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Official ARIMIDEX® (anastrozole) 1 mg Tablets
ARIMIDEX® (anastrozole) Tablets Side Effects


ARIMIDEX Side Effects

Like all medications, ARIMIDEX has potential side effects. Listed below are some of the most common side effects you should be familiar with when taking or considering taking ARIMIDEX.

These tips for managing side effects are only suggestions and are not meant to be tried without the knowledge of your doctor or health care provider. If you’re experiencing serious discomfort, contact your doctor immediately. Always talk to your doctor before making any changes to your medication routine.

If you experience hot flashes

Hot flashes are one of the most common side effects of hormonal treatment, and they have a lot to do with the hormonal changes within your body. These changes can be caused by menopause and medication, and may be influenced by lifestyle.

Knowing what can trigger hot flashes may help you manage them:

  • Alcohol
  • Spicy foods
  • Stress
  • Caffeine
  • Hot rooms
  • Smoking
  • Sunshine
  • Confined spaces


It may help to write down when your hot flashes occur and what you were eating, doing, and feeling at the time. That way, you can start to figure out the things that trigger your hot flashes—and try to avoid them. Talk to your doctor about certain medications that may reduce hot flashes. There may be an option that's right for you.

Many women find that stress is also one of the most common triggers of hot flashes. To help avoid being stressed, try these ideas:

  • Meditation or yoga. Make sure to check with your doctor before starting any exercise program
  • Watch a funny movie. A little laughter never hurts

If you experience nausea and vomiting

Certain cancer treatments can change the way your body responds to food. You may, for example, experience symptoms of nausea and vomiting, or changes in taste, smell, or bowel habits, as a result of these treatments. While symptoms are usually temporary, you may need to adjust what, when, and how you eat to keep up your strength during treatment.


On days when you simply can't bring yourself to eat, don't worry. Just do what you can to make yourself feel better, and get back to eating as soon as you can. If your appetite doesn't return in a few days, talk to your doctor. Specific medications may help. Let your doctor know if nausea/vomiting is interfering with your daily activities. He or she can discuss treatment options with you.

If you experience joint symptoms

Some women taking hormonal treatment may experience joint pain. Sometimes this joint pain is the result of taking hormonal treatment, like aromatase inhibitors, and sometimes it can be a result of a preexisting joint condition.


Talk to your doctor to discuss treatment options, such as over-the-counter pain relievers like acetaminophen or prescription pain relievers. Or, apply a little heat. Try using a heat pack or taking a hot shower.

If you experience bone loss

Postmenopausal women in general may be at increased risk for bone loss (osteoporosis) due to decreasing levels of estrogen in the body. Certain hormonal treatments for breast cancer can increase this risk. The impact breast cancer can have on your bones depends on several factors, including:

  • How strong your bones were (measured by a bone mineral density [BMD] test) before you were diagnosed with breast cancer
  • Which type of breast cancer treatments you receive
  • Your menopausal status


  • Make sure you eat a balanced diet full of calcium and vitamin D
  • Weight-bearing exercise, such as walking, can help. Consider doing it with a friend to help stay motivated. Talk to your doctor before starting any exercise program
  • Avoid smoking and limit your alcohol consumption

Talk to your doctor to see if you need to have a BMD test to help determine if you are at risk for osteoporosis.

If you experience weakness and fatigue

Treatment-related fatigue can be physically and mentally draining. Unlike normal tiredness—relieved by rest, exercise, or a good night's sleep—fatigue brought on by cancer treatments can leave you feeling wiped out, even after getting plenty of rest. It may also make it hard to concentrate or think clearly.


  • Don't overdo it. Be aware of your energy levels and pace yourself accordingly. Listen to your body
  • If you can't beat fatigue with rest or moderate activity, talk to your doctor. Treatment-related fatigue can also be related to anemia—a manageable condition that occurs when your red blood cell count is low

If you experience swelling (lymphedema)

Some women who have had breast cancer that affected the lymph nodes may develop lymphedema. This is a swelling of the arm that is caused by an accumulation of lymph fluid. It sometimes occurs after surgery or radiation treatment for breast cancer. Some signs of lymphedema include increased thickness of your skin, a feeling of tightness, and decreased flexibility.


These precautions may help you avoid or manage lymphedema:

  • Keep your affected arm elevated when possible and when resting
  • Ask your doctor about wearing a compression sleeve to help pooling fluid drain
  • Ask about massage for the affected arm
  • Perform gentle exercises to maintain flexibility and range of motion
  • Carry your handbag or shopping bags on the unaffected arm
  • Wear gloves when gardening or washing dishes to protect yourself from infection
  • Apply moisturizing cream to the arm daily
  • Avoid wearing anything tight on the affected arm, including clothing, watchbands, or bracelets
  • Use your unaffected arm for blood tests, injections, and blood pressure checks whenever possible

Call your doctor if your arm or hand becomes red, warm, or swollen. You may have an infection that requires immediate treatment.

Important Safety Information About ARIMIDEX

  • Prescription ARIMIDEX is only for postmenopausal women. ARIMIDEX should not be taken if you are pregnant because it may harm your unborn child. Do not take ARIMIDEX if you are allergic to any of its ingredients
  • Based on information from a study in patients with early breast cancer, women with a history of blockages in heart arteries (ischemic heart disease) who take ARIMIDEX may have a slight increase in this type of heart disease compared to similar patients who take tamoxifen
  • ARIMIDEX can cause bone softening/weakening (osteoporosis) increasing the chance of fractures. In a clinical study in early breast cancer, there were more fractures (including fractures of the spine, hip, and wrist) with ARIMIDEX (10%) than with tamoxifen (7%)
  • In a clinical study in early breast cancer, some patients taking ARIMIDEX had an increase in cholesterol. Skin reactions, allergic reactions, and changes in blood tests of liver function have also been reported
  • In the early breast cancer clinical trial, the most common side effects seen with ARIMIDEX include hot flashes, joint symptoms (including arthritis and arthralgia), weakness, mood changes, pain, back pain, sore throat, nausea and vomiting, rash, depression, high blood pressure, osteoporosis, fractures, swelling of arms/legs, insomnia, and headache
  • In advanced breast cancer trials, the most common side effects seen with ARIMIDEX versus tamoxifen include hot flashes, nausea, decreased energy and weakness, pain, back pain, headache, bone pain, increased cough, shortness of breath, sore throat, and swelling of arms and legs. Joint pain/stiffness has been reported in association with the use of ARIMIDEX
  • ARIMIDEX should not be taken with tamoxifen or estrogen-containing therapies

Approved Uses for ARIMIDEX

ARIMIDEX is approved for adjuvant treatment (treatment following surgery with or without radiation) of postmenopausal women with hormone receptor-positive early breast cancer.

ARIMIDEX is approved for the initial treatment of postmenopausal women with hormone receptor-positive or hormone receptor-unknown locally advanced or metastatic breast cancer and for the treatment of postmenopausal women with advanced breast cancer that has progressed following treatment with tamoxifen. Patients with hormone receptor-negative disease and patients who did not previously respond to tamoxifen therapy rarely responded to ARIMIDEX.

For more information, see your doctor.

Please see full Prescribing Information.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit or call 1-800-FDA-1088.

This site is intended for US consumers only.

The information on this Web site should not take the place of talking with your doctor or health care professional. If you have any questions about your condition, or if you would like more information about ARIMIDEX, talk to your doctor or pharmacist. Only you and your health care professional can decide if ARIMIDEX is right for you.