Femara (letrozole) is a potent, nonsteroidal aromatase inhibitor indicated for the adjuvant treatment of postmenopausal women with hormone receptor-positive early breast cancer. It is also approved for the extended adjuvant treatment of early breast cancer in postmenopausal women who have received standard tamoxifen therapy, as well as first-line treatment of advanced or metastatic breast cancer in postmenopausal women. By selectively inhibiting the aromatase enzyme, Femara significantly reduces estrogen production, creating an unfavorable environment for hormone-dependent tumor growth. Its targeted mechanism offers a sophisticated approach to endocrine therapy with a well-established efficacy and safety profile demonstrated in multiple large-scale clinical trials.

Features

• Contains letrozole as the active pharmaceutical ingredient
• Available in 2.5 mg film-coated tablets
• Nonsteroidal aromatase inhibitor class medication
• High specificity for aromatase enzyme inhibition
• Manufactured under current Good Manufacturing Practices (cGMP)
• Bioequivalent to the reference listed drug
• Stable shelf life of 36 months when stored properly
• Requires prescription dispensing only

Benefits

• Demonstrated improvement in disease-free survival in hormone receptor-positive early breast cancer
• Significant reduction in contralateral breast cancer incidence
• Superior efficacy compared to tamoxifen in advanced disease settings
• Favorable toxicity profile with manageable side effects
• Oral administration allows for convenient outpatient treatment
• Well-established long-term safety data from extensive clinical experience

Common use

Femara is primarily prescribed for the adjuvant treatment of hormone receptor-positive early breast cancer in postmenopausal women. It is commonly used following primary treatments such as surgery, radiation, or chemotherapy to reduce the risk of cancer recurrence. In metastatic settings, Femara serves as first-line endocrine therapy for hormone receptor-positive advanced breast cancer. Additionally, it is utilized as extended adjuvant therapy after completion of standard tamoxifen treatment. Off-label uses include ovulation induction in fertility treatments under specialist supervision, though this application requires careful risk-benefit assessment.

Dosage and direction

The recommended dosage of Femara is one 2.5 mg tablet taken orally once daily, with or without food. Treatment should continue for prescribed duration, typically five years for adjuvant therapy, unless disease progression or unacceptable toxicity occurs. Tablets should be swallowed whole with water and not crushed or chewed. Administration should occur at approximately the same time each day to maintain consistent drug levels. Dose adjustments are generally not required for elderly patients or those with mild to moderate renal impairment. For patients with severe hepatic impairment, careful monitoring is recommended though no specific dose adjustment is provided.

Precautions

Patients should undergo comprehensive bone density assessment before initiating therapy and periodically during treatment due to increased risk of osteoporosis and fractures. Regular monitoring of lipid profiles is recommended as letrozole may elevate cholesterol levels. Caution is advised in patients with pre-existing hepatic impairment, requiring appropriate liver function monitoring. Patients should be advised about potential dizziness and cautioned against driving or operating machinery if affected. Adequate calcium and vitamin D supplementation should be considered to support bone health. Regular follow-up appointments are essential to monitor treatment response and manage adverse effects.

Contraindications

Femara is contraindicated in premenopausal women, as it may induce ovulation and is ineffective without ovarian suppression. It should not be used in patients with known hypersensitivity to letrozole or any component of the formulation. Concomitant use with estrogen-containing therapies is contraindicated as these may diminish Femara’s therapeutic effect. The medication is contraindicated in pregnant women due to potential fetal harm, and pregnancy must be excluded before initiation. Patients with severe hepatic impairment (Child-Pugh class C) should generally avoid use unless potential benefits outweigh risks under close supervision.

Possible side effect

Common adverse reactions include hot flashes (27-33%), arthralgia (21-25%), fatigue (16-19%), and increased sweating (11-14%). Musculoskeletal events such as bone pain and arthritis may occur in approximately 13% of patients. Gastrointestinal disturbances including nausea (13-19%) and constipation (8-10%) are frequently reported. Cardiovascular effects may include hypertension (5-9%) and palpitations. Less common but serious side effects include osteoporosis with increased fracture risk, elevated cholesterol levels, and rarely, cardiovascular events. Most side effects are mild to moderate in severity and often diminish with continued therapy.

Drug interaction

Strong CYP3A4 inducers such as rifampicin may decrease letrozole concentrations, potentially reducing efficacy. CYP2A6 and CYP2C19 inhibitors may increase letrozole exposure, though clinical significance remains uncertain. Tamoxifen co-administration reduces letrozole plasma concentrations by approximately 38% and is not recommended. Estrogen-containing therapies may interfere with pharmacological action and should be avoided. No clinically significant interactions have been observed with warfarin, though monitoring is advised during concomitant use. Caution is warranted with medications that affect bone metabolism or cardiovascular risk.

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. Doubling the dose to make up for a missed dose is not recommended. Patients should maintain a consistent dosing routine and may benefit from using reminder systems. If multiple doses are missed, medical advice should be sought regarding continuation of therapy. Treatment interruptions beyond several days may require reassessment of therapeutic strategy.

Overdose

No specific antidote exists for letrozole overdose. Reported cases of overdose (up to 62.5 mg) have shown no severe adverse events. Symptomatic and supportive care is recommended, with attention to possible exaggerated pharmacological effects including hot flashes, nausea, and vomiting. Gastric lavage may be considered if ingestion occurred within a short timeframe. Monitoring of vital signs and symptomatic treatment should be instituted as necessary. Dialysis is unlikely to be beneficial due to high protein binding. Medical toxicology consultation is advised for significant overdoses.

Storage

Store at room temperature between 15-30°C (59-86°F) in the original container. Protect from light and moisture. Keep the bottle tightly closed with the desiccant provided. Do not store in bathroom areas where humidity levels may fluctuate. Keep out of reach of children and pets. Do not use beyond the expiration date printed on packaging. Proper disposal of unused medication should follow local regulations, typically through medication take-back programs.

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Treatment decisions should be made in consultation with a qualified healthcare professional familiar with the patient’s specific medical history. Individual responses to therapy may vary, and not all potential side effects or interactions are listed here. Full prescribing information should be reviewed before initiating treatment. The efficacy and safety data described are based on clinical trial populations and may not fully represent real-world experience.

Reviews

Clinical studies demonstrate Femara’s consistent efficacy profile, with the BIG 1-98 trial showing significant improvement in disease-free survival compared to tamoxifen (84.0% vs 81.1% at 8.7 years). Meta-analyses confirm aromatase inhibitors’ superiority over tamoxifen in reducing recurrence risk, particularly in node-positive disease. Patient-reported outcomes indicate generally good tolerability, though musculoskeletal symptoms remain a treatment challenge for some individuals. Long-term follow-up data support sustained benefit with appropriate management of side effects. Real-world evidence correlates with clinical trial findings, confirming Femara’s position as a cornerstone of endocrine therapy in appropriate patient populations.