Anastrozole Capsules

Overview of Anastrozole Capsules

Dosage Strength

Compounded: 0.1 mg, 0.75 mg Capsule Compounded: 0.125 mg, 0.25 mg, 0.5 mg Tablet Commercial: 1 mg Tablet

General Information

A nonsteroidal aromatase inhibitor is anastrozole. The fourth generation of aromatase inhibitors, anastrozole is very effective and selective for aromatase. In postmenopausal women with breast cancer, anastrozole considerably lowers serum estradiol levels and provides an alternative to tamoxifen. Anastrozole does not prevent the synthesis of adrenal steroid hormones like the early aromatase inhibitor aminoglutethimide does. As a result, patients on anastrozole do not need to get replacement therapy with glucocorticoids or mineralocorticoids. In patients with advanced breast cancer, anastrozole may provide a survival advantage to megestrol because it produces less weight gain. The preferred medicine class and standard of care for postmenopausal women with early breast cancer that is hormone-receptor positive is thought to be aromatase inhibitors. All postmenopausal women with early breast cancer that has hormone receptor positivity are advised to take adjuvant aromatase inhibitor therapy, according to the American Society of Clinical Oncology. Options include sequential therapy with 2–3 years or 5 years of tamoxifen followed by 2–3 years or 5 years of an aromatase inhibitor, or 5 years of an aromatase inhibitor. 1 Long-term statistics show that the gains in disease-free longevity continue for 5 years after drug use is stopped (see Dosage). 23

Even though it is not FDA-approved, numerous studies have demonstrated that using anastrozole sequentially following 2–3 years of tamoxifen enhances disease-free lifespan even more when compared to those receiving tamoxifen for 5 years. 45

In December 1995, the FDA first granted anastrozole approval for the treatment of postmenopausal women with advanced breast cancer whose condition worsened while receiving tamoxifen. Anastrozole was approved by the FDA in September 2000 for use as the first-line therapy for postmenopausal women with advanced or metastatic breast cancer. In September 2002, approval was granted for the adjuvant therapy of early breast cancer in postmenopausal women with hormone receptor positive illness.


1.Winer EP, Hudis C, Burnstein HJ, et al. American Society of Clinical Oncology technology assessment on the use of aromatase inhibitors as adjuvant therapy for postmenopausal women with hormone receptor-positive breast cancer: status report 2004. J Clin On
2.The ATAC (Arimidex, Tamoxifen Alone or in Combination) Trialists’ Group. Results of the ATAC (Arimidex, Tamoxifen, Alone or in Combination) trial after completion of 5 years’ adjuvant treatment for breast cancer. Lancet 2005;365:60-62.
3.The Arimidex, Tamoxifen, Alone or in Combination (ATAC) Trialists’ Group. Effect of anastrozole and tamoxifen as adjuvant treatment for early-stage breast cancer: 100-month analysis of the ATAC trial. Lancet Oncol 2008;9:45-53.
4.Boccardo F, Rubagotti A, Puntoni M, et al. Switching anastrozole versus continued tamoxifen treatment of early breast cancer: preliminary results of the Italian tamoxifen anastrozole trial. J Clin Oncol 2005;23:5138-47.
5.Jonat W, Gnant M, Boccardo F, et al. Effectiveness of switching from adjuvant tamoxifen to anastrozole in postmenopausal women with hormone-sensitive early-stage breast cancer: a meta-analysis. Lancet Oncol 2006;7:991-6.
6.Goss PE, Gwyn KMEH. Current perspectives on aromatase inhibitors in breast cancer. J Clin Oncol 1994;12:2460-70.
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8.Bradlow HL. A reassessment of the role of breast tumor aromatization. Cancer Res 1982;3382-6.
9.Arimidex (anastrozole) package insert. Wilmington DE: AstraZeneca Pharmaceuticals LP; 2013 May.
10.Varelas FK, Papanicolaou AN, Vavasti-Christaki N, et al. The effect of anastrazole on symptomatic uterine leiomyomata. Obstet Gynecol 2007;110:643-9.
11.Jakesz R, JOnat W, Gnant M, et al. Switching of postmenopausal women with endocrine-responsive early breast cancer to anastrozole after 2 years’ adjuvant tamoxifen: combined results of ABCSG trial 8 and ARNO 95 trial. Lancet 2005;366:455-62.
12.Arimidex (anastrozole) package insert. Wilmington DE: AstraZeneca Pharmaceuticals LP; 2009 Apr.
13.Arimidex® (anastrozole) package insert. Wilmington DE: AstraZeneca Pharmaceuticals LP; 2002 Oct.
14.The ATAC (Arimidex, Tamoxifen Alone or in Combination) Trialists’ Group. Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early breast cancer: first results of the ATAC randomise
15.Kendall A, Dowsett M, Folkerd E, et al. Caution: vaginal estradiol appears to be contraindicated in postmenopausal women on adjuvant aromatase inhibitors. Ann Oncol 2006;17:584—7.
16.Kroboth PD, Slalek FS, Pittenger AL et al. DHEA and DHEA-S: a review. J Clin Pharmacol 1999;39:327—48.
17.Aromasin® (exemestane) package insert. Kalamazoo MI: Pharmacia & Upjohn Company; 2005 Oct.
18.Femara® (letrozole) package insert. East Hanover, NJ: Novartis Pharmaceuticals Corporation; 2003 Feb.
19.Teslac (testolactone) package insert. Princeton, NJ: Mead-Johnson Oncology Products, Bristol-Myers Squibb, Co.; 1998 Dec.

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