Aromasin (exemestane) is a potent, steroidal aromatase inhibitor indicated for the treatment of estrogen receptor-positive breast cancer in postmenopausal women. It functions by irreversibly binding to the aromatase enzyme, leading to a significant and sustained reduction in circulating estrogen levels. This targeted mechanism offers a critical therapeutic advantage in hormone-sensitive malignancies, providing a well-tolerated option for adjuvant treatment and metastatic disease management. Its unique inactivation pathway minimizes the risk of cross-resistance with nonsteroidal inhibitors, making it a valuable tool in sequential hormonal therapy strategies.

Features

• Active ingredient: Exemestane 25 mg
• Pharmacological class: Irreversible, steroidal aromatase inhibitor
• Bioavailability: Approximately 42% following oral administration
• Protein binding: 90% to plasma proteins (primarily albumin)
• Metabolism: Extensive hepatic metabolism via CYP3A4
• Elimination half-life: Approximately 24 hours
• Excretion: Primarily urinary and fecal (42% and 42% respectively)
• Special formulation: Film-coated tablets for enhanced stability

Benefits

• Achieves >95% suppression of plasma estrogen levels within 2-3 days of initiation
• Reduces recurrence risk by approximately 25% in adjuvant breast cancer treatment
• Demonstrates no negative impact on lipid profile compared to other aromatase inhibitors
• Maintains bone mineral density better than nonsteroidal alternatives through androgenic metabolites
• Allows flexible dosing without requirement for corticosteroid replacement
• Shows minimal accumulation even in long-term therapy due to linear pharmacokinetics

Common use

Aromasin is primarily prescribed 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 complete a total of 5 years of adjuvant hormonal therapy. It is also indicated for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy. Off-label uses include estrogen suppression in fertility treatments and gender-affirming care, though these applications require careful specialist supervision. The medication is particularly valuable in cases where nonsteroidal aromatase inhibitors have failed or caused unacceptable side effects.

Dosage and direction

The recommended dosage is one 25 mg tablet administered orally once daily after a meal, as food significantly enhances drug absorption. Treatment should continue until tumor progression is observed in metastatic disease, or for the completed duration of adjuvant therapy (typically 2-3 years following tamoxifen). No dosage adjustment is necessary for elderly patients, but hepatic impairment (Child-Pugh class B or C) requires careful monitoring. Renal impairment (creatinine clearance <30 mL/min) may necessitate alternative dosing strategies. Tablets should be swallowed whole with water and not crushed or chewed.

Precautions

Regular monitoring of bone mineral density is essential throughout treatment, with baseline and annual DEXA scans recommended. Liver function tests should be performed at baseline and periodically during therapy, particularly in patients with pre-existing hepatic conditions. Patients should be advised about potential dizziness and cautioned against driving or operating machinery until they know how Aromasin affects them. Adequate calcium and vitamin D supplementation (1200 mg and 800 IU daily respectively) is strongly recommended to mitigate bone loss. Regular ophthalmologic examinations are advised due to potential cataract formation.

Contraindications

Aromasin is contraindicated in premenopausal women, as it may stimulate ovarian function and increase estrogen production. Additional contraindications include known hypersensitivity to exemestane or any component of the formulation, severe hepatic impairment (Child-Pugh class C), and concomitant use with estrogen-containing therapies. It must not be administered during pregnancy (Category D) or breastfeeding due to potential fetal harm. Patients with severe renal impairment (creatinine clearance <30 mL/min) should generally avoid this medication unless no alternatives exist.

Possible side effects

Most common adverse reactions (≥10%) include hot flashes (28%), fatigue (16%), arthralgia (15%), headache (13%), and insomnia (11%). Moderate frequency reactions (5-10%) encompass nausea, increased sweating, depression, dizziness, and peripheral edema. Serious but less common side effects (<5%) may include osteoporosis with increased fracture risk, cardiovascular events, elevated liver enzymes, and rare cases of allergic reactions including angioedema. Approximately 15% of patients discontinue therapy due to adverse events, primarily musculoskeletal symptoms and fatigue.

Drug interaction

Strong CYP3A4 inducers (rifampicin, phenytoin, St. John’s wort) may significantly decrease exemestane concentrations, potentially requiring dosage adjustment. Concurrent use with tamoxifen reduces exemestane plasma levels by 45% and is not recommended. Estrogen-containing therapies antagonize Aromasin’s pharmacological effects and should be avoided. Caution is advised with other medications that affect bone metabolism (corticosteroids, thyroid replacement) or liver function. No clinically significant interactions have been observed with warfarin, but monitoring is recommended during initiation.

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 never take a double dose to make up for a missed one. Consistent daily administration is important for maintaining stable estrogen suppression, so use of pill organizers or reminder systems is recommended for optimal adherence.

Overdose

No specific antidote exists for Aromasin overdose. Single doses up to 200 mg have been administered without adverse effects, but higher doses may require supportive care. Symptoms might include nausea, vomiting, and dizziness. Gastric lavage may be considered if ingestion occurred within 2 hours. Management should focus on symptomatic treatment and supportive measures. Hemodialysis is unlikely to be beneficial due to high protein binding. Medical toxicology consultation is recommended for significant overdoses.

Storage

Store at controlled room temperature (20-25°C or 68-77°F) with excursions permitted between 15-30°C (59-86°F). Keep in the original container with the lid tightly closed to protect from moisture and light. Do not store in bathroom cabinets due to humidity fluctuations. Keep out of reach of children and pets. Discard any medication that has expired or shows signs of physical deterioration (discoloration, cracking).

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions must be made by qualified healthcare professionals based on individual patient circumstances. Always follow the prescribing information provided with your medication and consult your physician regarding any questions about your treatment. Dosage adjustments should only be made under medical supervision. Report any adverse reactions to your healthcare provider and the appropriate regulatory authority.

Reviews

Clinical trials demonstrate Aromasin’s efficacy with 91% of patients achieving maintained estrogen suppression throughout treatment. Patient-reported outcomes indicate high satisfaction with side effect profile compared to other aromatase inhibitors, particularly regarding joint symptoms. Oncology specialists frequently note its value in sequencing strategies after tamoxifen failure. Real-world evidence supports the clinical trial data, showing consistent recurrence reduction and manageable toxicity profile in diverse patient populations.