Exemestane
AROMASIN
Pronunciation: ex-e-MES-tayn (a-ROEM-a-sin)
What it isSteroidal, irreversible aromatase inhibitor; hormone-receptor-positive breast cancer after menopause.
Why this oneUnlike anastrozole and letrozole, it permanently inactivates aromatase and can be used after a nonsteroidal inhibitor.
What limits itAccelerated bone loss and arthralgia limit treatment. It is ineffective before menopause unless ovarian function is suppressed.
Exemestane prescription history
Animated chart of estimated U.S. prescriptions per year, Oral anticancer meds (1953–2026). Exemestane enters in 1999 (estimated).
FDA-approved for
- hormone-receptor-positive breast cancer (1999)
Principal riskAccelerated bone loss and arthralgia
Classes and tags
Clinical profile
Legacy pregnancy categoryMultiple / indication-, trimester- or formulation-dependent
Defining liabilityThrombotic, metabolic, hepatic, skeletal or reproductive toxicity varies by hormonal target.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Adjuvant early breast cancer (ER+, after 2–3 yr tamoxifen) | Postmenopausal women | 25 mg QD after a meal | 25 mg QD after a meal | 25 mg QD |
| Advanced breast cancer (progressed after tamoxifen) | Postmenopausal women | 25 mg QD after a meal | 25 mg QD after a meal | 25 mg QD |
Renal No adjustment needed
Hepatic No adjustment needed
Instructions
- Take one 25 mg tablet once daily after a meal
Available strengths
- tab 25 mg
Cautions
- Reductions in bone mineral density over time — assess BMD by densitometry at baseline in at-risk women
- Assess 25-hydroxy vitamin D before starting; supplement if deficient
- Not indicated in premenopausal women
- Embryo-fetal toxicity — advise effective contraception during and for 1 month after last dose
- Do not coadminister with systemic estrogen-containing agents (interferes with action)
Adverse reactions
- Hot flushes
- Fatigue
- Arthralgia
- Headache
- Insomnia
- Increased sweating
- Nausea (advanced disease)
Pregnancy Can cause fetal harm (abortions, embryo-fetal toxicity in animals); advise risk to fetus
Lactation Advise not to breastfeed during treatment and for 1 month after final dose
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 25 mg | tab | 30 qd | $22.43 | offered |
Generic entry2011
Open Exemestane in the interactive console ↗
Self-check
- Is exemestane’s aromatase inhibition reversible?
No—irreversible. - What is required for exemestane use before menopause?
Ovarian suppression.