Dosing and uses of Aromasin (exemestane)
Adult dosage forms and strengths
tablet
- 25mg
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
Dosage modifications
Coadministration with potent CYP3A4 inducers: 50 mg PO qDay
Dosing Considerations
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)
Pediatric dosage forms and strengths
Safety and efficacy not established
Aromasin (exemestane) adverse (side) effects
>10%
Fatigue (22%)
Nausea (18%)
Hot flashes (13%)
Depression (13%)
Pain (13%)
Insomnia (11%)
1-10%
Anxiety (10%)
Dyspnea (10%)
Dizziness (8%)
Headache (8%)
Edema (7%)
Vomiting (7%)
Flu-like syndrome (6%)
Abdominal pain (6%)
Anorexia (6%)
Cough (6%)
Hypertension (5%)
Constipation (5%)
Diarrhea (4%)
<1%
Cardiac failure
Uterine polyps
Endometrial hyperplasia
Gastric ulcer
Frequency not defined
Hepatitis
Visual disturbances
Postmarketing Reports
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
Warnings
Contraindications
Hypersensitivity
Women who are or may become pregnant; premenopausal women
Cautions
Uncontrolled hypertension
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
Not indicated for breast cancer in premenopausal women
Advise females of reproductive potential to use effective contraception during treatment and for 1 month after final dose
Based on findings in animals, male and female fertility may be impaired by treatment
Pregnancy and lactation
Pregnancy category: X
Lactation: Excretion in milk unknown; because of potential for serious adverse reactions in breast-fed infants, advise women not to breastfeed during treatment and for 1 month after final dose
Pregnancy categories
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.
Pharmacology of Aromasin (exemestane)
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
Pharmacokinetics
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%)
