How Anastrozole Works
Anastrozole is a non-steroidal (third-generation) aromatase inhibitor. The aromatase enzyme converts androgens such as testosterone into estrogens, mainly estradiol; anastrozole inhibits the conversion of androgens to estrogens by aromatase, which lowers estrogen levels. MDPI
What Is Approved, and What This Is
Anastrozole is FDA-approved as a 1 mg tablet to treat hormone-receptor–positive breast cancer in postmenopausal women. These sublingual drops are a compounded preparation made to a prescriber's order and are not an FDA-approved product.
Why It Is Compounded as Sublingual Drops
The commercial product comes in a single 1 mg tablet strength. Liquid drops let a prescriber order much smaller, finely adjustable doses — here, 0.1 mg per 0.2 mL — and titrate in small steps. Drops are also an option for patients who prefer not to swallow a tablet or capsule.
An Honest Note on Absorption
Sublingual delivery is sometimes used to bypass first-pass liver metabolism for drugs that are poorly absorbed by mouth. Anastrozole is different: it already has excellent oral bioavailability, and published pharmacokinetic data specific to the sublingual route for anastrozole are limited. These drops are therefore offered as a precise-dosing and delivery option at the prescriber's discretion — not on a claim that the sublingual route improves how well anastrozole is absorbed. Bayview Pharmacy
A Note on Off-Label Use
Some prescribers use anastrozole off-label — for example, to manage elevated estradiol in men on testosterone therapy, using small, titrated doses. Aromatase inhibitors have also been studied off-label in boys for growth-related conditions, though long-term safety in males is not established and routine use is not recommended. These uses are not FDA-approved; whether and how to use anastrozole is the prescriber's clinical decision.
Clinical Context and Safety
Anastrozole lowers estrogen, which has important roles in bone, lipids, and other systems in both women and men. Selection, dosing, and monitoring are the prescriber's responsibility.
Quality and Compliance
Mixwell Compounding Pharmacy prepares these drops in our purpose-built, USP <795>-compliant lab to the prescriber's exact instructions, dispensed only with a valid prescription. Mixwell is a non-sterile pharmacy and does not prepare sterile products or injectables. Compounded medications are not reviewed or approved by the FDA. Nothing here promises a specific result, and compounded preparations are not presented as superior to commercially available products.
References
- Punjani N, Bernie H, Salter C, et al. The Utilization and Impact of Aromatase Inhibitor Therapy in Men With Elevated Estradiol Levels on Testosterone Therapy. Sex Med. 2021;9(4):100378. doi:10.1016/j.esxm.2021.100378.
- de Ronde W, de Jong FH. Aromatase inhibitors in men: effects and therapeutic options. Reprod Biol Endocrinol. 2011;9:93.
- The Clinical Pharmacology of Anastrozole. touchONCOLOGY (Oncology & Hematology Review). 2019.
- ARIMIDEX (anastrozole) Prescribing Information. U.S. Food and Drug Administration.
- Professional Compounding Centers of America (PCCA). Formulation science and compounding resources. https://www.pccarx.com/Blog/