An advisory issued last month by the Food and Drug Administration, which first approved Fosamax in the 1990s to treat and prevent osteoporosis, along with reports in medical journals linking bisphosphonates with some rare medical problems including unusual thigh fractures, has heightened scrutiny of the long-term use of these medications.
While the F.D.A. cautioned that it was not clear that oral bisphosphonates had caused the rare thigh breaks, it said these kinds of bone fractures might be related to lengthy treatments with the drugs. The agency will now require the labels on Fosamax, Actonel, Boniva, Reclast and Atelvia and generic alternatives to state that the optimal period for using the drugs is unknown.
That uncertainty has shadowed the debate over how and when to prescribe these bone drugs, especially because they have been successful, by most accounts, in significantly reducing fractures over several years in postmenopausal women with osteoporosis.