This is a common side effect of Arimidex and is probably due to lower levels of oestrogen in the body while on this drug. There isn't a single remedy that works for all women but there are a number of things you can try.

Arimidex is a type of hormone treatment called an aromatase inhibitor. Unfortunately, pain in the joints (arthralgia) and in the muscles (myalgia) affect many women taking aromatase inhibitors for breast cancer.

The pain can affect the hands, knees, hips, lower back and shoulders. It may be there all the time or come and go. Some women notice that their joints are stiffer in the morning when they first get up.

If you have recently started taking Armidex the pains may settle over the next few months as your body adjusts to changes in hormone levels. However, this doesn't always happen.

Doctors can prescribe several different painkillers for joint and muscle pains. These range from simple painkillers such as paracetamol to anti-inflammatory painkillers such as ibuprofen, to opiate based medicines such as codeine or, for severe pain, morphine.

A drug called glucosamine, that is often used to treat arthritis, may also be helpful for some women. You can buy this over the counter in health shops and pharmacies but it is not suitable for everyone. In particular, it may affect blood sugar levels so may not be suited to people with diabetes. Before taking this it is best to talk things over with your family doctor or cancer specialist.

One small study suggested that some women who develop joint pain while on aromatase inhibitors, such as Arimidex, have low levels of Vitamin D. The study found that if these women took Vitamin D supplements some of their symptoms improved. Again, before trying vitamin supplements it is best to talk things over with your doctor, as taking vitamin D doses that are too high can be harmful.

Of course, not all joint pains while taking aromatase inhibitors are caused by the treatment. We can tell this because in research studies where half the women took an aromatase inhibitor and half took a sugar pill (placebo). 21 out of 100 women on aromatase inhibitors had joint pain and 16 out of 100 women on the placebo had joint pain. So, many women experience joint pain for other reasons including normal menopausal symptoms and the wear and tear of the ageing process.

If an aromatase inhibitor causes joint pains these will usually disappear soon after stopping the treatment.

For some women taking aromatase inhibitors, the joint pain is too severe to cope with and they cannot continue with the treatment.  In this situation, it is always best to talk things over with your cancer specialist. They may suggest trying a different type of aromatase inhibitor or switching to tamoxifen. Because tamoxifen works in a differently from aromatase inhibitors it tends to cause fewer problems with joint pain.

References

• Felson D and Cummings S. 2005. Aromatase inhibitors and the syndrome of arthralgias with estrogen deprivation. Review Arthritis and Rheumatism 52;9;2594-2598.
• Presant C et al Journal of Clinical Oncology, 2006 ASCO Annual Meeting Proceedings Part I. Vol 24, No. 18S (June 20 Supplement), 2006: 6137
• Management of short and long term toxicities of aromatase inhibitors. 2006 28th San Antonio Breast Cancer Symposium.