Feb. 8, 2012 -- Some drugs used to strengthen bones may increase the risk of an unusual type of fracture if patients take them for many years, a new study shows.
Overall, most people with osteoporosis, a loss of bone density over time, will suffer fewer broken bones if they take bisphosphonates, a category of drugs including Actonel, Atelvia, Boniva, and Fosamax that are used to treat the disease.
But a very small proportion of those who take the drugs may experience an unusual femur (thighbone) fracture if they take the drugs on a long-term basis.
Still, "we're preventing way more fractures than we're causing," says Richard M. Dell, MD, an orthopedic surgeon at Kaiser Permanente Medical Center in Cypress, Calif. He presented his findings today at the Annual Meeting of the American Academy of Orthopaedic Surgeons.
The fractures are called "atypical femur fractures" and sometimes happen after a fall but often without any noticeable cause.
The fractures happen in about three to seven out of 10,000 people, mostly women in their 60s and 70s. About a third of the people who suffer from this type of fracture feel pain before it happens.
About seven years ago, researchers began to notice that many of the people who experience these unusual fractures were taking bisphosphonates.
And they found that about 20% of the people who have this type of fracture in one leg also go on to experience a similar fracture in the opposite leg.