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What are Arimidex Side Effects?

Tricia Christensen
Tricia Christensen
Tricia Christensen
Tricia Christensen

Arimidex® or anastrozole is manufactured by Astra Zeneca®, and is a treatment used in post-menopausal women who have early stage breast cancer. It may be used singly or with drugs like tamoxifen. As with most cancer-fighting drugs, Arimidex® side effects can be significant, affecting many parts of the body. They are usually broken down into two groups: serious adverse effects that require medical attention, and less severe effects that, while uncomfortable, aren’t medically urgent.

In the latter group, some of the most common Arimidex® side effects include those that affect the gastrointestinal tract. The drug can cause constipation, diarrhea, general upset, and nausea or vomiting. Another regularly encountered problem with this medicine is generalized body pain. It is most frequently located in the back, but many women also have joint pain.

Hives may be an indication of a medication allergy.
Hives may be an indication of a medication allergy.

Since Arimidex® reduces estrogen levels, it’s also associated with a number of symptoms that feel like menopause. Among these are changes in mood, vaginal dryness, and breakthrough vaginal bleeding. The medicine is given post menopause so it’s possible some of these symptoms might be experienced anyway. For instance, hot flashes, which are one of the common Arimidex® side effects, can occur for several years after the end of menopause, but they may be exacerbated by the medicine.

Other less serious Arimidex® side effects include weight gain, dry mouth, and sleep disturbances. Some women experience tingling sensations, especially in the feet. Others may have trouble with thinning hair, appetite loss or excess perspiration.

Hot flashes may be a side effect of Armidex.
Hot flashes may be a side effect of Armidex.

Serious Arimidex® side effects may appear at once or occur over time. The medicine may exacerbate bone loss and cause osteoporosis. It’s also been shown that some women who take it develop cataracts. Some women will have allergic reactions to this medicine. Sudden development of hives, swelling of the face, lips or tongue, extreme itchiness, and difficulty breathing are medically urgent. There is no predicting if allergy will occur, and it could happen any time after the first dose of the drug is taken.

Nausea and vomiting are possible side effects of taking arimidex.
Nausea and vomiting are possible side effects of taking arimidex.

Additional Arimidex® side effects that need medical attention right away include changes in heart rhythm, swelling in the hands or arms, or developing flulike symptoms. The drug could affect the liver, resulting in jaundice which may be most noted by yellowing of the skin and the whites of the eyes. Sudden sharp pain in the upper right quadrant of the abdomen is also medically urgent, as are developing a rash with blisters, swelling in the arm or hand, or having changes to urination where need to void increases dramatically and may be painful.

Arimidex can cause sleep disturbances in some women.
Arimidex can cause sleep disturbances in some women.

The list of potential adverse effects looks daunting, but many women using this medication won’t experience most of these effects. It is important to understand the risks of taking any drug, and clearly Arimidex® side effects may be uncomfortable and serious for some women. These risks are usually weighed against drug benefits, and many doctors and patients find that the benefits of the drug are worth its potential for adverse effects.

Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...
Tricia Christensen
Tricia Christensen

Tricia has a Literature degree from Sonoma State University and has been a frequent WiseGEEK contributor for many years. She is especially passionate about reading and writing, although her other interests include medicine, art, film, history, politics, ethics, and religion. Tricia lives in Northern California and is currently working on her first novel.

Learn more...

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    • Hives may be an indication of a medication allergy.
      By: Jürgen Fälchle
      Hives may be an indication of a medication allergy.
    • Hot flashes may be a side effect of Armidex.
      By: Ana Blazic Pavlovic
      Hot flashes may be a side effect of Armidex.
    • Nausea and vomiting are possible side effects of taking arimidex.
      By: Alliance
      Nausea and vomiting are possible side effects of taking arimidex.
    • Arimidex can cause sleep disturbances in some women.
      By: Photographee.eu
      Arimidex can cause sleep disturbances in some women.
    • Diarrhea and constipation are possible side effects of taking arimidex.
      By: JPagetRFphotos
      Diarrhea and constipation are possible side effects of taking arimidex.
    • Some side effects of Arimidex mimic the symptoms of menopause because the drug reduces estrogen levels.
      By: rob3000
      Some side effects of Arimidex mimic the symptoms of menopause because the drug reduces estrogen levels.