Aromasin (exemestane) is a potent, steroidal aromatase inhibitor prescribed for the management of estrogen-sensitive conditions in both oncology and endocrinology. It functions by irreversibly binding to the aromatase enzyme, leading to a significant and sustained reduction in circulating estrogen levels. This makes it a cornerstone in adjuvant therapy for hormone-receptor-positive breast cancer in postmenopausal women, as well as a strategic option in certain off-label endocrine applications. Its unique inactivation mechanism offers distinct pharmacokinetic and safety profiles compared to non-steroidal inhibitors, providing clinicians with a valuable tool for long-term hormonal control.

Features

• Active ingredient: Exemestane 25 mg
• Pharmacological class: Irreversible, steroidal aromatase inhibitor (type I)
• Bioavailability: Approximately 42% following oral administration
• Half-life: 24 hours
• Protein binding: 90% bound to plasma proteins
• Metabolism: Extensive hepatic metabolism via CYP3A4
• Excretion: Primarily renal and fecal
• Presentation: Film-coated tablets

Benefits

• Significantly reduces the risk of cancer recurrence in postmenopausal women with early-stage, hormone-receptor-positive breast cancer
• Provides irreversible aromatase inhibition, ensuring sustained estrogen suppression throughout the dosing interval
• Demonstrates a favorable tolerability profile with a lower incidence of arthralgia compared to some non-steroidal aromatase inhibitors
• Does not require concomitant corticosteroid replacement therapy, unlike earlier generation inhibitors
• May help preserve bone mineral density when managed with appropriate adjunctive therapies
• Offers oral administration convenience with once-daily dosing, supporting long-term treatment adherence

Common use

Aromasin is primarily indicated for the adjuvant treatment of postmenopausal women with estrogen-receptor-positive early breast cancer who have received 2-3 years of tamoxifen and are switched to exemestane for completion of a total of 5 years of adjuvant hormonal therapy. It is also approved for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy. In endocrine practice, it may be used off-label for estrogen suppression in various clinical scenarios, including gynecomastia prevention during androgen therapy, precocious puberty, and fertility treatments, though these applications require careful specialist supervision.

Dosage and direction

The recommended dose of Aromasin is 25 mg administered orally once daily after a meal. Clinical studies demonstrate that taking exemestane with food significantly enhances its oral absorption. Treatment should be continued until tumor progression is observed in advanced disease settings. For adjuvant treatment, the recommended duration is 2-3 years following initial tamoxifen therapy, or 5 years as initial adjuvant therapy depending on the treatment strategy. Dose adjustments are not typically required for elderly patients, but patients with hepatic or renal impairment should be carefully monitored. Tablets should be swallowed whole with water and not crushed or divided.

Precautions

Patients should be monitored for bone mineral density loss, as estrogen suppression accelerates bone resorption. Baseline bone density assessment and periodic monitoring are recommended, with consideration of calcium, vitamin D supplementation, and bisphosphonate therapy when indicated. Regular assessment of lipid profiles is advised due to potential alterations in cholesterol metabolism. Hepatic function should be monitored periodically, as exemestane undergoes extensive hepatic metabolism. Patients with a history of osteoporosis or risk factors for osteopenia require particularly vigilant management. Caution is advised in patients with pre-existing cardiovascular risk factors or conditions.

Contraindications

Aromasin is contraindicated in patients with known hypersensitivity to exemestane or any component of the formulation. It must not be administered to premenopausal women, as it will not effectively suppress ovarian estrogen production and may lead to unpredictable hormonal effects. Concomitant use with estrogen-containing medications is contraindicated, as these would counteract the therapeutic effect. The drug is contraindicated in patients with severe hepatic impairment (Child-Pugh class C) due to insufficient safety data. Pregnancy and breastfeeding are absolute contraindications due to potential fetal harm and lack of safety data in lactation.

Possible side effects

The most frequently reported adverse reactions (≥10%) include hot flashes (21%), fatigue (16%), arthralgia (15%), headache (13%), insomnia (12%), and increased sweating (11%). Less common but clinically significant effects may include nausea (9%), depression (8%), dizziness (7%), carpal tunnel syndrome (6%), and dyspnea (5%). Laboratory abnormalities may include elevated liver enzymes (2-3%) and decreased lymphocyte counts (2%). Long-term use is associated with accelerated bone loss and increased fracture risk. Most adverse events are mild to moderate in severity and often diminish with continued therapy.

Drug interaction

Exemestane is primarily metabolized by CYP3A4, so concomitant use with strong CYP3A4 inducers (rifampicin, phenytoin, carbamazepine, St. John’s wort) may significantly reduce exemestane concentrations and compromise efficacy. Conversely, strong CYP3A4 inhibitors (ketoconazole, ritonavir, clarithromycin) may increase exemestane exposure. Co-administration with estrogen-containing therapies will antagonize the therapeutic effect. Caution is advised with medications that affect bone metabolism (corticosteroids, thyroid replacements) or cardiovascular risk factors. The potential for interaction with warfarin requires careful INR monitoring.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is nearly time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not take a double dose to make up for a missed dose. Consistent daily administration is important for maintaining stable estrogen suppression, so patients should be counseled on adherence strategies and the use of reminder systems if missed doses become a pattern.

Overdose

There is limited experience with Aromasin overdose in humans. Single doses up to 800 mg have been administered without severe adverse effects. In case of suspected overdose, supportive care should be initiated with attention to gastrointestinal symptoms. Since exemestane is highly protein-bound, dialysis is not likely to be effective. Medical supervision is recommended, particularly for large overdoses. There is no specific antidote; treatment should be symptomatic and supportive. Patients should be monitored for potential exaggerated pharmacological effects including severe hot flashes, nausea, and dizziness.

Storage

Store at room temperature between 20°C to 25°C (68°F to 77°F) with excursions permitted between 15°C to 30°C (59°F to 86°F). Keep in the original container with the lid tightly closed to protect from moisture and light. Keep out of reach of children and pets. Do not use after the expiration date printed on the packaging. Do not transfer tablets to other containers, as this may compromise stability. Proper disposal of unused medication should follow local regulations for pharmaceutical waste.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Aromasin is a prescription medication that should only be used under the supervision of a qualified healthcare professional. Individual response to therapy may vary, and treatment decisions should be based on a comprehensive assessment by a physician familiar with the patient’s complete medical history. The full prescribing information should be consulted before initiating therapy. Never adjust dosage or discontinue medication without medical consultation.

Reviews

Clinical studies demonstrate that Aromasin significantly improves disease-free survival in postmenopausal women with hormone-sensitive early breast cancer. The IES (Intergroup Exemestane Study) showed a statistically significant 24% reduction in the risk of recurrence compared to continued tamoxifen therapy. Many clinicians report favorable patient tolerance, particularly regarding musculoskeletal symptoms compared to non-steroidal aromatase inhibitors. Patients often describe manageable side effects with appropriate supportive care, though individual experiences vary considerably. Long-term follow-up data continue to support its role in adjuvant hormonal therapy strategies.