exemestane

High Alert

Adjuvant treatment of breast cancer in postmenopausal women who have estrogen-receptor positive early disease and who have already received 2–3 yr of tamoxifen and are then switched to exemestane to complete a total of 5 yr of adjuvant therapy.
Treatment of advanced postmenopausal breast cancer that has progressed despite tamoxifen therapy.

Action ⬆ ⬇

Inhibits aromatase, an enzyme responsible for the conversion of androgen to estrogen. In postmenopausal women, the primary source of estrogen is androgen. Decreases circulating estrogen.

Therapeutic effects:

Decreased spread of estrogen-sensitive breast cancer.

Pharmacokinetics ⬆ ⬇

Absorption: 42% absorbed following oral administration.

Distribution: Extensively distributed to tissues.

Metabolism/Excretion: Mostly metabolized by the liver via the CYP3A4 isoenzyme; metabolites are excreted in urine (40%) and feces (40%); <1% excreted unchanged in urine.

Half-Life: 24 hr.

Time/Action Profile ⬆ ⬇

(suppression of circulating estrogen)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	2–3 days	4–5 days

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Premenopausal status;
OB: Pregnancy;
Lactation: Lactation.

Use Cautiously in:

Rep: Women of reproductive potential;

Adv. Reactions/Side Effects ⬆ ⬇

CV: hypertension, THROMBOEMBOLISM

Derm: ↑sweating, alopecia, hot flush, dermatitis

EENT: visual disturbances

GI: diarrhea, nausea

GU: endometrial hyperplasia, uterine polyps

MS: arthralgia, carpal tunnel syndrome, muscle cramps, osteoporosis, pain

Neuro: fatigue, depression, insomnia, neuropathy, paresthesia

Interactions ⬆ ⬇

Drug-drug:

Strong CYP3A4 inducers, including rifampin or phenytoin, may ↓ levels and effectiveness.
Estrogens can interfere with action.

Route/Dosage ⬆ ⬇

PO (Adults ): 25 mg once daily; Concurrent use with strong CYP3A4 inducers: 50 mg once daily.

Availability ⬆ ⬇

(Generic available)

Tablets: 25 mg

Assessment ⬆ ⬇

Assess patient for pain and other side effects periodically during therapy.
Monitor patients for bone mineral density loss and treat as appropriate.

Lab Test Considerations:

Verify negative pregnancy test within 7 days of starting exemestane.
- May cause ↑ GGT, AST, ALT, alkaline phosphatase, bilirubin, and serum creatinine levels.
- Assess 25-hydroxy vitamin D levels prior to starting therapy. Supplement vitamin D deficiency with vitamin D due to high prevalence of vitamin D deficiency in women with early breast cancer.

Implementation ⬆ ⬇

Take 1 tablet daily after a meal.

Patient/Family Teaching ⬆ ⬇

Instruct patient to take exemestane as directed at the same time each day. Take missed doses as soon as remembered unless it is almost time for next dose. Do not double doses. Advise patient to read the Patient Information leaflet before starting and with each Rx refill in case of changes.
Advise patient not to take other estrogen-containing agents; may interfere with action of exemestane.
Inform patient that lower level of estrogen may lead to decreased bone mineral density over time and increased risk of osteoporosis and fracture. Women with osteoporosis or at risk of osteoporosis should have their bone mineral density formally assessed by bone densitometry at end of treatment.
Advise patient to notify health care professional immediately if chest pain or signs of heart failure or stroke occur.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: May cause fetal harm. Advise females of reproductive potential to use effective contraception and avoid breastfeeding during therapy and for at least 1 mo after last dose. May impair female and male fertility.
Explain need for follow-up blood tests to check liver and kidney function.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇