Exemestane Administration Guidelines
Exemestane is administered orally at a dose of 25 mg once daily for 5 years. 1
Dosage and Administration Details
- Exemestane is taken as a 25 mg tablet by mouth once daily
- Standard duration of therapy is 5 years when used for breast cancer risk reduction
- Oral administration allows for convenient at-home dosing
- No special timing requirements with respect to meals
Patient Selection Criteria
Exemestane is indicated for:
- Postmenopausal women ≥35 years of age
- Women with a 5-year projected absolute breast cancer risk ≥1.66% (according to the NCI Breast Cancer Risk Assessment Tool)
- Women with lobular carcinoma in situ (LCIS) or atypical hyperplasia
- As an alternative to tamoxifen and/or raloxifene for breast cancer risk reduction
Exemestane should not be used in:
- Premenopausal women 1
- Women who are pregnant or may become pregnant 2
- Nursing mothers (women should not breastfeed during treatment and for 1 month after the final dose) 2
Mechanism of Action
Exemestane works as an irreversible, steroidal aromatase inactivator that:
- Acts as a false substrate for the aromatase enzyme
- Binds irreversibly to the active site of the enzyme ("suicide inhibition")
- Significantly lowers circulating estrogen concentrations in postmenopausal women
- Has no detectable effect on adrenal biosynthesis of corticosteroids or aldosterone 2
Efficacy
- Reduces the relative incidence of invasive breast cancer by 65% compared to placebo 1
- Particularly effective for reducing estrogen receptor (ER) positive breast cancers 1
- Maximum suppression of circulating estrogens (85-95%) is achieved at the 25 mg dose 2
- After a single dose, maximal suppression of circulating estrogens occurs 2-3 days after dosing and persists for 4-5 days 2
Monitoring and Follow-up
- No specific laboratory monitoring is required for exemestane administration
- Regular breast cancer screening should continue as per standard guidelines
- Abnormal vaginal bleeding should be evaluated promptly
- Discussions with patients should include both risks and benefits of exemestane in the preventive setting 1
Common Side Effects
- Mild nausea
- Hot flushes
- Fatigue
- Increased sweating
- Dizziness 3
Important Considerations
- Exemestane is not currently FDA-approved for breast cancer risk reduction (only for adjuvant treatment of early breast cancer and treatment of advanced breast cancer) 1
- The American Society of Clinical Oncology (ASCO) recommends exemestane as a moderate, evidence-based option for breast cancer risk reduction 1
- Exemestane has been shown to be effective in postmenopausal patients with tamoxifen-refractory advanced breast cancer 3
- The drug has a convenient once-daily oral dosing regimen that promotes adherence 4
By following these guidelines for exemestane administration, healthcare providers can effectively reduce breast cancer risk in appropriate postmenopausal women while minimizing potential adverse effects.