen. Updated January 29, 2024. Accessed January 30, 2024.

Cancer Care Ontario. Tamoxifen Monograph. Drug Formulary. Toronto, Ontario: Cancer Care Ontario. Available at: https://www.cancercareontario.ca/en/drugformulary/drugs/monograph/43996. Updated May 2022. Accessed January 22, 2024.

AstraZeneca. Nolvadex-D® Product Monograph. Mississauga, Ontario. Updated December 8, 2021.