Patients with weakened bones need not take costly bone-building drugs such as Fosamax for life to reap the medicine's protective benefits, suggests research published in this week's Journal of the American Medical Association.

A national study of 1,099 women with osteoporosis found that patients who stopped taking Fosamax after five years were at no greater risk for most fractures than women who remained on the drug for a full 10 years. Doctors think the drug, which has been on the market for only about a decade, builds up in patients' bones, providing prolonged protection from bone loss.

An accompanying JAMA editorial, penned by Duke University geriatrician Dr. Cathleen Colon-Emeric and published today, concludes that women who have done well on Fosamax may be able to safely consider taking a "holiday" from the drug. Only women who have taken the drug for five years without suffering a fracture or significant loss of bone density would be candidates, both the editorial and study article emphasize.

The authors of the study found that patients who discontinued Fosamax after five years were slightly more likely to develop fractures of the vertebrae. About 5.3 percent of patients who stopped taking the drug developed backbone fractures, compared with 2.4 percent of patients who took Fosamax for a decade. Patients at risk of developing such fractures would likely benefit from continuous treatment, study authors wrote.

Still, the study and editorial -- the first to provide specific guidelines to doctors and patients about the consequences of discontinuing Fosamax -- could lead millions of patients to quit taking the drug and pocket the savings. The drug costs upward of $60 a month.

Osteoporosis is a disease sometimes called the "bone thief" because it erodes bone strength over time. Most often it occurs in women, usually after menopause, but men also develop it. Last year, about 22 million Americans filled prescriptions for Fosamax, the most widely prescribed osteoporosis drug, generating nearly $1.5 billion in domestic sales for its manufacturer, Merck. About 44 million people in the United States either have osteoporosis or are at risk of developing it.

"No one can say for sure how many people would be affected, but my gut says it could be 50, 60, even 70 percent of patients could stop these drugs," said Dr. Kenneth Lyles, a Duke internist and geriatrician who specializes in bone disorders.

Lyles, who is one of Colon-Emeric's professional mentors, looked over her editorial before its publication in JAMA. He has been a paid consultant to Merck and other companies that make drugs in the same class as Fosamax.

May apply to others

The study looked only at Fosamax, but Lyles said he thinks the results likely apply to similar drugs, especially formulations that, like Fosamax, are taken once a week. If other doctors draw the same conclusion, that could reduce prescriptions for drugs such as Actonel, which is made by Procter & Gamble Pharmaceuticals.

Lyles said he is already discussing the results of the Fosamax study, which Merck paid for, with patients who might be candidates for stopping the drug. Although Fosamax and similar drugs are generally considered safe to take on a long-term basis, there are plenty of reasons patients might want to quit taking them, Lyles notes.

Bisphosphonates can cause upset stomach and esophageal problems. Some people find them inconvenient to take because they require patients to fast before swallowing doses and to remain sitting or standing at least 30 minutes.

In recent years, doctors and patients have become more concerned about Fosamax's link to a degenerative jaw problem that causes part of the jaw bone to die and become exposed. The jaw condition is most associated with cancer patients who received intravenous treatment with liquid bisphosphonates. But a small number of otherwise healthy osteoporosis patients who took a pill form of Fosamax also developed the jaw problem.

Who will give it up?

Harriett Young of Oxford, 64, who has taken Fosamax for the past six years, was happy to give up her prescription after a visit with Lyles this month. She decided to quit the drug after Lyles assured her that she met all the new clinical guidelines for discontinuing it. Young has never broken a bone, she is not in any pain and her latest bone density scans did not raise Lyles' concerns.

"Given a choice, if it's not going to help me and I've got enough of it in my body already, why take it?" Young said. She will have a bone density scan and follow-up appointment with Lyles next year to make sure her bone loss does not accelerate rapidly without the drug.

Dr. Conrad Flick, a Raleigh family physician who treats many patients with osteoporosis, said some people won't be so willing to forgo Fosamax.

"Someone with osteoporosis has an eight to 10 times greater risk of hip fracture," he said. "Since there is no new safety risk here, I think some people would just as soon continue [Fosamax]."

Lyles agrees. One patient with whom he discussed stopping Fosamax declined to do so, even though she has not suffered a bone fracture in five years and met all other criteria for stopping. Any additional risk of fracture wasn't worth it to her.

"It's something you discuss with every patient who comes to you," Lyles said. "People have to be allowed to deal with these issues personally."