DESCRIPTION
MECHANISM OF ACTION
• Permanently binds to and irreversibly inactivates aromatase.
• Inhibits the synthesis of estrogens by inhibiting the conversion of adrenal androgens (androstenedione and testosterone) to estrogens (estrone, estrone sulfate, and estradiol).
• No inhibitory effect on adrenal corticosteroid or aldosterone biosynthesis.
ABSORPTION
Excellent bioavailability via the oral route, with 85% of a dose absorbed within 2 hours of ingestion. Absorption is not affected by food.
DISTRIBUTION
Widely distributed throughout the body. About 90% of drug is bound to plasma proteins. Steady-state levels of drug are achieved after 7 days of a once-daily administration.
INDICATIONS
Treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen therapy.
DOSAGE RANGE
Recommended dose is 25 mg PO once daily after a meal.
DRUG INTERACTION 1
Phenytoin and other drugs that stimulate the liver microsomal CYP3A4 enzymes, including carbamazepine, rifampin, phenobarbital, and St. John’s Wort—These drugs may increase the metabolism of exemestane, resulting in its inactivation and lower effective drug levels.
DRUG INTERACTION 2
Drugs that inhibit the liver microsomal CYP3A4 enzymes, including ketoconazole, itraconazole, erythromycin, and clarithromycin—These drugs may decrease the metabolism of exemestane, resulting in increased drug levels and potentially increased toxicity.
SPECIAL CONSIDERATIONS
1. No dose adjustments are required for patients with either hepatic or renal dysfunction.
2. Should not be administered to premenopausal women.
3. Should not be administered with estrogen-containing agents, as they may interfere with antitumor activity.
4. Caution patients about the risk of hot flashes.
5. No need for glucocorticoid and/or mineralocorticoid replacement.
6. Pregnancy category D. Breastfeeding should be avoided.
TOXICITY 1
Hot flashes.
TOXICITY 2
Mild nausea.
TOXICITY 3
Fatigue.
TOXICITY 4
Headache.
TOXICITY 5
Musculoskeletal symptoms including carpal tunnel syndrome.
Exemestane.txt
Displaying Exemestane.txt.
SPECIFICATION
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