Drug class/mechanism of action: Hormonal agent, steroidal aromatase inhibitor.

Exemestane Dosage forms: 25-mg tablets.

Drug Interactions: Despite the fact that exemestane is metabolized by cytochrome P450 3A4, ketoconazole does not affect its half-life or AUC, and no other drug-drug interactions have been identified.

Metabolism/pharmacokinetics: After oral administration, approximately 40% of exemestane is absorbed from the GI tract. Absorption is increased by a fatty meal. It is highly protein bound in the plasma. Exemestane is metabolized in the liver by cytochrome P450 3A4 and aldoketoreductase. Metabolites are eliminated equally in urine and feces.

Toxicity: Through generally well tolerated, exemestane is expected to cause or exacerbate hot flashes or intermittent flushing is some women. Fatigue and mild nausea are common. Vomiting, headache, and dyspnea are uncommon. It is teratogenic and should not be used in premenopausal women.

Indications: FDA approved for treatment of estrogen-responsive metastatic breast cancer in postmenopausal women who have progressed on prior hormonal therapy.
Dosing: 25 mg orally once daily after meal.