Heart warning over 'brittle bones' drug.
Thousands of British women take Fosamax for the bone-thinning disease which is a common side effect of the menopause.
Researchers in the US have now found a link between the drug and atrial fibrillation, a type of rhythm disorder which causes the heart to beat erratically.
Although AF is not fatal in itself, it can cause the blood to pool and form potentially dangerous clots.
Fosamax is the name under which the drug alendronate is marketed by the pharmaceutical company Merck & Co. It belongs to a class of drugs known as bisphosphonates which prevent loss of bone density.
The American researchers led by Professor Susan Heckbert, from the University of Washington, in Seattle, studied 719 women who were diagnosed with AF over a three-year period.
They were compared with 966 randomly chosen women who did not have AF.