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Arimidex Side Effects

Generic name: anastrozole

Medically reviewed by Philip Thornton, DipPharm. Last updated on Oct 24, 2022.

Note: This document contains side effect information about anastrozole. Some dosage forms listed on this page may not apply to the brand name Arimidex.

Applies to anastrozole: oral tablet.

Serious side effects of Arimidex

Along with its needed effects, anastrozole (the active ingredient contained in Arimidex) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking anastrozole:

More common

Less common

  • Arm, back, or jaw pain
  • chest tightness or heaviness
  • chills
  • cough
  • cough producing mucus
  • difficult or painful urination
  • difficulty breathing
  • dizziness, severe
  • fever
  • headache, continuing
  • hoarseness
  • increased blood pressure
  • lower back or side pain
  • nausea
  • pain, tenderness, bluish color, or swelling of the foot or leg
  • sore throat
  • sweating
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  • vaginal bleeding (unexpected and heavy)

Incidence not known

  • Blistering, peeling, or loosening of the skin
  • confusion
  • constipation
  • dark urine
  • depression
  • diarrhea
  • difficulty swallowing
  • dry mouth
  • general tiredness and weakness
  • hives or welts, itching, skin rash
  • incoherent speech
  • increased urination
  • joint or muscle pain
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
  • light-colored stools
  • loss of appetite
  • metallic taste
  • muscle weakness
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sores, ulcers, or white spots in the mouth or on the lips
  • stomach pain
  • thirst
  • upper right abdominal pain
  • vomiting
  • weight loss
  • yellow eyes and skin

Other side effects of Arimidex

Some side effects of anastrozole may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Back pain
  • belching
  • body aches or pain
  • congestion
  • decrease in height
  • feeling of warmth
  • flushing or redness of the skin, especially on the face and neck
  • heartburn
  • increased appetite
  • indigestion
  • lack or loss of strength
  • mood or mental changes
  • pain in the back, ribs, arms, or legs
  • pain, general
  • pelvic pain
  • runny nose
  • stomach discomfort or upset
  • tender, swollen glands in the neck
  • trouble in swallowing
  • voice changes

Less common

  • Anxiety
  • breast pain
  • dryness of the vagina
  • general feeling of discomfort or illness
  • joint stiffness
  • loss of hair
  • numbness or tingling of the hands or feet
  • shivering
  • sleepiness
  • trouble sleeping
  • weight gain

Incidence not known

  • Difficulty in moving
  • muscle cramps or stiffness
  • swollen joints

For Healthcare Professionals

Applies to anastrozole: compounding powder, oral tablet.


Cardiovascular side effects have included hypertension (up to 13%), edema (up to 11%), including peripheral edema (up to 9%). Ischemic cardiovascular disease (4%) has also been reported.[Ref]


Very common (10% or more): Arthritis/arthralgia/arthrosis/joint disorder/joint pain/joint stiffness (36%), back pain (12%), bone pain (12%), osteoporosis (11%), fracture (10%)

Common (1% to 10%): Myalgia, anorexia

Uncommon (0.1% to 1%): Trigger finger[Ref]


Very common (10% or more): Nausea (20%), vomiting (11%)

Common (1% to 10%): Abdominal pain, diarrhea, constipation, dyspepsia, gastrointestinal disorder, dry mouth[Ref]


Very common (10% or more): Fatigue/asthenia (19%), pain (17%), accidental injury (10%), lymphedema (10%), peripheral edema (10%)

Common (1% to 10%): Infection, flu syndrome, cyst, fever, neck pain, malaise[Ref]


Very common (10% or more): Mood disturbances (19%), depression, insomnia[Ref]

Nervous system

Very common (10% or more): Headache (18%), depression (13%), insomnia (10%)

Common (1% to 10%): Dizziness, anxiety, paresthesia, hypertonia, cerebrovascular event (cerebrovascular accident, cerebral ischemia, cerebral infarct), somnolence, confusion, nervousness, carpal tunnel syndrome, sensory disturbances (e.g., taste loss and taste perversion)[Ref]


Very common (10% or more): Rash (11%)

Common (1% to 10%): Sweating, alopecia/hair thinning, pruritus

Rare (less than 0.1%): Skin reactions (lesions, ulcers blisters), erythema multiforme, cutaneous vasculitis (including Henoch-Schonlein purpura)

Very rare (less than 0.01%): Stevens-Johnson syndrome[Ref]


Very common (10% or more): Dyspnea (11%), increased cough (11%), pharyngitis (10%)

Common (1% to 10%): Sinusitis, bronchitis, rhinitis[Ref]


Common (1% to 10%): Urinary tract infection, breast pain, vulvovaginitis, vaginal hemorrhage, vaginitis, vaginal discharge, vaginal bleeding, vaginal dryness, pelvic pain, leukorrhea[Ref]


Common (1% to 10%): Anemia, leukopenia[Ref]


Common (1% to 10%): Increased gamma GT, increased SGOT, increased SGPT, increased alkaline phosphatase

Uncommon (0.1% to 1%): Hepatobiliary events (e.g., increased bilirubin), hepatitis

Rare (less than 0.1%): Changes in liver function (liver inflammation, liver pain, liver swelling)[Ref]


Common (1% to 10%): Weight gain, hypercholesterolemia, weight loss, anorexia

Uncommon (0.1% to 1%): Hypercalcemia (with or without an increase in parathyroid hormone)[Ref]


Common (1% to 10%): Allergic reactions

Uncommon (0.1% to 1%): Urticaria

Rare (less than 0.1%): Anaphylaxis, anaphylactoid reaction

Very rare (less than 0.01%): Angioedema[Ref]


Common (1% to 10%): Cataracts[Ref]


Common (1% to 10%): Neoplasm, tumor flare

Uncommon (0.1% to 1%): Endometrial cancer[Ref]

Frequently asked questions


1. "Product Information. Arimidex (anastrozole)." Astra-Zeneca Pharmaceuticals (2001):

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. Cerner Multum, Inc. "Australian Product Information." O 0

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.