May 13, 2011 -- Many doctors are changing the prescribing length of a class of osteoporosis medication known as bisphosphonates after mounting evidence has linked long-term use of the medication with femur fractures in postmenopausal women.
Fosamax, one bisphosphonate, is supposed to make bones stronger. But now there's mounting evidence that for some women, taking Fosamax or its generic alendronate for more than five years could suffer spontaneous fractures.
"It has not changed my approach to starting biphosphonates," said Dr. Gary Burke, chairman of the department of medicine at St. Luke's Roosevelt Hospital in New York.
But many doctors, including Burke, are now telling their patients to take a break from bisphosphonates after two or three years on the medication.
Sandy Potter, 59, of Queens, N.Y., who took Fosamax for nearly a decade, believes she has felt the effects of taking bisphosphonates. Potter was jumping rope with neighborhood children when she felt her thigh bone snap.
"I went up in the air and I came straight down to the ground," Potter said. "The pain was excruciating."
"We are seeing people just walking, walking down the steps, patients who are doing low-energy exercise," said Dr. Kenneth Egol, professor of orthopedic surgery at NYU Langone Medical Center. "Very unusual. The femur is one of the strongest bones in the body."
Egol said X-rays of some of his patients look more like an injury endured by a car accident than an otherwise minimal fall.
"Over the last 18 months we are seeing this more frequently," he said.
Sue Heller, 60, of Castle Rock, Colo., had been on Fosamax for almost 10 years. She broke both of her femur bones.
"I'm sure there are a lot of women who have brittle bones right now that maybe are ready to break, and they're not aware of it," said Heller. "And my heart aches for them."
Sales of the popular drug increased when doctors began prescribing it not only to women showing signs of osteoporosis, but also those who were osteopenic and, thus, at risk for the disease. Now, some doctors worry that staying on the drug for more than five years can cause some women's bones to become more brittle.
Weighing the Risks
This is not the first time that many doctors have reported an opposite effect for many people taking the drug. Fosamax has already been linked to severe musculoskeletal pain, as well as to a serious bone-related jaw disease called osteonecrosis.
Doctors said patients should still use the drugs because they still appear to prevent other, much more common fractures. But the report recommended the U.S. Food and Drug Administration rewrite the drugs' labels to warn doctors and patients about the possibility of femur fractures.
While the group said it is still unclear whether bisphosphonates actually cause fractures, the group also recommended that the FDA create an international registry to track reported cases better.
The American Society of Bone and Mineral Research task force looked at reports on 310 osteoporosis patients who reported a rare form of femur fracture, and found that 94 percent of patients had been taking one of the drugs.
"Based on the report, we now feel that there is a definitive relationship between these class of drugs and these fractures, and it's even stronger in those taking those drugs for a long time," said Dr. Elizabeth Shane, a professor of medicine at Columbia University College of Physicians and Surgeons and co-author of the report.
The reported cases of so-called atypical femur fractures represent less than 1 percent of all types of hip and thigh fractures.
According to David Burr, professor of anatomy and cell biology at Indiana University School of Medicine and co-author of the task force report, although some patients who have atypical fracture were shown to have taken bisphosphonates, it is unclear whether taking the bisphosphonates may have contributed to those who have experienced fractures.
"It's hard to tell from the written reports now which fractures reported are the atypical ones. For example, we don't know much about these patients' history," said Burr. "One advantage of the registry is to make the data collected more standardized to make it easier to study the information."
There's also not enough data to show why some patients get the rare fractures, said Burr.
Bisphosphonates: Osteoporosis Success Story, but Are They Linked to Broken Thighs?
Sales of the popular drugs increased when doctors began prescribing them not only to women with actual osteoporosis, but also to those who were osteopenic -- at risk for the disease.
In 2008, bisphosphonate sales exceeded $3.5 billion, according to data from IMS Health. More than 37 million prescriptions were written for Fosamax, the most popular of the drugs.
"They have essentially revolutionized the field," said Edward Puzas, professor of orthopedics at the University of Rochester Medical Center. Puzas was not part of the task force that released today's report.
Twenty-one of the 27 members of the task force reported they have financial relationships with pharmaceutical companies that produce bisphosphonates, or belong to professional organizations that may promote their use.
Don't Stop Taking Bisphosphonates, Experts Say
Many studies suggest an overall benefit from taking the medication for women who are at risk for osteoporosis. Bisphosphonates can help prevent hip and spine fractures that are more common than broken thighs and might lead to death for some women.
Therefore, many experts recommend osteoporosis patients continue to take bisphosphonates if prescribed by their doctor.
"We need to make sure that all of the medications are safe," said Puzas. "But in my opinion, and the results of the panel suggest that, the benefit of these medications greatly outweigh the risk."
Burr agreed: "Even though they may be associated with these rare fractures, they prevent other types of fractures."
While some physicians use bone density scans to help drive their decisions, doctors generally prescribe them to women who are at an increased risk for either osteoporosis or fractures from osteoporosis they already have.
"These drugs prevent many more fractures than they possibly create," said Burr.
Shane said she continues to prescribe bisphosphonates to her patients, and said each patient should be evaluated as an individual case. However, Shane said, patients taking bisphosphonates should follow up with their doctor if they have warning signs like hip, thigh or groin pain.
"I think we have to be responsible in acknowledging the pain and suffering people went through who have the rare fractures," she said, "but there's also pain in the more common fractures that these drugs help."