Older adults who take powerful prescription painkillers known as opioids face an increased risk of bone fractures, especially at moderately high medication doses, a new study finds.

Opioids are powerful narcotic pain medications that include morphine, oxycodone (Oxycontin and other brands) and hydrocodone (Vicodin and others).

The drugs work well against severe pain in the short term, but their longer-term effectiveness for chronic pain is less clear. Moreover, with longer use comes the risk of addiction, in addition to side effects such as nausea, constipation, dizziness and sedation.

That dizziness and sedation can also set opioid users up for falls, which, in older people especially, may result in serious fractures.

The new study, published in the Journal of General Internal Medicine, confirms the risk of fracture associated with opioids, and also shows that moderately higher drug doses further the hazard.

Researchers found that among more than 2,300 older adults with chronic pain, the risk of suffering a bone fracture was higher when patients were using an opioid for a prolonged period than when they were opioid- free.

The individuals in the study were 60 years of age or older. None of the patients was suffering from cancer-related pain. (Guidelines for treating severe cancer pain are often different than guidelines for non-cancer pain.)

The annual rate of fractures among study participants who were not currently using opioids was just under 4 percent, while current users showed a fracture rate of 6 percent. And among patients currently taking opioid doses of at least 50 milligrams per day, the annual fracture rate was 10 percent.

According to the researchers, 50 milligrams is considered to be in the moderate range for opioid doses.

“Some of these fractures were significant,” said senior researcher Dr.

Michael Von Korff, of the Group Health Research Institute in Seattle.

In an interview, he noted that 37 percent of fracture victims ended up in the hospital and nearly one-quarter entered a nursing home within one month of the accident.

The findings come at a time when long-term opioid use for non-cancer- related pain is coming under increased scrutiny.

About 8 million Americans are using opioids to control chronic pain, Von Korff said, yet the long-term effectiveness of the drugs is uncertain, and may vary widely from person to person. Some people find relief, while others find their pain actually worsens, Von Korff noted.

A report published in October by the Cochrane Collaboration, an international medical research organization, concluded that for older adults with osteoarthritis, the risks of long-term opioids may outweigh the modest pain relief.

And in a separate study published this week in the Annals of Internal Medicine, Von Korff’s team highlights the potential for overdose among people with legitimate prescriptions.

The researchers found that among 10,000 patients on opioids for at least three months, 51 suffered at least one overdose, with fatal results for six. As in this latest study, higher medication doses conferred a greater risk.

The bottom line, Von Korff said, is that “these drugs need to be taken cautiously and under close medical supervision.”

The current study included 2,341 older adults who, at some point between 2000 and 2005, were prescribed opioids for at least 90 days - most commonly for chronic back pain, osteoarthritis or pain in the extremities.

To limit the risks of falls and other side effects, Von Korff said that patients on opioids should work with a single physician who is aware of all the medications they are taking. That will help avoid any potentially hazardous drug interactions.

And given the importance of dosage, Von Korff said, “never use more medication than your doctor has prescribed.”

He also advised opioid users who feel overly sedated or have had dizziness or falls to tell their doctors about it.

SOURCE: Journal of General Internal Medicine, online January 5, 2010.