Aromasin Side Effects Center

Last updated on RxList: 12/2/2021
Aromasin Side Effects Center

What Is Aromasin?

Aromasin (exemestane) is an antineoplastic (anticancer) agent used to treat breast cancer in postmenopausal women. Aromasin is often given to women whose cancer has progressed even after taking tamoxifen (Nolvadex, Soltamox) for 2 to 3 years.

What Are Side Effects of Aromasin?

Common side effects of Aromasin include:

  • hot flashes,
  • headache,
  • hair loss,
  • joint/bone/muscle pain,
  • tiredness,
  • anxiety,
  • unusual or increased sweating,
  • nausea,
  • upset stomach,
  • diarrhea,
  • dizziness,
  • depression, and
  • trouble sleeping (insomnia).

Tell your doctor if you have serious side effects of Aromasin including:

  • bone fractures,
  • mental/mood changes (such as depression, anxiety),
  • vaginal bleeding,
  • persistent nausea or vomiting,
  • unusual tiredness,
  • dark urine, or
  • yellowing eyes or skin.

Dosage for Aromasin?

The recommended dose of Aromasin in early and advanced breast cancer is one 25 mg tablet once daily after a meal.

What Drugs, Substances, or Supplements Interact with Aromasin?

Aromasin may interact with rifampin, St. John's wort, or seizure medication. Discuss all medications you are taking with your doctor.

Aromasin During Pregnancy and Breastfeeding

Aromasin must not be used during pregnancy. It may harm a fetus. Aromasin is used mainly in women after menopause. If you are near menopause or have not gone through menopause and your doctor has prescribed this for you, discuss with your doctor whether you need to use reliable forms of birth control. Do not use birth control products containing estrogen. Consult your doctor for more details. If you become pregnant or think you may be pregnant, tell your doctor immediately. It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

Additional Information

Our Aromasin Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Breast Cancer Awareness: Symptoms, Diagnosis, and Treatment See Slideshow
Aromasin Consumer Information

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • chest pain or pressure;
  • new or unusual bone pain;
  • swelling in your hands or feet;
  • feeling short of breath, even with mild exertion; or
  • signs of a blood clot--sudden numbness or weakness, problems with vision or speech, swelling or redness in an arm or leg.

Common side effects may include:

  • hot flashes;
  • headache, feeling tired;
  • joint pain;
  • nausea;
  • increased appetite;
  • sleep problems (insomnia); or
  • increased sweating.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


A lump in the breast is almost always cancer. See Answer
Aromasin Professional Information


The following clinically significant adverse reactions are described elsewhere in the labeling:

  • Reductions in Bone Mineral Density (BMD) [see WARNINGS AND PRECAUTIONS]

Clinical Trial Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

Adjuvant Therapy

The data described below reflect exposure to AROMASIN in 2325 postmenopausal women with early breast cancer. AROMASIN tolerability in postmenopausal women with early breast cancer was evaluated in two well-controlled trials: the IES study [See Clinical Studies] and the 027 study (a randomized, placebo-controlled, double-blind, parallel group study specifically designed to assess the effects of exemestane on bone metabolism, hormones, lipids, and coagulation factors over 2 years of treatment).

The median duration of adjuvant treatment was 27.4 months and 27.3 months for patients receiving AROMASIN or tamoxifen, respectively, within the IES study and 23.9 months for patients receiving AROMASIN or placebo within the 027 study. Median duration of observation after randomization for AROMASIN was 34.5 months and for tamoxifen was 34.6 months. Median duration of observation was 30 months for both groups in the 027 study.

Certain adverse reactions, which were expected based on the known pharmacological properties and side effect profiles of test drugs, were actively sought through a positive checklist. Signs and symptoms were graded for severity using CTC in both studies. Within the IES study, the presence of some illnesses/conditions was monitored through a positive checklist without assessment of severity. These included myocardial infarction, other cardiovascular disorders, gynecological disorders, osteoporosis, osteoporotic fractures, other primary cancer, and hospitalizations.

Within the IES study, discontinuations due to adverse reactions occurred in 6% and 5% of patients receiving AROMASIN and tamoxifen, respectively, and in 12% and 4.1% of patients receiving exemestane or placebo respectively within study 027.

Deaths due to any cause were reported for 1.3% of the exemestane treated patients and 1.4% of the tamoxifen treated patients within the IES study. There were 6 deaths due to stroke on the exemestane arm compared to 2 on tamoxifen. There were 5 deaths due to cardiac failure on the exemestane arm compared to 2 on tamoxifen.

The incidence of cardiac ischemic events (myocardial infarction, angina, and myocardial ischemia) was 1.6% in exemestane treated patients and 0.6% in tamoxifen treated patients in the IES study. Cardiac failure was observed in 0.4% of exemestane treated patients and 0.3% of tamoxifen treated patients.

In the adjuvant treatment of early breast cancer, the most common adverse reactions occurring in ≥10% of patients in any treatment group (AROMASIN vs. tamoxifen) were hot flushes (21% vs. 20%), fatigue (16% vs. 15%), arthralgia (15% vs. 9%), headache (13% vs. 11%), insomnia (12% vs. 9%), and increased sweating (12% vs. 10%). Discontinuation rates due to AEs were similar between AROMASIN and tamoxifen (6% vs. 5%). Incidences of cardiac ischemic events (myocardial infarction, angina, and myocardial ischemia) were AROMASIN 1.6%, tamoxifen 0.6%. Incidence of cardiac failure: AROMASIN 0.4%, tamoxifen 0.3%.

Treatment-emergent adverse reactions and illnesses including all causalities and occurring with an incidence of ≥5% in either treatment group of the IES study during or within one month of the end of treatment are shown in Table 2.

Table 2. Incidence (%) of Adverse Reactions of all Grades1 and Illnesses Occurring in (≥5%) of Patients in Any Treatment Group in Study IES in Postmenopausal Women with Early Breast Cancer

% of patients
Body system and Adverse Reaction by MedDRA dictionary AROMASIN
25 mg daily
20 mg daily2
  Visual disturbances3 5 3.8
  Nausea3 9 9
General Disorders
  Fatigue3 16 15
  Arthralgia 15 9
  Pain in limb 9 6
  Back pain 9 7
  Osteoarthritis 6 4.5
Nervous System
  Headache3 13 11
  Dizziness3 10 8
    Insomnia3 12 9
    Depression 6 6
Skin & Subcutaneous Tissue
  Increased sweating3 12 10
  Hot flushes3 21 20
  Hypertension 10 8
1Graded according to Common Toxicity Criteria;
275 patients received tamoxifen 30 mg daily;
3 Event actively sought.

In the IES study, as compared to tamoxifen, AROMASIN was associated with a higher incidence of events in musculoskeletal disorders and in nervous system disorders, including the following events occurring with frequency lower than 5% (osteoporosis [4.6% vs. 2.8%], osteochondrosis and trigger finger [0.3% vs. 0% for both events], paresthesia [2.6% vs. 0.9%], carpal tunnel syndrome [2.4% vs. 0.2%], and neuropathy [0.6% vs. 0.1%]). Diarrhea was also more frequent in the exemestane group (4.2% vs. 2.2%). Clinical fractures were reported in 94 patients receiving exemestane (4.2%) and 71 patients receiving tamoxifen (3.1%). After a median duration of therapy of about 30 months and a median follow-up of about 52 months, gastric ulcer was observed at a slightly higher frequency in the AROMASIN group compared to tamoxifen (0.7% vs. <0.1%). The majority of patients on AROMASIN with gastric ulcer received concomitant treatment with non-steroidal anti-inflammatory agents and/or had a prior history.

Tamoxifen was associated with a higher incidence of muscle cramps [3.1% vs. 1.5%], thromboembolism [2.0% vs. 0.9%], endometrial hyperplasia [1.7% vs. 0.6%], and uterine polyps [2.4% vs. 0.4%].

Common adverse reactions occurring in study 027 are described in Table 3.

Table 3. Incidence of Selected Treatment-Emergent Adverse Reactions of all CTC Grades* Occurring in ≥ 5% of Patients in Either Arm in Study 027

Adverse Reaction Exemestane
(% incidence)
(% incidence)
Hot flushes 33 25
Arthralgia 29 29
Increased sweating 18 21
Alopecia 15 4.1
Hypertension 15 7
Insomnia 14 15
Nausea 12 16
Fatigue 11 19
Abdominal pain 11 14
Depression 10 7
Diarrhea 10 1.4
Dizziness 10 10
Dermatitis 8 1.4
Headache 7 4.1
Myalgia 6 4.1
Edema 6 7
*Most events were CTC grade 1–2

Treatment Of Advanced Breast Cancer

A total of 1058 patients were treated with exemestane 25 mg once daily in the clinical trials program. One death was considered possibly related to treatment with exemestane; an 80-year-old woman with known coronary artery disease had a myocardial infarction with multiple organ failure after 9 weeks on study treatment. In the clinical trials program, 3% of the patients discontinued treatment with exemestane because of adverse reactions, 2.7% of patients discontinued exemestane within the first 10 weeks of treatment.

In the comparative study, adverse reactions were assessed for 358 patients treated with AROMASIN and 400 patients treated with megestrol acetate. Fewer patients receiving AROMASIN discontinued treatment because of adverse reactions than those treated with megestrol acetate (2% vs. 5%). Adverse reactions that were considered drug related or of indeterminate cause included hot flashes (13% vs. 5%), nausea (9% vs. 5%), fatigue (8% vs. 10%), increased sweating (4% vs. 8%), and increased appetite (3% vs. 6%) for AROMASIN and megestrol acetate, respectively. The proportion of patients experiencing an excessive weight gain (>10% of their baseline weight) was significantly higher with megestrol acetate than with AROMASIN (17% vs. 8%).

In the treatment of advanced breast cancer, the most common adverse reactions included hot flushes (13% vs. 5%), nausea (9% vs. 5%), fatigue (8% vs. 10%), increased sweating (4% vs. 8%), and increased appetite (3% vs. 6%) for AROMASIN and megestrol acetate, respectively.

Table 4 shows the adverse reactions of all CTC grades, regardless of causality, reported in 5% or greater of patients in the study treated either with AROMASIN or megestrol acetate.

Table 4. Incidence (%) of Adverse Reactions of all Grades* and Causes Occurring in ≥5% of Advanced Breast Cancer Patients In Each Treatment Arm in the Comparative Study

Body system and Adverse Reaction by WHO ART dictionary AROMASIN
25 mg once daily
Megestrol Acetate
40 mg QID
Autonomic Nervous
  Increased sweating 6 9
Body as a Whole
  Fatigue 22 29
  Hot flashes 13 6
  Pain 13 13
  Influenza-like symptoms 6 5
  Edema (includes edema, peripheral edema, leg edema) 7 6
  Hypertension 5 6
  Depression 13 9
  Insomnia 11 9
  Anxiety 10 11
  Dizziness 8 6
  Headache 8 7
  Nausea 18 12
  Vomiting 7 4
  Abdominal pain 6 11
  Anorexia 6 5
  Constipation 5 8
  Diarrhea 4 5
  Increased appetite 3 6
  Dyspnea 10 15
  Coughing 6 7
*Graded according to Common Toxicity Criteria

Adverse reactions of any cause (from 2% to 5%) reported in the comparative study for patients receiving AROMASIN 25 mg once daily were fever, generalized weakness, paresthesia, pathological fracture, bronchitis, sinusitis, rash, itching, urinary tract infection, and lymphedema.

Additional adverse reactions of any cause observed in the overall clinical trials program (N = 1058) in 5% or greater of patients treated with exemestane 25 mg once daily but not in the comparative study included pain at tumor sites (8%), asthenia (6%), and fever (5%). Adverse reactions of any cause reported in 2% to 5% of all patients treated with exemestane 25 mg in the overall clinical trials program but not in the comparative study included chest pain, hypoesthesia, confusion, dyspepsia, arthralgia, back pain, skeletal pain, infection, upper respiratory tract infection, pharyngitis, rhinitis, and alopecia.

Post-Marketing Experience

The following adverse reactions have been identified during post approval use of AROMASIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Immune system disorders - hypersensitivity

Hepatobiliary disorders - hepatitis including cholestatic hepatitis

Nervous system disorders - paresthesia

Musculoskeletal and connective tissue disorder - tenosynovitis stenosans

Skin and subcutaneous tissue disorders - acute generalized exanthematous pustulosis, urticaria, pruritus


Drugs That Induce CYP 3A4

Co-medications that induce CYP 3A4 (e.g., rifampicin, phenytoin, carbamazepine, phenobarbital, or St. John’s wort) may significantly decrease exposure to exemestane. Dose modification is recommended for patients who are also receiving a strong CYP 3A4 inducer [see DOSAGE AND ADMINISTRATION and CLINICAL PHARMACOLOGY].

Read the entire FDA prescribing information for Aromasin (Exemestane)

© Aromasin Patient Information is supplied by Cerner Multum, Inc. and Aromasin Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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