Addiction Drug May Help Ease Fibromyalgia

April 18 -- FRIDAY, April 17 (HealthDay News) -- Low doses of an inexpensive drug called naltrexone -- already used for years to treat drug addiction -- helped reduce pain and fatigue in women with the painful disorder fibromyalgia, a new study has found.

"Physicians have been using this off-label for a while," said study co-author Jarred Younger, an instructor in anesthesia and pain medicine at Stanford University School of Medicine. The findings were published online April 17 in the journal Pain Medicine.

Fibromyalgia is a chronic ailment, marked by musculoskeletal pain and sensitivity to being touched. Some experts say it may affect up to 4 percent of the population.

Three prescription drugs are also on the market to treat fibromyalgia, Younger said. But, he added, "the three drugs don't solve the problem for everyone. Some don't respond to any of these drugs."

Younger said he got the idea to study naltrexone after hearing that some other doctors had success with it and after hearing from some members of fibromyalgia support groups that it had worked for them.

While the results of the small study look promising, Younger said it's too early to recommend the drug until more research is in.

In the study, he gave all 10 women a handheld computer and told them to enter daily reports of pain and other symptoms, describing them all on a scale of not bad to worst. The women were taken off their current fibromyalgia medication, then began to take placebo for two weeks (although they did not know it was placebo). Next they took naltrexone for 8 weeks. They then went through a two-week ''washout" period.

The researchers then evaluated their symptoms. "The drug reduced symptoms by 30 percent compared to placebo," Younger said. It was a statistically significant difference, he said.

That was an overall result, and the drug worked better for some than others. "Six out of the 10 were strong respondents, with at least a 50 percent reduction in symptoms," Younger said. It didn't work for all 10 women, he said, and some did not respond at all.