Arimidex drug indication and side effects, anastrozole
May 20 2016 by
Ray Sahelian, M.D.

Arimidex is a medication indicated for adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. In 2005 the results of the "Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial were published and showed a benefit for Arimidex over tamoxifen in terms of disease-free survival for breast cancer patients.

Indication, what is it good for?
Arimidex is indicated for the first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer

Arimidex is indicated for the treatment of advanced breast cancer in postmenopausal women with disease progression following tamoxifen therapy. Patients with estrogen receptor-negative disease and patients who did not respond to previous tamoxifen therapy rarely respond to Arimidex.

This medication is only used by postmenopausal women.

Is Arimidex used for early breast cancer (ex: stage one, negative node, clear margins, non-invasive). I keep reading Arimidex medication is used for metastatic breast cancer.
   Arimidex is used to treat breast cancer in postmenopausal women and often given to women whose cancer has progressed even after taking tamoxifen medication. It is used as a treatment for post-menopausal women with advanced breast cancer that is hormone-receptor-positive. It is also used to treat locally advanced breast cancer.

Arimidex side effects
As add-on therapy for early-stage breast cancer Arimidex is less likely than tamoxifen to cause side effects, including serious events and those leading to treatment discontinuation, new research suggests.
   Arimidex does increase the risk of bone fractures, but the risk does not extend beyond the treatment phase. The current ATAC analysis, which appears in the medical journal Lancet Oncology, includes follow-up data for 3125 women who completed 5 years of treatment with anastrozole and 3116 similar women treated with tamoxifen. The average follow-up period was 68 months. The overall rate of side effects was significantly lower with anastrozole than with tamoxifen: 61 percent vs. 68 percent. Serious side effects were nearly half as common with anastrozole: 5 percent vs. 9 percent.
Eleven percent of anastrozole-treated patients experienced side effects leading to treatment discontinuation compared with 14 percent of tamoxifen-treated patients. Tamoxifen has received much praise since it first became available in the 1970s, but the newer types of drugs such as anastrozole have really knocked tamoxifen off its perch.
   The study was funded by AstraZeneca, which developed both Arimidex and tamoxifen (Nolvadex), although the latter agent has been available in a generic form for several years. Lancet Oncology, 2006.

Lancet Oncol. 2014 Dec. Changes in bone mineral density at 3 years in postmenopausal women receiving anastrozole and risedronate in the IBIS-II bone substudy: an international, double-blind, randomised, placebo-controlled trial. Aromatase inhibitors prevent breast cancer in postmenopausal women at high risk of the disease but are associated with accelerated bone loss.

Pregnancy
Arimidex is a pharmaceutical drug that can cause fetal harm when administered to a pregnant woman. Before starting treatment with Arimidex, pregnancy must be excluded.