In an animal model for fibromyalgia, researchers showed that combining low-dose irradiation with the FDA-approved drug Cymbalta (duloxetine) may be a potential strategy for managing fibromyalgia symptoms.
The study, “Evidences for amelioration of reserpine-induced fibromyalgia in rat by low dose of gamma irradiation and duloxetine,” was published in the International Journal of Radiation Biology.
Cymbalta was approved by the U.S. Food and Drug Administration for the treatment of pain associated with fibromyalgia, among other indications, and belongs to the class of serotonin/norepinephrine reuptake inhibitors (SNRIs). The drug is also approved for the treatment of depression and generalized anxiety disorder, and may be prescribed when mood problems are a serious symptom of fibromyalgia.
In the study, a team of researchers investigated whether low-dose irradiation alone or in combination with Cymbalta exerts a therapeutic effect in fibromyalgia. Low-dose irradiation has been shown to improve symptoms in patients with many disorders, including neuronal damages.
Researchers tested both therapeutic approaches (low-dose irradiation alone vs. low-dose irradiation plus Cymbalta) in an experimental model of fibromyalgia induced by reserpine in rats. (Reserpine is used to treat high blood pressure, agitation associated with certain conditions like schizophrenia, and other conditions.)
They first induced fibromyalgia by administering reserpine to rats for three consecutive days. Cymbalta was given to rats one hour before a forced swimming test (FST), and rats were exposed to a single dose of gamma radiation one day before the FST.
The team observed that reserpine prolonged the immobility period in the FST by 56% when compared to the normal group. Reserpine also caused a significant reduction in important neurotransmitters that cause persistent pain and could cause central augmentation and pain symptoms in fibromyalgia patients.
Low-dose irradiation alone or combined with Cymbalta completely reversed the negative effects of reserpine-induced fibromyalgia.
“Our results demonstrated that [low-dose irradiation] attenuated the reserpine-induced elevation in malondialdehyde (MDA) formation content (by 47%) and nitric oxide content (by 49%) as well as depletion in glutathione (GSH) content (by 23%) in brain tissues,” the researchers wrote.
Combining Cymbalta with low-dose irradiation showed a more pronounced therapeutic effect.
These results suggest a potential therapeutic role for low-dose irradiation alone or in combination with Cymbalta for fibromyalgia. But further studies are required to fully understand the mechanisms underlying these effects.