FRIDAY, Sept. 9 (HealthDay News) -- U.S. Food and Drug Administration advisers recommended Friday that osteoporosis drugs such as Fosamax, Actonel, Boniva and Reclast come with revised labels, clarifying how long a patient should take a drug before potential health risks set in.

The drugs, known as bisphosphonates, are taken to prevent fractures related to postmenopausal osteoporosis. But researchers have linked long-term use with a small risk of unusual fractures of the thigh bone, death of the jawbone (osteonecrosis of the jaw) and possibly esophageal cancer.

By a 17-6 vote, the FDA advisers recommended that the drug labels -- or package inserts -- should be clarified, detailing the best duration of use for each drug. But the advisers did not offer specific wording changes; the label wording could vary for each drug, the Associated Press reported.

The revised labels should "be very clear that efficacy may fall off after a period of time, perhaps five years," panelist Dr. Lewis Nelson, director of the medical toxicology fellowship program at New York University, said after the vote, Bloomberg News reported. "Serious concerns have been raised about risk, and those need to be continually evaluated as well."

The FDA is not compelled to follow the recommendations of its advisory committees but it usually does so.

According to the FDA, in 2009 more than 5 million prescriptions were filled for bisphosphonates, which inhibit bone loss.

Dr. Elizabeth Shane, past president of the American Society for Bone and Mineral Research, who was scheduled to testify before the committee, said reports linking bisphosphonates with atypical fractures and osteonecrosis of the jaw are "extremely rare, when considered in the context of how many people take bisphosphonates for osteoporosis." She was "less certain about the esophageal cancer issue," she added.

While these side effects shouldn't be downplayed, "when you consider the number of very dangerous, life-threatening fractures that are prevented by these drugs, the benefits dwarf the side effects," said Shane, also a professor of medicine at Columbia University in New York City.

However, she said bisphosphonates should only be prescribed to those at the highest risk of fracture. "In the past we might have used them in people who aren't at such high risk of fracture in the hope that they would prevent fractures down the line," she said. "We have moved to targeting people at high short-term risk, which means in the next five to 10 years."

According to Shane, the absolute risk of developing osteonecrosis of the jaw is between 1 in 10,000 and 1 in 400,000 among people taking these drugs for osteoporosis.

But when high-dose bisphosphonates are used to slow the spread of bone cancer, the risk rises, affecting anywhere from 1 percent to 15 percent of patients, she said.

For atypical femur (thigh) fractures, the absolute risk linked to bisphosphonates is about 1 to 5 fractures in 10,000 bisphosphonate users, she said.

Besides hip fractures, bisphosphonates prevent spine, wrist and arm fractures, Shane said.

The FDA asked the advisory committee to consider whether current data support long-term use of bisphosphonates for treating or preventing osteoporosis. The experts also were to consider whether a time limit should be placed on the drugs' use, and if patients who need long-term therapy would benefit from a "drug holiday," meaning time off the medication.

"I am really not in favor of putting a limit on use of bisphosphonates and dictating the use of drug holidays," Shane said. "We have very little evidence to support the use of drug holidays or no drug holidays."

Dr. Nelson Watts, director of the University of Cincinnati Bone Health and Osteoporosis Center and co-author of a 2010 study on long-term use of bisphosphonates, said length of treatment should be considered on an individual basis. His study suggested patients at mild risk might discontinue drug treatment after five years for as long as no fractures occurred and no bone loss was evident. Higher-risk patients could take the drugs for 10 years and perhaps then take a "holiday" from bisphosphonates of one or two years.

"It would probably be helpful if FDA or some official organization could provide guidelines on duration of treatment, details of drug holidays, etc., but there is probably not enough information in the literature for recommendations based on science," Watts said before Friday's vote.

Common bisphosphonates are taken in tablet form or by injection. They include: Fosamax (alendronate sodium) made by Merck & Co., Inc.; Actonel and Atelvia (risedronate sodium) made by Warner Chilcott; Boniva (ibandronate sodium) from Roche Therapeutics, Inc.; and Reclast (zoledronic acid) from Novartis Pharmaceuticals Corp.

More information

For more information on osteoporosis, visit the U.S. National Library of Medicine.