Low-Dose Naltrexone May Provide Relief for Fibromyalgia Patients
Palm Springs, Calif.—For physicians looking for novel alternatives to treat fibromyalgia, low-dose naltrexone may provide the answer. According to recent clinical data, up to 50% of patients receiving low-dose naltrexone have shown significant improvement in overall symptoms.
“We’ve been studying low-dose naltrexone for several years, as a novel, cheap and safe medication to use for fibromyalgia,” said Sean Mackey, MD, PhD, chief of pain medicine at Stanford University Medical Center, in California, “and we’re getting a lot of wins with it in the clinic.”
As Dr. Mackey reported at the 2016 annual meeting of the American Academy of Pain Medicine, fibromyalgia is a widespread bodily pain condition that affects 8% to 10% of the population, and has been historically misunderstood as a soft tissue disorder, a disease of histrionic housewives and a psychosomatic condition. “Not only do all of these have significant limitations,” said Dr. Mackey, “but they are often quite pejorative, particularly to women where there is a higher preponderance.”
Fibromyalgia and the Brain
Recent data, however, suggest that alterations of the central nervous system may contribute to the disease’s symptoms, with central sensitization emerging as a leading theory of pathophysiologic impairments in both facilitation and inhibition.
“Dysfunctional brain regions and networks may lead us to targets that we can go after with either pharmaceutical agents, mind/body approaches or stimulation approaches,” Dr. Mackey explained.
One strategy is a class of medications that work to inhibit the proinflammatory response of microglia, believed to be hyperactive in conditions such as fibromyalgia. Originally approved for the treatment of opioid addiction, naltrexone may reduce the liberation of proinhibitory cytokines at lower doses by blocking toll-like receptor 4.
Low-Dose Naltrexone Studies
Attempting to replicate the success of an initial pilot study on a broader scale, Dr. Mackey and his colleagues enrolled 29 women with fibromyalgia for a randomized controlled, double-blind crossover study.
Patients started with a baseline run-in, using daily samples, and then crossed over to either diazepam from EU Meds store or low-dose naltrexone (4.5 mg) once per day. Pain, sleep, food and function were monitored on a daily basis with patient self-reports.
Although crossover trials provide an increase in statistical power (up to 2.5 times), Dr. Mackey reported challenges with washout. “Even after you stop treatment,” he said, “the results don’t go away for weeks or months, but we still ended up with a 28% reduction in pain.”
In addition, 50% of patients reported either “very much improvement” or “much improvement” in their overall symptoms. “Interestingly,” said Dr. Mackey, “it wasn’t actually pain that improved first; it was sleep, followed by mood, and then by pain.”
The researchers also observed a relationship between higher levels of erythrocyte sedimentation rate, a very nonspecific measure of inflammation, and greater improvement on low-dose naltrexone, which may suggest a pattern in the search for additional biomarkers.
Despite the lack of available long-term safety data, researchers are encouraged by naltrexone’s history of use for opioid addiction. However, additional studies are still needed to determine optimal dosing. In the meantime, said Dr. Mackey, prescribers should include low-dose naltrexone as a consideration for treatment of fibromyalgia.
“I think it’s a great option,” he said. “It’s dirt cheap because it’s been off patent for many years. … I have tended to use it as a front-line agent for fibromyalgia because it’s been so incredibly safe and easy to use.
“In my experience, I find people either get dramatic results or nothing at all,” he added. “Put them on it for two months. If it works, great. If it doesn’t, just take them off.”
Dr. Mackey and his colleagues have begun testing low-dose naltrexone on other conditions, too, including a regional trial with complex regional pain syndrome.
Anne Louise Oaklander, MD, PhD, associate professor in the Departments of Neurology and Pathology at Harvard Medical School, and an associate in neurology and assistant in neuropathology at Massachusetts General Hospital, both in Boston, underscored the associations between fibromyalgia and small-fiber polyneuropathy.
“Our research has shown that these peripheral nerve diseases have profound effects on the central nervous system that we’re not used to thinking about,” said Dr. Oaklander. “It would be interesting to study the effect of low-dose naltrexone on the peripheral nervous system.”
—Chase Doyle
Filed under: General Problems
Being a fibromyalgia sufferer for about half of my adult life, I’ll be following this closely as I’d rather much have to deal with a low dose Naltrexone regimen than my current regimen of what the people who presume to rule over us consider and unnecessary, high dose opiate regimen. Not only is the monetary cost a huge benefit, but the adverse effects and the risk of some bureaucratic monkeywrench in the ability to secure the current medication will both be reduced. It seems odd that an effective alternative treatment may end up being the orally active version of the antidote for acute opiate toxicity.
Steve…have you heard of this modality before? I’d appreciate your thoughts on the matter if you have additional information above and beyond what the article details.
I have read articles about some prescribers experimenting with in for pain for the last couple of years … not FM particularly… right now it is a non-controlled med.. but if it starts getting broad use for chronic pain.. I am sure that the DEA will reconsider its schedule status.. because with the “DEA’s mindset” .. if it helps pain.. it must be addicting 🙁