The cause of fibromyalgia is unknown, but researchers generally believe that people with the condition have "amplified" pain signals due to abnormal sensory processing in the central nervous system.
One theory has held that fibromyalgia "wind-up" pain -- in which repeated touches create pain that intensifies with each new contact -- is caused by an abnormality in the spinal cord structures that process NMDA.
But in the new study, dextromethorphan was as effective at easing pain in the 14 women with fibromyalgia as it was for 10 women without the condition.
Since dextromethorphan acts on NMDA receptors, the findings suggest that people with fibromyalgia do not have a "radically altered" NMDA system, according to Staud's team.
For the study, the women underwent two tests, in which either a heated probe or a rubber-tipped peg repeatedly tapped their hands until they said they felt a certain degree of pain. As expected, women with fibromyalgia had a lower threshold for pain.
A single dose of dextromethorphan, however, reduced the women's pain response to the tests -- with women with fibromyalgia benefiting as much as those without the condition.
Saturday, June 11, 2005
The news of this study first came out a week or so ago and I didn't post it because the articles I read basically just said "dextromethorphan reduces pain in FMS but won't be available as a treatment for FMS for at least five years." Not very helpful (though I am tempted to just buy some cought syrup and see how that goes.) But today I found an article explaining how the study shed some light on the deformed-spinal-cord theory that is so hot with chiropractors and the like.