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Pharmacologic class: Aromatase inhibitor

Therapeutic class: Hormonal antineoplastic

Pregnancy risk category D


Inhibits conversion of androgens to estrogen, which reduces estrogen concentrations and limits cancer cell growth in estrogen-dependent breast tumors


Tablets: 25 mg

Indications and dosages

Advanced breast cancer

Adults: 25 mg P.O. once daily after a meal


• Hypersensitivity to drug or its components

• Premenopausal women, including pregnant women


Use cautiously in:

• moderate to severe hepatic insufficiency or renal impairment

• concurrent use of estrogencontaining drugs

• breastfeeding patients

• children (safety and efficacy not established).


• Administer after meals with a full glass of water.

• Know that drug shouldn't be taken by premenopausal women or by patients receiving drugs that contain estrogen.

Adverse reactions

CNS: headache, dizziness, confusion, asthenia, fatigue, weakness, hypoesthesia, paresthesia, pain, anxiety, insomnia, depression

CV: hypertension, chest pain

EENT: sinusitis

GI: nausea, vomiting, diarrhea, constipation, abdominal pain, dyspepsia, anorexia

GU: urinary tract infection

Musculoskeletal: pathologic fractures, arthritis, back pain, skeletal pain

Respiratory: dyspnea, cough, bronchitis, upper respiratory tract infection

Skin: rash, itching, alopecia, diaphoresis

Other: increased appetite, fever, hot flashes, infection, flulike symptoms, edema, lymphedema


Drug-drug. CYP3A4 inducers: decreased exemestane blood level

Patient monitoring

• Monitor vital signs, especially blood pressure.

• Check for adverse GI reactions. Give antiemetics, as prescribed, for nausea and vomiting.

• Assess bowel elimination pattern. Increase fluids and administer stool softeners, as needed, to ease constipation.

• Monitor pain level. Administer analgesics, as prescribed, to relieve pain.

• Monitor liver function tests, CBC, and blood urea nitrogen, creatinine, and electrolyte levels.

Patient teaching

• Advise patient to take with full glass of water after a meal.

• Tell patient to report depression, insomnia, or excessive anxiety.

• Instruct patient to wear cotton clothing to let skin breathe if drug causes increased sweating or hot flashes.

• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(ex-e-mes-tane) ,


(trade name)


Therapeutic: antineoplastics
Pharmacologic: aromatase inhibitors
Pregnancy Category: X


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.


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.


Absorption: 42% absorbed following oral administration.
Distribution: Extensively distributed.
Metabolism and Excretion: Mostly metabolized by the liver (CYP3A4 enzyme system); 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)

POunknown2–3 days4–5 days


Contraindicated in: Hypersensitivity;Premenopausal status; Obstetric: Pregnancy (may cause fetal harm); Lactation: Breast feeding should be avoided.
Use Cautiously in: Pediatric: Safe and effective use not established.

Adverse Reactions/Side Effects

Central nervous system

  • fatigue (most frequent)
  • depression
  • insomnia


  • thromboembolism (life-threatening)
  • hypertension


  • diarrhea
  • nausea


  • endometrial hyperplasia
  • uterine polyps


  • visual disturbances


  • alopecia (most frequent)
  • hot flashes (most frequent)
  • increased sweating (most frequent)
  • dermatitis


  • arthralgia (most frequent)
  • musculoskeletal pain
  • carpal tunnel syndrome
  • muscle cramps
  • osteoporosis


  • neuropathy
  • paresthesia


Drug-Drug interaction

CYP3A4 inducers including rifampin or phenytoin may ↓ levels and effectiveness; ↑ daily dose to 50 mg once daily.Estrogens can interfere with action.


Oral (Adults) 25 mg once daily; Concurrent use with CYP3A4 inducers—50 mg once daily.

Availability (generic available)

Tablets: 25 mg

Nursing implications

Nursing assessment

  • Assess patient for pain and other side effects periodically during therapy.
  • Lab Test Considerations: May cause ↑ GTT, AST, ALT, alkaline phosphatase, bilirubin, and 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.

Potential Nursing Diagnoses

Acute pain (Side Effects)


  • 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; changes may occur.
  • 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.
  • 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.
  • Exemestane is teratogenic; advise female patients to use effective contraception during therapy and to avoid breast feeding.
  • Explain need for follow-up blood tests to check liver and kidney function.

Evaluation/Desired Outcomes

  • Slowing of disease progression in women with breast cancer.
Drug Guide, © 2015 Farlex and Partners


An irreversible, steroidal aromatase-inactivating anti-oestrogen used in postmenopausal women with oestrogen-dependent/oestrogen-receptor-positive breast cancer.
Adverse effects
Hot flushes, nausea, fatigue, increased sweating.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.
References in periodicals archive ?
The company added that the Exemestane Tablets in 25mg is the generic version of Pfizer's Aromasin Tablets.
"We are pleased to offer physicians and patients a cost-effective alternative to Aromasin," stated Rusty Field, president and chief executive officer of Upsher-Smith.
New findings have found exemestane (Aromasin) may reduce breast cancer recurrence among premenopausal women compared with tamoxifen when given along with ovarian suppression.
Notably absent in the new guidelines is an endorsement of the aromatase inhibitor exemestane (Aromasin).
Table 1: Metabolism and Transport Effects (10-13) Arimidex Aromasin Femara Tamoxifen CYP1A2 weakly inhibits CYP2A6 minor substrate minor weakly substrate inhibits weakly inhibits CYP3A4 weakly major substrate minor major substrate inhibits weakly induces substrate weakly inhibits CYP2B6 minor substrate weakly inhibits CYP2C8 weakly weakly inhibits inhibits CYP2C9 weakly major substrate inhibits weakly inhibits CYP2C19 weakly inhibits CYP2D6 major substrate CYP2E1 minor substrate + minor substrate ++ major substrate [down arrow] weakly inhibits [down arrow] [down arrow] strongly induces [up arrow] weakly inhibits CYP2D6 Polymorphisms
ISLAMABAD -- In what may be seen as a positive development, it has emerged that the anti-estrogen drug Aromasin reduces the risk of breast cancer recurrence by about one-third in postmenopausal women previously treated with tamoxifen.
For many women, hormone therapy means treatment with the drug tamoxifen; fulvestrant (Faslodex), a drug that works similarly to tamoxifen but eliminates the estrogen receptor instead of blocking it; or an aromatase inhibitor, such as anastrozole (Arimidex), letrozole (Femara) or exemestane (Aromasin).
Aromatase inhibitors (Arimidex, Aromasin, or Femara) have fewer side effects and more benefits than tamoxifen.
TPMT ** Tabloid, [30] thioguanine (GlaxoSmithKine) DPD ** Xeloda, [31] capecitabine (Hoffman La Roche Inc.) ER-PGR ** Aromasin, [32] exemestane (Pfizer) G6PD ** Elitek, [33] rasburicase (Sanofi- synthelabo Inc.) ER * Nolvadex, [34] tamoxifen (AstraZeneca) ER * Arimidex, [35] anastrozole (AstraZeneca) ER ** Faslodex, [36] fulvestrant (AstraZeneca) UGT1A1 ** Camptosar, [37] irinotecan (Pfizer) ERCC1 * Camptosar, [38] irinotecan (Pfizer) tpmt * Platinol, [39] cisplatin, (Bristol-Myers Squibb Company) tpmt ** Tabloid, [40] thioguanine (GlaxoSmithKline) CDK 4 and 6 * Palbociclib, PD- [41] 0332991 (Pfizer) * This biomarkers are used for diagnostic and prognostic purposes to determine the proper cause of treatment (investigational diagnostics and/or drugs).
In postmenopausal women, however, exemestane (Aromasin), an aromatase inhibitor, is the safer, better choice, even though the drug's use in chemoprevention is, for now, off label, she said.
After my chemotherapy ended, I could choose to take five years of an oral hormonal drug called Tamoxifen, or I could suppress my ovaries by taking a drug called Lupron or Zoladex and take five years of an Aromatase Inhibitor such as Letrozole (brand name Femara), Exemestane (Aromasin), or Anastrozole (Arimidex), or I could take five years of Tamoxifen and follow it up with another five years of an Aromatase Inhibitor.