Aromatase is the enzyme in the body responsible for the conversion of testosterone to estrogen. Anastrozole is a highly potent and specific aromatase enzyme inhibitor. It significantly increases testosterone levels by suppressing serum estradiol levels and increasing gonadotropin levels. Aromatase inhibitors are considered to be a standard of therapy and drug class of choice for the treatment of early breast cancer in postmenopausal women with hormone-receptor positive disease.1 Given its unique effects on testosterone and estrogen levels, anastrozole has also been used off-label for the treatment of male hypogonadism. It has been studied that men taking testosterone replacement therapy maintain therapeutic levels of testosterone longer and experience less gonadotropin suppression when anastrozole is part of the therapeutic regimen.2
One benefit of anastrozole over earlier generation aromatase inhibitors is that it does not inhibit adrenal steroid synthesis. This means patients taking anastrozole do not require glucocorticoid or mineralocorticoid replacement therapy.1
Anastrozole is commonly indicated for the first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor unknown locally advanced or metastatic breast cancer. It is an adjunct therapy in the treatment of postmenopausal women with early breast cancer.3 It is also used as an off-label treatment of excessive estrogen production in men.2
Commercially-Available Anastrozole Options
Anastrozole was first approved for human use in the U.S. in 1995 for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed during tamoxifen therapy. Today, anastrozole is available commercially as a 1 mg oral tablet. Clinical effects can be very substantial at this dosage.3
Compounded Anastrozole Options
Since anastrozole is already commercially available as an oral tablet, compounded anastrozole capsules are reserved for patients that require a smaller dosage than what is FDA approved as determined by a prescriber. Anastrozole is commonly compounded into oral capsules in the following strengths:
0.1 mg 0.25 mg
0.125 mg 0.75 mg
Store this medication at 68°F to 77°F (20°C to 25°C) and away from heat, moisture and light. Keep all medicine out of the reach of children. Throw away any unused medicine after the beyond use date. Do not flush unused medications or pour down a sink or drain.
- 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
- Coadministration of anastrozole sustains therapeutic testosterone levels in hypogonadal men undergoing testosterone pellet insertion. J Sex Med. 2014 Jan;11(1):254-61.
- Arimidex (anastrozole) package insert. Wilmington DE: AstraZeneca Pharmaceuticals LP; 2013 May.
Compounding Pharmacy Statement
Anastrozole capsules are compounded with drug components whose suppliers are registered with the FDA. While Galleria Medical Pharmacy adheres to USP <795> guidelines and applicable state and federal regulations to meet the required quality standards, the statements made regarding compounded anastrozole capsules have not been evaluated by the FDA for safety or clinical effectiveness. As such, this preparation is not intended to diagnose, treat, cure, or prevent any disease. For inquiries concerning this preparation, please contact (504) 267-9876.