Aromasin (Exemestane)

Overview

Aromasin is a prescription medication containing the active ingredient exemestane, classified as a steroidal aromatase inhibitor used primarily in the treatment of breast cancer in postmenopausal women. It works by irreversibly inhibiting the aromatase enzyme, which is responsible for converting androgens into estrogens, thereby lowering estrogen levels that can fuel the growth of certain breast tumors. Aromasin is mainly prescribed for estrogen-receptor positive early breast cancer as an adjuvant therapy after initial treatment with tamoxifen, and for advanced breast cancer that has progressed following tamoxifen therapy. It is taken orally in tablet form and has been a valuable option in hormone therapy for breast cancer since its FDA approval.¹³

Forms and Variations

Aromasin is available exclusively as oral tablets containing 25 mg of exemestane. The formulation includes inactive ingredients such as mannitol, crospovidone, polysorbate 80, and others to aid in tablet stability and absorption. There are no alternative forms like injections or liquids commercially available. The choice of this specific form is due to exemestane’s pharmacokinetics and ease of administration, allowing once-daily dosing. The steroidal structure of exemestane distinguishes it from non-steroidal aromatase inhibitors, which may influence tolerability and mechanism of action.¹²

Dosage and Administration

The typical recommended dose of Aromasin is 25 mg once daily, taken orally after a meal to enhance absorption. Treatment duration often extends up to five years, especially when used as adjuvant therapy following 2 to 3 years of tamoxifen. Consistent daily intake is important to maintain effective estrogen suppression. Patients are advised to follow their healthcare provider’s instructions closely and not to miss doses. Aromasin should not be taken concurrently with hormone replacement therapy, as this can reduce its effectiveness.³⁴

Scientific Research and Mechanism of Action

Exemestane, the active compound in Aromasin, functions as an irreversible steroidal aromatase inactivator. Aromatase is the key enzyme converting androgens to estrogens, particularly in postmenopausal women where peripheral tissues become the main estrogen source. By binding covalently to aromatase, exemestane permanently disables the enzyme, leading to a significant reduction in circulating estrogen levels. This estrogen deprivation slows or halts the growth of estrogen-dependent breast cancer cells. Clinical trials have demonstrated Aromasin’s efficacy in reducing recurrence risk in early breast cancer and in treating advanced disease after tamoxifen failure. Research continues to explore its long-term benefits and comparative effectiveness versus other aromatase inhibitors.²³

Benefits and Potential Uses

Aromasin is primarily used for the adjuvant treatment of estrogen-receptor positive early breast cancer in postmenopausal women, especially after 2 to 3 years of tamoxifen therapy to complete a total of 5 years of hormonal treatment. It is also indicated for advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen. By lowering estrogen levels, Aromasin reduces the risk of cancer recurrence and slows tumor progression. Potential uses under investigation include its role in combination therapies and in patients with hormone-resistant breast cancer. Aromasin’s steroidal mechanism may offer benefits in certain patient populations compared to non-steroidal aromatase inhibitors.¹⁴

Side Effects and Risks

Common side effects of Aromasin include hot flashes, fatigue, joint pain, headache, and increased sweating. Because it lowers estrogen, it may also cause bone thinning (osteoporosis) and increase fracture risk. Other possible adverse effects include nausea, dizziness, and insomnia. Aromasin is contraindicated in premenopausal women, pregnant or breastfeeding women, and those allergic to exemestane. Caution is advised in patients with liver or kidney impairment. Long-term estrogen suppression requires monitoring for bone health and cardiovascular risk.³⁴

Interactions and Precautions

Aromasin may interact with hormone replacement therapies, which can reduce its effectiveness. It is important to avoid concurrent use with estrogen-containing medications. Patients with liver or kidney disease should use Aromasin cautiously, as metabolism and clearance may be affected. Aromasin is not suitable for premenopausal women or those who are pregnant or may become pregnant due to potential harm to the fetus. Before surgery or medical procedures, inform healthcare providers about Aromasin use to manage bleeding risk and hormonal status. Regular monitoring by a healthcare professional is essential during treatment.³⁴

Impact on Biomarkers

Aromasin significantly reduces serum estrogen levels, including estradiol and estrone, which are key biomarkers in estrogen-receptor positive breast cancer. It may also influence bone turnover markers due to its effect on bone metabolism. Monitoring of liver function tests and lipid profiles may be recommended during treatment. Reduction in estrogen biomarkers correlates with therapeutic efficacy in breast cancer management.²³

Overdose and Toxicity

There is limited data on Aromasin overdose, but excessive intake may increase the risk of severe estrogen deprivation symptoms such as profound bone loss, severe hot flashes, and fatigue. Symptoms of toxicity could include nausea, vomiting, dizziness, and hypotension. The safe upper limit is not well established; therefore, patients should adhere strictly to prescribed doses and seek immediate medical attention if overdose is suspected.³

Disclaimer

The information provided in this document is for educational purposes only and does not constitute medical advice. It is essential to consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.