Research explains the reasons why the analgesics in Fibromyalgia do not help
People with Fibromyalgia, a common condition of chronic pain, often say they do not respond to the type of medication that relieves the suffering of others.
New research from the University of Michigan, Health System, helps explain why: It has found that fibromyalgia patients have decreased the ability to bind a type of brain receptor that is the target of opioid analgesics, such as morphine.
The study included a positron emission tomography (PET) scan of the brain of fibromyalgia patients and the same number of people of the same sex and age, without the condition that is often debilitating.
The results showed that fibromyalgia patients had reduced the availability of the mu-opioid receptor (MOR) in these regions of the brain that generally process and soften pain signals – precisely, the nucleus accumbens, the anterior cingulate and the tonsils.
painkillers do not help in fibromyalgia
“The reduced availability of the recipient was associated with more pain in people with fibromyalgia,” says lead author Richard E. Harris, Ph.D., a researcher in the Rheumatology Division of the Department of Internal Medicine at UM Medical School, and Researcher at the UM. Chronic Pain and Fatigue Research Center.
“These findings could explain why opioids are thought to be ineffective in people with fibromyalgia,” he says.
THE FINDINGS APPEAR IN THE JOURNAL OF NEUROSCIENCE.
“The finding is significant because it was difficult to determine the causes of pain in fibromyalgia patients, to the point that the acceptance of the disease is slow by doctors.”
Opioid analgesics work because they bind to opioid receptors in the brain and spine. In addition to morphine, they include codeine, and drugs contain propoxyphene such as Darvocet, which contain hydrocodone such as Vicodin and those that contain oxycodone such as Oxycontin.
The researchers’ theory is based on their finding of the lower availability of MORs in three regions. The brain of people with Fibromyalgia and says that pain relievers are not capable of being tied as well as in the minds of people without the condition.
More simply: when pain relievers cannot bind to receptors, they cannot so effectively relieve the patient’s pain, says Harris.
The reduced availability of receptors could be the result of a reduced amount of opioid receptors, an increase in the release of endogenous opioids (opioids, such as endorphins, which are typically produced by the body), or both, says Harris.
THE TEAM OF RESEARCHERS ALSO FOUND A POSSIBLE LINK WITH DEPRESSION.
PET scanners showed that fibromyalgia patients with more depressive symptoms had reductions in the potential for binding MOR in the tonsils, a region of the brain that they think modulates the mood and emotional dimension of pain. The study subjects were 17 women with Fibromyalgia and 17 women without the condition.