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Anastrozole, sold under the brand name Arimidex among others, is an antiestrogenic medication used in addition to other treatments for breast cancer.

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Common side effects of anastrozole include hot flashes, altered mood, joint pain, and nausea. It is on the World Health Organization's List of Essential Medicines. Anastrozole is available as a generic medication.

Medical uses

Breast cancer

Anastrozole is used in the treatment and prevention of breast cancer in women. After more than 5 years the group that received anastrozole had better results than the tamoxifen group.

Available forms

Anastrozole is available in the form of 1&nbsp;mg oral tablets. No alternative forms or routes are available. The medication has been found to achieve 96.7% to 97.3% inhibition of aromatase at a dosage of 1&nbsp;mg/day and 98.1% inhibition of aromatase at a dosage of 10&nbsp;mg/day in humans. As such, 1&nbsp;mg/day is considered to be the minimal dosage required to achieve maximal suppression of aromatase with anastrozole. As such, anastrozole may have peripheral selectivity in humans, although this has yet to be confirmed. It is also known as α,α,α',α'-tetramethyl-5-(1H-1,2,4-triazol-1-ylmethyl)-m-benzenediacetonitrile.

History

Anastrozole was patented by Imperial Chemical Industries (ICI) in 1987 and was approved for medical use, specifically the treatment of breast cancer, in 1995. However, it is also marketed under a variety of other brand names throughout the world.

Anastrozole was under development for the treatment of female infertility but did not complete development and hence was never approved for this indication.

An anastrozole and levonorgestrel vaginal ring (developmental code name BAY 98–7196) was under development for use as a hormonal contraceptive and treatment for endometriosis. Development was discontinued in November 2018, and the formulation was never marketed.

Anastrozole increases testosterone levels in males and has been studied as an alternative method of androgen replacement therapy in men with hypogonadism. However, there are concerns about its long-term influence on bone mineral density in this patient population, as well as other adverse effects.