Readers’ alert: drug side-effects:Breast cancer drug can weaken bones

Have you any up-to-date information on anastrozole, which I have been taking for two and a half years, following breast cancer in 1996 and lymph-node secondaries in 2002? I sensed some concern regarding this drug on my last check-up, when the oncologist encouraged me to have a bone scan, previously never suggested. – Elizabeth Loftus, Dorset

WDDTY replies: Anastrozole (Arimidex) is a potent selective, non-steroidal aromatase inhibitor that blocks oestrogen, identified as stimulating breast cancer. It also lowers oestrogen levels in the circulation, and this may cause a reduction in bone mineral density.

In fact, AstraZeneca’s laboratory tests from two groups of patients in a drug trial revealed that those taking anastrozole for 12 or 24 months had bone density decreases overall and in the lumbar (lower back) spine.

The drug is not recommended for use in premenopausal women as its safety and efficacy have yet to be established.