NEWS: Snapping thigh bones caused by bisphosphonates?

Hard on the heels of the FDA’s January 2008 alert about serious joint bone and muscle pain associated with the bisphosphonates, comes a worrying series of reports of spontaneous fracturing of the femur (thigh bone) in women who have taken Fosamax for several years.

There have long been concerns that the bisphosphonate action of suppressing bone turnover may cause bone to deteriorate in strength and become more brittle over time. It would seem that those fears are being realized and although still small, the number of spontaneous fractures is prompting an FDA investigation of the phenomenon. Reports from Singapore, Hong Kong and the US all have a similar story to tell: the thighbones of women patients on Fosamax for five years or more have simply snapped while they were walking or standing. Some individuals experienced hip and thigh pain leading up to the event, and others had no warning whatsoever. Biopsies after fracture have shown severely depressed bone formation.

Bisphosphonates are becoming easier to take, with once-a-month Boniva (enthusiastically promoted by actress Sally Field), and once-a-year Reclast now available. These are much higher doses than daily and weekly Fosamax and we don’t have evidence from clinical trials to reassure us that the side-effects with these higher doses are not even greater. In her 2005 editorial on the long term safety of bisphosphonates Dr Susan Ott Associate Professor of Medicine at the University of Washington warned: ‘The bisphosphonates in doses used today suppress bone formation to a greater extent than the other antiresorbing medications, so it is possible that microdamage accumulation would develop after 15 or 20 yr—just about the time between menopause and the usual onset of osteoporotic fractures. Certainly this is an issue that requires long-term, carefully designed research.’
Maybe the damage is occurring sooner than she expected. In a July 2008 New York Times article Dr Ott admits to having now seen instances of spontaneous fracture: “I have several similar patients myself. …Prior to these recent articles, there were a few cases here and a few cases there, but they are kind of starting to add up.”
The long term effects of bisphosphonates remain unknown. These drugs accumulate in the body, alter the chemical structure of bone, and have an indefinite half life. This means that the drug’s effect goes on, for better or worse. Stopping the drug doesn’t mean that it leaves the body
Recent evidence for jaw necrosis and other bone necrosis (bone death) associated with bisphosphonate are a further warning that these are drugs with the potential for serious harm.
Vioxx, HRT, Prozac… the list of blockbuster drugs once heralded as safe and effective but later found to put consumers at serious risk goes on. Are bisphosphonates, the multi-billion dollar wonder drugs for bones with over 10 million users worldwide going to end up discredited and discarded also?