FDA Panel Unclear on Osteoporosis Drug Labels Sept. 9, 2011 -- Labels on bisphosphonates, a type of medication used to treat and prevent osteoporosis, should further clarify how long patients can take them, an FDA advisory panel voted today.

But the panel backed off giving any specific time limits.

Bisphosphonates include Aclasta, Actonel, Altevia, Boniva, Fosamax, and Reclast. Four million to 5 million Americans fill prescriptions for the drugs every year, according to the FDA

The FDA convened the meeting because of emerging safety concerns related to long-term use -- generally considered more than three to five years -- of bisphosphonates.

In particular, the agency has received reports of osteonecrosis, or bone death, of the jaw and unusual fractures of the femur, or thigh bone, in women who had taken the drugs for several years or more.

Meanwhile, some research suggests that because bisphosphonates remain in bone for years, women could still benefit after they stop taking them.

A Visual Guide to Osteoporosis