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anastrozole (Arimidex)

Tradename: Arimidex. Indications: 1) treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy - estrogen receptor positive status [10] 2) prevention of breast cancer in high-risk women [12] 3) patients with estrogen receptor-negative breast cancer & patients who did not respond initially to tamoxifen rarely respond to anastrozole 4) approved for 1st line therapy (alternative to tamoxifen) - may be more effective than tamoxifen for treatment of early breast cancer [5,8] 5) treatment of ovarian cancer Warnings: - use with caution in patients with hyperlipidemia Dosage: 1 mg PO QD * 5 years of therapy for prevention of breast cancer - 10 years of therapy improves disease-free survival vs 5 years [13] Tabs: 1 mg. Adverse effects: 1) common (> 5%) - flushing & hot flashes - little to mild nausea (10%) - vomiting - increased bone & tumor pain 2) less common (2-5%) - hypertension, somnolence, confusion, insomnia, anxiety, nervousness, fever, malaise, hair thinning, pruritus, breast pain, weight loss, urinary tract infection, thrombophlebitis, myalgia, arthralgia, pathological fracture, neck pain, sinusitis, bronchitis, rhinitis, flu-like syndrome, infection 3) other: - weight gain - carpal tunnel syndrome - xerophthalmia - anastrozole more likely cause of musculoskeletal pain than alendronate or zoledronate [11] 4) does not cause osteoporosis [9] Drug interactions: 1) inhibits activity of cytochromes P-450 1A2, 2C8/9, 3A4 at high concentrations 2) it is unlikely to cause clinically significant effects on cyt P-450 mediated drug metabolism Mechanism of action: 1) aromatase inhibitor 2) suppresses estrogen synthesis

Interactions

drug adverse effects of aromatase inhibitors

Related

breast cancer cytochrome P450 19A1 (aromatase, estrogen synthetase, CYP19A1)

General

antineoplastic endocrine agent aromatase inhibitor

Properties

INHIBITS: cytochrome P450 19A1 MISC-INFO: pregnancy-category C

Database Correlations

PUBCHEM cid=2187

References

  1. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  2. The Prescriber's Letter, vol 6 #11, Nov 1999
  3. The Prescriber's Letter, vol 7 #10, Oct 2000, pg 57
  4. The Prescriber's Letter, vol 8 #2, Feb 2001, pg 10
  5. The Prescriber's Letter, vol 9 #2, Feb 2002, pg 10
  6. Journal Watch 22(17):136, 2002 The ATAC Trialists' Group, Lancet 359:2131, 2002 http://www.thelancet.com/journal/vol359/iss9324/full/llan.359.9324.original_research.21481.1
  7. Prescriber's Letter 12(1): 2005 Arimidex (Anastrozole) for Early Breast Cancer; an Update Detail-Document#: 210113 (subscription needed) http://www.prescribersletter.com
  8. Boccardo F, Rubagotti A, Puntoni M, Guglielmini P, Amoroso D, Fini A, Paladini G, Mesiti M, Romeo D, Rinaldini M, Scali S, Porpiglia M, Benedetto C, Restuccia N, Buzzi F, Franchi R, Massidda B, Distante V, Amadori D, Sismondi P. Switching to anastrozole versus continued tamoxifen treatment of early breast cancer: preliminary results of the Italian Tamoxifen Anastrozole Trial. J Clin Oncol. 2005 Aug 1;23(22):5138-47. Epub 2005 Jul 11. PMID: 16009955
  9. Eastell R et al, Effect of anastrozole on bone mineral density: 5-year results from the Anastrozole, Tamoxifen, Alone or in Combination trial 18233230. J Clin Oncol 2008, 26:1051 PMID: 18309940
  10. Medical Knowledge Self Assessment Program (MKSAP) 18, American College of Physicians, Philadelphia 2018
  11. Geriatric Review Syllabus, 10th edition (GRS10) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2019 - Geriatric Review Syllabus, 11th edition (GRS11) Harper GM, Lyons WL, Potter JF (eds) American Geriatrics Society, 2022
  12. Cuzick J, Sestak I, Forbes JF et al Use of anastrozole for breast cancer prevention (IBIS-II): long-term results of a randomised controlled trial. Lancet. Dec 12, 2019 PMID: 31839281 Free Article https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(19)32955-1/fulltext
  13. Iwase T et al. Postoperative adjuvant anastrozole for 10 or 5 years in patients with hormone receptor-positive breast cancer: AERAS, a randomized multicenter open-label phase III trial. J Clin Oncol 2023 Apr 20; [e-pub]. PMID: 37079878 https://ascopubs.org/doi/10.1200/JCO.22.00577