Exemestane

AROMASIN

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.

FDA-approved for

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

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)

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

NO BOXED WARNINGS

Principal riskAccelerated bone loss and arthralgia

Cost, est. cash$10–$1,000/month

Generic entry2011

Therapeutic safety burden2 / 4

Overdose danger2 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk3 / 4

Legacy pregnancy categoryMultiple / indication-, trimester- or formulation-dependent

Defining liabilityThrombotic, metabolic, hepatic, skeletal or reproductive toxicity varies by hormonal target.