Brand and Other Names:Aromasin
- Classes: Antineoplastics, Aromatase Inhibitor
Dosing & Uses
Dosage Forms & Strengths
Postmenopausal ER-Positive Breast Cancer
25 mg PO qDay; continue until tumor progression
Breast Cancer Adjuvant Treatment
Switch to exemestane after 2-3 years of tamoxifen treatment
25 mg PO qDay; continue until tumor progression
Take after meals
Breast Cancer Prevention (Off-label)
2013 ASCO guidelines suggest exemestane as an alternative to tamoxifen or raloxifene to prevent invasive breast cancer in high risk women
25 mg PO qDay for 5 years
Coadministration with potent CYP3A4 inducers: 50 mg PO qDay
High risk of breast cancer is defined as at least 1 breast biopsy showing lobular carcinoma in situ (LCIS) or atypical hyperplasia, 1 or more first-degree relatives with breast cancer, or a 5-year predicted risk of breast cancer >1.66% (based on the modified Gail model)
Safety and efficacy not established
Serious - Use Alternative
Significant - Monitor Closely
Hot flashes (13%)
Flu-like syndrome (6%)
Abdominal pain (6%)
Frequency not defined
Immune system disorders: Hypersensitivity
Hepatobiliary disorders: Hepatitis including cholestatic hepatitis
Nervous system disorder: Paresthesia
Skin and subcutaneous tissue disorders: Acute generalized exanthematous pustulosis, urticaria, pruritus
Pregnancy, premenopausal women
Do not administer with concomitant estrogens
Routine assessment of 25-hydroxy vitamin D levels prior to the start of aromatase inhibitor treatment should be performed, due to the high prevalence of vitamin D deficiency in women with early breast cancer; women with vitamin D deficiency should receive supplementation with vitamin D
Reductions in bone mineral density (BMD), women with or at risk of osteoporosis should have their BMD formally assessed by bone densitometry at the commencement of treatment
Pregnancy & Lactation
Pregnancy Category: D
Lactation: excretion in milk unknown; use with caution
A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA:Information not available.
Mechanism of Action
Aromatase inhibitor - blocks conversion of androgens to estrogens by binding to the heme group of aromatase enzyme, which in turn inhibits its activity
Half-Life: 24 hr
Protein Bound: 90%
Peak time: 1.2 (women with breast cancer)
Metabolism: via CYP3A4 (extensive)
Excretion: Urine (39-45%); feces (35-48%)
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